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// Copyright (c) 2011 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 SKIA_EXT_CANVAS_PAINT_WAYLAND_H_
#define SKIA_EXT_CANVAS_PAINT_WAYLAND_H_
#pragma once
#include "base/logging.h"
#include "skia/ext/canvas_paint_common.h"
#include "skia/ext/platform_canvas.h"
#include <cairo/cairo.h>
namespace skia {
// A class designed to translate skia painting into a region in a Wayland window
// surface. On construction, it will set up a context for painting into, and on
// destruction, it will commit it to the Wayland window surface.
// Note: The created context is always inialized to (0, 0, 0, 0).
template <class T>
class CanvasPaintT : public T {
public:
// This constructor assumes the result is opaque.
CanvasPaintT(cairo_surface_t* cairo_window_surface,
cairo_rectangle_t* region)
: context_(NULL),
cairo_window_surface_(cairo_window_surface),
region_(region),
composite_alpha_(false) {
init(true);
}
CanvasPaintT(cairo_surface_t* cairo_window_surface,
cairo_rectangle_t* region,
bool opaque)
: context_(NULL),
cairo_window_surface_(cairo_window_surface),
region_(region),
composite_alpha_(false) {
init(opaque);
}
virtual ~CanvasPaintT() {
if (!is_empty()) {
PlatformCanvas* canvas = GetPlatformCanvas(this);
canvas->restoreToCount(1);
// Blit the dirty rect to the window.
CHECK(cairo_window_surface_);
cairo_t* cr = cairo_create(cairo_window_surface_);
CHECK(cr);
if (composite_alpha_)
cairo_set_operator(cr, CAIRO_OPERATOR_SOURCE);
cairo_surface_t* source_surface = cairo_get_target(context_);
CHECK(source_surface);
// Flush cairo's cache of the surface.
cairo_surface_mark_dirty(source_surface);
cairo_set_source_surface(cr, source_surface, region_->x, region_->y);
cairo_rectangle(cr,
region_->x,
region_->y,
region_->width,
region_->height);
cairo_fill(cr);
cairo_destroy(cr);
}
}
// Sets whether the bitmap is composited in such a way that the alpha channel
// is honored. This is only useful if you've enabled an RGBA colormap on the
// widget. The default is false.
void set_composite_alpha(bool composite_alpha) {
composite_alpha_ = composite_alpha;
}
// Returns true if the invalid region is empty. The caller should call this
// function to determine if anything needs painting.
bool is_empty() const {
return region_->width == 0 && region_->height == 0;
}
private:
void init(bool opaque) {
PlatformCanvas* canvas = GetPlatformCanvas(this);
if (!canvas->initialize(region_->width, region_->height, opaque, NULL)) {
// Cause a deliberate crash;
CHECK(false);
}
// No need to clear the canvas, because cairo automatically performs the
// clear.
// Need to translate so that the dirty region appears at the origin of the
// surface.
canvas->translate(-SkDoubleToScalar(region_->x),
-SkDoubleToScalar(region_->y));
context_ = BeginPlatformPaint(canvas);
}
cairo_t* context_;
cairo_surface_t* cairo_window_surface_;
cairo_rectangle_t* region_;
// See description above setter.
bool composite_alpha_;
// Disallow copy and assign.
CanvasPaintT(const CanvasPaintT&);
CanvasPaintT& operator=(const CanvasPaintT&);
};
typedef CanvasPaintT<PlatformCanvas> PlatformCanvasPaint;
} // namespace skia
#endif // SKIA_EXT_CANVAS_PAINT_WAYLAND_H_
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