Allow for colored rendering (#3276)

* Allow for colored rendering

Available with all engines (CRE, PDF, Images).
Needs to manually add setting: "color_rendering" = true

* Disable color for djvudocument

* Use Screen:isColorEnabled()

* Bump base

frontend/device/generic/device.lua

@@ -57,6 +57,11 @@ function Device:init()
         error("screen/framebuffer must be implemented")
     end
 
+    self.screen.isColorEnabled = function()
+        if G_reader_settings:has("color_rendering") then return G_reader_settings:isTrue("color_rendering") end
+        return self.screen.color
+    end
+
     local is_eink = G_reader_settings:readSetting("eink")
     self.screen.eink = (is_eink == nil) or is_eink
 

frontend/document/credocument.lua

@@ -239,10 +239,15 @@ function CreDocument:drawCurrentView(target, x, y, rect, pos)
         self.buffer:free()
         self.buffer = nil
     end
+    local color = Screen:isColorEnabled()
     if not self.buffer then
-        self.buffer = Blitbuffer.new(rect.w, rect.h)
+        -- If we use TYPE_BBRGB32 (and LVColorDrawBuf drawBuf(..., 32) in cre.cpp),
+        -- we get inverted Red and Blue in the blitbuffer (could be that
+        -- crengine/src/lvdrawbuf.cpp treats our 32bits not as RGBA).
+        -- But it is all fine if we use TYPE_BBRGB16.
+        self.buffer = Blitbuffer.new(rect.w, rect.h, color and Blitbuffer.TYPE_BBRGB16 or nil)
     end
-    self._document:drawCurrentPage(self.buffer)
+    self._document:drawCurrentPage(self.buffer, color)
     target:blitFrom(self.buffer, x, y, 0, 0, rect.w, rect.h)
 end
 

frontend/document/djvudocument.lua

@@ -1,6 +1,6 @@
-local KoptOptions = require("ui/data/koptoptions")
 local Document = require("document/document")
 local DrawContext = require("ffi/drawcontext")
+local KoptOptions = require("ui/data/koptoptions")
 
 local DjvuDocument = Document:new{
     _document = false,
@@ -10,6 +10,7 @@ local DjvuDocument = Document:new{
     dc_null = DrawContext.new(),
     options = KoptOptions,
     koptinterface = nil,
+    is_color_capable = false,
 }
 
 -- check DjVu magic string to validate

frontend/document/document.lua

@@ -1,12 +1,13 @@
-local TileCacheItem = require("document/tilecacheitem")
-local DrawContext = require("ffi/drawcontext")
-local Configurable = require("configurable")
 local Blitbuffer = require("ffi/blitbuffer")
-local lfs = require("libs/libkoreader-lfs")
+local Cache = require("cache")
 local CacheItem = require("cacheitem")
+local Configurable = require("configurable")
+local DrawContext = require("ffi/drawcontext")
 local Geom = require("ui/geometry")
 local Math = require("optmath")
-local Cache = require("cache")
+local Screen = require("device").screen
+local TileCacheItem = require("document/tilecacheitem")
+local lfs = require("libs/libkoreader-lfs")
 local logger = require("logger")
 
 --[[
@@ -31,6 +32,10 @@ local Document = {
 
     -- flag to show that the document is edited and needs to write back to disk
     is_edited = false,
+
+    -- whether this document can be rendered in color
+    is_color_capable = true,
+
 }
 
 function Document:new(from_o)
@@ -298,12 +303,16 @@ function Document:renderPage(pageno, rect, zoom, rotation, gamma, render_mode)
     end
 
     -- prepare cache item with contained blitbuffer
+    local bbtype = nil -- use Blitbuffer default greyscale type
+    if self.is_color_capable and Screen:isColorEnabled() then
+        bbtype = Blitbuffer.TYPE_BBRGB32
+    end
     tile = TileCacheItem:new{
         persistent = true,
         size = size.w * size.h + 64, -- estimation
         excerpt = size,
         pageno = pageno,
-        bb = Blitbuffer.new(size.w, size.h)
+        bb = Blitbuffer.new(size.w, size.h, bbtype)
     }
 
     -- create a draw context

frontend/document/pdfdocument.lua

@@ -1,8 +1,9 @@
 local Cache = require("cache")
 local CacheItem = require("cacheitem")
-local KoptOptions = require("ui/data/koptoptions")
 local Document = require("document/document")
 local DrawContext = require("ffi/drawcontext")
+local KoptOptions = require("ui/data/koptoptions")
+local Screen = require("device").screen
 local logger = require("logger")
 local util = require("util")
 
@@ -16,6 +17,7 @@ local PdfDocument = Document:new{
 
 function PdfDocument:init()
     local pdf = require("ffi/mupdf")
+    pdf.color = Screen:isColorEnabled()
     self.koptinterface = require("document/koptinterface")
     self.configurable:loadDefaults(self.options)
     local ok

frontend/document/picdocument.lua

@@ -1,5 +1,6 @@
 local Document = require("document/document")
 local DrawContext = require("ffi/drawcontext")
+local Screen = require("device").screen
 local pic = nil
 
 local PicDocument = Document:new{
@@ -10,6 +11,7 @@ local PicDocument = Document:new{
 
 function PicDocument:init()
     if not pic then pic = require("ffi/pic") end
+    pic.color = Screen:isColorEnabled()
     local ok
     ok, self._document = pcall(pic.openDocument, self.file)
     if not ok then