ui/gfx/skia_utils_gtk.cc

// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "ui/gfx/skia_utils_gtk.h"

#include <gdk/gdk.h>

namespace gfx {

const int kSkiaToGDKMultiplier = 257;

// GDK_COLOR_RGB multiplies by 257 (= 0x10001) to distribute the bits evenly
// See: http://www.mindcontrol.org/~hplus/graphics/expand-bits.html
// To get back, we can just right shift by eight
// (or, formulated differently, i == (i*257)/256 for all i < 256).

SkColor GdkColorToSkColor(GdkColor color) {
  return SkColorSetRGB(color.red >> 8, color.green >> 8, color.blue >> 8);
}

GdkColor SkColorToGdkColor(SkColor color) {
  GdkColor gdk_color = {
      0,
      static_cast<guint16>(SkColorGetR(color) * kSkiaToGDKMultiplier),
      static_cast<guint16>(SkColorGetG(color) * kSkiaToGDKMultiplier),
      static_cast<guint16>(SkColorGetB(color) * kSkiaToGDKMultiplier)
  };
  return gdk_color;
}

}  // namespace gfx