Wayland support for views. views_desktop on Wayland.

skia/ext/canvas_paint_wayland.h

+// 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/platform_canvas.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.
+template <class T>
+class CanvasPaintT : public T {
+ public:
+  // This constructor assumes the result is opaque.
+  CanvasPaintT(cairo_surface_t* cairo_window_surface,
+               cairo_rectangle_int_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_int_t* region,
+               bool opaque)
+      : context_(NULL),
+        cairo_window_surface_(cairo_window_surface),
+        region_(region),
+        composite_alpha_(false) {
+    init(opaque);
+  }
+
+  virtual ~CanvasPaintT() {
+    if (!is_empty()) {
+      T::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) {
+    if (!T::initialize(region_->width, region_->height, opaque, NULL)) {
+      // Cause a deliberate crash;
+      CHECK(false);
+    }
+
+    // Need to translate so that the dirty region appears at the origin of the
+    // surface.
+    T::translate(-SkIntToScalar(region_->x), -SkIntToScalar(region_->y));
+
+    context_ = BeginPlatformPaint(this);
+  }
+
+  cairo_t* context_;
+  cairo_surface_t* cairo_window_surface_;
+  cairo_rectangle_int_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_