skia/ext/opacity_filter_canvas.h

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef SKIA_EXT_OPACITY_FILTER_CANVAS_H
   6 #define SKIA_EXT_OPACITY_FILTER_CANVAS_H
   7
   8 #include "third_party/skia/include/utils/SkPaintFilterCanvas.h"
   9
  10 namespace skia {
  11
  12 // This filter canvas allows setting an opacity on every draw call to a canvas,
  13 // and to disable image filtering. Note that the opacity setting is only
  14 // correct in very limited conditions: when there is only zero or one opaque,
  15 // nonlayer draw for every pixel in the surface.
  16 class SK_API OpacityFilterCanvas : public SkPaintFilterCanvas {
  17  public:
  18   OpacityFilterCanvas(SkCanvas* canvas,
  19                       float opacity,
  20                       bool disable_image_filtering);
  21
  22  protected:
  23   void onFilterPaint(SkPaint* paint, Type type) const override;
  24
  25   void onDrawPicture(const SkPicture* picture,
  26                      const SkMatrix* matrix,
  27                      const SkPaint* paint) override;
  28
  29  private:
  30   typedef SkPaintFilterCanvas INHERITED;
  31
  32   int alpha_;
  33   bool disable_image_filtering_;
  34 };
  35
  36 }  // namespace skia
  37
  38 #endif  // SKIA_EXT_OPACITY_FILTER_CANVAS_H