daaafa6e81
BUG=skia: R=djsollen@google.com, scroggo@google.com Review URL: https://codereview.chromium.org/253633003 git-svn-id: http://skia.googlecode.com/svn/trunk@14431 2bbb7eff-a529-9590-31e7-b0007b416f81
84 lines
3.8 KiB
C++
84 lines
3.8 KiB
C++
/*
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* Copyright 2006 The Android Open Source Project
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#ifndef SkBlurMask_DEFINED
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#define SkBlurMask_DEFINED
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#include "SkBlurTypes.h"
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#include "SkShader.h"
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#include "SkMask.h"
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#include "SkRRect.h"
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class SkBlurMask {
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public:
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static bool BlurRect(SkScalar sigma, SkMask *dst, const SkRect &src, SkBlurStyle,
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SkIPoint *margin = NULL,
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SkMask::CreateMode createMode =
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SkMask::kComputeBoundsAndRenderImage_CreateMode);
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static bool BlurRRect(SkScalar sigma, SkMask *dst, const SkRRect &src, SkBlurStyle,
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SkIPoint *margin = NULL,
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SkMask::CreateMode createMode =
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SkMask::kComputeBoundsAndRenderImage_CreateMode);
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// forceQuality will prevent BoxBlur from falling back to the low quality approach when sigma
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// is very small -- this can be used predict the margin bump ahead of time without completely
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// replicating the internal logic. This permits not only simpler caching of blurred results,
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// but also being able to predict precisely at what pixels the blurred profile of e.g. a
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// rectangle will lie.
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static bool BoxBlur(SkMask* dst, const SkMask& src,
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SkScalar sigma, SkBlurStyle style, SkBlurQuality quality,
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SkIPoint* margin = NULL, bool force_quality=false);
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// the "ground truth" blur does a gaussian convolution; it's slow
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// but useful for comparison purposes.
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static bool BlurGroundTruth(SkScalar sigma, SkMask* dst, const SkMask& src, SkBlurStyle,
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SkIPoint* margin = NULL);
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// If radius > 0, return the corresponding sigma, else return 0
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static SkScalar ConvertRadiusToSigma(SkScalar radius);
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// If sigma > 0.5, return the corresponding radius, else return 0
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static SkScalar ConvertSigmaToRadius(SkScalar sigma);
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/* Helper functions for analytic rectangle blurs */
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/** Look up the intensity of the (one dimnensional) blurred half-plane.
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@param profile The precomputed 1D blur profile; memory allocated by and managed by
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ComputeBlurProfile below.
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@param loc the location to look up; The lookup will clamp invalid inputs, but
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meaningful data are available between 0 and blurred_width
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@param blurred_width The width of the final, blurred rectangle
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@param sharp_width The width of the original, unblurred rectangle.
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*/
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static uint8_t ProfileLookup(const uint8_t* profile, int loc, int blurred_width, int sharp_width);
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/** Allocate memory for and populate the profile of a 1D blurred halfplane. The caller
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must free the memory. The amount of memory allocated will be exactly 6*sigma bytes.
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@param sigma The standard deviation of the gaussian blur kernel
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@param profile_out The location to store the allocated profile curve
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*/
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static void ComputeBlurProfile(SkScalar sigma, uint8_t** profile_out);
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/** Compute an entire scanline of a blurred step function. This is a 1D helper that
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will produce both the horizontal and vertical profiles of the blurry rectangle.
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@param pixels Location to store the resulting pixel data; allocated and managed by caller
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@param profile Precomputed blur profile computed by ComputeBlurProfile above.
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@param width Size of the pixels array.
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@param sigma Standard deviation of the gaussian blur kernel used to compute the profile;
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this implicitly gives the size of the pixels array.
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*/
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static void ComputeBlurredScanline(uint8_t* pixels, const uint8_t* profile,
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unsigned int width, SkScalar sigma);
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};
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#endif
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