djvu: enable color rendering (#3361)

* djvu: enable color rendering

* Bump base

frontend/document/djvudocument.lua

@@ -1,3 +1,4 @@
+local Blitbuffer = require("ffi/blitbuffer")
 local Document = require("document/document")
 local DrawContext = require("ffi/drawcontext")
 local KoptOptions = require("ui/data/koptoptions")
@@ -10,7 +11,7 @@ local DjvuDocument = Document:new{
     dc_null = DrawContext.new(),
     options = KoptOptions,
     koptinterface = nil,
-    is_color_capable = false,
+    color_bb_type = Blitbuffer.TYPE_BBRGB24,
 }
 
 -- check DjVu magic string to validate
@@ -33,7 +34,7 @@ function DjvuDocument:init()
     end
 
     local ok
-    ok, self._document = pcall(djvu.openDocument, self.file, self.djvulibre_cache_size)
+    ok, self._document = pcall(djvu.openDocument, self.file, self.render_color, self.djvulibre_cache_size)
     if not ok then
         error(self._document)  -- will contain error message
     end
@@ -43,6 +44,13 @@ function DjvuDocument:init()
     self:_readMetadata()
 end
 
+function DjvuDocument:updateColorRendering()
+    Document.updateColorRendering(self) -- will set self.render_color
+    if self._document then
+        self._document:setColorRendering(self.render_color)
+    end
+end
+
 function DjvuDocument:getProps()
     local _, _, docname = self.file:find(".*/(.*)")
     docname = docname or self.file

frontend/document/document.lua

@@ -35,6 +35,8 @@ local Document = {
 
     -- whether this document can be rendered in color
     is_color_capable = true,
+    -- bb type needed by engine for color rendering
+    color_bb_type = Blitbuffer.TYPE_BBRGB32,
 
 }
 
@@ -337,7 +339,7 @@ function Document:renderPage(pageno, rect, zoom, rotation, gamma, render_mode)
         size = size.w * size.h + 64, -- estimation
         excerpt = size,
         pageno = pageno,
-        bb = Blitbuffer.new(size.w, size.h, self.render_color and Blitbuffer.TYPE_BBRGB32 or nil)
+        bb = Blitbuffer.new(size.w, size.h, self.render_color and self.color_bb_type or nil)
     }
 
     -- create a draw context