blob: 4dce30d6166c4c8bf580af244a0ee19042d5af68 [file] [log] [blame]
/*
* Copyright 2023 Google LLC
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "include/core/SkMatrix.h"
#include "include/core/SkPaint.h"
#include "include/core/SkPath.h"
#include "include/core/SkPathEffect.h"
#include "include/core/SkPathTypes.h"
#include "include/core/SkPathUtils.h"
#include "include/core/SkPixmap.h"
#include "include/core/SkPoint.h"
#include "include/core/SkRRect.h"
#include "include/core/SkRect.h"
#include "include/core/SkScalar.h"
#include "include/core/SkStrokeRec.h"
#include "include/private/base/SkAssert.h"
#include "include/private/base/SkCPUTypes.h"
#include "include/private/base/SkDebug.h"
#include "include/private/base/SkFloatingPoint.h"
#include "include/private/base/SkTemplates.h"
#include "src/base/SkTLazy.h"
#include "src/base/SkZip.h"
#include "src/core/SkAutoBlitterChoose.h"
#include "src/core/SkBlendModePriv.h"
#include "src/core/SkBlitter_A8.h"
#include "src/core/SkDevice.h"
#include "src/core/SkDrawBase.h"
#include "src/core/SkDrawProcs.h"
#include "src/core/SkMask.h"
#include "src/core/SkMaskFilterBase.h"
#include "src/core/SkPathEffectBase.h"
#include "src/core/SkPathPriv.h"
#include "src/core/SkRasterClip.h"
#include "src/core/SkRectPriv.h"
#include "src/core/SkScan.h"
#include <algorithm>
#include <cstddef>
#include <optional>
class SkBitmap;
class SkBlitter;
class SkGlyph;
class SkMaskFilter;
using namespace skia_private;
///////////////////////////////////////////////////////////////////////////////
SkDrawBase::SkDrawBase() {}
bool SkDrawBase::computeConservativeLocalClipBounds(SkRect* localBounds) const {
if (fRC->isEmpty()) {
return false;
}
SkMatrix inverse;
if (!fCTM->invert(&inverse)) {
return false;
}
SkIRect devBounds = fRC->getBounds();
// outset to have slop for antialasing and hairlines
devBounds.outset(1, 1);
inverse.mapRect(localBounds, SkRect::Make(devBounds));
return true;
}
///////////////////////////////////////////////////////////////////////////////
void SkDrawBase::drawPaint(const SkPaint& paint) const {
SkDEBUGCODE(this->validate();)
if (fRC->isEmpty()) {
return;
}
SkIRect devRect;
devRect.setWH(fDst.width(), fDst.height());
SkAutoBlitterChoose blitter(*this, nullptr, paint);
SkScan::FillIRect(devRect, *fRC, blitter.get());
}
///////////////////////////////////////////////////////////////////////////////
static inline SkPoint compute_stroke_size(const SkPaint& paint, const SkMatrix& matrix) {
SkASSERT(matrix.rectStaysRect());
SkASSERT(SkPaint::kFill_Style != paint.getStyle());
SkVector size;
SkPoint pt = { paint.getStrokeWidth(), paint.getStrokeWidth() };
matrix.mapVectors(&size, &pt, 1);
return SkPoint::Make(SkScalarAbs(size.fX), SkScalarAbs(size.fY));
}
static bool easy_rect_join(const SkRect& rect, const SkPaint& paint, const SkMatrix& matrix,
SkPoint* strokeSize) {
if (rect.isEmpty() || SkPaint::kMiter_Join != paint.getStrokeJoin() ||
paint.getStrokeMiter() < SK_ScalarSqrt2) {
return false;
}
*strokeSize = compute_stroke_size(paint, matrix);
return true;
}
SkDrawBase::RectType SkDrawBase::ComputeRectType(const SkRect& rect,
const SkPaint& paint,
const SkMatrix& matrix,
SkPoint* strokeSize) {
RectType rtype;
const SkScalar width = paint.getStrokeWidth();
const bool zeroWidth = (0 == width);
SkPaint::Style style = paint.getStyle();
if ((SkPaint::kStrokeAndFill_Style == style) && zeroWidth) {
style = SkPaint::kFill_Style;
}
if (paint.getPathEffect() || paint.getMaskFilter() ||
!matrix.rectStaysRect() || SkPaint::kStrokeAndFill_Style == style) {
rtype = kPath_RectType;
} else if (SkPaint::kFill_Style == style) {
rtype = kFill_RectType;
} else if (zeroWidth) {
rtype = kHair_RectType;
} else if (easy_rect_join(rect, paint, matrix, strokeSize)) {
rtype = kStroke_RectType;
} else {
rtype = kPath_RectType;
}
return rtype;
}
static const SkPoint* rect_points(const SkRect& r) {
return reinterpret_cast<const SkPoint*>(&r);
}
static SkPoint* rect_points(SkRect& r) {
return reinterpret_cast<SkPoint*>(&r);
}
static void draw_rect_as_path(const SkDrawBase& orig,
const SkRect& prePaintRect,
const SkPaint& paint,
const SkMatrix& ctm) {
SkDrawBase draw(orig);
draw.fCTM = &ctm;
SkPath tmp;
tmp.addRect(prePaintRect);
tmp.setFillType(SkPathFillType::kWinding);
draw.drawPath(tmp, paint, nullptr, true);
}
void SkDrawBase::drawRect(const SkRect& prePaintRect, const SkPaint& paint,
const SkMatrix* paintMatrix, const SkRect* postPaintRect) const {
SkDEBUGCODE(this->validate();)
// nothing to draw
if (fRC->isEmpty()) {
return;
}
SkTCopyOnFirstWrite<SkMatrix> matrix(fCTM);
if (paintMatrix) {
SkASSERT(postPaintRect);
matrix.writable()->preConcat(*paintMatrix);
} else {
SkASSERT(!postPaintRect);
}
SkPoint strokeSize;
RectType rtype = ComputeRectType(prePaintRect, paint, *fCTM, &strokeSize);
if (kPath_RectType == rtype) {
draw_rect_as_path(*this, prePaintRect, paint, *matrix);
return;
}
SkRect devRect;
const SkRect& paintRect = paintMatrix ? *postPaintRect : prePaintRect;
// skip the paintMatrix when transforming the rect by the CTM
fCTM->mapPoints(rect_points(devRect), rect_points(paintRect), 2);
devRect.sort();
// look for the quick exit, before we build a blitter
SkRect bbox = devRect;
if (paint.getStyle() != SkPaint::kFill_Style) {
// extra space for hairlines
if (paint.getStrokeWidth() == 0) {
bbox.outset(1, 1);
} else {
// For kStroke_RectType, strokeSize is already computed.
const SkPoint& ssize = (kStroke_RectType == rtype)
? strokeSize
: compute_stroke_size(paint, *fCTM);
bbox.outset(SkScalarHalf(ssize.x()), SkScalarHalf(ssize.y()));
}
}
if (SkPathPriv::TooBigForMath(bbox)) {
return;
}
if (!SkRectPriv::FitsInFixed(bbox) && rtype != kHair_RectType) {
draw_rect_as_path(*this, prePaintRect, paint, *matrix);
return;
}
SkIRect ir = bbox.roundOut();
if (fRC->quickReject(ir)) {
return;
}
SkAutoBlitterChoose blitterStorage(*this, matrix, paint);
const SkRasterClip& clip = *fRC;
SkBlitter* blitter = blitterStorage.get();
// we want to "fill" if we are kFill or kStrokeAndFill, since in the latter
// case we are also hairline (if we've gotten to here), which devolves to
// effectively just kFill
switch (rtype) {
case kFill_RectType:
if (paint.isAntiAlias()) {
SkScan::AntiFillRect(devRect, clip, blitter);
} else {
SkScan::FillRect(devRect, clip, blitter);
}
break;
case kStroke_RectType:
if (paint.isAntiAlias()) {
SkScan::AntiFrameRect(devRect, strokeSize, clip, blitter);
} else {
SkScan::FrameRect(devRect, strokeSize, clip, blitter);
}
break;
case kHair_RectType:
if (paint.isAntiAlias()) {
SkScan::AntiHairRect(devRect, clip, blitter);
} else {
SkScan::HairRect(devRect, clip, blitter);
}
break;
default:
SkDEBUGFAIL("bad rtype");
}
}
static SkScalar fast_len(const SkVector& vec) {
SkScalar x = SkScalarAbs(vec.fX);
SkScalar y = SkScalarAbs(vec.fY);
if (x < y) {
using std::swap;
swap(x, y);
}
return x + SkScalarHalf(y);
}
bool SkDrawTreatAAStrokeAsHairline(SkScalar strokeWidth, const SkMatrix& matrix,
SkScalar* coverage) {
SkASSERT(strokeWidth > 0);
// We need to try to fake a thick-stroke with a modulated hairline.
if (matrix.hasPerspective()) {
return false;
}
SkVector src[2], dst[2];
src[0].set(strokeWidth, 0);
src[1].set(0, strokeWidth);
matrix.mapVectors(dst, src, 2);
SkScalar len0 = fast_len(dst[0]);
SkScalar len1 = fast_len(dst[1]);
if (len0 <= SK_Scalar1 && len1 <= SK_Scalar1) {
if (coverage) {
*coverage = SkScalarAve(len0, len1);
}
return true;
}
return false;
}
void SkDrawBase::drawRRect(const SkRRect& rrect, const SkPaint& paint) const {
SkDEBUGCODE(this->validate());
if (fRC->isEmpty()) {
return;
}
{
// TODO: Investigate optimizing these options. They are in the same
// order as SkDrawBase::drawPath, which handles each case. It may be
// that there is no way to optimize for these using the SkRRect path.
SkScalar coverage;
if (SkDrawTreatAsHairline(paint, *fCTM, &coverage)) {
goto DRAW_PATH;
}
if (paint.getPathEffect() || paint.getStyle() != SkPaint::kFill_Style) {
goto DRAW_PATH;
}
}
if (paint.getMaskFilter()) {
// Transform the rrect into device space.
SkRRect devRRect;
if (rrect.transform(*fCTM, &devRRect)) {
SkAutoBlitterChoose blitter(*this, nullptr, paint);
if (as_MFB(paint.getMaskFilter())->filterRRect(devRRect, *fCTM, *fRC, blitter.get())) {
return; // filterRRect() called the blitter, so we're done
}
}
}
DRAW_PATH:
// Now fall back to the default case of using a path.
SkPath path;
path.addRRect(rrect);
this->drawPath(path, paint, nullptr, true);
}
void SkDrawBase::drawDevPath(const SkPath& devPath, const SkPaint& paint, bool drawCoverage,
SkBlitter* customBlitter, bool doFill) const {
if (SkPathPriv::TooBigForMath(devPath)) {
return;
}
SkBlitter* blitter = nullptr;
SkAutoBlitterChoose blitterStorage;
if (nullptr == customBlitter) {
blitter = blitterStorage.choose(*this, nullptr, paint, drawCoverage);
} else {
blitter = customBlitter;
}
if (paint.getMaskFilter()) {
SkStrokeRec::InitStyle style = doFill ? SkStrokeRec::kFill_InitStyle
: SkStrokeRec::kHairline_InitStyle;
if (as_MFB(paint.getMaskFilter())->filterPath(devPath, *fCTM, *fRC, blitter, style)) {
return; // filterPath() called the blitter, so we're done
}
}
void (*proc)(const SkPath&, const SkRasterClip&, SkBlitter*);
if (doFill) {
if (paint.isAntiAlias()) {
proc = SkScan::AntiFillPath;
} else {
proc = SkScan::FillPath;
}
} else { // hairline
if (paint.isAntiAlias()) {
switch (paint.getStrokeCap()) {
case SkPaint::kButt_Cap:
proc = SkScan::AntiHairPath;
break;
case SkPaint::kSquare_Cap:
proc = SkScan::AntiHairSquarePath;
break;
case SkPaint::kRound_Cap:
proc = SkScan::AntiHairRoundPath;
break;
}
} else {
switch (paint.getStrokeCap()) {
case SkPaint::kButt_Cap:
proc = SkScan::HairPath;
break;
case SkPaint::kSquare_Cap:
proc = SkScan::HairSquarePath;
break;
case SkPaint::kRound_Cap:
proc = SkScan::HairRoundPath;
break;
}
}
}
proc(devPath, *fRC, blitter);
}
void SkDrawBase::drawPath(const SkPath& origSrcPath, const SkPaint& origPaint,
const SkMatrix* prePathMatrix, bool pathIsMutable,
bool drawCoverage, SkBlitter* customBlitter) const {
SkDEBUGCODE(this->validate();)
// nothing to draw
if (fRC->isEmpty()) {
return;
}
SkPath* pathPtr = const_cast<SkPath*>(&origSrcPath);
bool doFill = true;
SkPath tmpPathStorage;
SkPath* tmpPath = &tmpPathStorage;
SkTCopyOnFirstWrite<SkMatrix> matrix(fCTM);
tmpPath->setIsVolatile(true);
if (prePathMatrix) {
if (origPaint.getPathEffect() || origPaint.getStyle() != SkPaint::kFill_Style) {
SkPath* result = pathPtr;
if (!pathIsMutable) {
result = tmpPath;
pathIsMutable = true;
}
pathPtr->transform(*prePathMatrix, result);
pathPtr = result;
} else {
matrix.writable()->preConcat(*prePathMatrix);
}
}
SkTCopyOnFirstWrite<SkPaint> paint(origPaint);
{
SkScalar coverage;
if (SkDrawTreatAsHairline(origPaint, *matrix, &coverage)) {
const auto bm = origPaint.asBlendMode();
if (SK_Scalar1 == coverage) {
paint.writable()->setStrokeWidth(0);
} else if (bm && SkBlendMode_SupportsCoverageAsAlpha(bm.value())) {
U8CPU newAlpha;
#if 0
newAlpha = SkToU8(SkScalarRoundToInt(coverage * origPaint.getAlpha()));
#else
// this is the old technique, which we preserve for now so
// we don't change previous results (testing)
// the new way seems fine, its just (a tiny bit) different
int scale = (int)(coverage * 256);
newAlpha = origPaint.getAlpha() * scale >> 8;
#endif
SkPaint* writablePaint = paint.writable();
writablePaint->setStrokeWidth(0);
writablePaint->setAlpha(newAlpha);
}
}
}
if (paint->getPathEffect() || paint->getStyle() != SkPaint::kFill_Style) {
SkRect cullRect;
const SkRect* cullRectPtr = nullptr;
if (this->computeConservativeLocalClipBounds(&cullRect)) {
cullRectPtr = &cullRect;
}
doFill = skpathutils::FillPathWithPaint(*pathPtr, *paint, tmpPath, cullRectPtr, *fCTM);
pathPtr = tmpPath;
}
// avoid possibly allocating a new path in transform if we can
SkPath* devPathPtr = pathIsMutable ? pathPtr : tmpPath;
// transform the path into device space
pathPtr->transform(*matrix, devPathPtr);
#if defined(SK_BUILD_FOR_FUZZER)
if (devPathPtr->countPoints() > 1000) {
return;
}
#endif
this->drawDevPath(*devPathPtr, *paint, drawCoverage, customBlitter, doFill);
}
void SkDrawBase::paintMasks(SkZip<const SkGlyph*, SkPoint>, const SkPaint&) const {
SkASSERT(false);
}
void SkDrawBase::drawBitmap(const SkBitmap&, const SkMatrix&, const SkRect*,
const SkSamplingOptions&, const SkPaint&) const {
SkASSERT(false);
}
////////////////////////////////////////////////////////////////////////////////////////////////
#ifdef SK_DEBUG
void SkDrawBase::validate() const {
SkASSERT(fCTM != nullptr);
SkASSERT(fRC != nullptr);
const SkIRect& cr = fRC->getBounds();
SkIRect br;
br.setWH(fDst.width(), fDst.height());
SkASSERT(cr.isEmpty() || br.contains(cr));
}
#endif
////////////////////////////////////////////////////////////////////////////////////////////////
bool SkDrawBase::ComputeMaskBounds(const SkRect& devPathBounds, const SkIRect& clipBounds,
const SkMaskFilter* filter, const SkMatrix* filterMatrix,
SkIRect* bounds) {
// init our bounds from the path
*bounds = devPathBounds.makeOutset(SK_ScalarHalf, SK_ScalarHalf).roundOut();
SkIPoint margin = SkIPoint::Make(0, 0);
if (filter) {
SkASSERT(filterMatrix);
SkMask srcM(nullptr, *bounds, 0, SkMask::kA8_Format);
SkMaskBuilder dstM;
if (!as_MFB(filter)->filterMask(&dstM, srcM, *filterMatrix, &margin)) {
return false;
}
}
// trim the bounds to reflect the clip (plus whatever slop the filter needs)
// Ugh. Guard against gigantic margins from wacky filters. Without this
// check we can request arbitrary amounts of slop beyond our visible
// clip, and bring down the renderer (at least on finite RAM machines
// like handsets, etc.). Need to balance this invented value between
// quality of large filters like blurs, and the corresponding memory
// requests.
static constexpr int kMaxMargin = 128;
if (!bounds->intersect(clipBounds.makeOutset(std::min(margin.fX, kMaxMargin),
std::min(margin.fY, kMaxMargin)))) {
return false;
}
return true;
}
static void draw_into_mask(const SkMask& mask, const SkPath& devPath,
SkStrokeRec::InitStyle style) {
SkDrawBase draw;
draw.fBlitterChooser = SkA8Blitter_Choose;
if (!draw.fDst.reset(mask)) {
return;
}
SkRasterClip clip;
SkMatrix matrix;
SkPaint paint;
clip.setRect(SkIRect::MakeWH(mask.fBounds.width(), mask.fBounds.height()));
matrix.setTranslate(-SkIntToScalar(mask.fBounds.fLeft),
-SkIntToScalar(mask.fBounds.fTop));
draw.fRC = &clip;
draw.fCTM = &matrix;
paint.setAntiAlias(true);
switch (style) {
case SkStrokeRec::kHairline_InitStyle:
SkASSERT(!paint.getStrokeWidth());
paint.setStyle(SkPaint::kStroke_Style);
break;
case SkStrokeRec::kFill_InitStyle:
SkASSERT(paint.getStyle() == SkPaint::kFill_Style);
break;
}
draw.drawPath(devPath, paint);
}
bool SkDrawBase::DrawToMask(const SkPath& devPath, const SkIRect& clipBounds,
const SkMaskFilter* filter, const SkMatrix* filterMatrix,
SkMaskBuilder* dst, SkMaskBuilder::CreateMode mode,
SkStrokeRec::InitStyle style) {
if (devPath.isEmpty()) {
return false;
}
if (SkMaskBuilder::kJustRenderImage_CreateMode != mode) {
// By using infinite bounds for inverse fills, ComputeMaskBounds is able to clip it to
// 'clipBounds' outset by whatever extra margin the mask filter requires.
static const SkRect kInverseBounds = { SK_ScalarNegativeInfinity, SK_ScalarNegativeInfinity,
SK_ScalarInfinity, SK_ScalarInfinity};
SkRect pathBounds = devPath.isInverseFillType() ? kInverseBounds
: devPath.getBounds();
if (!ComputeMaskBounds(pathBounds, clipBounds, filter,
filterMatrix, &dst->bounds()))
return false;
}
if (SkMaskBuilder::kComputeBoundsAndRenderImage_CreateMode == mode) {
dst->format() = SkMask::kA8_Format;
dst->rowBytes() = dst->fBounds.width();
size_t size = dst->computeImageSize();
if (0 == size) {
// we're too big to allocate the mask, abort
return false;
}
dst->image() = SkMaskBuilder::AllocImage(size, SkMaskBuilder::kZeroInit_Alloc);
}
if (SkMaskBuilder::kJustComputeBounds_CreateMode != mode) {
draw_into_mask(*dst, devPath, style);
}
return true;
}
void SkDrawBase::drawDevicePoints(SkCanvas::PointMode mode, size_t count,
const SkPoint pts[], const SkPaint& paint,
SkDevice* device) const {
// if we're in lines mode, force count to be even
if (SkCanvas::kLines_PointMode == mode) {
count &= ~(size_t)1;
}
SkASSERT(pts != nullptr);
SkDEBUGCODE(this->validate();)
// nothing to draw
if (!count || fRC->isEmpty()) {
return;
}
// needed?
if (!SkIsFinite(&pts[0].fX, count * 2)) {
return;
}
switch (mode) {
case SkCanvas::kPoints_PointMode: {
// temporarily mark the paint as filling.
SkPaint newPaint(paint);
newPaint.setStyle(SkPaint::kFill_Style);
SkScalar width = newPaint.getStrokeWidth();
SkScalar radius = SkScalarHalf(width);
if (newPaint.getStrokeCap() == SkPaint::kRound_Cap) {
if (device) {
for (size_t i = 0; i < count; ++i) {
SkRect r = SkRect::MakeLTRB(pts[i].fX - radius, pts[i].fY - radius,
pts[i].fX + radius, pts[i].fY + radius);
device->drawOval(r, newPaint);
}
} else {
SkPath path;
SkMatrix preMatrix;
path.addCircle(0, 0, radius);
for (size_t i = 0; i < count; i++) {
preMatrix.setTranslate(pts[i].fX, pts[i].fY);
// pass true for the last point, since we can modify
// then path then
path.setIsVolatile((count-1) == i);
this->drawPath(path, newPaint, &preMatrix, (count-1) == i);
}
}
} else {
SkRect r;
for (size_t i = 0; i < count; i++) {
r.fLeft = pts[i].fX - radius;
r.fTop = pts[i].fY - radius;
r.fRight = r.fLeft + width;
r.fBottom = r.fTop + width;
if (device) {
device->drawRect(r, newPaint);
} else {
this->drawRect(r, newPaint);
}
}
}
break;
}
case SkCanvas::kLines_PointMode:
if (2 == count && paint.getPathEffect()) {
// most likely a dashed line - see if it is one of the ones
// we can accelerate
SkStrokeRec stroke(paint);
SkPathEffectBase::PointData pointData;
SkPath path = SkPath::Line(pts[0], pts[1]);
SkRect cullRect = SkRect::Make(fRC->getBounds());
if (as_PEB(paint.getPathEffect())->asPoints(&pointData, path, stroke, *fCTM,
&cullRect)) {
// 'asPoints' managed to find some fast path
SkPaint newP(paint);
newP.setPathEffect(nullptr);
newP.setStyle(SkPaint::kFill_Style);
if (!pointData.fFirst.isEmpty()) {
if (device) {
device->drawPath(pointData.fFirst, newP);
} else {
this->drawPath(pointData.fFirst, newP);
}
}
if (!pointData.fLast.isEmpty()) {
if (device) {
device->drawPath(pointData.fLast, newP);
} else {
this->drawPath(pointData.fLast, newP);
}
}
if (pointData.fSize.fX == pointData.fSize.fY) {
// The rest of the dashed line can just be drawn as points
SkASSERT(pointData.fSize.fX == SkScalarHalf(newP.getStrokeWidth()));
if (SkPathEffectBase::PointData::kCircles_PointFlag & pointData.fFlags) {
newP.setStrokeCap(SkPaint::kRound_Cap);
} else {
newP.setStrokeCap(SkPaint::kButt_Cap);
}
if (device) {
device->drawPoints(SkCanvas::kPoints_PointMode,
pointData.fNumPoints,
pointData.fPoints,
newP);
} else {
this->drawDevicePoints(SkCanvas::kPoints_PointMode,
pointData.fNumPoints,
pointData.fPoints,
newP,
device);
}
break;
} else {
// The rest of the dashed line must be drawn as rects
SkASSERT(!(SkPathEffectBase::PointData::kCircles_PointFlag &
pointData.fFlags));
SkRect r;
for (int i = 0; i < pointData.fNumPoints; ++i) {
r.setLTRB(pointData.fPoints[i].fX - pointData.fSize.fX,
pointData.fPoints[i].fY - pointData.fSize.fY,
pointData.fPoints[i].fX + pointData.fSize.fX,
pointData.fPoints[i].fY + pointData.fSize.fY);
if (device) {
device->drawRect(r, newP);
} else {
this->drawRect(r, newP);
}
}
}
break;
}
}
[[fallthrough]]; // couldn't take fast path
case SkCanvas::kPolygon_PointMode: {
count -= 1;
SkPath path;
SkPaint p(paint);
p.setStyle(SkPaint::kStroke_Style);
size_t inc = (SkCanvas::kLines_PointMode == mode) ? 2 : 1;
path.setIsVolatile(true);
for (size_t i = 0; i < count; i += inc) {
path.moveTo(pts[i]);
path.lineTo(pts[i+1]);
if (device) {
device->drawPath(path, p, true);
} else {
this->drawPath(path, p, nullptr, true);
}
path.rewind();
}
break;
}
}
}