@ -103,7 +103,7 @@ function ImageViewer:init()
w = Screen : getWidth ( ) ,
h = Screen : getHeight ( ) ,
}
local diagonal = math.sqrt ( math.pow ( Screen : getWidth ( ) , 2 ) + math.pow ( Screen : getHeight ( ) , 2 ) )
local diagonal = math.sqrt ( Screen : getWidth ( ) ^ 2 + Screen : getHeight ( ) ^ 2 )
self.ges_events = {
Tap = { GestureRange : new { ges = " tap " , range = range } } ,
-- Zoom in/out (Pinch & Spread are not triggered if user is too
@ -636,48 +636,57 @@ function ImageViewer:onPanRelease(_, ges)
end
-- Zoom events
function ImageViewer : onZoomIn( inc )
function ImageViewer : _refreshScaleFactor( )
if self.scale_factor == 0 then
-- Get the scale_factor made out for best fit
self.scale_factor = self._scale_factor_0 or self._image_wg : getScaleFactor ( )
end
end
if not inc then
-- default for key zoom event
inc = 0.2
end
-- Compute new scale factor for rescaled image dimensions
local new_factor = self.scale_factor * ( 1 + inc )
function ImageViewer : _applyNewScaleFactor ( new_factor )
-- Make sure self.scale_factor is up-to-date
self : _refreshScaleFactor ( )
-- We destroy ImageWidget on update, so only request this the first time,
-- in order to avoid jitter in the results given differing memory consumption at different zoom levels...
if not self._m ax_scale_factor then
if not self._min_scale_factor or not self._max_scale_factor then
self._min_scale_factor , self._max_scale_factor = self._image_wg : getScaleFactorExtrema ( )
end
-- Clamp to sane values
new_factor = math.min ( new_factor , self._max_scale_factor )
new_factor = math.max ( new_factor , self._min_scale_factor )
if new_factor ~= self.scale_factor then
self.scale_factor = new_factor
self : update ( )
else
if self.scale_factor == self._max_scale_factor then
logger.dbg ( " ImageViewer:onZoomIn: Hit the max scaling factor: " , self.scale_factor )
if self.scale_factor == self._min_scale_factor then
logger.dbg ( " ImageViewer: Hit the min scaling factor: " , self.scale_factor )
elseif self.scale_factor == self._max_scale_factor then
logger.dbg ( " ImageViewer: Hit the max scaling factor: " , self.scale_factor )
else
logger.dbg ( " ImageViewer:onZoomIn: No change in scaling factor: " , self.scale_factor )
logger.dbg ( " ImageViewer: No change in scaling factor:" , self.scale_factor )
end
end
end
function ImageViewer : onZoomIn ( inc )
self : _refreshScaleFactor ( )
if not inc then
-- default for key zoom event
inc = 0.2
end
-- Compute new scale factor for rescaled image dimensions
local new_factor = self.scale_factor * ( 1 + inc )
self : _applyNewScaleFactor ( new_factor )
return true
end
function ImageViewer : onZoomOut ( dec )
if self.scale_factor == 0 then
-- Get the scale_factor made out for best fit
self.scale_factor = self._scale_factor_0 or self._image_wg : getScaleFactor ( )
end
self : _refreshScaleFactor ( )
if not dec then
-- default for key zoom event
dec = 0.2
elseif dec >= 0.75 then
-- Larger reductions tend to be fairly jarring, so limit to 75%.
@ -685,70 +694,90 @@ function ImageViewer:onZoomOut(dec)
dec = 0.75
end
-- Compute new scale factor for rescaled image dimensions
local new_factor = self.scale_factor * ( 1 - dec )
self : _applyNewScaleFactor ( new_factor )
return true
end
if not self._min_scale_factor then
self._min_scale_factor , self._max_scale_factor = self._image_wg : getScaleFactorExtrema ( )
end
-- Clamp to sane values
new_factor = math.max ( new_factor , self._min_scale_factor )
if new_factor ~= self.scale_factor then
self.scale_factor = new_factor
self : update ( )
else
if self.scale_factor == self._min_scale_factor then
logger.dbg ( " ImageViewer:onZoomOut: Hit the min scaling factor: " , self.scale_factor )
else
logger.dbg ( " ImageViewer:onZoomOut: No change in scaling factor: " , self.scale_factor )
end
end
--[[
function ImageViewer : onZoomToHeight ( height )
local new_factor = height / self._image_wg : getOriginalHeight ( )
self : _applyNewScaleFactor ( new_factor )
return true
end
function ImageViewer : onZoomToWidth ( width )
local new_factor = width / self._image_wg : getOriginalWidth ( )
self : _applyNewScaleFactor ( new_factor )
return true
end
function ImageViewer : onZoomToDiagonal ( d )
-- It's trigonometry time!
-- c.f., https://math.stackexchange.com/a/3369637
local r = self._image_wg : getOriginalWidth ( ) / self._image_wg : getOriginalHeight ( )
local h = math.sqrt ( d ^ 2 / ( r ^ 2 + 1 ) )
local w = h * r
-- Matches ImageWidget's best-fit computation in _render
local new_factor = math.min ( w / self._image_wg : getOriginalWidth ( ) , h / self._image_wg : getOriginalHeight ( ) )
self : _applyNewScaleFactor ( new_factor )
return true
end
--]]
function ImageViewer : onSpread ( _ , ges )
if not self._image_wg then
return
end
-- We get the position where spread was done
-- First, get center ratio we would have had if we did a pan to there,
-- so we can have the zoom centered on there
if self._image_wg then
self._center_x_ratio , self._center_y_ratio = self._image_wg : getPanByCenterRatio ( ges.pos . x - Screen : getWidth ( ) / 2 , ges.pos . y - Screen : getHeight ( ) / 2 )
end
-- Set some zoom increase value from pinch distance.
-- Making it relative to the smallest dimension between the currently scaled image or the Screen makes it less annoying
-- when approaching both very small scale factors (where the image dimensions are many times smaller than the screen),
self._center_x_ratio , self._center_y_ratio = self._image_wg : getPanByCenterRatio ( ges.pos . x - Screen : getWidth ( ) / 2 , ges.pos . y - Screen : getHeight ( ) / 2 )
-- We compute a scaling percentage (which will *modify* the current scaling factor),
-- based on the gesture distance (it's the sum of the travel of both fingers).
-- Making this distance relative to the smallest dimension between
-- the currently scaled image or the Screen makes it less annoying when approaching both very small scale factors
-- (where the image dimensions are many times smaller than the screen),
-- meaning using the image dimensions here takes less zoom steps to get it back to a sensible size;
-- *and* large scale factors (where the image dimensions are larger than the screen),
-- meaning using the screen dimensions here makes zoom steps, again, slightly more potent.
local inc
if ges.direction == " vertical " then
inc = ges.distance / math.min ( Screen : getHeight ( ) , self._image_wg : getCurrentHeight ( ) )
local img_h = self._image_wg : getCurrentHeight ( )
local screen_h = Screen : getHeight ( )
self : onZoomIn ( ges.distance / math.min ( screen_h , img_h ) )
elseif ges.direction == " horizontal " then
inc = ges.distance / math.min ( Screen : getWidth ( ) , self._image_wg : getCurrentWidth ( ) )
local img_w = self._image_wg : getCurrentWidth ( )
local screen_w = Screen : getWidth ( )
self : onZoomIn ( ges.distance / math.min ( screen_w , img_w ) )
else
local tl = Geom : new { x = 0 , y = 0 }
local br = Geom : new { x = Screen : getWidth ( ) - 1 , y = Screen : getHeight ( ) - 1 }
local screen_diag = tl : distance ( br )
inc = ges.distance / math.min ( screen_diag , self._image_wg : getCurrentDiagonal ( ) )
local img_d = self._image_wg : getCurrentDiagonal ( )
local screen_d = math.sqrt ( Screen : getWidth ( ) ^ 2 + Screen : getHeight ( ) ^ 2 )
self : onZoomIn ( ges.distance / math.min ( screen_d , img_d ) )
end
self : onZoomIn ( inc )
return true
end
function ImageViewer : onPinch ( _ , ges )
if not self._image_wg then
return
end
-- With Pinch, unlike Spread, it feels more natural if we keep the same center point.
-- Set some zoom decrease value from pinch distance
local dec
if ges.direction == " vertical " then
dec = ges.distance / math.min ( Screen : getHeight ( ) , self._image_wg : getCurrentHeight ( ) )
local img_h = self._image_wg : getCurrentHeight ( )
local screen_h = Screen : getHeight ( )
self : onZoomOut ( ges.distance / math.min ( screen_h , img_h ) )
elseif ges.direction == " horizontal " then
dec = ges.distance / math.min ( Screen : getWidth ( ) , self._image_wg : getCurrentWidth ( ) )
local img_w = self._image_wg : getCurrentWidth ( )
local screen_w = Screen : getWidth ( )
self : onZoomOut ( ges.distance / math.min ( screen_w , img_w ) )
else
local tl = Geom : new { x = 0 , y = 0 }
local br = Geom : new { x = Screen : getWidth ( ) - 1 , y = Screen : getHeight ( ) - 1 }
local screen_diag = tl : distance ( br )
dec = ges.distance / math.min ( screen_diag , self._image_wg : getCurrentDiagonal ( ) )
local img_d = self._image_wg : getCurrentDiagonal ( )
local screen_d = math.sqrt ( Screen : getWidth ( ) ^ 2 + Screen : getHeight ( ) ^ 2 )
self : onZoomOut ( ges.distance / math.min ( screen_d , img_d ) )
end
self : onZoomOut ( dec )
return true
end
NiLuJe
2 years ago
committed by
GitHub