package tview import ( "strings" "unicode" "unicode/utf8" "github.com/gdamore/tcell/v2" "github.com/rivo/uniseg" ) const ( // The minimum capacity of the text area's piece chain slice. pieceChainMinCap = 10 // The minimum capacity of the text area's edit buffer. editBufferMinCap = 200 // The maximum number of bytes making up a grapheme cluster. In theory, this // could be longer but it would be highly unusual. maxGraphemeClusterSize = 40 // The default value for the [TextArea.minCursorPrefix] variable. minCursorPrefixDefault = 5 // The default value for the [TextArea.minCursorSuffix] variable. minCursorSuffixDefault = 3 ) // Types of user actions on a text area. type taAction int const ( taActionOther taAction = iota taActionTypeSpace // Typing a space character. taActionTypeNonSpace // Typing a non-space character. taActionBackspace // Deleting the previous character. taActionDelete // Deleting the next character. ) // NewLine is the string sequence to be inserted when hitting the Enter key in a // TextArea. The default is "\n" but you may change it to "\r\n" if required. var NewLine = "\n" // textAreaSpan represents a range of text in a text area. The text area widget // roughly follows the concept of Piece Chains outlined in // http://www.catch22.net/tuts/neatpad/piece-chains with some modifications. // This type represents a "span" (or "piece") and thus refers to a subset of the // text in the editor as part of a doubly-linked list. // // In most places where we reference a position in the text, we use a // three-element int array. The first element is the index of the referenced // span in the piece chain. The second element is the offset into the span's // referenced text (relative to the span's start), its value is always >= 0 and // < span.length. The third element is the state of the text parser at that // position. // // A range of text is represented by a span range which is a starting position // (3-int array) and an ending position (3-int array). The starting position // references the first character of the range, the ending position references // the position after the last character of the range. The end of the text is // therefore always [3]int{1, 0, 0}, position 0 of the ending sentinel. // // Sentinel spans are dummy spans not referring to any text. There are always // two sentinel spans: the starting span at index 0 of the [TextArea.spans] // slice and the ending span at index 1. type textAreaSpan struct { // Links to the previous and next textAreaSpan objects as indices into the // [TextArea.spans] slice. The sentinel spans (index 0 and 1) have -1 as // their previous or next links, respectively. previous, next int // The start index and the length of the text segment this span represents. // If "length" is negative, the span represents a substring of // [TextArea.initialText] and the actual length is its absolute value. If it // is positive, the span represents a substring of [TextArea.editText]. For // the sentinel spans (index 0 and 1), both values will be 0. Others will // never have a zero length. offset, length int } // textAreaUndoItem represents an undoable edit to the text area. It describes // the two spans wrapping a text change. type textAreaUndoItem struct { before, after int // The index of the copied "before" and "after" spans into the "spans" slice. originalBefore, originalAfter int // The original indices of the "before" and "after" spans. pos [3]int // The cursor position to be assumed after applying an undo. length int // The total text length at the time the undo item was created. continuation bool // If true, this item is a continuation of the previous undo item. It is handled together with all other undo items in the same continuation sequence. } // TextArea implements a simple text editor for multi-line text. Multi-color // text is not supported. Word-wrapping is enabled by default but can be turned // off or be changed to character-wrapping. // // At this point, a text area cannot be added to a [Form]. This will be added in // the future. // // # Navigation and Editing // // A text area is always in editing mode and no other mode exists. The following // keys can be used to move the cursor (subject to what the user's terminal // supports and how it is configured): // // - Left arrow: Move left. // - Right arrow: Move right. // - Down arrow: Move down. // - Up arrow: Move up. // - Ctrl-A, Home: Move to the beginning of the current line. // - Ctrl-E, End: Move to the end of the current line. // - Ctrl-F, page down: Move down by one page. // - Ctrl-B, page up: Move up by one page. // - Alt-Up arrow: Scroll the page up, leaving the cursor in its position. // - Alt-Down arrow: Scroll the page down, leaving the cursor in its position. // - Alt-Left arrow: Scroll the page to the left, leaving the cursor in its // position. Ignored if wrapping is enabled. // - Alt-Right arrow: Scroll the page to the right, leaving the cursor in its // position. Ignored if wrapping is enabled. // - Alt-B, Ctrl-Left arrow: Jump to the beginning of the current or previous // word. // - Alt-F, Ctrl-Right arrow: Jump to the end of the current or next word. // // Words are defined according to [Unicode Standard Annex #29]. We skip any // words that contain only spaces or punctuation. // // Entering a character will insert it at the current cursor location. // Subsequent characters are shifted accordingly. If the cursor is outside the // visible area, any changes to the text will move it into the visible area. The // following keys can also be used to modify the text: // // - Enter: Insert a newline character (see [NewLine]). // - Tab: Insert a tab character (\t). It will be rendered like [TabSize] // spaces. (This may eventually be changed to behave like regular tabs.) // - Ctrl-H, Backspace: Delete one character to the left of the cursor. // - Ctrl-D, Delete: Delete the character under the cursor (or the first // character on the next line if the cursor is at the end of a line). // - Alt-Backspace: Delete the word to the left of the cursor. // - Ctrl-K: Delete everything under and to the right of the cursor until the // next newline character. // - Ctrl-W: Delete from the start of the current word to the left of the // cursor. // - Ctrl-U: Delete the current line, i.e. everything after the last newline // character before the cursor up until the next newline character. This may // span multiple visible rows if wrapping is enabled. // // Text can be selected by moving the cursor while holding the Shift key, to the // extent that this is supported by the user's terminal. The Ctrl-L key can be // used to select the entire text. (Ctrl-A already binds to the "Home" key.) // // When text is selected: // // - Entering a character will replace the selected text with the new // character. // - Backspace, delete, Ctrl-H, Ctrl-D: Delete the selected text. // - Ctrl-Q: Copy the selected text into the clipboard, unselect the text. // - Ctrl-X: Copy the selected text into the clipboard and delete it. // - Ctrl-V: Replace the selected text with the clipboard text. If no text is // selected, the clipboard text will be inserted at the cursor location. // // The Ctrl-Q key was chosen for the "copy" function because the Ctrl-C key is // the default key to stop the application. If your application frees up the // global Ctrl-C key and you want to bind it to the "copy to clipboard" // function, you may use [Box.SetInputCapture] to override the Ctrl-Q key to // implement copying to the clipboard. Note that using your terminal's / // operating system's key bindings for copy+paste functionality may not have the // expected effect as tview will not be able to handle these keys. Pasting text // using your operating system's or terminal's own methods may be very slow as // each character will be pasted individually. However, some terminals support // pasting text blocks which is supported by the text area, see // [Application.EnablePaste] for details. // // The default clipboard is an internal text buffer local to this text area // instance, i.e. the operating system's clipboard is not used. If you want to // implement your own clipboard (or make use of your operating system's // clipboard), you can use [TextArea.SetClipboard] which provides all the // functionality needed to implement your own clipboard. // // The text area also supports Undo: // // - Ctrl-Z: Undo the last change. // - Ctrl-Y: Redo the last Undo change. // // Undo does not affect the clipboard. // // If the mouse is enabled, the following actions are available: // // - Left click: Move the cursor to the clicked position or to the end of the // line if past the last character. // - Left double-click: Select the word under the cursor. // - Left click while holding the Shift key: Select text. // - Scroll wheel: Scroll the text. // // [Unicode Standard Annex #29]: https://unicode.org/reports/tr29/ type TextArea struct { *Box // Whether or not this text area is disabled/read-only. disabled bool // The size of the text area. If set to 0, the text area will use the entire // available space. width, height int // The text to be shown in the text area when it is empty. placeholder string // The label text shown, usually when part of a form. label string // The width of the text area's label. labelWidth int // Styles: // The label style. labelStyle tcell.Style // The style of the text. Background colors different from the Box's // background color may lead to unwanted artefacts. textStyle tcell.Style // The style of the selected text. selectedStyle tcell.Style // The style of the placeholder text. placeholderStyle tcell.Style // Text manipulation related fields: // The text area's text prior to any editing. It is referenced by spans with // a negative length. initialText string // Any text that's been added by the user at some point. We only ever append // to this buffer. It is referenced by spans with a positive length. editText strings.Builder // The total length of all text in the text area. length int // The maximum number of bytes allowed in the text area. If 0, there is no // limit. maxLength int // The piece chain. The first two spans are sentinel spans which don't // reference anything and always remain in the same place. Spans are never // deleted from this slice. spans []textAreaSpan // An optional function which transforms grapheme clusters. This can be used // to hide characters from the screen while preserving the original text. transform func(cluster, rest string, boundaries int) (newCluster string, newBoundaries int) // Display, navigation, and cursor related fields: // If set to true, lines that are longer than the available width are // wrapped onto the next line. If set to false, any characters beyond the // available width are discarded. wrap bool // If set to true and if wrap is also true, lines are split at spaces or // after punctuation characters. wordWrap bool // The index of the first line shown in the text area. rowOffset int // The number of cells to be skipped on each line (not used in wrap mode). columnOffset int // The inner height and width of the text area the last time it was drawn. lastHeight, lastWidth int // The width of the currently known widest line, as determined by // [TextArea.extendLines]. widestLine int // Text positions and states of the start of lines. Each element is a span // position (see [textAreaSpan]). Not all lines of the text may be contained // at any time, extend as needed with the [TextArea.extendLines] function. lineStarts [][3]int // The cursor always points to the next position where a new character would // be placed. The selection start is the same as the cursor as long as there // is no selection. When there is one, the selection is between // selectionStart and cursor. cursor, selectionStart struct { // The row and column in screen space but relative to the start of the // text which may be outside the text area's box. The column value may // be larger than where the cursor actually is if the line the cursor // is on is shorter. The actualColumn is the position as it is seen on // screen. These three values may not be determined yet, in which case // the row is negative. row, column, actualColumn int // The textAreaSpan position with state for the actual next character. pos [3]int } // The minimum width of text (if available) to be shown left of the cursor. minCursorPrefix int // The minimum width of text (if available) to be shown right of the cursor. minCursorSuffix int // Set to true when the mouse is dragging to select text. dragging bool // Clipboard related fields: // The internal clipboard. clipboard string // The function to call when the user copies/cuts a text selection to the // clipboard. copyToClipboard func(string) // The function to call when the user pastes text from the clipboard. pasteFromClipboard func() string // Undo/redo related fields: // The last action performed by the user. lastAction taAction // The undo stack's items. Each item is a copy of the span before the // modified span range and a copy of the span after the modified span range. // To undo an action, the two referenced spans are put back into their // original place. Undos and redos decrease or increase the nextUndo value. // Thus, the next undo action is not always the last item. undoStack []textAreaUndoItem // The current undo/redo position on the undo stack. If no undo or redo has // been performed yet, this is the same as len(undoStack). nextUndo int // Event handlers: // An optional function which is called when the input has changed. changed func() // An optional function which is called when the position of the cursor or // the selection has changed. moved func() // A callback function set by the Form class and called when the user leaves // this form item. finished func(tcell.Key) } // NewTextArea returns a new text area. Use [TextArea.SetText] to set the // initial text. func NewTextArea() *TextArea { t := &TextArea{ Box: NewBox(), wrap: true, wordWrap: true, placeholderStyle: tcell.StyleDefault.Background(Styles.PrimitiveBackgroundColor).Foreground(Styles.TertiaryTextColor), labelStyle: tcell.StyleDefault.Foreground(Styles.SecondaryTextColor), textStyle: tcell.StyleDefault.Background(Styles.PrimitiveBackgroundColor).Foreground(Styles.PrimaryTextColor), selectedStyle: tcell.StyleDefault.Background(Styles.PrimaryTextColor).Foreground(Styles.PrimitiveBackgroundColor), spans: make([]textAreaSpan, 2, pieceChainMinCap), // We reserve some space to avoid reallocations right when editing starts. lastAction: taActionOther, minCursorPrefix: minCursorPrefixDefault, minCursorSuffix: minCursorSuffixDefault, } t.editText.Grow(editBufferMinCap) t.spans[0] = textAreaSpan{previous: -1, next: 1} t.spans[1] = textAreaSpan{previous: 0, next: -1} t.cursor.pos = [3]int{1, 0, -1} t.selectionStart = t.cursor t.SetClipboard(nil, nil) return t } // SetText sets the text of the text area. All existing text is deleted and // replaced with the new text. Any edits are discarded, no undos are available. // This function is typically only used to initialize the text area with a text // after it has been created. To clear the text area's text (again, no undos), // provide an empty string. // // If cursorAtTheEnd is false, the cursor is placed at the start of the text. If // it is true, it is placed at the end of the text. For very long texts, placing // the cursor at the end can be an expensive operation because the entire text // needs to be parsed and laid out. // // If you want to set text and preserve undo functionality, use // [TextArea.Replace] instead. func (t *TextArea) SetText(text string, cursorAtTheEnd bool) *TextArea { t.spans = t.spans[:2] t.initialText = text t.editText.Reset() t.lineStarts = nil t.length = len(text) t.rowOffset = 0 t.columnOffset = 0 t.reset() t.cursor.row, t.cursor.actualColumn, t.cursor.column = 0, 0, 0 t.cursor.pos = [3]int{1, 0, -1} t.undoStack = t.undoStack[:0] t.nextUndo = 0 if len(text) > 0 { t.spans = append(t.spans, textAreaSpan{ previous: 0, next: 1, offset: 0, length: -len(text), }) t.spans[0].next = 2 t.spans[1].previous = 2 if cursorAtTheEnd { t.cursor.row = -1 if t.lastWidth > 0 { t.findCursor(true, 0) } } else { t.cursor.pos = [3]int{2, 0, -1} } } else { t.spans[0].next = 1 t.spans[1].previous = 0 } t.selectionStart = t.cursor if t.changed != nil { t.changed() } if t.lastWidth > 0 && t.moved != nil { t.moved() } return t } // GetText returns the entire text of the text area. Note that this will newly // allocate the entire text. func (t *TextArea) GetText() string { if t.length == 0 { return "" } var text strings.Builder text.Grow(t.length) spanIndex := t.spans[0].next for spanIndex != 1 { span := &t.spans[spanIndex] if span.length < 0 { text.WriteString(t.initialText[span.offset : span.offset-span.length]) } else { text.WriteString(t.editText.String()[span.offset : span.offset+span.length]) } spanIndex = t.spans[spanIndex].next } return text.String() } // getTextBeforeCursor returns the text of the text area up until the cursor. // Note that this will result in a new allocation for the returned text. func (t *TextArea) getTextBeforeCursor() string { if t.length == 0 || t.cursor.pos[0] == t.spans[0].next && t.cursor.pos[1] == 0 { return "" } var text strings.Builder spanIndex := t.spans[0].next for spanIndex != 1 { span := &t.spans[spanIndex] length := span.length if length < 0 { if t.cursor.pos[0] == spanIndex { length = -t.cursor.pos[1] } text.WriteString(t.initialText[span.offset : span.offset-length]) } else { if t.cursor.pos[0] == spanIndex { length = t.cursor.pos[1] } text.WriteString(t.editText.String()[span.offset : span.offset+length]) } if t.cursor.pos[0] == spanIndex { break } spanIndex = t.spans[spanIndex].next } return text.String() } // getTextAfterCursor returns the text of the text area after the cursor. Note // that this will result in a new allocation for the returned text. func (t *TextArea) getTextAfterCursor() string { if t.length == 0 || t.cursor.pos[0] == 1 { return "" } var text strings.Builder spanIndex := t.cursor.pos[0] cursorOffset := t.cursor.pos[1] for spanIndex != 1 { span := &t.spans[spanIndex] length := span.length if length < 0 { text.WriteString(t.initialText[span.offset+cursorOffset : span.offset-length]) } else { text.WriteString(t.editText.String()[span.offset+cursorOffset : span.offset+length]) } spanIndex = t.spans[spanIndex].next cursorOffset = 0 } return text.String() } // HasSelection returns whether the selected text is non-empty. func (t *TextArea) HasSelection() bool { return t.selectionStart != t.cursor } // GetSelection returns the currently selected text and its start and end // positions within the entire text as a half-open interval. If the returned // text is an empty string, the start and end positions are the same and can be // interpreted as the cursor position. // // Calling this function will result in string allocations as well as a search // for text positions. This is expensive if the text has been edited extensively // already. Use [TextArea.HasSelection] first if you are only interested in // selected text. func (t *TextArea) GetSelection() (text string, start int, end int) { from, to := t.selectionStart.pos, t.cursor.pos if t.cursor.row < t.selectionStart.row || (t.cursor.row == t.selectionStart.row && t.cursor.actualColumn < t.selectionStart.actualColumn) { from, to = to, from } if from[0] == 1 { start = t.length } if to[0] == 1 { end = t.length } var ( index int selection strings.Builder inside bool ) for span := t.spans[0].next; span != 1; span = t.spans[span].next { var spanText string length := t.spans[span].length if length < 0 { length = -length spanText = t.initialText } else { spanText = t.editText.String() } spanText = spanText[t.spans[span].offset : t.spans[span].offset+length] if from[0] == span && to[0] == span { if from != to { selection.WriteString(spanText[from[1]:to[1]]) } start = index + from[1] end = index + to[1] break } else if from[0] == span { if from != to { selection.WriteString(spanText[from[1]:]) } start = index + from[1] inside = true } else if to[0] == span { if from != to { selection.WriteString(spanText[:to[1]]) } end = index + to[1] break } else if inside && from != to { selection.WriteString(spanText) } index += length } if selection.Len() != 0 { text = selection.String() } return } // GetCursor returns the current cursor position where the first character of // the entire text is in row 0, column 0. If the user has selected text, the // "from" values will refer to the beginning of the selection and the "to" // values to the end of the selection (exclusive). They are the same if there // is no selection. func (t *TextArea) GetCursor() (fromRow, fromColumn, toRow, toColumn int) { fromRow, fromColumn = t.selectionStart.row, t.selectionStart.actualColumn toRow, toColumn = t.cursor.row, t.cursor.actualColumn if toRow < fromRow || (toRow == fromRow && toColumn < fromColumn) { fromRow, fromColumn, toRow, toColumn = toRow, toColumn, fromRow, fromColumn } if t.length > 0 && t.wrap && fromColumn >= t.lastWidth { // This happens when a row has text all the way until the end, pushing the cursor outside the viewport. fromRow++ fromColumn = 0 } if t.length > 0 && t.wrap && toColumn >= t.lastWidth { toRow++ toColumn = 0 } return } // GetTextLength returns the string length of the text in the text area. func (t *TextArea) GetTextLength() int { return t.length } // Replace replaces a section of the text with new text. The start and end // positions refer to index positions within the entire text string (as a // half-open interval). They may be the same, in which case text is inserted at // the given position. If the text is an empty string, text between start and // end is deleted. Index positions will be shifted to line up with character // boundaries. A "changed" event will be triggered. // // Previous selections are cleared. The cursor will be located at the end of the // replaced text. Scroll offsets will not be changed. A "moved" event will be // triggered. // // The effects of this function can be undone (and redone) by the user. func (t *TextArea) Replace(start, end int, text string) *TextArea { t.Select(start, end) row := t.selectionStart.row t.cursor.pos = t.replace(t.selectionStart.pos, t.cursor.pos, text, false) t.cursor.row = -1 t.truncateLines(row - 1) t.findCursor(false, row) t.selectionStart = t.cursor if t.moved != nil { t.moved() } // The "changed" event will have been triggered by the "replace" function. return t } // Select selects a section of the text. The start and end positions refer to // index positions within the entire text string (as a half-open interval). They // may be the same, in which case the cursor is placed at the given position. // Any previous selection is removed. Scroll offsets will be preserved. // // Index positions will be shifted to line up with character boundaries. func (t *TextArea) Select(start, end int) *TextArea { oldFrom, oldTo := t.selectionStart, t.cursor defer func() { if (oldFrom != t.selectionStart || oldTo != t.cursor) && t.moved != nil { t.moved() } }() // Clamp input values. if start < 0 { start = 0 } if start > t.length { start = t.length } if end < 0 { end = 0 } if end > t.length { end = t.length } if end < start { start, end = end, start } // Find the cursor positions. var row, index int t.cursor.row, t.cursor.pos = -1, [3]int{1, 0, -1} t.selectionStart = t.cursor RowLoop: for { if row >= len(t.lineStarts) { t.extendLines(t.lastWidth, row) if row >= len(t.lineStarts) { break } } // Check the spans of this row. pos := t.lineStarts[row] var ( next [3]int lineIndex int ) if row+1 < len(t.lineStarts) { next = t.lineStarts[row+1] } else { next = [3]int{1, 0, -1} } for { if pos[0] == next[0] { if start >= index+lineIndex && start < index+lineIndex+next[1]-pos[1] || end >= index+lineIndex && end < index+lineIndex+next[1]-pos[1] { break } index += lineIndex + next[1] - pos[1] row++ continue RowLoop // Move on to the next row. } else { length := t.spans[pos[0]].length if length < 0 { length = -length } if start >= index+lineIndex && start < index+lineIndex+length-pos[1] || end >= index+lineIndex && end < index+lineIndex+length-pos[1] { break } lineIndex += length - pos[1] pos[0], pos[1] = t.spans[pos[0]].next, 0 } } // One of the indices is in this row. Step through it. pos = t.lineStarts[row] endPos := pos var ( cluster, text string column, width int ) for pos != next { if t.selectionStart.row < 0 && start <= index { t.selectionStart.row, t.selectionStart.column, t.selectionStart.actualColumn = row, column, column t.selectionStart.pos = pos } if t.cursor.row < 0 && end <= index { t.cursor.row, t.cursor.column, t.cursor.actualColumn = row, column, column t.cursor.pos = pos break RowLoop } cluster, text, _, width, pos, endPos = t.step(text, pos, endPos) index += len(cluster) column += width } } if t.cursor.row < 0 { t.findCursor(false, 0) // This only happens if we couldn't find the locations above. t.selectionStart = t.cursor } return t } // SetWrap sets the flag that, if true, leads to lines that are longer than the // available width being wrapped onto the next line. If false, any characters // beyond the available width are not displayed. func (t *TextArea) SetWrap(wrap bool) *TextArea { if t.wrap != wrap { t.wrap = wrap t.reset() } return t } // SetWordWrap sets the flag that causes lines that are longer than the // available width to be wrapped onto the next line at spaces or after // punctuation marks (according to [Unicode Standard Annex #14]). This flag is // ignored if the flag set with [TextArea.SetWrap] is false. The text area's // default is word-wrapping. // // [Unicode Standard Annex #14]: https://www.unicode.org/reports/tr14/ func (t *TextArea) SetWordWrap(wrapOnWords bool) *TextArea { if t.wordWrap != wrapOnWords { t.wordWrap = wrapOnWords t.reset() } return t } // SetPlaceholder sets the text to be displayed when the text area is empty. func (t *TextArea) SetPlaceholder(placeholder string) *TextArea { t.placeholder = placeholder return t } // SetLabel sets the text to be displayed before the text area. func (t *TextArea) SetLabel(label string) *TextArea { t.label = label return t } // GetLabel returns the text to be displayed before the text area. func (t *TextArea) GetLabel() string { return t.label } // SetLabelWidth sets the screen width of the label. A value of 0 will cause the // primitive to use the width of the label string. func (t *TextArea) SetLabelWidth(width int) *TextArea { t.labelWidth = width return t } // GetLabelWidth returns the screen width of the label. func (t *TextArea) GetLabelWidth() int { return t.labelWidth } // SetSize sets the screen size of the input element of the text area. The input // element is always located next to the label which is always located in the // top left corner. If any of the values are 0 or larger than the available // space, the available space will be used. func (t *TextArea) SetSize(rows, columns int) *TextArea { t.width = columns t.height = rows return t } // GetFieldWidth returns this primitive's field width. func (t *TextArea) GetFieldWidth() int { return t.width } // GetFieldHeight returns this primitive's field height. func (t *TextArea) GetFieldHeight() int { return t.height } // SetDisabled sets whether or not the item is disabled / read-only. func (t *TextArea) SetDisabled(disabled bool) FormItem { t.disabled = disabled if t.finished != nil { t.finished(-1) } return t } // GetDisabled returns whether or not the item is disabled / read-only. func (t *TextArea) GetDisabled() bool { return t.disabled } // SetMaxLength sets the maximum number of bytes allowed in the text area. A // value of 0 means there is no limit. If the text area currently contains more // bytes than this, it may violate this constraint. func (t *TextArea) SetMaxLength(maxLength int) *TextArea { t.maxLength = maxLength return t } // setMinCursorPadding sets a minimum width to be reserved left and right of the // cursor. This is ignored if wrapping is enabled. func (t *TextArea) setMinCursorPadding(prefix, suffix int) *TextArea { t.minCursorPrefix = prefix t.minCursorSuffix = suffix return t } // SetLabelStyle sets the style of the label. func (t *TextArea) SetLabelStyle(style tcell.Style) *TextArea { t.labelStyle = style return t } // GetLabelStyle returns the style of the label. func (t *TextArea) GetLabelStyle() tcell.Style { return t.labelStyle } // SetTextStyle sets the style of the text. func (t *TextArea) SetTextStyle(style tcell.Style) *TextArea { t.textStyle = style return t } // GetTextStyle returns the style of the text. func (t *TextArea) GetTextStyle() tcell.Style { return t.textStyle } // SetSelectedStyle sets the style of the selected text. func (t *TextArea) SetSelectedStyle(style tcell.Style) *TextArea { t.selectedStyle = style return t } // SetPlaceholderStyle sets the style of the placeholder text. func (t *TextArea) SetPlaceholderStyle(style tcell.Style) *TextArea { t.placeholderStyle = style return t } // GetPlaceholderStyle returns the style of the placeholder text. func (t *TextArea) GetPlaceholderStyle() tcell.Style { return t.placeholderStyle } // GetOffset returns the text's offset, that is, the number of rows and columns // skipped during drawing at the top or on the left, respectively. Note that the // column offset is ignored if wrapping is enabled. func (t *TextArea) GetOffset() (row, column int) { return t.rowOffset, t.columnOffset } // SetOffset sets the text's offset, that is, the number of rows and columns // skipped during drawing at the top or on the left, respectively. If wrapping // is enabled, the column offset is ignored. These values may get adjusted // automatically to ensure that some text is always visible. func (t *TextArea) SetOffset(row, column int) *TextArea { t.rowOffset, t.columnOffset = row, column return t } // SetClipboard allows you to implement your own clipboard by providing a // function that is called when the user wishes to store text in the clipboard // (copyToClipboard) and a function that is called when the user wishes to // retrieve text from the clipboard (pasteFromClipboard). // // Providing nil values will cause the default clipboard implementation to be // used. Note that the default clipboard is local to this text area instance. // Copying text to other widgets will not work. func (t *TextArea) SetClipboard(copyToClipboard func(string), pasteFromClipboard func() string) *TextArea { t.copyToClipboard = copyToClipboard if t.copyToClipboard == nil { t.copyToClipboard = func(text string) { t.clipboard = text } } t.pasteFromClipboard = pasteFromClipboard if t.pasteFromClipboard == nil { t.pasteFromClipboard = func() string { return t.clipboard } } return t } // GetClipboardText returns the current text of the clipboard by calling the // pasteFromClipboard function set with [TextArea.SetClipboard]. func (t *TextArea) GetClipboardText() string { return t.pasteFromClipboard() } // SetChangedFunc sets a handler which is called whenever the text of the text // area has changed. func (t *TextArea) SetChangedFunc(handler func()) *TextArea { t.changed = handler return t } // SetMovedFunc sets a handler which is called whenever the cursor position or // the text selection has changed. func (t *TextArea) SetMovedFunc(handler func()) *TextArea { t.moved = handler return t } // SetFinishedFunc sets a callback invoked when the user leaves this form item. func (t *TextArea) SetFinishedFunc(handler func(key tcell.Key)) FormItem { t.finished = handler return t } // Focus is called when this primitive receives focus. func (t *TextArea) Focus(delegate func(p Primitive)) { // If we're part of a form and this item is disabled, there's nothing the // user can do here so we're finished. if t.finished != nil && t.disabled { t.finished(-1) return } t.Box.Focus(delegate) } // SetFormAttributes sets attributes shared by all form items. func (t *TextArea) SetFormAttributes(labelWidth int, labelColor, bgColor, fieldTextColor, fieldBgColor tcell.Color) FormItem { t.labelWidth = labelWidth t.backgroundColor = bgColor t.labelStyle = t.labelStyle.Foreground(labelColor) t.textStyle = tcell.StyleDefault.Foreground(fieldTextColor).Background(fieldBgColor) return t } // replace deletes a range of text and inserts the given text at that position. // If the resulting text would exceed the maximum length, the function does not // do anything. The function returns the end position of the deleted/inserted // range. // // The function can hang if "deleteStart" is located after "deleteEnd". // // Undo events are always generated unless continuation is true and text is // either appended to the end of a span or a span is shortened at the beginning // or the end (and nothing else). // // This function only modifies [TextArea.lineStarts] to update span references // but does not change it to reflect the new layout. // // A "changed" event will be triggered. func (t *TextArea) replace(deleteStart, deleteEnd [3]int, insert string, continuation bool) [3]int { // Maybe nothing needs to be done? if deleteStart == deleteEnd && insert == "" || t.maxLength > 0 && len(insert) > 0 && t.length+len(insert) >= t.maxLength { return deleteEnd } // Notify at the end. if t.changed != nil { defer t.changed() } // Handle a few cases where we don't put anything onto the undo stack for // increased efficiency. if continuation { // Same action as the one before. An undo item was already generated for // this block of (same) actions. We're also only changing one character. switch { case insert == "" && deleteStart[1] != 0 && deleteEnd[1] == 0: // Simple backspace. Just shorten this span. length := t.spans[deleteStart[0]].length if length < 0 { t.length -= -length - deleteStart[1] length = -deleteStart[1] } else { t.length -= length - deleteStart[1] length = deleteStart[1] } t.spans[deleteStart[0]].length = length return deleteEnd case insert == "" && deleteStart[1] == 0 && deleteEnd[1] != 0: // Simple delete. Just clip the beginning of this span. t.spans[deleteEnd[0]].offset += deleteEnd[1] if t.spans[deleteEnd[0]].length < 0 { t.spans[deleteEnd[0]].length += deleteEnd[1] } else { t.spans[deleteEnd[0]].length -= deleteEnd[1] } t.length -= deleteEnd[1] deleteEnd[1] = 0 return deleteEnd case insert != "" && deleteStart == deleteEnd && deleteEnd[1] == 0: previous := t.spans[deleteStart[0]].previous bufferSpan := t.spans[previous] if bufferSpan.length > 0 && bufferSpan.offset+bufferSpan.length == t.editText.Len() { // Typing individual characters. Simply extend the edit buffer. length, _ := t.editText.WriteString(insert) t.spans[previous].length += length t.length += length return deleteEnd } } } // All other cases generate an undo item. before := t.spans[deleteStart[0]].previous after := deleteEnd[0] if deleteEnd[1] > 0 { after = t.spans[deleteEnd[0]].next } t.undoStack = t.undoStack[:t.nextUndo] t.undoStack = append(t.undoStack, textAreaUndoItem{ before: len(t.spans), after: len(t.spans) + 1, originalBefore: before, originalAfter: after, length: t.length, pos: t.cursor.pos, continuation: continuation, }) t.spans = append(t.spans, t.spans[before]) t.spans = append(t.spans, t.spans[after]) t.nextUndo++ // Adjust total text length by subtracting everything between "before" and // "after". Inserted spans will be added back. for index := deleteStart[0]; index != after; index = t.spans[index].next { if t.spans[index].length < 0 { t.length += t.spans[index].length } else { t.length -= t.spans[index].length } } t.spans[before].next = after t.spans[after].previous = before // We go from left to right, connecting new spans as needed. We update // "before" as the span to connect new spans to. // If we start deleting in the middle of a span, connect a partial span. if deleteStart[1] != 0 { span := textAreaSpan{ previous: before, next: after, offset: t.spans[deleteStart[0]].offset, length: deleteStart[1], } if t.spans[deleteStart[0]].length < 0 { span.length = -span.length } t.length += deleteStart[1] // This was previously subtracted. t.spans[before].next = len(t.spans) t.spans[after].previous = len(t.spans) before = len(t.spans) for row, lineStart := range t.lineStarts { // Also redirect line starts until the end of this new span. if lineStart[0] == deleteStart[0] { if lineStart[1] >= deleteStart[1] { t.lineStarts = t.lineStarts[:row] // Everything else is unknown at this point. break } t.lineStarts[row][0] = len(t.spans) } } t.spans = append(t.spans, span) } // If we insert text, connect a new span. if insert != "" { span := textAreaSpan{ previous: before, next: after, offset: t.editText.Len(), } span.length, _ = t.editText.WriteString(insert) t.length += span.length t.spans[before].next = len(t.spans) t.spans[after].previous = len(t.spans) before = len(t.spans) t.spans = append(t.spans, span) } // If we stop deleting in the middle of a span, connect a partial span. if deleteEnd[1] != 0 { span := textAreaSpan{ previous: before, next: after, offset: t.spans[deleteEnd[0]].offset + deleteEnd[1], } length := t.spans[deleteEnd[0]].length if length < 0 { span.length = length + deleteEnd[1] t.length -= span.length // This was previously subtracted. } else { span.length = length - deleteEnd[1] t.length += span.length // This was previously subtracted. } t.spans[before].next = len(t.spans) t.spans[after].previous = len(t.spans) deleteEnd[0], deleteEnd[1] = len(t.spans), 0 t.spans = append(t.spans, span) } return deleteEnd } // Draw draws this primitive onto the screen. func (t *TextArea) Draw(screen tcell.Screen) { t.Box.DrawForSubclass(screen, t) // Prepare x, y, width, height := t.GetInnerRect() if width <= 0 || height <= 0 { return // We have no space for anything. } columnOffset := t.columnOffset if t.wrap { columnOffset = 0 } // Draw label. _, labelBg, _ := t.labelStyle.Decompose() if t.labelWidth > 0 { labelWidth := t.labelWidth if labelWidth > width { labelWidth = width } printWithStyle(screen, t.label, x, y, 0, labelWidth, AlignLeft, t.labelStyle, labelBg == tcell.ColorDefault) x += labelWidth width -= labelWidth } else { _, _, drawnWidth := printWithStyle(screen, t.label, x, y, 0, width, AlignLeft, t.labelStyle, labelBg == tcell.ColorDefault) x += drawnWidth width -= drawnWidth } // What's the space for the input element? if t.width > 0 && t.width < width { width = t.width } if t.height > 0 && t.height < height { height = t.height } if width <= 0 { return // No space left for the text area. } // Draw the input element if necessary. _, bg, _ := t.textStyle.Decompose() if t.disabled { bg = t.backgroundColor } if bg != t.backgroundColor { for row := 0; row < height; row++ { for column := 0; column < width; column++ { screen.SetContent(x+column, y+row, ' ', nil, t.textStyle) } } } // Show/hide the cursor at the end. defer func() { if t.HasFocus() { row, column := t.cursor.row, t.cursor.actualColumn if t.length > 0 && t.wrap && column >= t.lastWidth { // This happens when a row has text all the way until the end, pushing the cursor outside the viewport. row++ column = 0 } if row >= 0 && row-t.rowOffset >= 0 && row-t.rowOffset < height && column-columnOffset >= 0 && column-columnOffset < width { screen.ShowCursor(x+column-columnOffset, y+row-t.rowOffset) } else { screen.HideCursor() } } }() // No text, show placeholder. if t.length == 0 { t.lastHeight, t.lastWidth = height, width t.cursor.row, t.cursor.column, t.cursor.actualColumn, t.cursor.pos = 0, 0, 0, [3]int{1, 0, -1} t.rowOffset, t.columnOffset = 0, 0 if len(t.placeholder) > 0 { t.drawPlaceholder(screen, x, y, width, height) } return // We're done already. } // Make sure the visible lines are broken over. firstDrawing := t.lastWidth == 0 if t.lastWidth != width && t.lineStarts != nil { t.reset() } t.lastHeight, t.lastWidth = height, width t.extendLines(width, t.rowOffset+height) if len(t.lineStarts) <= t.rowOffset { return // It's scrolled out of view. } // If the cursor position is unknown, find it. This usually only happens // before the screen is drawn for the first time. if t.cursor.row < 0 { t.findCursor(true, 0) if t.selectionStart.row < 0 { t.selectionStart = t.cursor } if firstDrawing && t.moved != nil { t.moved() } } // Print the text. var cluster, text string line := t.rowOffset pos := t.lineStarts[line] endPos := pos posX, posY := 0, 0 for pos[0] != 1 { var clusterWidth int cluster, text, _, clusterWidth, pos, endPos = t.step(text, pos, endPos) // Prepare drawing. runes := []rune(cluster) style := t.selectedStyle fromRow, fromColumn := t.cursor.row, t.cursor.actualColumn toRow, toColumn := t.selectionStart.row, t.selectionStart.actualColumn if fromRow > toRow || fromRow == toRow && fromColumn > toColumn { fromRow, fromColumn, toRow, toColumn = toRow, toColumn, fromRow, fromColumn } if toRow < line || toRow == line && toColumn <= posX || fromRow > line || fromRow == line && fromColumn > posX { style = t.textStyle if t.disabled { style = style.Background(t.backgroundColor) } } // Selected tabs are a bit special. if cluster == "\t" && style == t.selectedStyle { for colX := 0; colX < clusterWidth && posX+colX-columnOffset < width; colX++ { screen.SetContent(x+posX+colX-columnOffset, y+posY, ' ', nil, style) } } // Draw character. if posX+clusterWidth-columnOffset <= width && posX-columnOffset >= 0 && clusterWidth > 0 { screen.SetContent(x+posX-columnOffset, y+posY, runes[0], runes[1:], style) } // Advance. posX += clusterWidth if line+1 < len(t.lineStarts) && t.lineStarts[line+1] == pos { // We must break over. posY++ if posY >= height { break // Done. } posX = 0 line++ } } } // drawPlaceholder draws the placeholder text into the given rectangle. It does // not do anything if the text area already contains text or if there is no // placeholder text. func (t *TextArea) drawPlaceholder(screen tcell.Screen, x, y, width, height int) { // We use a TextView to draw the placeholder. It will take care of word // wrapping etc. textView := NewTextView(). SetText(t.placeholder). SetTextStyle(t.placeholderStyle) textView.SetRect(x, y, width, height) textView.Draw(screen) } // reset resets many of the local variables of the text area because they cannot // be used anymore and must be recalculated, typically after the text area's // size has changed. func (t *TextArea) reset() { t.truncateLines(0) if t.wrap { t.cursor.row = -1 t.selectionStart.row = -1 } t.widestLine = 0 } // extendLines traverses the current text and extends [TextArea.lineStarts] such // that it describes at least maxLines+1 lines (or less if the text is shorter). // Text is laid out for the given width while respecting the wrapping settings. // It is assumed that if [TextArea.lineStarts] already has entries, they obey // the same rules. // // If width is 0, nothing happens. func (t *TextArea) extendLines(width, maxLines int) { if width <= 0 { return } // Start with the first span. if len(t.lineStarts) == 0 { if len(t.spans) > 2 { t.lineStarts = append(t.lineStarts, [3]int{t.spans[0].next, 0, -1}) } else { return // No text. } } // Determine starting positions and starting spans. pos := t.lineStarts[len(t.lineStarts)-1] // The starting position is the last known line. endPos := pos var ( cluster, text string lineWidth, clusterWidth, boundaries int lastGraphemeBreak, lastLineBreak [3]int widthSinceLineBreak int ) for pos[0] != 1 { // Get the next grapheme cluster. cluster, text, boundaries, clusterWidth, pos, endPos = t.step(text, pos, endPos) lineWidth += clusterWidth widthSinceLineBreak += clusterWidth // Any line breaks? if !t.wrap || lineWidth <= width { if boundaries&uniseg.MaskLine == uniseg.LineMustBreak && (len(text) > 0 || uniseg.HasTrailingLineBreakInString(cluster)) { // We must break over. t.lineStarts = append(t.lineStarts, pos) if lineWidth > t.widestLine { t.widestLine = lineWidth } lineWidth = 0 lastGraphemeBreak = [3]int{} lastLineBreak = [3]int{} widthSinceLineBreak = 0 if len(t.lineStarts) > maxLines { break // We have enough lines, we can stop. } continue } } else { // t.wrap && lineWidth > width if !t.wordWrap || lastLineBreak == [3]int{} { if lastGraphemeBreak != [3]int{} { // We have at least one character on each line. // Break after last grapheme. t.lineStarts = append(t.lineStarts, lastGraphemeBreak) if lineWidth > t.widestLine { t.widestLine = lineWidth } lineWidth = clusterWidth lastLineBreak = [3]int{} } } else { // t.wordWrap && lastLineBreak != [3]int{} // Break after last line break opportunity. t.lineStarts = append(t.lineStarts, lastLineBreak) if lineWidth > t.widestLine { t.widestLine = lineWidth } lineWidth = widthSinceLineBreak lastLineBreak = [3]int{} } } // Analyze break opportunities. if boundaries&uniseg.MaskLine == uniseg.LineCanBreak { lastLineBreak = pos widthSinceLineBreak = 0 } lastGraphemeBreak = pos // Can we stop? if len(t.lineStarts) > maxLines { break } } if lineWidth > t.widestLine { t.widestLine = lineWidth } } // truncateLines truncates the trailing lines of the [TextArea.lineStarts] // slice such that len(lineStarts) <= fromLine. If fromLine is negative, a value // of 0 is assumed. If it is greater than the length of lineStarts, nothing // happens. func (t *TextArea) truncateLines(fromLine int) { if fromLine < 0 { fromLine = 0 } if fromLine < len(t.lineStarts) { t.lineStarts = t.lineStarts[:fromLine] } } // findCursor determines the cursor position if its "row" value is < 0 // (=unknown) but only its span position ("pos" value) is known. If the cursor // position is already known (row >= 0), it can also be used to modify row and // column offsets such that the cursor is visible during the next call to // [TextArea.Draw], by setting "clamp" to true. // // To determine the cursor position, "startRow" helps reduce processing time by // indicating the lowest row in which searching should start. Set this to 0 if // you don't have any information where the cursor might be (but know that this // is expensive for long texts). // // The cursor's desired column will be set to its actual column. func (t *TextArea) findCursor(clamp bool, startRow int) { defer func() { t.cursor.column = t.cursor.actualColumn }() if !clamp && t.cursor.row >= 0 || t.lastWidth <= 0 { return // Nothing to do. } // Clamp to viewport. if clamp && t.cursor.row >= 0 { cursorRow := t.cursor.row if t.wrap && t.cursor.actualColumn >= t.lastWidth { cursorRow++ // A row can push the cursor just outside the viewport. It will wrap onto the next line. } if cursorRow < t.rowOffset { // We're above the viewport. t.rowOffset = cursorRow } else if cursorRow >= t.rowOffset+t.lastHeight { // We're below the viewport. t.rowOffset = cursorRow - t.lastHeight + 1 if t.rowOffset >= len(t.lineStarts) { t.extendLines(t.lastWidth, t.rowOffset) if t.rowOffset >= len(t.lineStarts) { t.rowOffset = len(t.lineStarts) - 1 if t.rowOffset < 0 { t.rowOffset = 0 } } } } if !t.wrap { if t.cursor.actualColumn < t.columnOffset+t.minCursorPrefix { // We're left of the viewport. t.columnOffset = t.cursor.actualColumn - t.minCursorPrefix if t.columnOffset < 0 { t.columnOffset = 0 } } else if t.cursor.actualColumn >= t.columnOffset+t.lastWidth-t.minCursorSuffix { // We're right of the viewport. t.columnOffset = t.cursor.actualColumn - t.lastWidth + t.minCursorSuffix if t.columnOffset >= t.widestLine { t.columnOffset = t.widestLine - 1 if t.columnOffset < 0 { t.columnOffset = 0 } } } } return } // The screen position of the cursor is unknown. Find it. This can be // expensive. First, find the row. row := startRow if row < 0 { row = 0 } RowLoop: for { // Examine the current row. if row+1 >= len(t.lineStarts) { t.extendLines(t.lastWidth, row+1) } if row >= len(t.lineStarts) { t.cursor.row, t.cursor.actualColumn, t.cursor.pos = row, 0, [3]int{1, 0, -1} break // It's the end of the text. } // Check this row's spans to see if the cursor is in this row. pos := t.lineStarts[row] for pos[0] != 1 { if row+1 >= len(t.lineStarts) { break // It's the last row so the cursor must be in this row. } if t.cursor.pos[0] == pos[0] { // The cursor is in this span. if t.lineStarts[row+1][0] == pos[0] { // The next row starts with the same span. if t.cursor.pos[1] >= t.lineStarts[row+1][1] { // The cursor is not in this row. row++ continue RowLoop } else { // The cursor is in this row. break } } else { // The next row starts with a different span. The cursor // must be in this row. break } } else { // The cursor is in a different span. if t.lineStarts[row+1][0] == pos[0] { // The next row starts with the same span. This row is // irrelevant. row++ continue RowLoop } else { // The next row starts with a different span. Move towards it. pos = [3]int{t.spans[pos[0]].next, 0, -1} } } } // Try to find the screen position in this row. pos = t.lineStarts[row] endPos := pos column := 0 var text string for { if pos[0] == 1 || t.cursor.pos[0] == pos[0] && t.cursor.pos[1] == pos[1] { // We found the position. We're done. t.cursor.row, t.cursor.actualColumn, t.cursor.pos = row, column, pos break RowLoop } var clusterWidth int _, text, _, clusterWidth, pos, endPos = t.step(text, pos, endPos) if row+1 < len(t.lineStarts) && t.lineStarts[row+1] == pos { // We reached the end of the line. Go to the next one. row++ continue RowLoop } column += clusterWidth } } if clamp && t.cursor.row >= 0 { // We know the position now. Adapt offsets. t.findCursor(true, startRow) } } // setTransform sets the transform function to be used when drawing the text. // This function is called for each grapheme cluster and can be used to modify // the cluster, the cluster's screen width, and the cluster's boundaries. The // function is called with the original cluster, the rest of the text, the // original cluster's width, and the original cluster's boundaries. The function // must return the new cluster, the new width, and the new boundaries. This only // affects the drawing of the text, not the text content itself. The boundaries // values correspond to the values returned by // [github.com/rivo/uniseg.StepString]. func (t *TextArea) setTransform(transform func(cluster, rest string, boundaries int) (newCluster string, newBoundaries int)) { t.transform = transform } // step is similar to [github.com/rivo/uniseg.StepString] but it iterates over // the piece chain, starting with "pos", a span position plus state (which may // be -1 for the start of the text). The returned "boundaries" value is the same // value returned by [github.com/rivo/uniseg.StepString], "width" is the screen // width of the grapheme. The "pos" and "endPos" positions refer to the start // and the end of the "text" string, respectively. For the first call, text may // be empty and pos/endPos may be the same. For consecutive calls, provide // "rest" as the text and "newPos" and "newEndPos" as the new positions/states. // An empty "rest" string indicates the end of the text. The "endPos" state is // irrelevant. func (t *TextArea) step(text string, pos, endPos [3]int) (cluster, rest string, boundaries, width int, newPos, newEndPos [3]int) { if pos[0] == 1 { return // We're already past the end. } // We want to make sure we have a text at least the size of a grapheme // cluster. span := t.spans[pos[0]] if len(text) < maxGraphemeClusterSize && (span.length < 0 && -span.length-pos[1] >= maxGraphemeClusterSize || span.length > 0 && t.spans[pos[0]].length-pos[1] >= maxGraphemeClusterSize) { // We can use a substring of one span. if span.length < 0 { text = t.initialText[span.offset+pos[1] : span.offset-span.length] } else { text = t.editText.String()[span.offset+pos[1] : span.offset+span.length] } endPos = [3]int{span.next, 0, -1} } else { // We have to compose the text from multiple spans. for len(text) < maxGraphemeClusterSize && endPos[0] != 1 { endSpan := t.spans[endPos[0]] var moreText string if endSpan.length < 0 { moreText = t.initialText[endSpan.offset+endPos[1] : endSpan.offset-endSpan.length] } else { moreText = t.editText.String()[endSpan.offset+endPos[1] : endSpan.offset+endSpan.length] } if len(moreText) > maxGraphemeClusterSize { moreText = moreText[:maxGraphemeClusterSize] } text += moreText endPos[1] += len(moreText) if endPos[1] >= endSpan.length { endPos[0], endPos[1] = endSpan.next, 0 } } } // Run the grapheme cluster iterator. cluster, text, boundaries, pos[2] = uniseg.StepString(text, pos[2]) pos[1] += len(cluster) for pos[0] != 1 && (span.length < 0 && pos[1] >= -span.length || span.length >= 0 && pos[1] >= span.length) { pos[0] = span.next if span.length < 0 { pos[1] += span.length } else { pos[1] -= span.length } span = t.spans[pos[0]] } if t.transform != nil { cluster, boundaries = t.transform(cluster, text, boundaries) } if cluster == "\t" { width = TabSize } else { width = boundaries >> uniseg.ShiftWidth } return cluster, text, boundaries, width, pos, endPos } // moveCursor sets the cursor's screen position and span position for the given // row and column which are screen space coordinates relative to the top-left // corner of the text area's full text (visible or not). The column value may be // negative, in which case, the cursor will be placed at the end of the line. // The cursor's actual position will be aligned with a grapheme cluster // boundary. The next call to [TextArea.Draw] will attempt to keep the cursor in // the viewport. func (t *TextArea) moveCursor(row, column int) { // Are we within the range of rows? if len(t.lineStarts) <= row { // No. Extent the line buffer. t.extendLines(t.lastWidth, row) } if len(t.lineStarts) == 0 { return // No lines. Nothing to do. } if row < 0 { // We're at the start of the text. row = 0 column = 0 } else if row >= len(t.lineStarts) { // We're already past the end. row = len(t.lineStarts) - 1 column = -1 } // Iterate through this row until we find the position. t.cursor.row, t.cursor.actualColumn = row, 0 if t.wrap { t.cursor.actualColumn = 0 } pos := t.lineStarts[row] endPos := pos var text string for pos[0] != 1 { var clusterWidth int oldPos := pos // We may have to revert to this position. _, text, _, clusterWidth, pos, endPos = t.step(text, pos, endPos) if len(t.lineStarts) > row+1 && pos == t.lineStarts[row+1] || // We've reached the end of the line. column >= 0 && t.cursor.actualColumn+clusterWidth > column { // We're past the requested column. pos = oldPos break } t.cursor.actualColumn += clusterWidth } if column < 0 { t.cursor.column = t.cursor.actualColumn } else { t.cursor.column = column } t.cursor.pos = pos t.findCursor(true, row) } // moveWordRight moves the cursor to the end of the current or next word. If // after is set to true, the cursor will be placed after the word. If false, the // cursor will be placed on the last character of the word. If clamp is set to // true, the cursor will be visible during the next call to [TextArea.Draw]. func (t *TextArea) moveWordRight(after, clamp bool) { // Because we rely on clampToCursor to calculate the new screen position, // this is an expensive operation for large texts. pos := t.cursor.pos endPos := pos var ( cluster, text string inWord bool ) for pos[0] != 0 { var boundaries int oldPos := pos cluster, text, boundaries, _, pos, endPos = t.step(text, pos, endPos) if oldPos == t.cursor.pos { continue // Skip the first character. } firstRune, _ := utf8.DecodeRuneInString(cluster) if !unicode.IsSpace(firstRune) && !unicode.IsPunct(firstRune) { inWord = true } if inWord && boundaries&uniseg.MaskWord != 0 { if !after { pos = oldPos } break } } startRow := t.cursor.row t.cursor.row, t.cursor.column, t.cursor.actualColumn = -1, 0, 0 t.cursor.pos = pos t.findCursor(clamp, startRow) } // moveWordLeft moves the cursor to the beginning of the current or previous // word. If clamp is true, the cursor will be visible during the next call to // [TextArea.Draw]. func (t *TextArea) moveWordLeft(clamp bool) { // We go back row by row, trying to find the last word boundary before the // cursor. row := t.cursor.row if row+1 < len(t.lineStarts) { t.extendLines(t.lastWidth, row+1) } if row >= len(t.lineStarts) { row = len(t.lineStarts) - 1 } for row >= 0 { pos := t.lineStarts[row] endPos := pos var lastWordBoundary [3]int var ( cluster, text string inWord bool boundaries int ) for pos[0] != 1 && pos != t.cursor.pos { oldBoundaries := boundaries oldPos := pos cluster, text, boundaries, _, pos, endPos = t.step(text, pos, endPos) firstRune, _ := utf8.DecodeRuneInString(cluster) wordRune := !unicode.IsSpace(firstRune) && !unicode.IsPunct(firstRune) if oldBoundaries&uniseg.MaskWord != 0 { if pos != t.cursor.pos && !inWord && wordRune { // A boundary transitioning from a space/punctuation word to // a letter word. lastWordBoundary = oldPos } inWord = false } if wordRune { inWord = true } } if lastWordBoundary[0] != 0 { // We found something. t.cursor.pos = lastWordBoundary break } row-- } if row < 0 { // We didn't find anything. We're at the start of the text. t.cursor.pos = [3]int{t.spans[0].next, 0, -1} row = 0 } t.cursor.row, t.cursor.column, t.cursor.actualColumn = -1, 0, 0 t.findCursor(clamp, row) } // deleteLine deletes all characters between the last newline before the cursor // and the next newline after the cursor (inclusive). func (t *TextArea) deleteLine() { // We go back row by row, trying to find the last mandatory line break // before the cursor. startRow := t.cursor.row if t.cursor.actualColumn == 0 && t.cursor.pos[0] == 1 { startRow-- // If we're at the very end, delete the row before. } if startRow+1 < len(t.lineStarts) { t.extendLines(t.lastWidth, startRow+1) } if len(t.lineStarts) == 0 { return // Nothing to delete. } if startRow >= len(t.lineStarts) { startRow = len(t.lineStarts) - 1 } for startRow >= 0 { // What's the last rune before the start of the line? pos := t.lineStarts[startRow] span := t.spans[pos[0]] var text string if pos[1] > 0 { // Extract text from this span. if span.length < 0 { text = t.initialText } else { text = t.editText.String() } text = text[:span.offset+pos[1]] } else { // Extract text from the previous span. if span.previous != 0 { span = t.spans[span.previous] if span.length < 0 { text = t.initialText[:span.offset-span.length] } else { text = t.editText.String()[:span.offset+span.length] } } } if uniseg.HasTrailingLineBreakInString(text) { // The row before this one ends with a mandatory line break. This is // the first line we will delete. break } startRow-- } if startRow < 0 { // We didn't find anything. It'll be the first line. startRow = 0 } // Find the next line break after the cursor. pos := t.cursor.pos endPos := pos var cluster, text string for pos[0] != 1 { cluster, text, _, _, pos, endPos = t.step(text, pos, endPos) if uniseg.HasTrailingLineBreakInString(cluster) { break } } // Delete the text. t.cursor.pos = t.replace(t.lineStarts[startRow], pos, "", false) t.cursor.row = -1 t.truncateLines(startRow) t.findCursor(true, startRow) } // getSelection returns the current selection as span locations where the first // returned location is always before or the same as the second returned // location. This assumes that the cursor and selection positions are known. The // third return value is the starting row of the selection. func (t *TextArea) getSelection() ([3]int, [3]int, int) { from := t.selectionStart.pos to := t.cursor.pos row := t.selectionStart.row if t.cursor.row < t.selectionStart.row || (t.cursor.row == t.selectionStart.row && t.cursor.actualColumn < t.selectionStart.actualColumn) { from, to = to, from row = t.cursor.row } return from, to, row } // getSelectedText returns the text of the current selection. func (t *TextArea) getSelectedText() string { var text strings.Builder from, to, _ := t.getSelection() for from[0] != to[0] { span := t.spans[from[0]] if span.length < 0 { text.WriteString(t.initialText[span.offset+from[1] : span.offset-span.length]) } else { text.WriteString(t.editText.String()[span.offset+from[1] : span.offset+span.length]) } from[0], from[1] = span.next, 0 } if from[0] != 1 && from[1] < to[1] { span := t.spans[from[0]] if span.length < 0 { text.WriteString(t.initialText[span.offset+from[1] : span.offset+to[1]]) } else { text.WriteString(t.editText.String()[span.offset+from[1] : span.offset+to[1]]) } } return text.String() } // InputHandler returns the handler for this primitive. func (t *TextArea) InputHandler() func(event *tcell.EventKey, setFocus func(p Primitive)) { return t.WrapInputHandler(func(event *tcell.EventKey, setFocus func(p Primitive)) { if t.disabled { return } // All actions except a few specific ones are "other" actions. newLastAction := taActionOther defer func() { t.lastAction = newLastAction }() // Trigger a "moved" event if requested. if t.moved != nil { selectionStart, cursor := t.selectionStart, t.cursor defer func() { if selectionStart != t.selectionStart || cursor != t.cursor { t.moved() } }() } // Process the different key events. switch key := event.Key(); key { case tcell.KeyLeft: // Move one grapheme cluster to the left. if event.Modifiers()&tcell.ModAlt == 0 { // Regular movement. if event.Modifiers()&tcell.ModShift == 0 && t.selectionStart.pos != t.cursor.pos { // Move to the start of the selection. if t.selectionStart.row < t.cursor.row || (t.selectionStart.row == t.cursor.row && t.selectionStart.actualColumn < t.cursor.actualColumn) { t.cursor = t.selectionStart } t.findCursor(true, t.cursor.row) } else if event.Modifiers()&tcell.ModMeta != 0 || event.Modifiers()&tcell.ModCtrl != 0 { // This captures Ctrl-Left on some systems. t.moveWordLeft(event.Modifiers()&tcell.ModShift != 0) } else if t.cursor.actualColumn == 0 { // Move to the end of the previous row. if t.cursor.row > 0 { t.moveCursor(t.cursor.row-1, -1) } } else { // Move one grapheme cluster to the left. t.moveCursor(t.cursor.row, t.cursor.actualColumn-1) } if event.Modifiers()&tcell.ModShift == 0 { t.selectionStart = t.cursor } } else if !t.wrap { // This doesn't work on all terminals. // Just scroll. t.columnOffset-- if t.columnOffset < 0 { t.columnOffset = 0 } } case tcell.KeyRight: // Move one grapheme cluster to the right. if event.Modifiers()&tcell.ModAlt == 0 { // Regular movement. if event.Modifiers()&tcell.ModShift == 0 && t.selectionStart.pos != t.cursor.pos { // Move to the end of the selection. if t.selectionStart.row > t.cursor.row || (t.selectionStart.row == t.cursor.row && t.selectionStart.actualColumn > t.cursor.actualColumn) { t.cursor = t.selectionStart } t.findCursor(true, t.cursor.row) } else if t.cursor.pos[0] != 1 { if event.Modifiers()&tcell.ModMeta != 0 || event.Modifiers()&tcell.ModCtrl != 0 { // This captures Ctrl-Right on some systems. t.moveWordRight(event.Modifiers()&tcell.ModShift != 0, true) } else { // Move one grapheme cluster to the right. var clusterWidth int _, _, _, clusterWidth, t.cursor.pos, _ = t.step("", t.cursor.pos, t.cursor.pos) if len(t.lineStarts) <= t.cursor.row+1 { t.extendLines(t.lastWidth, t.cursor.row+1) } if t.cursor.row+1 < len(t.lineStarts) && t.lineStarts[t.cursor.row+1] == t.cursor.pos { // We've reached the end of the line. t.cursor.row++ t.cursor.actualColumn = 0 t.cursor.column = 0 t.findCursor(true, t.cursor.row) } else { // Move one character to the right. t.moveCursor(t.cursor.row, t.cursor.actualColumn+clusterWidth) } } } if event.Modifiers()&tcell.ModShift == 0 { t.selectionStart = t.cursor } } else if !t.wrap { // This doesn't work on all terminals. // Just scroll. t.columnOffset++ if t.columnOffset >= t.widestLine { t.columnOffset = t.widestLine - 1 if t.columnOffset < 0 { t.columnOffset = 0 } } } case tcell.KeyDown: // Move one row down. if event.Modifiers()&tcell.ModAlt == 0 { // Regular movement. column := t.cursor.column t.moveCursor(t.cursor.row+1, t.cursor.column) t.cursor.column = column if event.Modifiers()&tcell.ModShift == 0 { t.selectionStart = t.cursor } } else { // Just scroll. t.rowOffset++ if t.rowOffset >= len(t.lineStarts) { t.extendLines(t.lastWidth, t.rowOffset) if t.rowOffset >= len(t.lineStarts) { t.rowOffset = len(t.lineStarts) - 1 if t.rowOffset < 0 { t.rowOffset = 0 } } } } case tcell.KeyUp: // Move one row up. if event.Modifiers()&tcell.ModAlt == 0 { // Regular movement. column := t.cursor.column t.moveCursor(t.cursor.row-1, t.cursor.column) t.cursor.column = column if event.Modifiers()&tcell.ModShift == 0 { t.selectionStart = t.cursor } } else { // Just scroll. t.rowOffset-- if t.rowOffset < 0 { t.rowOffset = 0 } } case tcell.KeyHome, tcell.KeyCtrlA: // Move to the start of the line. t.moveCursor(t.cursor.row, 0) if event.Modifiers()&tcell.ModShift == 0 { t.selectionStart = t.cursor } case tcell.KeyEnd, tcell.KeyCtrlE: // Move to the end of the line. t.moveCursor(t.cursor.row, -1) if event.Modifiers()&tcell.ModShift == 0 { t.selectionStart = t.cursor } case tcell.KeyPgDn, tcell.KeyCtrlF: // Move one page down. column := t.cursor.column t.moveCursor(t.cursor.row+t.lastHeight, t.cursor.column) t.cursor.column = column if event.Modifiers()&tcell.ModShift == 0 { t.selectionStart = t.cursor } case tcell.KeyPgUp, tcell.KeyCtrlB: // Move one page up. column := t.cursor.column t.moveCursor(t.cursor.row-t.lastHeight, t.cursor.column) t.cursor.column = column if event.Modifiers()&tcell.ModShift == 0 { t.selectionStart = t.cursor } case tcell.KeyEnter: // Insert a newline. from, to, row := t.getSelection() t.cursor.pos = t.replace(from, to, NewLine, t.lastAction == taActionTypeSpace) t.cursor.row = -1 t.truncateLines(row - 1) t.findCursor(true, row) t.selectionStart = t.cursor newLastAction = taActionTypeSpace case tcell.KeyTab: // Insert a tab character. It will be rendered as TabSize spaces. // But forwarding takes precedence. if t.finished != nil { t.finished(key) return } from, to, row := t.getSelection() t.cursor.pos = t.replace(from, to, "\t", t.lastAction == taActionTypeSpace) t.cursor.row = -1 t.truncateLines(row - 1) t.findCursor(true, row) t.selectionStart = t.cursor newLastAction = taActionTypeSpace case tcell.KeyBacktab, tcell.KeyEscape: // Only used in forms. if t.finished != nil { t.finished(key) return } case tcell.KeyRune: if event.Modifiers()&tcell.ModAlt > 0 { // We accept some Alt- key combinations. switch event.Rune() { case 'f': if event.Modifiers()&tcell.ModShift == 0 { t.moveWordRight(false, true) t.selectionStart = t.cursor } else { t.moveWordRight(true, true) } case 'b': t.moveWordLeft(true) if event.Modifiers()&tcell.ModShift == 0 { t.selectionStart = t.cursor } } } else { // Other keys are simply accepted as regular characters. r := event.Rune() from, to, row := t.getSelection() newLastAction = taActionTypeNonSpace if unicode.IsSpace(r) { newLastAction = taActionTypeSpace } t.cursor.pos = t.replace(from, to, string(r), newLastAction == t.lastAction || t.lastAction == taActionTypeNonSpace && newLastAction == taActionTypeSpace) t.cursor.row = -1 t.truncateLines(row - 1) t.findCursor(true, row) t.selectionStart = t.cursor } case tcell.KeyBackspace, tcell.KeyBackspace2: // Delete backwards. tcell.KeyBackspace is the same as tcell.CtrlH. from, to, row := t.getSelection() if from != to { // Simply delete the current selection. t.cursor.pos = t.replace(from, to, "", false) t.cursor.row = -1 t.truncateLines(row - 1) t.findCursor(true, row) t.selectionStart = t.cursor break } beforeCursor := t.cursor if event.Modifiers()&tcell.ModAlt == 0 { // Move the cursor back by one grapheme cluster. if t.cursor.actualColumn == 0 { // Move to the end of the previous row. if t.cursor.row > 0 { t.moveCursor(t.cursor.row-1, -1) } } else { // Move one grapheme cluster to the left. t.moveCursor(t.cursor.row, t.cursor.actualColumn-1) } newLastAction = taActionBackspace } else { // Move the cursor back by one word. t.moveWordLeft(false) } // Remove that last grapheme cluster. if t.cursor.pos != beforeCursor.pos { t.cursor, beforeCursor = beforeCursor, t.cursor // So we put the right position on the stack. t.cursor.pos = t.replace(beforeCursor.pos, t.cursor.pos, "", t.lastAction == taActionBackspace) // Delete the character. t.cursor.row = -1 t.truncateLines(beforeCursor.row - 1) t.findCursor(true, beforeCursor.row-1) } t.selectionStart = t.cursor case tcell.KeyDelete, tcell.KeyCtrlD: // Delete forward. from, to, row := t.getSelection() if from != to { // Simply delete the current selection. t.cursor.pos = t.replace(from, to, "", false) t.cursor.row = -1 t.truncateLines(row - 1) t.findCursor(true, row) t.selectionStart = t.cursor break } if t.cursor.pos[0] != 1 { _, _, _, _, endPos, _ := t.step("", t.cursor.pos, t.cursor.pos) t.cursor.pos = t.replace(t.cursor.pos, endPos, "", t.lastAction == taActionDelete) // Delete the character. t.cursor.pos[2] = endPos[2] t.truncateLines(t.cursor.row - 1) t.findCursor(true, t.cursor.row) newLastAction = taActionDelete } t.selectionStart = t.cursor case tcell.KeyCtrlK: // Delete everything under and to the right of the cursor until before the next newline character. pos := t.cursor.pos endPos := pos var cluster, text string for pos[0] != 1 { var boundaries int oldPos := pos cluster, text, boundaries, _, pos, endPos = t.step(text, pos, endPos) if boundaries&uniseg.MaskLine == uniseg.LineMustBreak { if uniseg.HasTrailingLineBreakInString(cluster) { pos = oldPos } break } } t.cursor.pos = t.replace(t.cursor.pos, pos, "", false) row := t.cursor.row t.cursor.row = -1 t.truncateLines(row - 1) t.findCursor(true, row) t.selectionStart = t.cursor case tcell.KeyCtrlW: // Delete from the start of the current word to the left of the cursor. pos := t.cursor.pos t.moveWordLeft(true) t.cursor.pos = t.replace(t.cursor.pos, pos, "", false) row := t.cursor.row - 1 t.cursor.row = -1 t.truncateLines(row) t.findCursor(true, row) t.selectionStart = t.cursor case tcell.KeyCtrlU: // Delete the current line. t.deleteLine() t.selectionStart = t.cursor case tcell.KeyCtrlL: // Select everything. t.selectionStart.row, t.selectionStart.column, t.selectionStart.actualColumn = 0, 0, 0 t.selectionStart.pos = [3]int{t.spans[0].next, 0, -1} row := t.cursor.row t.cursor.row = -1 t.cursor.pos = [3]int{1, 0, -1} t.findCursor(false, row) case tcell.KeyCtrlQ: // Copy to clipboard. if t.cursor != t.selectionStart { t.copyToClipboard(t.getSelectedText()) t.selectionStart = t.cursor } case tcell.KeyCtrlX: // Cut to clipboard. if t.cursor != t.selectionStart { t.copyToClipboard(t.getSelectedText()) from, to, row := t.getSelection() t.cursor.pos = t.replace(from, to, "", false) t.cursor.row = -1 t.truncateLines(row - 1) t.findCursor(true, row) t.selectionStart = t.cursor } case tcell.KeyCtrlV: // Paste from clipboard. from, to, row := t.getSelection() t.cursor.pos = t.replace(from, to, t.pasteFromClipboard(), false) t.cursor.row = -1 t.truncateLines(row - 1) t.findCursor(true, row) t.selectionStart = t.cursor case tcell.KeyCtrlZ: // Undo. if t.nextUndo <= 0 { break } for t.nextUndo > 0 { t.nextUndo-- undo := t.undoStack[t.nextUndo] t.spans[undo.originalBefore], t.spans[undo.before] = t.spans[undo.before], t.spans[undo.originalBefore] t.spans[undo.originalAfter], t.spans[undo.after] = t.spans[undo.after], t.spans[undo.originalAfter] t.cursor.pos, t.undoStack[t.nextUndo].pos = undo.pos, t.cursor.pos t.length, t.undoStack[t.nextUndo].length = undo.length, t.length if !undo.continuation { break } } t.cursor.row = -1 t.truncateLines(0) // This is why Undo is expensive for large texts. (t.lineStarts can get largely unusable after an undo.) t.findCursor(true, 0) t.selectionStart = t.cursor if t.changed != nil { defer t.changed() } case tcell.KeyCtrlY: // Redo. if t.nextUndo >= len(t.undoStack) { break } for t.nextUndo < len(t.undoStack) { undo := t.undoStack[t.nextUndo] t.spans[undo.originalBefore], t.spans[undo.before] = t.spans[undo.before], t.spans[undo.originalBefore] t.spans[undo.originalAfter], t.spans[undo.after] = t.spans[undo.after], t.spans[undo.originalAfter] t.cursor.pos, t.undoStack[t.nextUndo].pos = undo.pos, t.cursor.pos t.length, t.undoStack[t.nextUndo].length = undo.length, t.length t.nextUndo++ if t.nextUndo < len(t.undoStack) && !t.undoStack[t.nextUndo].continuation { break } } t.cursor.row = -1 t.truncateLines(0) // This is why Redo is expensive for large texts. (t.lineStarts can get largely unusable after an undo.) t.findCursor(true, 0) t.selectionStart = t.cursor if t.changed != nil { defer t.changed() } } }) } // MouseHandler returns the mouse handler for this primitive. func (t *TextArea) MouseHandler() func(action MouseAction, event *tcell.EventMouse, setFocus func(p Primitive)) (consumed bool, capture Primitive) { return t.WrapMouseHandler(func(action MouseAction, event *tcell.EventMouse, setFocus func(p Primitive)) (consumed bool, capture Primitive) { if t.disabled { return false, nil } x, y := event.Position() rectX, rectY, _, _ := t.GetInnerRect() if !t.InRect(x, y) { return false, nil } // Trigger a "moved" event at the end if requested. if t.moved != nil { selectionStart, cursor := t.selectionStart, t.cursor defer func() { if selectionStart != t.selectionStart || cursor != t.cursor { t.moved() } }() } // Turn mouse coordinates into text coordinates. labelWidth := t.labelWidth if labelWidth == 0 && t.label != "" { labelWidth = TaggedStringWidth(t.label) } column := x - rectX - labelWidth row := y - rectY if !t.wrap { column += t.columnOffset } row += t.rowOffset // Process mouse actions. switch action { case MouseLeftDown: t.moveCursor(row, column) if event.Modifiers()&tcell.ModShift == 0 { t.selectionStart = t.cursor } setFocus(t) consumed = true capture = t t.dragging = true case MouseMove: if !t.dragging { break } t.moveCursor(row, column) consumed = true case MouseLeftUp: t.moveCursor(row, column) consumed = true capture = nil t.dragging = false case MouseLeftDoubleClick: // Select word. // Left down/up was already triggered so we are at the correct // position. t.moveWordLeft(false) t.selectionStart = t.cursor t.moveWordRight(true, false) consumed = true case MouseScrollUp: if t.rowOffset > 0 { t.rowOffset-- } consumed = true case MouseScrollDown: t.rowOffset++ if t.rowOffset >= len(t.lineStarts) { t.rowOffset = len(t.lineStarts) - 1 if t.rowOffset < 0 { t.rowOffset = 0 } } consumed = true case MouseScrollLeft: if t.columnOffset > 0 { t.columnOffset-- } consumed = true case MouseScrollRight: t.columnOffset++ if t.columnOffset >= t.widestLine { t.columnOffset = t.widestLine - 1 if t.columnOffset < 0 { t.columnOffset = 0 } } consumed = true } return }) } // PasteHandler returns the handler for this primitive. func (t *TextArea) PasteHandler() func(pastedText string, setFocus func(p Primitive)) { return t.WrapPasteHandler(func(pastedText string, setFocus func(p Primitive)) { from, to, row := t.getSelection() t.cursor.pos = t.replace(from, to, pastedText, false) t.cursor.row = -1 t.truncateLines(row - 1) t.findCursor(true, row) t.selectionStart = t.cursor }) }