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* 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 SkShader_DEFINED
#define SkShader_DEFINED
#include "include/core/SkColor.h"
#include "include/core/SkFlattenable.h"
#include "include/core/SkRefCnt.h"
#include "include/private/base/SkAPI.h"
class SkBlender;
class SkColorFilter;
class SkColorSpace;
class SkImage;
class SkMatrix;
enum class SkBlendMode;
enum class SkTileMode;
struct SkRect;
/** \class SkShader
* Shaders specify the source color(s) for what is being drawn. If a paint
* has no shader, then the paint's color is used. If the paint has a
* shader, then the shader's color(s) are use instead, but they are
* modulated by the paint's alpha. This makes it easy to create a shader
* once (e.g. bitmap tiling or gradient) and then change its transparency
* w/o having to modify the original shader... only the paint's alpha needs
* to be modified.
class SK_API SkShader : public SkFlattenable {
* Returns true if the shader is guaranteed to produce only opaque
* colors, subject to the SkPaint using the shader to apply an opaque
* alpha value. Subclasses should override this to allow some
* optimizations.
virtual bool isOpaque() const { return false; }
* Iff this shader is backed by a single SkImage, return its ptr (the caller must ref this
* if they want to keep it longer than the lifetime of the shader). If not, return nullptr.
SkImage* isAImage(SkMatrix* localMatrix, SkTileMode xy[2]) const;
bool isAImage() const {
return this->isAImage(nullptr, (SkTileMode*)nullptr) != nullptr;
// Methods to create combinations or variants of shaders
* Return a shader that will apply the specified localMatrix to this shader.
* The specified matrix will be applied before any matrix associated with this shader.
sk_sp<SkShader> makeWithLocalMatrix(const SkMatrix&) const;
* Create a new shader that produces the same colors as invoking this shader and then applying
* the colorfilter.
sk_sp<SkShader> makeWithColorFilter(sk_sp<SkColorFilter>) const;
* Return a shader that will compute this shader in a specific color space.
* By default, all shaders operate in the destination (surface) color space.
* The results of a shader are still always converted to the destination - this
* API has no impact on simple shaders or images. Primarily, it impacts shaders
* that perform mathematical operations, like Blend shaders, or runtime shaders.
sk_sp<SkShader> makeWithWorkingColorSpace(sk_sp<SkColorSpace>) const;
SkShader() = default;
friend class SkShaderBase;
using INHERITED = SkFlattenable;
namespace SkShaders {
SK_API sk_sp<SkShader> Empty();
SK_API sk_sp<SkShader> Color(SkColor);
SK_API sk_sp<SkShader> Color(const SkColor4f&, sk_sp<SkColorSpace>);
SK_API sk_sp<SkShader> Blend(SkBlendMode mode, sk_sp<SkShader> dst, sk_sp<SkShader> src);
SK_API sk_sp<SkShader> Blend(sk_sp<SkBlender>, sk_sp<SkShader> dst, sk_sp<SkShader> src);
SK_API sk_sp<SkShader> CoordClamp(sk_sp<SkShader>, const SkRect& subset);