chrome/browser/ui/gtk/gtk_chrome_button.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 "chrome/browser/ui/gtk/gtk_chrome_button.h"

#include "base/basictypes.h"
#include "chrome/browser/ui/gtk/nine_box.h"
#include "grit/ui_resources.h"
#include "ui/gfx/gtk_util.h"

namespace {

// The theme graphics for when the mouse is over the button.
NineBox* g_nine_box_prelight;
// The theme graphics for when the button is clicked.
NineBox* g_nine_box_active;

}  // namespace

G_BEGIN_DECLS

#define GTK_CHROME_BUTTON_GET_PRIVATE(o) (G_TYPE_INSTANCE_GET_PRIVATE ((o),\
                                          GTK_TYPE_CHROME_BUTTON,\
                                          GtkChromeButtonPrivate))
typedef struct _GtkChromeButtonPrivate GtkChromeButtonPrivate;

struct _GtkChromeButtonPrivate {
  int paint_state;

  // If true, we use images provided by the theme instead of GTK's default
  // button rendering.
  gboolean use_gtk_rendering;

  gdouble hover_state;
};

G_DEFINE_TYPE(GtkChromeButton, gtk_chrome_button, GTK_TYPE_BUTTON)
static gboolean gtk_chrome_button_expose(GtkWidget* widget,
                                         GdkEventExpose* event);

static void gtk_chrome_button_class_init(GtkChromeButtonClass* button_class) {
  gtk_rc_parse_string(
      "style \"chrome-button\" {"
      "  xthickness = 2 "
      "  GtkButton::child-displacement-x = 0"
      "  GtkButton::child-displacement-y = 0"
      "  GtkButton::inner-border = { 0, 0, 0, 0 }"
      "}"
      "widget_class \"*.<GtkChromeButton>\" style \"chrome-button\"");

  GtkWidgetClass* widget_class =
      reinterpret_cast<GtkWidgetClass*>(button_class);
  widget_class->expose_event = gtk_chrome_button_expose;

  g_nine_box_prelight = new NineBox(
      IDR_TEXTBUTTON_HOVER_TOP_LEFT,
      IDR_TEXTBUTTON_HOVER_TOP,
      IDR_TEXTBUTTON_HOVER_TOP_RIGHT,
      IDR_TEXTBUTTON_HOVER_LEFT,
      IDR_TEXTBUTTON_HOVER_CENTER,
      IDR_TEXTBUTTON_HOVER_RIGHT,
      IDR_TEXTBUTTON_HOVER_BOTTOM_LEFT,
      IDR_TEXTBUTTON_HOVER_BOTTOM,
      IDR_TEXTBUTTON_HOVER_BOTTOM_RIGHT);

  g_nine_box_active = new NineBox(
      IDR_TEXTBUTTON_PRESSED_TOP_LEFT,
      IDR_TEXTBUTTON_PRESSED_TOP,
      IDR_TEXTBUTTON_PRESSED_TOP_RIGHT,
      IDR_TEXTBUTTON_PRESSED_LEFT,
      IDR_TEXTBUTTON_PRESSED_CENTER,
      IDR_TEXTBUTTON_PRESSED_RIGHT,
      IDR_TEXTBUTTON_PRESSED_BOTTOM_LEFT,
      IDR_TEXTBUTTON_PRESSED_BOTTOM,
      IDR_TEXTBUTTON_PRESSED_BOTTOM_RIGHT);

  GObjectClass* gobject_class = G_OBJECT_CLASS(button_class);
  g_type_class_add_private(gobject_class, sizeof(GtkChromeButtonPrivate));
}

static void gtk_chrome_button_init(GtkChromeButton* button) {
  GtkChromeButtonPrivate* priv = GTK_CHROME_BUTTON_GET_PRIVATE(button);
  priv->paint_state = -1;
  priv->use_gtk_rendering = FALSE;
  priv->hover_state = -1.0;

  gtk_widget_set_can_focus(GTK_WIDGET(button), FALSE);
}

static gboolean gtk_chrome_button_expose(GtkWidget* widget,
                                         GdkEventExpose* event) {
  GtkChromeButtonPrivate *priv = GTK_CHROME_BUTTON_GET_PRIVATE(widget);
  int paint_state = priv->paint_state < 0 ?
                    gtk_widget_get_state(widget) : priv->paint_state;

  if (priv->use_gtk_rendering) {
    // We have the superclass handle this expose when we aren't using custom
    // rendering AND we're in either the prelight or active state so that we
    // get the button border for the current GTK theme drawn.
    if (paint_state == GTK_STATE_PRELIGHT || paint_state == GTK_STATE_ACTIVE) {
      // Set the state of button->depressed so we paint pressed even if the
      // actual state of the button is something else.
      GTK_BUTTON(widget)->depressed = (paint_state == GTK_STATE_ACTIVE);
      return GTK_WIDGET_CLASS(gtk_chrome_button_parent_class)->expose_event
          (widget, event);
    }
  } else {
    double effective_hover_state = paint_state == GTK_STATE_PRELIGHT ?
                                   1.0 : 0.0;
    // |paint_state| overrides |hover_state|.
    if (priv->hover_state >= 0.0 && priv->paint_state < 0)
      effective_hover_state = priv->hover_state;

    if (paint_state == GTK_STATE_ACTIVE) {
      g_nine_box_active->RenderToWidget(widget);
    } else {
      g_nine_box_prelight->RenderToWidgetWithOpacity(widget,
                                                     effective_hover_state);
    }
  }

  // If we have a child widget, draw it.
  if (gtk_bin_get_child(GTK_BIN(widget))) {
    gtk_container_propagate_expose(GTK_CONTAINER(widget),
                                   gtk_bin_get_child(GTK_BIN(widget)),
                                   event);
  }

  return FALSE;
}

GtkWidget* gtk_chrome_button_new(void) {
  return GTK_WIDGET(g_object_new(GTK_TYPE_CHROME_BUTTON, NULL));
}

void gtk_chrome_button_set_paint_state(GtkChromeButton* button,
                                       GtkStateType state) {
  g_return_if_fail(GTK_IS_CHROME_BUTTON(button));

  GtkChromeButtonPrivate *priv = GTK_CHROME_BUTTON_GET_PRIVATE(button);
  priv->paint_state = state;

  gtk_widget_queue_draw(GTK_WIDGET(button));
}

void gtk_chrome_button_unset_paint_state(GtkChromeButton* button) {
  g_return_if_fail(GTK_IS_CHROME_BUTTON(button));

  GtkChromeButtonPrivate *priv = GTK_CHROME_BUTTON_GET_PRIVATE(button);
  priv->paint_state = -1;

  gtk_widget_queue_draw(GTK_WIDGET(button));
}

void gtk_chrome_button_set_use_gtk_rendering(GtkChromeButton* button,
                                             gboolean value) {
  g_return_if_fail(GTK_IS_CHROME_BUTTON(button));
  GtkChromeButtonPrivate *priv = GTK_CHROME_BUTTON_GET_PRIVATE(button);
  priv->use_gtk_rendering = value;
}

void gtk_chrome_button_set_hover_state(GtkChromeButton* button,
                                       gdouble state) {
  GtkChromeButtonPrivate* priv = GTK_CHROME_BUTTON_GET_PRIVATE(button);
  if (state >= 0.0 && state <= 1.0)
    priv->hover_state = state;
  else
    priv->hover_state = -1.0;
  gtk_widget_queue_draw(GTK_WIDGET(button));
}

G_END_DECLS