src/core/SkGpuBlurUtils.h

/*
 * Copyright 2013 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef SkGpuBlurUtils_DEFINED
#define SkGpuBlurUtils_DEFINED

#if SK_SUPPORT_GPU
#include "src/gpu/GrRenderTargetContext.h"

class GrContext;
class GrTexture;

struct SkRect;

namespace SkGpuBlurUtils {
/**
 * Applies a 2D Gaussian blur to a given texture. The blurred result is returned
 * as a renderTargetContext in case the caller wishes to draw into the result.
 * The GrSurfaceOrigin of the result will watch the GrSurfaceOrigin of srcView. The output
 * color type, color space, and alpha type will be the same as the src.
 *
 * Note: one of sigmaX and sigmaY should be non-zero!
 * @param context         The GPU context
 * @param srcView         The source to be blurred.
 * @param srcColorType    The colorType of srcProxy
 * @param srcAlphaType    The alphaType of srcProxy
 * @param colorSpace      Color space of the source.
 * @param dstBounds       The destination bounds, relative to the source texture.
 * @param srcBounds       The source bounds, relative to the source texture's offset. No pixels
 *                        will be sampled outside of this rectangle.
 * @param sigmaX          The blur's standard deviation in X.
 * @param sigmaY          The blur's standard deviation in Y.
 * @param tileMode        The mode to handle samples outside bounds.
 * @param fit             backing fit for the returned render target context
 * @return                The renderTargetContext containing the blurred result.
 */
std::unique_ptr<GrRenderTargetContext> GaussianBlur(GrRecordingContext* context,
                                                    GrSurfaceProxyView srcView,
                                                    GrColorType srcColorType,
                                                    SkAlphaType srcAlphaType,
                                                    sk_sp<SkColorSpace> colorSpace,
                                                    SkIRect dstBounds,
                                                    SkIRect srcBounds,
                                                    float sigmaX,
                                                    float sigmaY,
                                                    SkTileMode mode,
                                                    SkBackingFit fit = SkBackingFit::kApprox);
};

#endif
#endif