5a9a981edf
Expand the sweep gradient definition to include a color stop angular range ([0, 360] by default). Color stop positions in [0,1] are mapped to this range, and drawing outside is controlled by a tile mode param. This is closer to the CSS gradients spec and allows us to use fewer color stops in Blink conic gradients. Impl-wise, the remapping is effected after t calculation, and before tiling. Change-Id: I5d71be01d134404d6eb9d7e2a904ec636b39f855 Reviewed-on: https://skia-review.googlesource.com/27704 Commit-Queue: Florin Malita <fmalita@chromium.org> Reviewed-by: Brian Salomon <bsalomon@google.com> Reviewed-by: Mike Klein <mtklein@chromium.org>
230 lines
14 KiB
C++
230 lines
14 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 SkGradientShader_DEFINED
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#define SkGradientShader_DEFINED
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#include "SkShader.h"
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/** \class SkGradientShader
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SkGradientShader hosts factories for creating subclasses of SkShader that
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render linear and radial gradients.
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*/
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class SK_API SkGradientShader {
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public:
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enum Flags {
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/** By default gradients will interpolate their colors in unpremul space
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* and then premultiply each of the results. By setting this flag, the
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* gradients will premultiply their colors first, and then interpolate
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* between them.
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*/
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kInterpolateColorsInPremul_Flag = 1 << 0,
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};
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/** Returns a shader that generates a linear gradient between the two specified points.
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<p />
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@param pts The start and end points for the gradient.
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@param colors The array[count] of colors, to be distributed between the two points
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@param pos May be NULL. array[count] of SkScalars, or NULL, of the relative position of
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each corresponding color in the colors array. If this is NULL,
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the the colors are distributed evenly between the start and end point.
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If this is not null, the values must begin with 0, end with 1.0, and
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intermediate values must be strictly increasing.
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@param count Must be >=2. The number of colors (and pos if not NULL) entries.
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@param mode The tiling mode
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*/
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static sk_sp<SkShader> MakeLinear(const SkPoint pts[2],
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const SkColor colors[], const SkScalar pos[], int count,
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SkShader::TileMode mode,
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uint32_t flags, const SkMatrix* localMatrix);
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static sk_sp<SkShader> MakeLinear(const SkPoint pts[2],
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const SkColor colors[], const SkScalar pos[], int count,
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SkShader::TileMode mode) {
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return MakeLinear(pts, colors, pos, count, mode, 0, NULL);
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}
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/** Returns a shader that generates a linear gradient between the two specified points.
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<p />
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@param pts The start and end points for the gradient.
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@param colors The array[count] of colors, to be distributed between the two points
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@param pos May be NULL. array[count] of SkScalars, or NULL, of the relative position of
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each corresponding color in the colors array. If this is NULL,
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the the colors are distributed evenly between the start and end point.
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If this is not null, the values must begin with 0, end with 1.0, and
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intermediate values must be strictly increasing.
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@param count Must be >=2. The number of colors (and pos if not NULL) entries.
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@param mode The tiling mode
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*/
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static sk_sp<SkShader> MakeLinear(const SkPoint pts[2],
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const SkColor4f colors[], sk_sp<SkColorSpace> colorSpace,
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const SkScalar pos[], int count, SkShader::TileMode mode,
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uint32_t flags, const SkMatrix* localMatrix);
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static sk_sp<SkShader> MakeLinear(const SkPoint pts[2],
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const SkColor4f colors[], sk_sp<SkColorSpace> colorSpace,
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const SkScalar pos[], int count, SkShader::TileMode mode) {
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return MakeLinear(pts, colors, std::move(colorSpace), pos, count, mode, 0, NULL);
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}
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/** Returns a shader that generates a radial gradient given the center and radius.
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<p />
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@param center The center of the circle for this gradient
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@param radius Must be positive. The radius of the circle for this gradient
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@param colors The array[count] of colors, to be distributed between the center and edge of the circle
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@param pos May be NULL. The array[count] of SkScalars, or NULL, of the relative position of
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each corresponding color in the colors array. If this is NULL,
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the the colors are distributed evenly between the center and edge of the circle.
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If this is not null, the values must begin with 0, end with 1.0, and
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intermediate values must be strictly increasing.
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@param count Must be >= 2. The number of colors (and pos if not NULL) entries
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@param mode The tiling mode
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*/
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static sk_sp<SkShader> MakeRadial(const SkPoint& center, SkScalar radius,
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const SkColor colors[], const SkScalar pos[], int count,
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SkShader::TileMode mode,
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uint32_t flags, const SkMatrix* localMatrix);
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static sk_sp<SkShader> MakeRadial(const SkPoint& center, SkScalar radius,
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const SkColor colors[], const SkScalar pos[], int count,
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SkShader::TileMode mode) {
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return MakeRadial(center, radius, colors, pos, count, mode, 0, NULL);
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}
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/** Returns a shader that generates a radial gradient given the center and radius.
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<p />
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@param center The center of the circle for this gradient
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@param radius Must be positive. The radius of the circle for this gradient
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@param colors The array[count] of colors, to be distributed between the center and edge of the circle
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@param pos May be NULL. The array[count] of SkScalars, or NULL, of the relative position of
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each corresponding color in the colors array. If this is NULL,
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the the colors are distributed evenly between the center and edge of the circle.
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If this is not null, the values must begin with 0, end with 1.0, and
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intermediate values must be strictly increasing.
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@param count Must be >= 2. The number of colors (and pos if not NULL) entries
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@param mode The tiling mode
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*/
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static sk_sp<SkShader> MakeRadial(const SkPoint& center, SkScalar radius,
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const SkColor4f colors[], sk_sp<SkColorSpace> colorSpace,
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const SkScalar pos[], int count, SkShader::TileMode mode,
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uint32_t flags, const SkMatrix* localMatrix);
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static sk_sp<SkShader> MakeRadial(const SkPoint& center, SkScalar radius,
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const SkColor4f colors[], sk_sp<SkColorSpace> colorSpace,
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const SkScalar pos[], int count, SkShader::TileMode mode) {
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return MakeRadial(center, radius, colors, std::move(colorSpace), pos, count, mode, 0, NULL);
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}
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/**
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* Returns a shader that generates a conical gradient given two circles, or
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* returns NULL if the inputs are invalid. The gradient interprets the
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* two circles according to the following HTML spec.
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* http://dev.w3.org/html5/2dcontext/#dom-context-2d-createradialgradient
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*/
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static sk_sp<SkShader> MakeTwoPointConical(const SkPoint& start, SkScalar startRadius,
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const SkPoint& end, SkScalar endRadius,
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const SkColor colors[], const SkScalar pos[],
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int count, SkShader::TileMode mode,
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uint32_t flags, const SkMatrix* localMatrix);
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static sk_sp<SkShader> MakeTwoPointConical(const SkPoint& start, SkScalar startRadius,
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const SkPoint& end, SkScalar endRadius,
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const SkColor colors[], const SkScalar pos[],
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int count, SkShader::TileMode mode) {
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return MakeTwoPointConical(start, startRadius, end, endRadius, colors, pos, count, mode,
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0, NULL);
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}
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/**
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* Returns a shader that generates a conical gradient given two circles, or
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* returns NULL if the inputs are invalid. The gradient interprets the
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* two circles according to the following HTML spec.
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* http://dev.w3.org/html5/2dcontext/#dom-context-2d-createradialgradient
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*/
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static sk_sp<SkShader> MakeTwoPointConical(const SkPoint& start, SkScalar startRadius,
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const SkPoint& end, SkScalar endRadius,
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const SkColor4f colors[],
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sk_sp<SkColorSpace> colorSpace, const SkScalar pos[],
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int count, SkShader::TileMode mode,
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uint32_t flags, const SkMatrix* localMatrix);
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static sk_sp<SkShader> MakeTwoPointConical(const SkPoint& start, SkScalar startRadius,
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const SkPoint& end, SkScalar endRadius,
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const SkColor4f colors[],
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sk_sp<SkColorSpace> colorSpace, const SkScalar pos[],
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int count, SkShader::TileMode mode) {
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return MakeTwoPointConical(start, startRadius, end, endRadius, colors,
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std::move(colorSpace), pos, count, mode, 0, NULL);
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}
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/** Returns a shader that generates a sweep gradient given a center.
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<p />
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@param cx The X coordinate of the center of the sweep
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@param cx The Y coordinate of the center of the sweep
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@param colors The array[count] of colors, to be distributed around the center, within
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the gradient angle range.
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@param pos May be NULL. The array[count] of SkScalars, or NULL, of the relative
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position of each corresponding color in the colors array. If this is
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NULL, then the colors are distributed evenly within the angular range.
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If this is not null, the values must begin with 0, end with 1.0, and
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intermediate values must be strictly increasing.
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@param count Must be >= 2. The number of colors (and pos if not NULL) entries
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@param mode Tiling mode: controls drawing outside of the gradient angular range.
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@param startAngle Start of the angular range, corresponding to pos == 0.
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@param endAngle End of the angular range, corresponding to pos == 1.
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*/
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static sk_sp<SkShader> MakeSweep(SkScalar cx, SkScalar cy,
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const SkColor colors[], const SkScalar pos[], int count,
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SkShader::TileMode mode,
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SkScalar startAngle, SkScalar endAngle,
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uint32_t flags, const SkMatrix* localMatrix);
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static sk_sp<SkShader> MakeSweep(SkScalar cx, SkScalar cy,
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const SkColor colors[], const SkScalar pos[], int count,
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uint32_t flags, const SkMatrix* localMatrix) {
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return MakeSweep(cx, cy, colors, pos, count, SkShader::kClamp_TileMode, 0, 360, flags,
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localMatrix);
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}
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static sk_sp<SkShader> MakeSweep(SkScalar cx, SkScalar cy,
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const SkColor colors[], const SkScalar pos[], int count) {
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return MakeSweep(cx, cy, colors, pos, count, 0, nullptr);
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}
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/** Returns a shader that generates a sweep gradient given a center.
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<p />
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@param cx The X coordinate of the center of the sweep
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@param cx The Y coordinate of the center of the sweep
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@param colors The array[count] of colors, to be distributed around the center, within
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the gradient angle range.
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@param pos May be NULL. The array[count] of SkScalars, or NULL, of the relative
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position of each corresponding color in the colors array. If this is
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NULL, then the colors are distributed evenly within the angular range.
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If this is not null, the values must begin with 0, end with 1.0, and
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intermediate values must be strictly increasing.
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@param count Must be >= 2. The number of colors (and pos if not NULL) entries
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@param mode Tiling mode: controls drawing outside of the gradient angular range.
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@param startAngle Start of the angular range, corresponding to pos == 0.
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@param endAngle End of the angular range, corresponding to pos == 1.
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*/
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static sk_sp<SkShader> MakeSweep(SkScalar cx, SkScalar cy,
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const SkColor4f colors[], sk_sp<SkColorSpace> colorSpace,
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const SkScalar pos[], int count,
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SkShader::TileMode mode,
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SkScalar startAngle, SkScalar endAngle,
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uint32_t flags, const SkMatrix* localMatrix);
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static sk_sp<SkShader> MakeSweep(SkScalar cx, SkScalar cy,
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const SkColor4f colors[], sk_sp<SkColorSpace> colorSpace,
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const SkScalar pos[], int count,
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uint32_t flags, const SkMatrix* localMatrix) {
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return MakeSweep(cx, cy, colors, std::move(colorSpace), pos, count,
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SkShader::kClamp_TileMode, 0, 360, flags, localMatrix);
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}
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static sk_sp<SkShader> MakeSweep(SkScalar cx, SkScalar cy,
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const SkColor4f colors[], sk_sp<SkColorSpace> colorSpace,
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const SkScalar pos[], int count) {
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return MakeSweep(cx, cy, colors, std::move(colorSpace), pos, count, 0, nullptr);
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}
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SK_DECLARE_FLATTENABLE_REGISTRAR_GROUP()
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};
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#endif
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