readerview: add overlapped page dashed line marker

frontend/apps/reader/modules/readerview.lua

@@ -209,22 +209,26 @@ function ReaderView:paintTo(bb, x, y)
         end
     end
 
-    -- dim last read area
+    -- mark last read area of overlapped pages
     if not self.dim_area:isEmpty() and self:isOverlapAllowed() then
         if self.page_overlap_style == "dim" then
-            bb:dimRect(
-                self.dim_area.x, self.dim_area.y,
-                self.dim_area.w, self.dim_area.h
-            )
-        elseif self.page_overlap_style == "arrow" then
-            local center_offset = bit.rshift(self.arrow.height, 1)
-            -- Paint at the proper y origin depending on wheter we paged forward (dim_area.y == 0) or backward
-            self.arrow:paintTo(bb, 0, self.dim_area.y == 0 and self.dim_area.h - center_offset or self.dim_area.y - center_offset)
-        elseif self.page_overlap_style == "line" then
-            bb:paintRect(0, self.dim_area.y == 0 and self.dim_area.h or self.dim_area.y,
-                self.dim_area.w, Size.line.medium, Blitbuffer.COLOR_DARK_GRAY)
+            bb:dimRect(self.dim_area.x, self.dim_area.y, self.dim_area.w, self.dim_area.h)
+        else
+            -- Paint at the proper y origin depending on whether we paged forward (dim_area.y == 0) or backward
+            local y = self.dim_area.y == 0 and self.dim_area.h or self.dim_area.y
+            if self.page_overlap_style == "arrow" then
+                local center_offset = bit.rshift(self.arrow.height, 1)
+                self.arrow:paintTo(bb, 0, y - center_offset)
+            elseif self.page_overlap_style == "line" then
+                bb:paintRect(0, y, self.dim_area.w, Size.line.medium, Blitbuffer.COLOR_DARK_GRAY)
+            elseif self.page_overlap_style == "dashed_line" then
+                for i = 0, self.dim_area.w - 20, 20 do
+                    bb:paintRect(i, y, 14, Size.line.medium, Blitbuffer.COLOR_DARK_GRAY)
+                end
+            end
         end
     end
+
     -- draw saved highlight
     if self.highlight_visible then
         self:drawSavedHighlight(bb, x, y)