gtk_util.cc

// Copyright (c) 2010 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 "app/gtk_util.h"

#include <gtk/gtk.h>

#include "app/l10n_util.h"
#include "base/environment.h"
#include "base/logging.h"
#include "base/string_number_conversions.h"
#include "base/xdg_util.h"

namespace gtk_util {

void GetWidgetSizeFromResources(
    GtkWidget* widget, int width_chars, int height_lines,
    int* width, int* height) {
  DCHECK(GTK_WIDGET_REALIZED(widget))
      << " widget must be realized to compute font metrics correctly";

  double chars = 0;
  if (width)
    base::StringToDouble(l10n_util::GetStringUTF8(width_chars), &chars);

  double lines = 0;
  if (height)
    base::StringToDouble(l10n_util::GetStringUTF8(height_lines), &lines);

  GetWidgetSizeFromCharacters(widget, chars, lines, width, height);
}

uint8_t* BGRAToRGBA(const uint8_t* pixels, int width, int height, int stride) {
  if (stride == 0)
    stride = width * 4;

  uint8_t* new_pixels = static_cast<uint8_t*>(malloc(height * stride));

  // We have to copy the pixels and swap from BGRA to RGBA.
  for (int i = 0; i < height; ++i) {
    for (int j = 0; j < width; ++j) {
      int idx = i * stride + j * 4;
      new_pixels[idx] = pixels[idx + 2];
      new_pixels[idx + 1] = pixels[idx + 1];
      new_pixels[idx + 2] = pixels[idx];
      new_pixels[idx + 3] = pixels[idx + 3];
    }
  }

  return new_pixels;
}

void GetWidgetSizeFromCharacters(
    GtkWidget* widget, double width_chars, double height_lines,
    int* width, int* height) {
  DCHECK(GTK_WIDGET_REALIZED(widget))
      << " widget must be realized to compute font metrics correctly";
  PangoContext* context = gtk_widget_create_pango_context(widget);
  PangoFontMetrics* metrics = pango_context_get_metrics(context,
      widget->style->font_desc, pango_context_get_language(context));
  if (width) {
    *width = static_cast<int>(
        pango_font_metrics_get_approximate_char_width(metrics) *
        width_chars / PANGO_SCALE);
  }
  if (height) {
    *height = static_cast<int>(
        (pango_font_metrics_get_ascent(metrics) +
        pango_font_metrics_get_descent(metrics)) *
        height_lines / PANGO_SCALE);
  }
  pango_font_metrics_unref(metrics);
  g_object_unref(context);
}

int GetCharacterWidthForPixels(GtkWidget* widget, int pixel_width) {
  DCHECK(GTK_WIDGET_REALIZED(widget))
      << " widget must be realized to compute font metrics correctly";

  PangoContext* context = gtk_widget_create_pango_context(widget);
  PangoFontMetrics* metrics = pango_context_get_metrics(context,
      widget->style->font_desc, pango_context_get_language(context));

  // This technique (max of char and digit widths) matches the code in
  // gtklabel.c.
  int char_width = pixel_width * PANGO_SCALE /
      std::max(pango_font_metrics_get_approximate_char_width(metrics),
               pango_font_metrics_get_approximate_digit_width(metrics));

  pango_font_metrics_unref(metrics);
  g_object_unref(context);

  return char_width;
}

void ApplyMessageDialogQuirks(GtkWidget* dialog) {
  if (gtk_window_get_modal(GTK_WINDOW(dialog))) {
    // Work around a KDE 3 window manager bug.
    scoped_ptr<base::Environment> env(base::Environment::Create());
    if (base::DESKTOP_ENVIRONMENT_KDE3 == GetDesktopEnvironment(env.get()))
      gtk_window_set_skip_taskbar_hint(GTK_WINDOW(dialog), FALSE);
  }
}

}  // namespace gtk_util