"Simplify" HW/SW dithering checks

Make it a real Document property, updated at init & toggle time.

Also, simplify a bunch of redundant nested lookups in ReaderView
(self.ui.view is self, self.ui.document is self.document).

frontend/apps/reader/modules/readerkoptlistener.lua

@@ -33,6 +33,7 @@ function ReaderKoptListener:onReadSettings(config)
     if self.document.configurable.word_spacing == -1 then
         self.document.configurable.word_spacing = -0.2
     end
+    self.ui:handleEvent(Event:new("DitheringUpdate"))
 end
 
 function ReaderKoptListener:onSaveSettings()

frontend/apps/reader/modules/readerview.lua

@@ -164,7 +164,7 @@ function ReaderView:paintTo(bb, x, y)
     end
 
     -- draw page content
-    if self.ui.document.info.has_pages then
+    if self.ui.paging then
         if self.page_scroll then
             self:drawScrollPages(bb, x, y)
         else
@@ -220,15 +220,14 @@ function ReaderView:paintTo(bb, x, y)
     -- Most pages should not require dithering
     self.dialog.dithered = nil
     -- For KOpt, let the user choose.
-    if self.ui.document.info.has_pages then
+    if self.ui.paging then
-        -- Also enforce HW dithering in PicDocument
+        if self.document.hw_dithering then
-        if self.ui.document.is_pic or self.document.configurable.hw_dithering == 1 then
             self.dialog.dithered = true
         end
     else
         -- Whereas for CRe,
         -- If we're attempting to show a large enough amount of image data, request dithering (without triggering another repaint ;)).
-        local img_count, img_coverage = self.ui.document:getDrawnImagesStatistics()
+        local img_count, img_coverage = self.document:getDrawnImagesStatistics()
         -- With some nil guards because this may not be implemented in every engine ;).
         if img_count and img_count > 0 and img_coverage and img_coverage >= 0.075 then
             self.dialog.dithered = true
@@ -245,15 +244,15 @@ end
 Given coordinates on the screen return position in original page
 ]]--
 function ReaderView:screenToPageTransform(pos)
-    if self.ui.document.info.has_pages then
+    if self.ui.paging then
         if self.page_scroll then
             return self:getScrollPagePosition(pos)
         else
             return self:getSinglePagePosition(pos)
         end
     else
-        pos.page = self.ui.document:getCurrentPage()
+        pos.page = self.document:getCurrentPage()
-        -- local last_y = self.ui.document:getCurrentPos()
+        -- local last_y = self.document:getCurrentPos()
         logger.dbg("document has no pages at", pos)
         return pos
     end
@@ -263,7 +262,7 @@ end
 Given rectangle in original page return rectangle on the screen
 ]]--
 function ReaderView:pageToScreenTransform(page, rect)
-    if self.ui.document.info.has_pages then
+    if self.ui.paging then
         if self.page_scroll then
             return self:getScrollPageRect(page, rect)
         else
@@ -278,7 +277,7 @@ end
 Get page area on screen for a given page number
 --]]
 function ReaderView:getScreenPageArea(page)
-    if self.ui.document.info.has_pages then
+    if self.ui.paging then
         local area = Geom:new{x = 0, y = 0}
         if self.page_scroll then
             for _, state in ipairs(self.page_states) do
@@ -313,7 +312,7 @@ function ReaderView:drawPageSurround(bb, x, y)
         bb:paintRect(x, y, self.dimen.w, self.state.offset.y, self.outer_page_color)
         local bottom_margin = y + self.visible_area.h + self.state.offset.y
         bb:paintRect(x, bottom_margin, self.dimen.w, self.state.offset.y +
-            self.ui.view.footer:getHeight(), self.outer_page_color)
+            self.footer:getHeight(), self.outer_page_color)
     end
     if self.dimen.w > self.visible_area.w then
         bb:paintRect(x, y, self.state.offset.x, self.dimen.h, self.outer_page_color)
@@ -325,7 +324,7 @@ end
 function ReaderView:drawScrollPages(bb, x, y)
     local pos = Geom:new{x = x , y = y}
     for page, state in ipairs(self.page_states) do
-        self.ui.document:drawPage(
+        self.document:drawPage(
             bb,
             pos.x + state.offset.x,
             pos.y + state.offset.y,
@@ -347,7 +346,7 @@ end
 
 function ReaderView:getCurrentPageList()
     local pages = {}
-    if self.ui.document.info.has_pages then
+    if self.ui.paging then
         if self.page_scroll then
             for _, state in ipairs(self.page_states) do
                 table.insert(pages, state.page)
@@ -400,7 +399,7 @@ function ReaderView:drawPageGap(bb, x, y)
 end
 
 function ReaderView:drawSinglePage(bb, x, y)
-    self.ui.document:drawPage(
+    self.document:drawPage(
         bb,
         x + self.state.offset.x,
         y + self.state.offset.y,
@@ -438,7 +437,7 @@ function ReaderView:getSinglePageRect(rect_p)
 end
 
 function ReaderView:drawPageView(bb, x, y)
-    self.ui.document:drawCurrentViewByPage(
+    self.document:drawCurrentViewByPage(
         bb,
         x + self.state.offset.x,
         y + self.state.offset.y,
@@ -447,7 +446,7 @@ function ReaderView:drawPageView(bb, x, y)
 end
 
 function ReaderView:drawScrollView(bb, x, y)
-    self.ui.document:drawCurrentViewByPos(
+    self.document:drawCurrentViewByPos(
         bb,
         x + self.state.offset.x,
         y + self.state.offset.y,
@@ -467,7 +466,7 @@ function ReaderView:drawTempHighlight(bb, x, y)
 end
 
 function ReaderView:drawSavedHighlight(bb, x, y)
-    if self.ui.document.info.has_pages then
+    if self.ui.paging then
         self:drawPageSavedHighlight(bb, x, y)
     else
         self:drawXPointerSavedHighlight(bb, x, y)
@@ -482,7 +481,7 @@ function ReaderView:drawPageSavedHighlight(bb, x, y)
             for i = 1, #items do
                 local item = items[i]
                 local pos0, pos1 = item.pos0, item.pos1
-                local boxes = self.ui.document:getPageBoxesFromPositions(page, pos0, pos1)
+                local boxes = self.document:getPageBoxesFromPositions(page, pos0, pos1)
                 if boxes then
                     for _, box in pairs(boxes) do
                         local rect = self:pageToScreenTransform(page, box)
@@ -513,19 +512,19 @@ function ReaderView:drawXPointerSavedHighlight(bb, x, y)
                     -- Even in page mode, it's safer to use pos and ui.dimen.h
                     -- than pages' xpointers pos, even if ui.dimen.h is a bit
                     -- larger than pages' heights
-                    cur_view_top = self.ui.document:getCurrentPos()
+                    cur_view_top = self.document:getCurrentPos()
-                    if self.view_mode == "page" and self.ui.document:getVisiblePageCount() > 1 then
+                    if self.view_mode == "page" and self.document:getVisiblePageCount() > 1 then
                         cur_view_bottom = cur_view_top + 2 * self.ui.dimen.h
                     else
                         cur_view_bottom = cur_view_top + self.ui.dimen.h
                     end
                 end
-                local spos0 = self.ui.document:getPosFromXPointer(pos0)
+                local spos0 = self.document:getPosFromXPointer(pos0)
-                local spos1 = self.ui.document:getPosFromXPointer(pos1)
+                local spos1 = self.document:getPosFromXPointer(pos1)
                 local start_pos = math.min(spos0, spos1)
                 local end_pos = math.max(spos0, spos1)
                 if start_pos <= cur_view_bottom and end_pos >= cur_view_top then
-                    local boxes = self.ui.document:getScreenBoxesFromPositions(pos0, pos1, true) -- get_segments=true
+                    local boxes = self.document:getScreenBoxesFromPositions(pos0, pos1, true) -- get_segments=true
                     if boxes then
                         for _, box in pairs(boxes) do
                             local rect = self:pageToScreenTransform(page, box)
@@ -559,9 +558,9 @@ end
 
 function ReaderView:getPageArea(page, zoom, rotation)
     if self.use_bbox then
-        return self.ui.document:getUsedBBoxDimensions(page, zoom, rotation)
+        return self.document:getUsedBBoxDimensions(page, zoom, rotation)
     else
-        return self.ui.document:getPageDimensions(page, zoom, rotation)
+        return self.document:getPageDimensions(page, zoom, rotation)
     end
 end
 
@@ -572,17 +571,17 @@ function ReaderView:recalculate()
     -- Start by resetting the dithering flag early, so it doesn't carry over from the previous page.
     self.dialog.dithered = nil
 
-    if self.ui.document.info.has_pages and self.state.page then
+    if self.ui.paging and self.state.page then
         self.page_area = self:getPageArea(
             self.state.page,
             self.state.zoom,
             self.state.rotation)
         -- reset our size
         self.visible_area:setSizeTo(self.dimen)
-        if self.ui.view.footer_visible and not self.ui.view.footer.settings.reclaim_height then
+        if self.footer_visible and not self.footer.settings.reclaim_height then
-            self.visible_area.h = self.visible_area.h - self.ui.view.footer:getHeight()
+            self.visible_area.h = self.visible_area.h - self.footer:getHeight()
         end
-        if self.ui.document.configurable.writing_direction == 0 then
+        if self.document.configurable.writing_direction == 0 then
             -- starts from left of page_area
             self.visible_area.x = self.page_area.x
         else
@@ -609,8 +608,8 @@ function ReaderView:recalculate()
     end
     self.state.offset = Geom:new{x = 0, y = 0}
     if self.dimen.h > self.visible_area.h then
-        if self.ui.view.footer_visible and not self.ui.view.footer.settings.reclaim_height then
+        if self.footer_visible and not self.footer.settings.reclaim_height then
-            self.state.offset.y = (self.dimen.h - (self.visible_area.h + self.ui.view.footer:getHeight())) / 2
+            self.state.offset.y = (self.dimen.h - (self.visible_area.h + self.footer:getHeight())) / 2
         else
             self.state.offset.y = (self.dimen.h - self.visible_area.h) / 2
         end
@@ -740,9 +739,9 @@ function ReaderView:onSetFullScreen(full_screen)
 end
 
 function ReaderView:onSetScrollMode(page_scroll)
-    if self.ui.document.info.has_pages and page_scroll
+    if self.ui.paging and page_scroll
             and self.ui.zooming.paged_modes[self.zoom_mode]
-            and self.ui.document.configurable.text_wrap == 0 then
+            and self.document.configurable.text_wrap == 0 then
         UIManager:show(InfoMessage:new{
             text = _([[
 Continuous view (scroll mode) works best with zoom to page width, zoom to content width or zoom to rows.
@@ -754,7 +753,7 @@ In combination with zoom to fit page, page height, content height, content or co
 
     self.page_scroll = page_scroll
     if not page_scroll then
-        self.ui.document.configurable.page_scroll = 0
+        self.document.configurable.page_scroll = 0
     end
     self:recalculate()
     self.ui:handleEvent(Event:new("InitScrollPageStates"))
@@ -772,7 +771,7 @@ function ReaderView:onReadSettings(config)
             rotation_mode = config:readSetting("rotation_mode") -- Doc's
         else
             -- No doc specific rotation, pickup global defaults for the doc type
-            if self.ui.document.info.has_pages then
+            if self.ui.paging then
                 rotation_mode = G_reader_settings:readSetting("kopt_rotation_mode") or Screen.ORIENTATION_PORTRAIT
             else
                 rotation_mode = G_reader_settings:readSetting("copt_rotation_mode") or Screen.ORIENTATION_PORTRAIT
@@ -864,17 +863,17 @@ end
 
 function ReaderView:onReaderFooterVisibilityChange()
     -- Don't bother ReaderRolling with this nonsense, the footer's height is NOT handled via visible_area there ;)
-    if self.ui.document.info.has_pages and self.state.page then
+    if self.ui.paging and self.state.page then
         -- NOTE: Simply relying on recalculate would be a wee bit too much: it'd reset the in-page offsets,
         --       which would be wrong, and is also not necessary, since the footer is at the bottom of the screen ;).
         --       So, simply mangle visible_area's height ourselves...
-        if not self.ui.view.footer.settings.reclaim_height then
+        if not self.footer.settings.reclaim_height then
             -- NOTE: Yes, this means that toggling reclaim_height requires a page switch (for a proper recalculate).
             --       Thankfully, most of the time, the quirks are barely noticeable ;).
-            if self.ui.view.footer_visible then
+            if self.footer_visible then
-                self.visible_area.h = self.visible_area.h - self.ui.view.footer:getHeight()
+                self.visible_area.h = self.visible_area.h - self.footer:getHeight()
             else
-                self.visible_area.h = self.visible_area.h + self.ui.view.footer:getHeight()
+                self.visible_area.h = self.visible_area.h + self.footer:getHeight()
             end
         end
         self.ui:handleEvent(Event:new("ViewRecalculate", self.visible_area, self.page_area))
@@ -889,6 +888,33 @@ function ReaderView:onGammaUpdate(gamma)
     Notification:notify(T(_("Font gamma set to: %1."), gamma))
 end
 
+-- For ReaderKOptListener
+function ReaderView:onDitheringUpdate()
+    -- Do the device cap checks again, to avoid snafus when sharing configs between devices
+    if Device:hasEinkScreen() then
+        if Device:canHWDither() then
+            if self.document.configurable.hw_dithering then
+                self.document.hw_dithering = self.document.configurable.hw_dithering == 1
+            end
+        elseif Screen.fb_bpp == 8 then
+            if self.document.configurable.sw_dithering then
+                self.document.sw_dithering = self.document.configurable.sw_dithering == 1
+            end
+        end
+    end
+end
+
+-- For KOptOptions
+function ReaderView:onHWDitheringUpdate(toggle)
+    self.document.hw_dithering = toggle
+    Notification:notify(T(_("Hardware dithering set to: %1."), tostring(toggle)))
+end
+
+function ReaderView:onSWDitheringUpdate(toggle)
+    self.document.sw_dithering = toggle
+    Notification:notify(T(_("Software dithering set to: %1."), tostring(toggle)))
+end
+
 function ReaderView:onFontSizeUpdate(font_size)
     self.ui:handleEvent(Event:new("ReZoom", font_size))
     Notification:notify(T(_("Font zoom set to: %1."), font_size))
@@ -909,7 +935,7 @@ end
 function ReaderView:onSetViewMode(new_mode)
     if new_mode ~= self.view_mode then
         self.view_mode = new_mode
-        self.ui.document:setViewMode(new_mode)
+        self.document:setViewMode(new_mode)
         self.ui:handleEvent(Event:new("ChangeViewMode"))
         Notification:notify(T( _("View mode set to: %1"), optionsutil:getOptionText("SetViewMode", new_mode)))
     end
@@ -1006,7 +1032,7 @@ function ReaderView:checkAutoSaveSettings()
 end
 
 function ReaderView:isOverlapAllowed()
-    if self.ui.document.info.has_pages then
+    if self.ui.paging then
         return not self.page_scroll
             and (self.ui.paging.zoom_mode ~= "page"
                 or (self.ui.paging.zoom_mode == "page" and self.ui.paging.is_reflowed))

frontend/document/document.lua

@@ -75,9 +75,14 @@ function Document:_init()
         date = ""
     }
 
-    -- Should be updated by a call to Document.updateColorRendering(self)
+    -- Should be updated by a call to Document.updateColorRendering(self) in subclasses
-    -- in subclasses
     self.render_color = false
+
+    -- Those may be updated via KOptOptions, or the DitheringUpdate event.
+    -- Whether HW dithering is enabled
+    self.hw_dithering = false
+    -- Whether SW dithering is enabled
+    self.sw_dithering = false
 end
 
 -- override this method to open a document
@@ -496,9 +501,7 @@ Draw page content to blitbuffer.
 function Document:drawPage(target, x, y, rect, pageno, zoom, rotation, gamma, render_mode)
     local tile = self:renderPage(pageno, rect, zoom, rotation, gamma, render_mode)
     -- Enable SW dithering if requested (only available in koptoptions)
-    -- Much Like ReaderView, also enforce SW dithering in PicDocument if the device can't do HW dithering...
+    if self.sw_dithering then
-    if (self.is_pic and CanvasContext:hasEinkScreen() and not CanvasContext:canHWDither() and CanvasContext.fb_bpp == 8)
-    or (self.configurable.sw_dithering and self.configurable.sw_dithering == 1) then
         target:ditherblitFrom(tile.bb,
             x, y,
             rect.x - tile.excerpt.x,

frontend/document/picdocument.lua

@@ -26,6 +26,15 @@ function PicDocument:init()
     self.info.has_pages = true
     self.info.configurable = false
 
+    -- Enforce dithering in PicDocument
+    if CanvasContext:hasEinkScreen() then
+        if CanvasContext:canHWDither() then
+            self.hw_dithering = true
+        elseif CanvasContext.fb_bpp == 8 then
+            self.sw_dithering = true
+        end
+    end
+
     self:_readMetadata()
 end
 

frontend/ui/data/koptoptions.lua

@@ -502,6 +502,8 @@ This can also be used to remove some gray background or to convert a grayscale o
                 values = {0, 1},
                 default_value = 0,
                 advanced = true,
+                event = "HWDitheringUpdate",
+                args = {false, true},
                 show = Device:hasEinkScreen() and Device:canHWDither(),
                 name_text_hold_callback = optionsutil.showValues,
                 help_text = _([[Enable hardware dithering.]]),
@@ -513,6 +515,8 @@ This can also be used to remove some gray background or to convert a grayscale o
                 values = {0, 1},
                 default_value = 0,
                 advanced = true,
+                event = "SWDitheringUpdate",
+                args = {false, true},
                 show = Device:hasEinkScreen() and not Device:canHWDither() and Device.screen.fb_bpp == 8,
                 name_text_hold_callback = optionsutil.showValues,
                 help_text = _([[Enable software dithering.]]),