SkAlphaThresholdFilter.h revision 40eb3c100095c8573ddfdc553794b3182d7b18d1 
1/*
2 * Copyright 2013 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8#ifndef SkAlphaThresholdFilter_DEFINED
9#define SkAlphaThresholdFilter_DEFINED
10
11#include "SkRegion.h"
12#include "SkImageFilter.h"
13
14class SK_API SkAlphaThresholdFilter {
15public:
16    /**
17     * Creates an image filter that samples a region. If the sample is inside the
18     * region the alpha of the image is boosted up to a threshold value. If it is
19     * outside the region then the alpha is decreased to the threshold value.
20     * The 0,0 point of the region corresponds to the upper left corner of the
21     * source image.
22     */
23    static SkImageFilter* Create(const SkRegion& region, SkScalar innerThreshold, SkScalar outerThreshold);
24};
25
26#endif
27