src/gpu/SkGr.h

/*
 * Copyright 2017 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef SkGr_DEFINED
#define SkGr_DEFINED

#include "include/core/SkBlender.h"
#include "include/core/SkCanvas.h"
#include "include/core/SkColor.h"
#include "include/core/SkImageInfo.h"
#include "include/core/SkSamplingOptions.h"
#include "include/gpu/GrTypes.h"
#include "include/private/SkColorData.h"
#include "src/core/SkBlendModePriv.h"
#include "src/gpu/GrBlend.h"
#include "src/gpu/GrCaps.h"
#include "src/gpu/GrColor.h"
#include "src/gpu/GrSamplerState.h"

class GrCaps;
class GrColorInfo;
class GrColorSpaceXform;
class GrDirectContext;
class GrFragmentProcessor;
class GrPaint;
class GrRecordingContext;
class GrResourceProvider;
class GrTextureProxy;
class SkBitmap;
class SkData;
class SkMatrix;
class SkMatrixProvider;
class SkPaint;
class SkPixelRef;
class SkPixmap;
struct SkIRect;

namespace skgpu {
class UniqueKey;
}

////////////////////////////////////////////////////////////////////////////////
// Color type conversions

static inline GrColor SkColorToPremulGrColor(SkColor c) {
    SkPMColor pm = SkPreMultiplyColor(c);
    unsigned r = SkGetPackedR32(pm);
    unsigned g = SkGetPackedG32(pm);
    unsigned b = SkGetPackedB32(pm);
    unsigned a = SkGetPackedA32(pm);
    return GrColorPackRGBA(r, g, b, a);
}

static inline GrColor SkColorToUnpremulGrColor(SkColor c) {
    unsigned r = SkColorGetR(c);
    unsigned g = SkColorGetG(c);
    unsigned b = SkColorGetB(c);
    unsigned a = SkColorGetA(c);
    return GrColorPackRGBA(r, g, b, a);
}

/** Similar, but using SkPMColor4f. */
SkPMColor4f SkColorToPMColor4f(SkColor, const GrColorInfo&);

/** Converts an SkColor4f to the destination color space. */
SkColor4f SkColor4fPrepForDst(SkColor4f, const GrColorInfo&);

////////////////////////////////////////////////////////////////////////////////
// SkTileMode conversion

static constexpr GrSamplerState::WrapMode SkTileModeToWrapMode(SkTileMode tileMode) {
    switch (tileMode) {
        case SkTileMode::kClamp:  return GrSamplerState::WrapMode::kClamp;
        case SkTileMode::kDecal:  return GrSamplerState::WrapMode::kClampToBorder;
        case SkTileMode::kMirror: return GrSamplerState::WrapMode::kMirrorRepeat;
        case SkTileMode::kRepeat: return GrSamplerState::WrapMode::kRepeat;
    }
    SkUNREACHABLE;
}

////////////////////////////////////////////////////////////////////////////////
// Paint conversion

/** Converts an SkPaint to a GrPaint for a given GrRecordingContext. The matrix is required in order
    to convert the SkShader (if any) on the SkPaint. The primitive itself has no color. */
bool SkPaintToGrPaint(GrRecordingContext*,
                      const GrColorInfo& dstColorInfo,
                      const SkPaint& skPaint,
                      const SkMatrixProvider& matrixProvider,
                      GrPaint* grPaint);

/** Replaces the SkShader (if any) on skPaint with the passed in GrFragmentProcessor, if not null.
    If null then it is assumed that the geometry processor is implementing a shader replacement.
    The processor should expect an unpremul input color and produce a premultiplied output color. */
bool SkPaintToGrPaintReplaceShader(GrRecordingContext*,
                                   const GrColorInfo& dstColorInfo,
                                   const SkPaint& skPaint,
                                   const SkMatrixProvider& matrixProvider,
                                   std::unique_ptr<GrFragmentProcessor> shaderFP,
                                   GrPaint* grPaint);

/** Blends the SkPaint's shader (or color if no shader) with the color which specified via a
    GrOp's GrPrimitiveProcesssor. */
bool SkPaintToGrPaintWithBlend(GrRecordingContext* context,
                               const GrColorInfo& dstColorInfo,
                               const SkPaint& skPaint,
                               const SkMatrixProvider& matrixProvider,
                               SkBlender* primColorBlender,
                               GrPaint* grPaint);

////////////////////////////////////////////////////////////////////////////////
// Misc Sk to Gr type conversions

static_assert((int)kZero_GrBlendCoeff == (int)SkBlendModeCoeff::kZero);
static_assert((int)kOne_GrBlendCoeff == (int)SkBlendModeCoeff::kOne);
static_assert((int)kSC_GrBlendCoeff == (int)SkBlendModeCoeff::kSC);
static_assert((int)kISC_GrBlendCoeff == (int)SkBlendModeCoeff::kISC);
static_assert((int)kDC_GrBlendCoeff == (int)SkBlendModeCoeff::kDC);
static_assert((int)kIDC_GrBlendCoeff == (int)SkBlendModeCoeff::kIDC);
static_assert((int)kSA_GrBlendCoeff == (int)SkBlendModeCoeff::kSA);
static_assert((int)kISA_GrBlendCoeff == (int)SkBlendModeCoeff::kISA);
static_assert((int)kDA_GrBlendCoeff == (int)SkBlendModeCoeff::kDA);
static_assert((int)kIDA_GrBlendCoeff == (int)SkBlendModeCoeff::kIDA);
// static_assert(SkXfermode::kCoeffCount == 10);

////////////////////////////////////////////////////////////////////////////////
// Texture management

/**
 * Policies for how to create textures for SkImages (and SkBitmaps).
 */
enum class GrImageTexGenPolicy : int {
    // Choose the cheapest way to generate the texture. Use GrResourceCache if appropriate.
    kDraw,
    // Always make a new texture that is uncached and unbudgeted.
    kNew_Uncached_Unbudgeted,
    // Always make a new texture that is uncached and budgeted.
    kNew_Uncached_Budgeted
};

/**
 * Creates a new texture with mipmap levels and copies the baseProxy into the base layer.
 */
sk_sp<GrSurfaceProxy> GrCopyBaseMipMapToTextureProxy(GrRecordingContext*,
                                                     sk_sp<GrSurfaceProxy> baseProxy,
                                                     GrSurfaceOrigin origin,
                                                     SkBudgeted = SkBudgeted::kYes);
/**
 * Same as GrCopyBaseMipMapToTextureProxy but takes the src as a view and returns a view with same
 * origin and swizzle as the src view.
 */
GrSurfaceProxyView GrCopyBaseMipMapToView(GrRecordingContext*,
                                          GrSurfaceProxyView,
                                          SkBudgeted = SkBudgeted::kYes);

/*
 * Create a texture proxy from the provided bitmap and add it to the texture cache using the key
 * also extracted from the bitmap. If GrMipmapped is kYes a non-mipmapped result may be returned
 * if mipmapping isn't supported or for a 1x1 bitmap. If GrMipmapped is kNo it indicates mipmaps
 * aren't required but a previously created mipmapped texture may still be returned. A color type is
 * returned as color type conversion may be performed if there isn't a texture format equivalent of
 * the bitmap's color type.
 */
std::tuple<GrSurfaceProxyView, GrColorType>
GrMakeCachedBitmapProxyView(GrRecordingContext*,
                            const SkBitmap&,
                            GrMipmapped = GrMipmapped::kNo);

/**
 * Like above but always uploads the bitmap and never inserts into the cache. Unlike above, the
 * texture may be approx or scratch and budgeted or not.
 */
std::tuple<GrSurfaceProxyView, GrColorType>
GrMakeUncachedBitmapProxyView(GrRecordingContext*,
                              const SkBitmap&,
                              GrMipmapped = GrMipmapped::kNo,
                              SkBackingFit = SkBackingFit::kExact,
                              SkBudgeted = SkBudgeted::kYes);

/**
 *  Our key includes the offset, width, and height so that bitmaps created by extractSubset()
 *  are unique.
 *
 *  The imageID is in the shared namespace (see SkNextID::ImageID())
 *      - SkBitmap/SkPixelRef
 *      - SkImage
 *      - SkImageGenerator
 */
void GrMakeKeyFromImageID(skgpu::UniqueKey* key, uint32_t imageID, const SkIRect& imageBounds);

/**
 * Makes a SkIDChangeListener from a skgpu::UniqueKey. The key will be invalidated in the resource
 * cache if the ID becomes invalid. This also modifies the key so that it will cause the listener
 * to be deregistered if the key is destroyed (to prevent unbounded listener growth when resources
 * are purged before listeners trigger).
 */
sk_sp<SkIDChangeListener> GrMakeUniqueKeyInvalidationListener(skgpu::UniqueKey*,
                                                              uint32_t contextID);

static inline bool GrValidCubicResampler(SkCubicResampler cubic) {
    return cubic.B >= 0 && cubic.C >= 0;
}

#endif