michael@0: 
michael@0: /*
michael@0:  * Copyright 2006 The Android Open Source Project
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: 
michael@0: 
michael@0: #ifndef SkBlurMask_DEFINED
michael@0: #define SkBlurMask_DEFINED
michael@0: 
michael@0: #include "SkShader.h"
michael@0: #include "SkMask.h"
michael@0: #include "SkRRect.h"
michael@0: 
michael@0: class SkBlurMask {
michael@0: public:
michael@0:     enum Style {
michael@0:         kNormal_Style,  //!< fuzzy inside and outside
michael@0:         kSolid_Style,   //!< solid inside, fuzzy outside
michael@0:         kOuter_Style,   //!< nothing inside, fuzzy outside
michael@0:         kInner_Style,   //!< fuzzy inside, nothing outside
michael@0: 
michael@0:         kStyleCount
michael@0:     };
michael@0: 
michael@0:     enum Quality {
michael@0:         kLow_Quality,   //!< box blur
michael@0:         kHigh_Quality   //!< three pass box blur (similar to gaussian)
michael@0:     };
michael@0: 
michael@0:     static bool BlurRect(SkScalar sigma, SkMask *dst, const SkRect &src,
michael@0:                          Style style,
michael@0:                          SkIPoint *margin = NULL,
michael@0:                          SkMask::CreateMode createMode =
michael@0:                                                 SkMask::kComputeBoundsAndRenderImage_CreateMode);
michael@0:     static bool BlurRRect(SkScalar sigma, SkMask *dst, const SkRRect &src,
michael@0:                          Style style,
michael@0:                          SkIPoint *margin = NULL,
michael@0:                          SkMask::CreateMode createMode =
michael@0:                                                 SkMask::kComputeBoundsAndRenderImage_CreateMode);
michael@0:     static bool BoxBlur(SkMask* dst, const SkMask& src,
michael@0:                         SkScalar sigma, Style style, Quality quality,
michael@0:                         SkIPoint* margin = NULL);
michael@0: 
michael@0:     // the "ground truth" blur does a gaussian convolution; it's slow
michael@0:     // but useful for comparison purposes.
michael@0:     static bool BlurGroundTruth(SkScalar sigma, SkMask* dst, const SkMask& src,
michael@0:                                 Style style,
michael@0:                                 SkIPoint* margin = NULL);
michael@0: 
michael@0:     static SkScalar ConvertRadiusToSigma(SkScalar radius);
michael@0: 
michael@0:     /* Helper functions for analytic rectangle blurs */
michael@0: 
michael@0:     /** Look up the intensity of the (one dimnensional) blurred half-plane.
michael@0:         @param profile The precomputed 1D blur profile; memory allocated by and managed by
michael@0:                        ComputeBlurProfile below.
michael@0:         @param loc the location to look up; The lookup will clamp invalid inputs, but
michael@0:                    meaningful data are available between 0 and blurred_width
michael@0:         @param blurred_width The width of the final, blurred rectangle
michael@0:         @param sharp_width The width of the original, unblurred rectangle.
michael@0:     */
michael@0:     static uint8_t ProfileLookup(const uint8_t* profile, int loc, int blurred_width, int sharp_width);
michael@0: 
michael@0:     /** Allocate memory for and populate the profile of a 1D blurred halfplane.  The caller
michael@0:         must free the memory.  The amount of memory allocated will be exactly 6*sigma bytes.
michael@0:         @param sigma The standard deviation of the gaussian blur kernel
michael@0:         @param profile_out The location to store the allocated profile curve
michael@0:     */
michael@0: 
michael@0:     static void ComputeBlurProfile(SkScalar sigma, uint8_t** profile_out);
michael@0: 
michael@0:     /** Compute an entire scanline of a blurred step function.  This is a 1D helper that
michael@0:         will produce both the horizontal and vertical profiles of the blurry rectangle.
michael@0:         @param pixels Location to store the resulting pixel data; allocated and managed by caller
michael@0:         @param profile Precomputed blur profile computed by ComputeBlurProfile above.
michael@0:         @param width Size of the pixels array.
michael@0:         @param sigma Standard deviation of the gaussian blur kernel used to compute the profile;
michael@0:                      this implicitly gives the size of the pixels array.
michael@0:     */
michael@0: 
michael@0:     static void ComputeBlurredScanline(uint8_t* pixels, const uint8_t* profile,
michael@0:                                        unsigned int width, SkScalar sigma);
michael@0: 
michael@0: 
michael@0: 
michael@0: };
michael@0: 
michael@0: #endif