chrome/browser/ui/libgtkui/gtk_util.h

// 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.

#ifndef CHROME_BROWSER_UI_LIBGTKUI_GTK_UTIL_H_
#define CHROME_BROWSER_UI_LIBGTKUI_GTK_UTIL_H_

#include <gtk/gtk.h>
#include <string>

#include "ui/native_theme/native_theme.h"

namespace aura {
class Window;
}

namespace base {
class CommandLine;
class Environment;
}

namespace color_utils {
struct HSL;
}

namespace ui {
class Accelerator;
}

namespace libgtkui {

// Default frame tints
extern const color_utils::HSL kDefaultTintFrameIncognito;
extern const color_utils::HSL kDefaultTintFrameIncognitoInactive;

extern const SkColor kInvalidColorIdColor;
extern const SkColor kURLTextColor;

// Generates the normal URL color, a green color used in unhighlighted URL
// text. It is a mix of |kURLTextColor| and the current text color.  Unlike the
// selected text color, it is more important to match the qualities of the
// foreground typeface color instead of taking the background into account.
SkColor NormalURLColor(SkColor foreground);

// Generates the selected URL color, a green color used on URL text in the
// currently highlighted entry in the autocomplete popup. It's a mix of
// |kURLTextColor|, the current text color, and the background color (the
// select highlight). It is more important to contrast with the background
// saturation than to look exactly like the foreground color.
SkColor SelectedURLColor(SkColor foreground, SkColor background);

void GtkInitFromCommandLine(const base::CommandLine& command_line);

// Returns the name of the ".desktop" file associated with our running process.
std::string GetDesktopName(base::Environment* env);

guint GetGdkKeyCodeForAccelerator(const ui::Accelerator& accelerator);

GdkModifierType GetGdkModifierForAccelerator(
    const ui::Accelerator& accelerator);

// Translates event flags into plaform independent event flags.
int EventFlagsFromGdkState(guint state);

// Style a GTK button as a BlueButton
void TurnButtonBlue(GtkWidget* button);

// Sets |dialog| as transient for |parent|, which will keep it on top and center
// it above |parent|. Do nothing if |parent| is nullptr.
void SetGtkTransientForAura(GtkWidget* dialog, aura::Window* parent);

// Gets the transient parent aura window for |dialog|.
aura::Window* GetAuraTransientParent(GtkWidget* dialog);

// Clears the transient parent for |dialog|.
void ClearAuraTransientParent(GtkWidget* dialog);

#if GTK_MAJOR_VERSION > 2
// These constants are defined in gtk/gtkenums.h in Gtk3.12 or later.
// They are added here as a convenience to avoid version checks, and
// can be removed once the sysroot is switched from Wheezy to Jessie.
#define GTK_STATE_FLAG_LINK static_cast<GtkStateFlags>(1 << 9)
#define GTK_STATE_FLAG_VISITED static_cast<GtkStateFlags>(1 << 10)
#define GTK_STATE_FLAG_CHECKED static_cast<GtkStateFlags>(1 << 11)

class CairoSurface {
 public:
  // Attaches a cairo surface to an SkBitmap so that GTK can render
  // into it.  |bitmap| must outlive this CairoSurface.
  explicit CairoSurface(SkBitmap& bitmap);

  // Creates a new cairo surface with the given size.  The memory for
  // this surface is deallocated when this CairoSurface is destroyed.
  explicit CairoSurface(const gfx::Size& size);

  ~CairoSurface();

  // Get the drawing context for GTK to use.
  cairo_t* cairo() { return cairo_; }

  // Returns the average of all pixels in the surface.  If |frame| is
  // true, the resulting alpha will be the average alpha, otherwise it
  // will be the max alpha across all pixels.
  SkColor GetAveragePixelValue(bool frame);

 private:
  cairo_surface_t* surface_;
  cairo_t* cairo_;
};

// Returns true iff the runtime version of Gtk used meets
// |major|.|minor|.|micro|.
bool GtkVersionCheck(int major, int minor = 0, int micro = 0);

// Similar in spirit to a std::unique_ptr.
template <typename T>
class ScopedGObject {
 public:
  explicit ScopedGObject(T* obj) : obj_(obj) {
    // Remove the floating reference from |obj_| if it has one.
    if (g_object_is_floating(obj_))
      g_object_ref_sink(obj_);
    DCHECK(G_OBJECT(obj_)->ref_count == 1);
  }

  ScopedGObject(const ScopedGObject<T>& other) = delete;

  ScopedGObject(ScopedGObject<T>&& other) : obj_(other.obj_) {
    other.obj_ = nullptr;
  }

  ~ScopedGObject() {
    if (obj_)
      Unref();
  }

  ScopedGObject<T>& operator=(const ScopedGObject<T>& other) = delete;

  ScopedGObject<T>& operator=(ScopedGObject<T>&& other) {
    g_object_unref(obj_);
    obj_ = other.obj_;
    other.obj_ = nullptr;
    return *this;
  }

  operator T*() { return obj_; }

 private:
  void Unref() { g_object_unref(obj_); }

  T* obj_;
};

template <>
inline void ScopedGObject<GtkStyleContext>::Unref() {
  // Versions of GTK earlier than 3.15.4 had a bug where a g_assert
  // would be triggered when trying to free a GtkStyleContext that had
  // a parent whose only reference was the child context in question.
  // This is a hack to work around that case.  See GTK commit
  // "gtkstylecontext: Don't try to emit a signal when finalizing".
  GtkStyleContext* context = obj_;
  while (context) {
    GtkStyleContext* parent = gtk_style_context_get_parent(context);
    if (parent && G_OBJECT(context)->ref_count == 1 &&
        !GtkVersionCheck(3, 15, 4)) {
      g_object_ref(parent);
      gtk_style_context_set_parent(context, nullptr);
      g_object_unref(context);
    } else {
      g_object_unref(context);
      return;
    }
    context = parent;
  }
}

typedef ScopedGObject<GtkStyleContext> ScopedStyleContext;
typedef ScopedGObject<GtkCssProvider> ScopedCssProvider;

// If |context| is nullptr, creates a new top-level style context
// specified by parsing |css_node|.  Otherwise, creates the child
// context with |context| as the parent.
ScopedStyleContext AppendCssNodeToStyleContext(GtkStyleContext* context,
                                               const std::string& css_node);

// Parses |css_selector| into a GtkStyleContext.  The format is a
// sequence of whitespace-separated objects.  Each object may have at
// most one object name at the beginning of the string, and any number
// of '.'-prefixed classes and ':'-prefixed pseudoclasses.  An example
// is "GtkButton.button.suggested-action:hover:active".  The caller
// must g_object_unref() the returned context.
ScopedStyleContext GetStyleContextFromCss(const char* css_selector);

SkColor GetFgColorFromStyleContext(GtkStyleContext* context);

// Overrides properties on |context| and all its parents with those
// provided by |css|.
void ApplyCssToContext(GtkStyleContext* context, const char* css);

// Get the 'color' property from the style context created by
// GetStyleContextFromCss(|css_selector|).
SkColor GetFgColor(const char* css_selector);

// Renders the backgrounds of all ancestors of |context|, then renders
// the background for |context| itself.
void RenderBackground(const gfx::Size& size,
                      cairo_t* cr,
                      GtkStyleContext* context);

// Renders a background from the style context created by
// GetStyleContextFromCss(|css_selector|) into a 24x24 bitmap and
// returns the average color.
SkColor GetBgColor(const char* css_selector);

// Renders the border from the style context created by
// GetStyleContextFromCss(|css_selector|) into a 24x24 bitmap and
// returns the average color.
SkColor GetBorderColor(const char* css_selector);

// On Gtk3.20 or later, behaves like GetBgColor.  Otherwise, returns
// the background-color property.
SkColor GetSelectionBgColor(const char* css_selector);

// Get the color of the GtkSeparator specified by |css_selector|.
SkColor GetSeparatorColor(const char* css_selector);
#endif

}  // namespace libgtkui

#endif  // CHROME_BROWSER_UI_LIBGTKUI_GTK_UTIL_H_