blob: c919d4bc051842306914a4db5f44d9c60f478814 [file] [log] [blame]
* Copyright 2014 Google Inc.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
#ifndef SkCanvasPriv_DEFINED
#define SkCanvasPriv_DEFINED
#include "include/core/SkCanvas.h"
#include "include/core/SkPaint.h"
#include "include/core/SkScalar.h"
#include "include/private/base/SkDebug.h"
#include "include/private/base/SkNoncopyable.h"
#include <cstddef>
class SkDevice;
class SkImageFilter;
class SkMatrix;
class SkReadBuffer;
struct SkRect;
class SkWriteBuffer;
namespace skgpu::graphite {
class TextureProxy;
class SkAutoCanvasMatrixPaint : SkNoncopyable {
SkAutoCanvasMatrixPaint(SkCanvas*, const SkMatrix*, const SkPaint*, const SkRect& bounds);
SkCanvas* fCanvas;
int fSaveCount;
class SkCanvasPriv {
// The lattice has pointers directly into the readbuffer
static bool ReadLattice(SkReadBuffer&, SkCanvas::Lattice*);
static void WriteLattice(SkWriteBuffer&, const SkCanvas::Lattice&);
// return the byte-size of the lattice, even if the buffer is null
// storage must be 4-byte aligned
static size_t WriteLattice(void* storage, const SkCanvas::Lattice&);
static int SaveBehind(SkCanvas* canvas, const SkRect* subset) {
return canvas->only_axis_aligned_saveBehind(subset);
static void DrawBehind(SkCanvas* canvas, const SkPaint& paint) {
// Exposed for testing on non-Android framework builds
static void ResetClip(SkCanvas* canvas) {
static SkDevice* TopDevice(const SkCanvas* canvas) {
return canvas->topDevice();
// The experimental_DrawEdgeAAImageSet API accepts separate dstClips and preViewMatrices arrays,
// where entries refer into them, but no explicit size is provided. Given a set of entries,
// computes the minimum length for these arrays that would provide index access errors.
static void GetDstClipAndMatrixCounts(const SkCanvas::ImageSetEntry set[], int count,
int* totalDstClipCount, int* totalMatrixCount);
static SkCanvas::SaveLayerRec ScaledBackdropLayer(const SkRect* bounds,
const SkPaint* paint,
const SkImageFilter* backdrop,
SkScalar backdropScale,
SkCanvas::SaveLayerFlags saveLayerFlags,
SkCanvas::FilterSpan filters = {}) {
return SkCanvas::SaveLayerRec(
bounds, paint, backdrop, nullptr, backdropScale, saveLayerFlags, filters);
static SkScalar GetBackdropScaleFactor(const SkCanvas::SaveLayerRec& rec) {
return rec.fExperimentalBackdropScale;
static void SetBackdropScaleFactor(SkCanvas::SaveLayerRec* rec, SkScalar scale) {
rec->fExperimentalBackdropScale = scale;
// Attempts to convert an image filter to its equivalent color filter, which if possible,
// modifies the paint to compose the image filter's color filter into the paint's color filter
// slot.
// Returns true if the paint has been modified.
// Requires the paint to have an image filter and the copy-on-write be initialized.
static bool ImageToColorFilter(SkPaint*);
* This constant is trying to balance the speed of ref'ing a subpicture into a parent picture,
* against the playback cost of recursing into the subpicture to get at its actual ops.
* For now we pick a conservatively small value, though measurement (and other heuristics like
* the type of ops contained) may justify changing this value.
constexpr int kMaxPictureOpsToUnrollInsteadOfRef = 1;
* We implement ImageFilters and MaskFilters for a given draw by creating a layer, then applying
* the filter to the pixels of that layer (its backing surface/image), and then we call restore()
* to blend that layer to the main canvas.
* If the paint has neither an image filter nor a mask filter, there will be no layer and paint()
* returns the original without modification.
* NOTE: This works by assuming all sources of color and shading are represented by the SkPaint.
* Operations like drawImageRect must convert to an equivalent drawRect call if there's a mask
* filter, or otherwise ensure there are no mask filters (e.g. drawAtlas).
class AutoLayerForImageFilter {
// `rawBounds` is the original bounds of the primitive about to be drawn, unmodified by the
// paint. It's used to determine the size of the offscreen layer for filters.
// If null, the clip will be used instead.
// If `skipMaskFilterLayer` is true, any SkMaskFilter on `paint` will be left as-is and is
// assumed to be handled by the SkDevice that handles the draw.
// Draw functions should use layer->paint() instead of the passed-in paint.
AutoLayerForImageFilter(SkCanvas* canvas,
const SkPaint& paint,
const SkRect* rawBounds,
bool skipMaskFilterLayer);
AutoLayerForImageFilter(const AutoLayerForImageFilter&) = delete;
AutoLayerForImageFilter& operator=(const AutoLayerForImageFilter&) = delete;
AutoLayerForImageFilter& operator=(AutoLayerForImageFilter&&);
const SkPaint& paint() const { return fPaint; }
// This is public so that a canvas can attempt to specially handle mask filters, specifically
// for blurs, and then if the attempt fails fall back on a regular draw with the same autolayer.
void addMaskFilterLayer(const SkRect* drawBounds);
void addImageFilterLayer(const SkRect* drawBounds);
void addLayer(const SkPaint& restorePaint, const SkRect* drawBounds, bool coverageOnly);
SkPaint fPaint;
SkCanvas* fCanvas;
int fTempLayersForFilters;
SkDEBUGCODE(int fSaveCount;)