// Copyright (c) 2009 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 "gfx/gtk_util.h"

#include <gdk/gdk.h>
#include <gtk/gtk.h>
#include <stdlib.h>

#include "base/basictypes.h"
#include "base/linux_util.h"
#include "gfx/rect.h"
#include "third_party/skia/include/core/SkBitmap.h"
#include "third_party/skia/include/core/SkUnPreMultiply.h"

namespace {

void FreePixels(guchar* pixels, gpointer data) {
  free(data);
}

}  // namespace

namespace gfx {

const GdkColor kGdkWhite = GDK_COLOR_RGB(0xff, 0xff, 0xff);
const GdkColor kGdkGray  = GDK_COLOR_RGB(0x7f, 0x7f, 0x7f);
const GdkColor kGdkBlack = GDK_COLOR_RGB(0x00, 0x00, 0x00);
const GdkColor kGdkGreen = GDK_COLOR_RGB(0x00, 0xff, 0x00);

GdkPixbuf* GdkPixbufFromSkBitmap(const SkBitmap* bitmap) {
  if (bitmap->isNull())
    return NULL;

  bitmap->lockPixels();

  int width = bitmap->width();
  int height = bitmap->height();
  int stride = bitmap->rowBytes();

  // SkBitmaps are premultiplied, we need to unpremultiply them.
  const int kBytesPerPixel = 4;
  uint8* divided = static_cast<uint8*>(malloc(height * stride));

  for (int y = 0, i = 0; y < height; y++) {
    for (int x = 0; x < width; x++) {
      uint32 pixel = bitmap->getAddr32(0, y)[x];

      int alpha = SkColorGetA(pixel);
      if (alpha != 0 && alpha != 255) {
        SkColor unmultiplied = SkUnPreMultiply::PMColorToColor(pixel);
        divided[i + 0] = SkColorGetR(unmultiplied);
        divided[i + 1] = SkColorGetG(unmultiplied);
        divided[i + 2] = SkColorGetB(unmultiplied);
        divided[i + 3] = alpha;
      } else {
        divided[i + 0] = SkColorGetR(pixel);
        divided[i + 1] = SkColorGetG(pixel);
        divided[i + 2] = SkColorGetB(pixel);
        divided[i + 3] = alpha;
      }
      i += kBytesPerPixel;
    }
  }

  // This pixbuf takes ownership of our malloc()ed data and will
  // free it for us when it is destroyed.
  GdkPixbuf* pixbuf = gdk_pixbuf_new_from_data(
      divided,
      GDK_COLORSPACE_RGB,  // The only colorspace gtk supports.
      true,  // There is an alpha channel.
      8,
      width, height, stride, &FreePixels, divided);

  bitmap->unlockPixels();
  return pixbuf;
}

void SubtractRectanglesFromRegion(GdkRegion* region,
                                  const std::vector<Rect>& cutouts) {
  for (size_t i = 0; i < cutouts.size(); ++i) {
    GdkRectangle rect = cutouts[i].ToGdkRectangle();
    GdkRegion* rect_region = gdk_region_rectangle(&rect);
    gdk_region_subtract(region, rect_region);
    // TODO(deanm): It would be nice to be able to reuse the GdkRegion here.
    gdk_region_destroy(rect_region);
  }
}

double GetPangoResolution() {
  static double resolution;
  static bool determined_resolution = false;
  if (!determined_resolution) {
    determined_resolution = true;
    PangoContext* default_context = gdk_pango_context_get();
    resolution = pango_cairo_context_get_resolution(default_context);
#if !defined(OS_CHROMEOS)
    // Until we switch to vector graphics, force the max DPI to 96.0.
    resolution = std::min(resolution, 96.);
#endif
    g_object_unref(default_context);
  }
  return resolution;
}

}  // namespace gfx