Implement Pango RenderText for Linux.

ui/gfx/gtk_util.h

Index: ui/gfx/gtk_util.h
===================================================================
--- ui/gfx/gtk_util.h	(revision 96870)
+++ ui/gfx/gtk_util.h	(working copy)
@@ -7,11 +7,13 @@
 #pragma once
 
 #include <glib-object.h>
+#include <pango/pango-layout.h>
 #include <stdint.h>
 
 #include <string>
 #include <vector>
 
+#include "base/i18n/rtl.h"
 #include "base/memory/scoped_ptr.h"
 #include "ui/base/ui_export.h"
 
@@ -26,6 +28,7 @@
 
 namespace gfx {
 
+class Font;
 class Rect;
 
 // Call gtk_init() using the argc and argv from command_line.
@@ -42,6 +45,17 @@
 UI_EXPORT void SubtractRectanglesFromRegion(GdkRegion* region,
                                             const std::vector<Rect>& cutouts);
 
+// Setup pango layout |layout|, including set layout text as |text|, font
+// description based on |font|, width as |width| in PANGO_SCALE for RTL lcoale,
+// and set up whether auto-detect directionality, alignment, ellipsis, word
+// wrapping, resolution etc.
+void SetupPangoLayout(PangoLayout* layout,

[msw, 2011/08/23 08:01:01]

Hmm, I didn't suspect that moving the declaration up here would require you to
move the definition from canvas_skia_linux.cc to gtk_util.cc. I think it's
generally bad to add functions to *_util files, can all this pango stuff live in
canvas_skia_linux.* or render_text_linux.*? I might be wrong here, please
confirm with oshima or someone else.

[xji, 2011/08/23 23:52:52]

Ah, I think I mis-interpreted your previous comments.
I thought you'd like move the definition into gtk_util.
I do not think it is a good idea either.

And it would be better to declare that in canvas_skia.h and still define that in
canvas_skia_linux.cc

+                      const string16& text,
+                      const gfx::Font& font,
+                      int width,
+                      base::i18n::TextDirection text_direction,
+                      int flags);
+
 // Creates and returns a PangoContext. The caller owns the context.
 PangoContext* GetPangoContext();
 
@@ -65,7 +79,6 @@
 // The caller is responsible for free()ing the data. If |stride| is 0, it's
 // assumed to be 4 * |width|.
 uint8_t* BGRAToRGBA(const uint8_t* pixels, int width, int height, int stride);
-

[msw, 2011/08/23 08:01:01]

replace this line. (I think the common/proper style includes it)

 }  // namespace gfx
 
 // It's not legal C++ to have a templatized typedefs, so we wrap it in a