/* * Copyright 2006 The Android Open Source Project * * Use of this source code is governed by a BSD-style license that can be * found in the LICENSE file. */ #ifndef SkBlurMask_DEFINED #define SkBlurMask_DEFINED #include "include/core/SkBlurTypes.h" #include "include/core/SkRRect.h" #include "include/core/SkShader.h" #include "src/core/SkMask.h" class SkBlurMask { public: static bool SK_WARN_UNUSED_RESULT BlurRect(SkScalar sigma, SkMask *dst, const SkRect &src, SkBlurStyle, SkIPoint *margin = nullptr, SkMask::CreateMode createMode = SkMask::kComputeBoundsAndRenderImage_CreateMode); static bool SK_WARN_UNUSED_RESULT BlurRRect(SkScalar sigma, SkMask *dst, const SkRRect &src, SkBlurStyle, SkIPoint *margin = nullptr, SkMask::CreateMode createMode = SkMask::kComputeBoundsAndRenderImage_CreateMode); // forceQuality will prevent BoxBlur from falling back to the low quality approach when sigma // is very small -- this can be used predict the margin bump ahead of time without completely // replicating the internal logic. This permits not only simpler caching of blurred results, // but also being able to predict precisely at what pixels the blurred profile of e.g. a // rectangle will lie. // // Calling details: // * calculate margin - if src.fImage is null, then this call only calculates the border. // * failure - if src.fImage is not null, failure is signal with dst->fImage being // null. static bool SK_WARN_UNUSED_RESULT BoxBlur(SkMask* dst, const SkMask& src, SkScalar sigma, SkBlurStyle style, SkIPoint* margin = nullptr); // the "ground truth" blur does a gaussian convolution; it's slow // but useful for comparison purposes. static bool SK_WARN_UNUSED_RESULT BlurGroundTruth(SkScalar sigma, SkMask* dst, const SkMask& src, SkBlurStyle, SkIPoint* margin = nullptr); // If radius > 0, return the corresponding sigma, else return 0 static SkScalar SK_API ConvertRadiusToSigma(SkScalar radius); // If sigma > 0.5, return the corresponding radius, else return 0 static SkScalar SK_API ConvertSigmaToRadius(SkScalar sigma); /* Helper functions for analytic rectangle blurs */ /** Look up the intensity of the (one dimnensional) blurred half-plane. @param profile The precomputed 1D blur profile; initialized by ComputeBlurProfile below. @param loc the location to look up; The lookup will clamp invalid inputs, but meaningful data are available between 0 and blurred_width @param blurred_width The width of the final, blurred rectangle @param sharp_width The width of the original, unblurred rectangle. */ static uint8_t ProfileLookup(const uint8_t* profile, int loc, int blurredWidth, int sharpWidth); /** Populate the profile of a 1D blurred halfplane. @param profile The 1D table to fill in @param size Should be 6*sigma bytes @param sigma The standard deviation of the gaussian blur kernel */ static void ComputeBlurProfile(uint8_t* profile, int size, SkScalar sigma); /** Compute an entire scanline of a blurred step function. This is a 1D helper that will produce both the horizontal and vertical profiles of the blurry rectangle. @param pixels Location to store the resulting pixel data; allocated and managed by caller @param profile Precomputed blur profile computed by ComputeBlurProfile above. @param width Size of the pixels array. @param sigma Standard deviation of the gaussian blur kernel used to compute the profile; this implicitly gives the size of the pixels array. */ static void ComputeBlurredScanline(uint8_t* pixels, const uint8_t* profile, unsigned int width, SkScalar sigma); }; #endif