blob: 35218f4e5a98dc3061007176909c3d004863d94c [file] [log] [blame]
/*
* Copyright 2018 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "src/core/SkGlyph.h"
#include "src/core/SkArenaAlloc.h"
#include "src/core/SkMakeUnique.h"
#include "src/core/SkScalerContext.h"
#include "src/pathops/SkPathOpsCubic.h"
#include "src/pathops/SkPathOpsQuad.h"
SkMask SkGlyph::mask() const {
// getMetrics had to be called.
SkASSERT(fMaskFormat != MASK_FORMAT_UNKNOWN);
SkMask mask;
mask.fImage = (uint8_t*)fImage;
mask.fBounds.setXYWH(fLeft, fTop, fWidth, fHeight);
mask.fRowBytes = this->rowBytes();
mask.fFormat = static_cast<SkMask::Format>(fMaskFormat);
return mask;
}
SkMask SkGlyph::mask(SkPoint position) const {
SkMask answer = this->mask();
answer.fBounds.offset(SkScalarFloorToInt(position.x()), SkScalarFloorToInt(position.y()));
return answer;
}
void SkGlyph::zeroMetrics() {
fAdvanceX = 0;
fAdvanceY = 0;
fWidth = 0;
fHeight = 0;
fTop = 0;
fLeft = 0;
}
static size_t bits_to_bytes(size_t bits) {
return (bits + 7) >> 3;
}
static size_t format_alignment(SkMask::Format format) {
switch (format) {
case SkMask::kBW_Format:
case SkMask::kA8_Format:
case SkMask::k3D_Format:
case SkMask::kSDF_Format:
return alignof(uint8_t);
case SkMask::kARGB32_Format:
return alignof(uint32_t);
case SkMask::kLCD16_Format:
return alignof(uint16_t);
default:
SK_ABORT("Unknown mask format.");
break;
}
return 0;
}
static size_t format_rowbytes(int width, SkMask::Format format) {
return format == SkMask::kBW_Format ? bits_to_bytes(width)
: width * format_alignment(format);
}
SkGlyph::SkGlyph(const SkGlyphPrototype& p)
: fWidth{p.width}
, fHeight{p.height}
, fTop{p.top}
, fLeft{p.left}
, fAdvanceX{p.advanceX}
, fAdvanceY{p.advanceY}
, fMaskFormat{(uint8_t)p.maskFormat}
, fForceBW{p.forceBW}
, fID{p.id}
{}
size_t SkGlyph::formatAlignment() const {
return format_alignment(this->maskFormat());
}
size_t SkGlyph::allocImage(SkArenaAlloc* alloc) {
SkASSERT(!this->isEmpty());
auto size = this->imageSize();
fImage = alloc->makeBytesAlignedTo(size, this->formatAlignment());
return size;
}
bool SkGlyph::setImage(SkArenaAlloc* alloc, SkScalerContext* scalerContext) {
if (!this->setImageHasBeenCalled()) {
// It used to be that getImage() could change the fMaskFormat. Extra checking to make
// sure there are no regressions.
SkDEBUGCODE(SkMask::Format oldFormat = this->maskFormat());
this->allocImage(alloc);
scalerContext->getImage(*this);
SkASSERT(oldFormat == this->maskFormat());
return true;
}
return false;
}
bool SkGlyph::setImage(SkArenaAlloc* alloc, const void* image) {
if (!this->setImageHasBeenCalled()) {
this->allocImage(alloc);
memcpy(fImage, image, this->imageSize());
return true;
}
return false;
}
bool SkGlyph::setMetricsAndImage(SkArenaAlloc* alloc, const SkGlyph& from) {
if (fImage == nullptr) {
fAdvanceX = from.fAdvanceX;
fAdvanceY = from.fAdvanceY;
fWidth = from.fWidth;
fHeight = from.fHeight;
fTop = from.fTop;
fLeft = from.fLeft;
fForceBW = from.fForceBW;
fMaskFormat = from.fMaskFormat;
return this->setImage(alloc, from.image());
}
return false;
}
size_t SkGlyph::rowBytes() const {
return format_rowbytes(fWidth, (SkMask::Format)fMaskFormat);
}
size_t SkGlyph::rowBytesUsingFormat(SkMask::Format format) const {
return format_rowbytes(fWidth, format);
}
size_t SkGlyph::imageSize() const {
if (this->isEmpty() || this->imageTooLarge()) { return 0; }
size_t size = this->rowBytes() * fHeight;
if (fMaskFormat == SkMask::k3D_Format) {
size *= 3;
}
return size;
}
void SkGlyph::installPath(SkArenaAlloc* alloc, const SkPath* path) {
SkASSERT(fPathData == nullptr);
SkASSERT(!this->setPathHasBeenCalled());
fPathData = alloc->make<SkGlyph::PathData>();
if (path != nullptr) {
fPathData->fPath = *path;
fPathData->fPath.updateBoundsCache();
fPathData->fPath.getGenerationID();
fPathData->fHasPath = true;
}
}
bool SkGlyph::setPath(SkArenaAlloc* alloc, SkScalerContext* scalerContext) {
if (!this->setPathHasBeenCalled()) {
SkPath path;
if (scalerContext->getPath(this->getPackedID(), &path)) {
this->installPath(alloc, &path);
} else {
this->installPath(alloc, nullptr);
}
return this->path() != nullptr;
}
return false;
}
bool SkGlyph::setPath(SkArenaAlloc* alloc, const SkPath* path) {
if (!this->setPathHasBeenCalled()) {
this->installPath(alloc, path);
return this->path() != nullptr;
}
return false;
}
const SkPath* SkGlyph::path() const {
// setPath must have been called previously.
SkASSERT(this->setPathHasBeenCalled());
if (fPathData->fHasPath) {
return &fPathData->fPath;
}
return nullptr;
}
static std::tuple<SkScalar, SkScalar> calculate_path_gap(
SkScalar topOffset, SkScalar bottomOffset, const SkPath& path) {
// Left and Right of an ever expanding gap around the path.
SkScalar left = SK_ScalarMax,
right = SK_ScalarMin;
auto expandGap = [&left, &right](SkScalar v) {
left = SkTMin(left, v);
right = SkTMax(right, v);
};
// Handle all the different verbs for the path.
SkPoint pts[4];
auto addLine = [&expandGap, &pts](SkScalar offset) {
SkScalar t = sk_ieee_float_divide(offset - pts[0].fY, pts[1].fY - pts[0].fY);
if (0 <= t && t < 1) { // this handles divide by zero above
expandGap(pts[0].fX + t * (pts[1].fX - pts[0].fX));
}
};
auto addQuad = [&expandGap, &pts](SkScalar offset) {
SkDQuad quad;
quad.set(pts);
double roots[2];
int count = quad.horizontalIntersect(offset, roots);
while (--count >= 0) {
expandGap(quad.ptAtT(roots[count]).asSkPoint().fX);
}
};
auto addCubic = [&expandGap, &pts](SkScalar offset) {
SkDCubic cubic;
cubic.set(pts);
double roots[3];
int count = cubic.horizontalIntersect(offset, roots);
while (--count >= 0) {
expandGap(cubic.ptAtT(roots[count]).asSkPoint().fX);
}
};
// Handle when a verb's points are in the gap between top and bottom.
auto addPts = [&expandGap, &pts, topOffset, bottomOffset](int ptCount) {
for (int i = 0; i < ptCount; ++i) {
if (topOffset < pts[i].fY && pts[i].fY < bottomOffset) {
expandGap(pts[i].fX);
}
}
};
SkPath::Iter iter(path, false);
SkPath::Verb verb;
while (SkPath::kDone_Verb != (verb = iter.next(pts))) {
switch (verb) {
case SkPath::kMove_Verb: {
break;
}
case SkPath::kLine_Verb: {
addLine(topOffset);
addLine(bottomOffset);
addPts(2);
break;
}
case SkPath::kQuad_Verb: {
SkScalar quadTop = SkTMin(SkTMin(pts[0].fY, pts[1].fY), pts[2].fY);
if (bottomOffset < quadTop) { break; }
SkScalar quadBottom = SkTMax(SkTMax(pts[0].fY, pts[1].fY), pts[2].fY);
if (topOffset > quadBottom) { break; }
addQuad(topOffset);
addQuad(bottomOffset);
addPts(3);
break;
}
case SkPath::kConic_Verb: {
SkASSERT(0); // no support for text composed of conics
break;
}
case SkPath::kCubic_Verb: {
SkScalar quadTop =
SkTMin(SkTMin(SkTMin(pts[0].fY, pts[1].fY), pts[2].fY), pts[3].fY);
if (bottomOffset < quadTop) { break; }
SkScalar quadBottom =
SkTMax(SkTMax(SkTMax(pts[0].fY, pts[1].fY), pts[2].fY), pts[3].fY);
if (topOffset > quadBottom) { break; }
addCubic(topOffset);
addCubic(bottomOffset);
addPts(4);
break;
}
case SkPath::kClose_Verb: {
break;
}
default: {
SkASSERT(0);
break;
}
}
}
return std::tie(left, right);
}
void SkGlyph::ensureIntercepts(const SkScalar* bounds, SkScalar scale, SkScalar xPos,
SkScalar* array, int* count, SkArenaAlloc* alloc) {
auto offsetResults = [scale, xPos](
const SkGlyph::Intercept* intercept,SkScalar* array, int* count) {
if (array) {
array += *count;
for (int index = 0; index < 2; index++) {
*array++ = intercept->fInterval[index] * scale + xPos;
}
}
*count += 2;
};
const SkGlyph::Intercept* match =
[this](const SkScalar bounds[2]) -> const SkGlyph::Intercept* {
if (!fPathData) {
return nullptr;
}
const SkGlyph::Intercept* intercept = fPathData->fIntercept;
while (intercept) {
if (bounds[0] == intercept->fBounds[0] && bounds[1] == intercept->fBounds[1]) {
return intercept;
}
intercept = intercept->fNext;
}
return nullptr;
}(bounds);
if (match) {
if (match->fInterval[0] < match->fInterval[1]) {
offsetResults(match, array, count);
}
return;
}
SkGlyph::Intercept* intercept = alloc->make<SkGlyph::Intercept>();
intercept->fNext = fPathData->fIntercept;
intercept->fBounds[0] = bounds[0];
intercept->fBounds[1] = bounds[1];
intercept->fInterval[0] = SK_ScalarMax;
intercept->fInterval[1] = SK_ScalarMin;
fPathData->fIntercept = intercept;
const SkPath* path = &(fPathData->fPath);
const SkRect& pathBounds = path->getBounds();
if (pathBounds.fBottom < bounds[0] || bounds[1] < pathBounds.fTop) {
return;
}
std::tie(intercept->fInterval[0], intercept->fInterval[1])
= calculate_path_gap(bounds[0], bounds[1], *path);
if (intercept->fInterval[0] >= intercept->fInterval[1]) {
intercept->fInterval[0] = SK_ScalarMax;
intercept->fInterval[1] = SK_ScalarMin;
return;
}
offsetResults(intercept, array, count);
}