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skia / skia / eb8a53033e88618cd56bfa3ed1c5a381180d5296 / . / src / core / SkScalerContext.cpp
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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.
*/
#include "src/core/SkScalerContext.h"
#include "include/core/SkColorType.h"
#include "include/core/SkDrawable.h"
#include "include/core/SkFont.h"
#include "include/core/SkFontMetrics.h"
#include "include/core/SkImageInfo.h"
#include "include/core/SkMaskFilter.h"
#include "include/core/SkPaint.h"
#include "include/core/SkPath.h"
#include "include/core/SkPathEffect.h"
#include "include/core/SkPixmap.h"
#include "include/core/SkStrokeRec.h"
#include "include/private/SkColorData.h"
#include "include/private/base/SkAlign.h"
#include "include/private/base/SkCPUTypes.h"
#include "include/private/base/SkDebug.h"
#include "include/private/base/SkFixed.h"
#include "include/private/base/SkMalloc.h"
#include "include/private/base/SkMutex.h"
#include "include/private/base/SkTo.h"
#include "src/base/SkArenaAlloc.h"
#include "src/base/SkAutoMalloc.h"
#include "src/core/SkAutoPixmapStorage.h"
#include "src/core/SkBlitter_A8.h"
#include "src/core/SkDescriptor.h"
#include "src/core/SkDrawBase.h"
#include "src/core/SkFontPriv.h"
#include "src/core/SkGlyph.h"
#include "src/core/SkMaskFilterBase.h"
#include "src/core/SkPaintPriv.h"
#include "src/core/SkRasterClip.h"
#include "src/core/SkTextFormatParams.h"
#include "src/core/SkWriteBuffer.h"
#include "src/utils/SkMatrix22.h"
#include <algorithm>
#include <cstring>
#include <limits>
#include <new>
///////////////////////////////////////////////////////////////////////////////
namespace {
static inline const constexpr bool kSkShowTextBlitCoverage = false;
static inline const constexpr bool kSkScalerContextDumpRec = false;
}
SkScalerContextRec SkScalerContext::PreprocessRec(const SkTypeface& typeface,
const SkScalerContextEffects& effects,
const SkDescriptor& desc) {
SkScalerContextRec rec =
*static_cast<const SkScalerContextRec*>(desc.findEntry(kRec_SkDescriptorTag, nullptr));
// Allow the typeface to adjust the rec.
typeface.onFilterRec(&rec);
if (effects.fMaskFilter) {
// Pre-blend is not currently applied to filtered text.
// The primary filter is blur, for which contrast makes no sense,
// and for which the destination guess error is more visible.
// Also, all existing users of blur have calibrated for linear.
rec.ignorePreBlend();
}
SkColor lumColor = rec.getLuminanceColor();
if (rec.fMaskFormat == SkMask::kA8_Format) {
U8CPU lum = SkComputeLuminance(SkColorGetR(lumColor),
SkColorGetG(lumColor),
SkColorGetB(lumColor));
lumColor = SkColorSetRGB(lum, lum, lum);
}
// TODO: remove CanonicalColor when we to fix up Chrome layout tests.
rec.setLuminanceColor(lumColor);
return rec;
}
SkScalerContext::SkScalerContext(sk_sp<SkTypeface> typeface, const SkScalerContextEffects& effects,
const SkDescriptor* desc)
: fRec(PreprocessRec(*typeface, effects, *desc))
, fTypeface(std::move(typeface))
, fPathEffect(sk_ref_sp(effects.fPathEffect))
, fMaskFilter(sk_ref_sp(effects.fMaskFilter))
// Initialize based on our settings. Subclasses can also force this.
, fGenerateImageFromPath(fRec.fFrameWidth >= 0 || fPathEffect != nullptr)
, fPreBlend(fMaskFilter ? SkMaskGamma::PreBlend() : SkScalerContext::GetMaskPreBlend(fRec))
{
if constexpr (kSkScalerContextDumpRec) {
SkDebugf("SkScalerContext checksum %x count %u length %u\n",
desc->getChecksum(), desc->getCount(), desc->getLength());
SkDebugf("%s", fRec.dump().c_str());
SkDebugf(" effects %p\n", desc->findEntry(kEffects_SkDescriptorTag, nullptr));
}
}
SkScalerContext::~SkScalerContext() {}
/**
* In order to call cachedDeviceLuminance, cachedPaintLuminance, or
* cachedMaskGamma the caller must hold the mask_gamma_cache_mutex and continue
* to hold it until the returned pointer is refed or forgotten.
*/
static SkMutex& mask_gamma_cache_mutex() {
static SkMutex& mutex = *(new SkMutex);
return mutex;
}
static SkMaskGamma* gLinearMaskGamma = nullptr;
static SkMaskGamma* gMaskGamma = nullptr;
static SkScalar gContrast = SK_ScalarMin;
static SkScalar gPaintGamma = SK_ScalarMin;
static SkScalar gDeviceGamma = SK_ScalarMin;
/**
* The caller must hold the mask_gamma_cache_mutex() and continue to hold it until
* the returned SkMaskGamma pointer is refed or forgotten.
*/
static const SkMaskGamma& cached_mask_gamma(SkScalar contrast, SkScalar paintGamma,
SkScalar deviceGamma) {
mask_gamma_cache_mutex().assertHeld();
if (0 == contrast && SK_Scalar1 == paintGamma && SK_Scalar1 == deviceGamma) {
if (nullptr == gLinearMaskGamma) {
gLinearMaskGamma = new SkMaskGamma;
}
return *gLinearMaskGamma;
}
if (gContrast != contrast || gPaintGamma != paintGamma || gDeviceGamma != deviceGamma) {
SkSafeUnref(gMaskGamma);
gMaskGamma = new SkMaskGamma(contrast, paintGamma, deviceGamma);
gContrast = contrast;
gPaintGamma = paintGamma;
gDeviceGamma = deviceGamma;
}
return *gMaskGamma;
}
/**
* Expands fDeviceGamma, fPaintGamma, fContrast, and fLumBits into a mask pre-blend.
*/
SkMaskGamma::PreBlend SkScalerContext::GetMaskPreBlend(const SkScalerContextRec& rec) {
SkAutoMutexExclusive ama(mask_gamma_cache_mutex());
const SkMaskGamma& maskGamma = cached_mask_gamma(rec.getContrast(),
rec.getPaintGamma(),
rec.getDeviceGamma());
// TODO: remove CanonicalColor when we to fix up Chrome layout tests.
return maskGamma.preBlend(rec.getLuminanceColor());
}
size_t SkScalerContext::GetGammaLUTSize(SkScalar contrast, SkScalar paintGamma,
SkScalar deviceGamma, int* width, int* height) {
SkAutoMutexExclusive ama(mask_gamma_cache_mutex());
const SkMaskGamma& maskGamma = cached_mask_gamma(contrast,
paintGamma,
deviceGamma);
maskGamma.getGammaTableDimensions(width, height);
size_t size = (*width)*(*height)*sizeof(uint8_t);
return size;
}
bool SkScalerContext::GetGammaLUTData(SkScalar contrast, SkScalar paintGamma, SkScalar deviceGamma,
uint8_t* data) {
SkAutoMutexExclusive ama(mask_gamma_cache_mutex());
const SkMaskGamma& maskGamma = cached_mask_gamma(contrast,
paintGamma,
deviceGamma);
const uint8_t* gammaTables = maskGamma.getGammaTables();
if (!gammaTables) {
return false;
}
int width, height;
maskGamma.getGammaTableDimensions(&width, &height);
size_t size = width*height * sizeof(uint8_t);
memcpy(data, gammaTables, size);
return true;
}
SkGlyph SkScalerContext::makeGlyph(SkPackedGlyphID packedID, SkArenaAlloc* alloc) {
return internalMakeGlyph(packedID, fRec.fMaskFormat, alloc);
}
/** Return the closest D for the given S. Returns std::numeric_limits<D>::max() for NaN. */
template <typename D, typename S> static constexpr D sk_saturate_cast(S s) {
static_assert(std::is_integral_v<D>);
s = s < std::numeric_limits<D>::max() ? s : std::numeric_limits<D>::max();
s = s > std::numeric_limits<D>::min() ? s : std::numeric_limits<D>::min();
return (D)s;
}
void SkScalerContext::SaturateGlyphBounds(SkGlyph* glyph, SkRect&& r) {
r.roundOut(&r);
glyph->fLeft = sk_saturate_cast<int16_t>(r.fLeft);
glyph->fTop = sk_saturate_cast<int16_t>(r.fTop);
glyph->fWidth = sk_saturate_cast<uint16_t>(r.width());
glyph->fHeight = sk_saturate_cast<uint16_t>(r.height());
}
void SkScalerContext::SaturateGlyphBounds(SkGlyph* glyph, SkIRect const & r) {
glyph->fLeft = sk_saturate_cast<int16_t>(r.fLeft);
glyph->fTop = sk_saturate_cast<int16_t>(r.fTop);
glyph->fWidth = sk_saturate_cast<uint16_t>(r.width64());
glyph->fHeight = sk_saturate_cast<uint16_t>(r.height64());
}
void SkScalerContext::GenerateMetricsFromPath(
SkGlyph* glyph, const SkPath& devPath, SkMask::Format format,
const bool verticalLCD, const bool a8FromLCD, const bool hairline)
{
// Only BW, A8, and LCD16 can be produced from paths.
if (glyph->fMaskFormat != SkMask::kBW_Format &&
glyph->fMaskFormat != SkMask::kA8_Format &&
glyph->fMaskFormat != SkMask::kLCD16_Format)
{
glyph->fMaskFormat = SkMask::kA8_Format;
}
SkRect bounds = devPath.getBounds();
if (!bounds.isEmpty()) {
const bool fromLCD = (glyph->fMaskFormat == SkMask::kLCD16_Format) ||
(glyph->fMaskFormat == SkMask::kA8_Format && a8FromLCD);
const bool needExtraWidth = (fromLCD && !verticalLCD) || hairline;
const bool needExtraHeight = (fromLCD && verticalLCD) || hairline;
if (needExtraWidth) {
bounds.roundOut(&bounds);
bounds.outset(1, 0);
}
if (needExtraHeight) {
bounds.roundOut(&bounds);
bounds.outset(0, 1);
}
}
SaturateGlyphBounds(glyph, std::move(bounds));
}
SkGlyph SkScalerContext::internalMakeGlyph(SkPackedGlyphID packedID, SkMask::Format format, SkArenaAlloc* alloc) {
auto zeroBounds = [](SkGlyph& glyph) {
glyph.fLeft = 0;
glyph.fTop = 0;
glyph.fWidth = 0;
glyph.fHeight = 0;
};
SkGlyph glyph{packedID};
glyph.fMaskFormat = format; // subclass may return a different value
GlyphMetrics mx = this->generateMetrics(glyph, alloc);
SkASSERT(!mx.neverRequestPath || !mx.computeFromPath);
glyph.fAdvanceX = mx.advance.fX;
glyph.fAdvanceY = mx.advance.fY;
glyph.fMaskFormat = mx.maskFormat;
glyph.fScalerContextBits = mx.extraBits;
if (mx.computeFromPath || (fGenerateImageFromPath && !mx.neverRequestPath)) {
SkDEBUGCODE(glyph.fAdvancesBoundsFormatAndInitialPathDone = true;)
this->internalGetPath(glyph, alloc);
const SkPath* devPath = glyph.path();
if (devPath) {
const bool doVert = SkToBool(fRec.fFlags & SkScalerContext::kLCD_Vertical_Flag);
const bool a8LCD = SkToBool(fRec.fFlags & SkScalerContext::kGenA8FromLCD_Flag);
const bool hairline = glyph.pathIsHairline();
GenerateMetricsFromPath(&glyph, *devPath, format, doVert, a8LCD, hairline);
}
} else {
SaturateGlyphBounds(&glyph, std::move(mx.bounds));
if (mx.neverRequestPath) {
glyph.setPath(alloc, nullptr, false);
}
}
SkDEBUGCODE(glyph.fAdvancesBoundsFormatAndInitialPathDone = true;)
// if either dimension is empty, zap the image bounds of the glyph
if (0 == glyph.fWidth || 0 == glyph.fHeight) {
zeroBounds(glyph);
return glyph;
}
if (fMaskFilter) {
// only want the bounds from the filter
SkMask src(nullptr, glyph.iRect(), glyph.rowBytes(), glyph.maskFormat());
SkMaskBuilder dst;
SkMatrix matrix;
fRec.getMatrixFrom2x2(&matrix);
if (as_MFB(fMaskFilter)->filterMask(&dst, src, matrix, nullptr)) {
if (dst.fBounds.isEmpty()) {
zeroBounds(glyph);
return glyph;
}
SkASSERT(dst.fImage == nullptr);
SaturateGlyphBounds(&glyph, dst.fBounds);
glyph.fMaskFormat = dst.fFormat;
}
}
return glyph;
}
static void applyLUTToA8Mask(SkMaskBuilder& mask, const uint8_t* lut) {
uint8_t* SK_RESTRICT dst = mask.image();
unsigned rowBytes = mask.fRowBytes;
for (int y = mask.fBounds.height() - 1; y >= 0; --y) {
for (int x = mask.fBounds.width() - 1; x >= 0; --x) {
dst[x] = lut[dst[x]];
}
dst += rowBytes;
}
}
static void pack4xHToMask(const SkPixmap& src, SkMaskBuilder& dst,
const SkMaskGamma::PreBlend& maskPreBlend,
const bool doBGR, const bool doVert) {
#define SAMPLES_PER_PIXEL 4
#define LCD_PER_PIXEL 3
SkASSERT(kAlpha_8_SkColorType == src.colorType());
const bool toA8 = SkMask::kA8_Format == dst.fFormat;
SkASSERT(SkMask::kLCD16_Format == dst.fFormat || toA8);
// doVert in this function means swap x and y when writing to dst.
if (doVert) {
SkASSERT(src.width() == (dst.fBounds.height() - 2) * 4);
SkASSERT(src.height() == dst.fBounds.width());
} else {
SkASSERT(src.width() == (dst.fBounds.width() - 2) * 4);
SkASSERT(src.height() == dst.fBounds.height());
}
const int sample_width = src.width();
const int height = src.height();
uint8_t* dstImage = dst.image();
size_t dstRB = dst.fRowBytes;
// An N tap FIR is defined by
// out[n] = coeff[0]*x[n] + coeff[1]*x[n-1] + ... + coeff[N]*x[n-N]
// or
// out[n] = sum(i, 0, N, coeff[i]*x[n-i])
// The strategy is to use one FIR (different coefficients) for each of r, g, and b.
// This means using every 4th FIR output value of each FIR and discarding the rest.
// The FIRs are aligned, and the coefficients reach 5 samples to each side of their 'center'.
// (For r and b this is technically incorrect, but the coeffs outside round to zero anyway.)
// These are in some fixed point repesentation.
// Adding up to more than one simulates ink spread.
// For implementation reasons, these should never add up to more than two.
// Coefficients determined by a gausian where 5 samples = 3 std deviations (0x110 'contrast').
// Calculated using tools/generate_fir_coeff.py
// With this one almost no fringing is ever seen, but it is imperceptibly blurry.
// The lcd smoothed text is almost imperceptibly different from gray,
// but is still sharper on small stems and small rounded corners than gray.
// This also seems to be about as wide as one can get and only have a three pixel kernel.
// TODO: calculate these at runtime so parameters can be adjusted (esp contrast).
static const unsigned int coefficients[LCD_PER_PIXEL][SAMPLES_PER_PIXEL*3] = {
//The red subpixel is centered inside the first sample (at 1/6 pixel), and is shifted.
{ 0x03, 0x0b, 0x1c, 0x33, 0x40, 0x39, 0x24, 0x10, 0x05, 0x01, 0x00, 0x00, },
//The green subpixel is centered between two samples (at 1/2 pixel), so is symetric
{ 0x00, 0x02, 0x08, 0x16, 0x2b, 0x3d, 0x3d, 0x2b, 0x16, 0x08, 0x02, 0x00, },
//The blue subpixel is centered inside the last sample (at 5/6 pixel), and is shifted.
{ 0x00, 0x00, 0x01, 0x05, 0x10, 0x24, 0x39, 0x40, 0x33, 0x1c, 0x0b, 0x03, },
};
size_t dstPB = toA8 ? sizeof(uint8_t) : sizeof(uint16_t);
for (int y = 0; y < height; ++y) {
uint8_t* dstP;
size_t dstPDelta;
if (doVert) {
dstP = SkTAddOffset<uint8_t>(dstImage, y * dstPB);
dstPDelta = dstRB;
} else {
dstP = SkTAddOffset<uint8_t>(dstImage, y * dstRB);
dstPDelta = dstPB;
}
const uint8_t* srcP = src.addr8(0, y);
// TODO: this fir filter implementation is straight forward, but slow.
// It should be possible to make it much faster.
for (int sample_x = -4; sample_x < sample_width + 4; sample_x += 4) {
int fir[LCD_PER_PIXEL] = { 0 };
for (int sample_index = std::max(0, sample_x - 4), coeff_index = sample_index - (sample_x - 4)
; sample_index < std::min(sample_x + 8, sample_width)
; ++sample_index, ++coeff_index)
{
int sample_value = srcP[sample_index];
for (int subpxl_index = 0; subpxl_index < LCD_PER_PIXEL; ++subpxl_index) {
fir[subpxl_index] += coefficients[subpxl_index][coeff_index] * sample_value;
}
}
for (int subpxl_index = 0; subpxl_index < LCD_PER_PIXEL; ++subpxl_index) {
fir[subpxl_index] /= 0x100;
fir[subpxl_index] = std::min(fir[subpxl_index], 255);
}
U8CPU r, g, b;
if (doBGR) {
r = fir[2];
g = fir[1];
b = fir[0];
} else {
r = fir[0];
g = fir[1];
b = fir[2];
}
if constexpr (kSkShowTextBlitCoverage) {
r = std::max(r, 10u);
g = std::max(g, 10u);
b = std::max(b, 10u);
}
if (toA8) {
U8CPU a = (r + g + b) / 3;
if (maskPreBlend.isApplicable()) {
a = maskPreBlend.fG[a];
}
*dstP = a;
} else {
if (maskPreBlend.isApplicable()) {
r = maskPreBlend.fR[r];
g = maskPreBlend.fG[g];
b = maskPreBlend.fB[b];
}
*(uint16_t*)dstP = SkPack888ToRGB16(r, g, b);
}
dstP = SkTAddOffset<uint8_t>(dstP, dstPDelta);
}
}
}
static inline int convert_8_to_1(unsigned byte) {
SkASSERT(byte <= 0xFF);
return byte >> 7;
}
static uint8_t pack_8_to_1(const uint8_t alpha[8]) {
unsigned bits = 0;
for (int i = 0; i < 8; ++i) {
bits <<= 1;
bits |= convert_8_to_1(alpha[i]);
}
return SkToU8(bits);
}
static void packA8ToA1(SkMaskBuilder& dstMask, const uint8_t* src, size_t srcRB) {
const int height = dstMask.fBounds.height();
const int width = dstMask.fBounds.width();
const int octs = width >> 3;
const int leftOverBits = width & 7;
uint8_t* dst = dstMask.image();
const int dstPad = dstMask.fRowBytes - SkAlign8(width)/8;
SkASSERT(dstPad >= 0);
SkASSERT(width >= 0);
SkASSERT(srcRB >= (size_t)width);
const size_t srcPad = srcRB - width;
for (int y = 0; y < height; ++y) {
for (int i = 0; i < octs; ++i) {
*dst++ = pack_8_to_1(src);
src += 8;
}
if (leftOverBits > 0) {
unsigned bits = 0;
int shift = 7;
for (int i = 0; i < leftOverBits; ++i, --shift) {
bits |= convert_8_to_1(*src++) << shift;
}
*dst++ = bits;
}
src += srcPad;
dst += dstPad;
}
}
void SkScalerContext::GenerateImageFromPath(
SkMaskBuilder& dstMask, const SkPath& path, const SkMaskGamma::PreBlend& maskPreBlend,
const bool doBGR, const bool verticalLCD, const bool a8FromLCD, const bool hairline)
{
SkASSERT(dstMask.fFormat == SkMask::kBW_Format ||
dstMask.fFormat == SkMask::kA8_Format ||
dstMask.fFormat == SkMask::kLCD16_Format);
SkPaint paint;
SkPath strokePath;
const SkPath* pathToUse = &path;
int srcW = dstMask.fBounds.width();
int srcH = dstMask.fBounds.height();
int dstW = srcW;
int dstH = srcH;
SkMatrix matrix;
matrix.setTranslate(-SkIntToScalar(dstMask.fBounds.fLeft),
-SkIntToScalar(dstMask.fBounds.fTop));
paint.setStroke(hairline);
paint.setAntiAlias(SkMask::kBW_Format != dstMask.fFormat);
const bool fromLCD = (dstMask.fFormat == SkMask::kLCD16_Format) ||
(dstMask.fFormat == SkMask::kA8_Format && a8FromLCD);
const bool intermediateDst = fromLCD || dstMask.fFormat == SkMask::kBW_Format;
if (fromLCD) {
if (verticalLCD) {
dstW = 4*dstH - 8;
dstH = srcW;
matrix.setAll(0, 4, -SkIntToScalar(dstMask.fBounds.fTop + 1) * 4,
1, 0, -SkIntToScalar(dstMask.fBounds.fLeft),
0, 0, 1);
} else {
dstW = 4*dstW - 8;
matrix.setAll(4, 0, -SkIntToScalar(dstMask.fBounds.fLeft + 1) * 4,
0, 1, -SkIntToScalar(dstMask.fBounds.fTop),
0, 0, 1);
}
// LCD hairline doesn't line up with the pixels, so do it the expensive way.
SkStrokeRec rec(SkStrokeRec::kFill_InitStyle);
if (hairline) {
rec.setStrokeStyle(1.0f, false);
rec.setStrokeParams(SkPaint::kButt_Cap, SkPaint::kRound_Join, 0.0f);
}
if (rec.needToApply() && rec.applyToPath(&strokePath, path)) {
pathToUse = &strokePath;
paint.setStyle(SkPaint::kFill_Style);
}
}
SkRasterClip clip;
clip.setRect(SkIRect::MakeWH(dstW, dstH));
const SkImageInfo info = SkImageInfo::MakeA8(dstW, dstH);
SkAutoPixmapStorage dst;
if (intermediateDst) {
if (!dst.tryAlloc(info)) {
// can't allocate offscreen, so empty the mask and return
sk_bzero(dstMask.image(), dstMask.computeImageSize());
return;
}
} else {
dst.reset(info, dstMask.image(), dstMask.fRowBytes);
}
sk_bzero(dst.writable_addr(), dst.computeByteSize());
SkDrawBase draw;
draw.fBlitterChooser = SkA8Blitter_Choose;
draw.fDst = dst;
draw.fRC = &clip;
draw.fCTM = &matrix;
draw.drawPath(*pathToUse, paint);
switch (dstMask.fFormat) {
case SkMask::kBW_Format:
packA8ToA1(dstMask, dst.addr8(0, 0), dst.rowBytes());
break;
case SkMask::kA8_Format:
if (fromLCD) {
pack4xHToMask(dst, dstMask, maskPreBlend, doBGR, verticalLCD);
} else if (maskPreBlend.isApplicable()) {
applyLUTToA8Mask(dstMask, maskPreBlend.fG);
}
break;
case SkMask::kLCD16_Format:
pack4xHToMask(dst, dstMask, maskPreBlend, doBGR, verticalLCD);
break;
default:
break;
}
}
void SkScalerContext::getImage(const SkGlyph& origGlyph) {
SkASSERT(origGlyph.fAdvancesBoundsFormatAndInitialPathDone);
const SkGlyph* unfilteredGlyph = &origGlyph;
// in case we need to call generateImage on a mask-format that is different
// (i.e. larger) than what our caller allocated by looking at origGlyph.
SkAutoMalloc tmpGlyphImageStorage;
SkGlyph tmpGlyph;
SkSTArenaAlloc<sizeof(SkGlyph::PathData)> tmpGlyphPathDataStorage;
if (fMaskFilter) {
// need the original bounds, sans our maskfilter
sk_sp<SkMaskFilter> mf = std::move(fMaskFilter);
tmpGlyph = this->makeGlyph(origGlyph.getPackedID(), &tmpGlyphPathDataStorage);
fMaskFilter = std::move(mf);
// Use the origGlyph storage for the temporary unfiltered mask if it will fit.
if (tmpGlyph.fMaskFormat == origGlyph.fMaskFormat &&
tmpGlyph.imageSize() <= origGlyph.imageSize())
{
tmpGlyph.fImage = origGlyph.fImage;
} else {
tmpGlyphImageStorage.reset(tmpGlyph.imageSize());
tmpGlyph.fImage = tmpGlyphImageStorage.get();
}
unfilteredGlyph = &tmpGlyph;
}
if (!fGenerateImageFromPath) {
generateImage(*unfilteredGlyph, unfilteredGlyph->fImage);
} else {
SkASSERT(origGlyph.setPathHasBeenCalled());
const SkPath* devPath = origGlyph.path();
if (!devPath) {
generateImage(*unfilteredGlyph, unfilteredGlyph->fImage);
} else {
SkMaskBuilder mask(static_cast<uint8_t*>(unfilteredGlyph->fImage),
unfilteredGlyph->iRect(), unfilteredGlyph->rowBytes(),
unfilteredGlyph->maskFormat());
SkASSERT(SkMask::kARGB32_Format != origGlyph.fMaskFormat);
SkASSERT(SkMask::kARGB32_Format != mask.fFormat);
const bool doBGR = SkToBool(fRec.fFlags & SkScalerContext::kLCD_BGROrder_Flag);
const bool doVert = SkToBool(fRec.fFlags & SkScalerContext::kLCD_Vertical_Flag);
const bool a8LCD = SkToBool(fRec.fFlags & SkScalerContext::kGenA8FromLCD_Flag);
const bool hairline = origGlyph.pathIsHairline();
GenerateImageFromPath(mask, *devPath, fPreBlend, doBGR, doVert, a8LCD, hairline);
}
}
if (fMaskFilter) {
// k3D_Format should not be mask filtered.
SkASSERT(SkMask::k3D_Format != unfilteredGlyph->fMaskFormat);
SkMaskBuilder srcMask;
SkAutoMaskFreeImage srcMaskOwnedImage(nullptr);
SkMatrix m;
fRec.getMatrixFrom2x2(&m);
if (as_MFB(fMaskFilter)->filterMask(&srcMask, unfilteredGlyph->mask(), m, nullptr)) {
// Filter succeeded; srcMask.fImage was allocated.
srcMaskOwnedImage.reset(srcMask.image());
} else if (unfilteredGlyph->fImage == tmpGlyphImageStorage.get()) {
// Filter did nothing; unfiltered mask is independent of origGlyph.fImage.
srcMask = SkMaskBuilder(static_cast<uint8_t*>(unfilteredGlyph->fImage),
unfilteredGlyph->iRect(), unfilteredGlyph->rowBytes(),
unfilteredGlyph->maskFormat());
} else if (origGlyph.iRect() == unfilteredGlyph->iRect()) {
// Filter did nothing; the unfiltered mask is in origGlyph.fImage and matches.
return;
} else {
// Filter did nothing; the unfiltered mask is in origGlyph.fImage and conflicts.
srcMask = SkMaskBuilder(static_cast<uint8_t*>(unfilteredGlyph->fImage),
unfilteredGlyph->iRect(), unfilteredGlyph->rowBytes(),
unfilteredGlyph->maskFormat());
size_t imageSize = unfilteredGlyph->imageSize();
tmpGlyphImageStorage.reset(imageSize);
srcMask.image() = static_cast<uint8_t*>(tmpGlyphImageStorage.get());
memcpy(srcMask.image(), unfilteredGlyph->fImage, imageSize);
}
SkASSERT_RELEASE(srcMask.fFormat == origGlyph.fMaskFormat);
SkMaskBuilder dstMask = SkMaskBuilder(static_cast<uint8_t*>(origGlyph.fImage),
origGlyph.iRect(), origGlyph.rowBytes(),
origGlyph.maskFormat());
SkIRect origBounds = dstMask.fBounds;
// Find the intersection of src and dst while updating the fImages.
if (srcMask.fBounds.fTop < dstMask.fBounds.fTop) {
int32_t topDiff = dstMask.fBounds.fTop - srcMask.fBounds.fTop;
srcMask.image() += srcMask.fRowBytes * topDiff;
srcMask.bounds().fTop = dstMask.fBounds.fTop;
}
if (dstMask.fBounds.fTop < srcMask.fBounds.fTop) {
int32_t topDiff = srcMask.fBounds.fTop - dstMask.fBounds.fTop;
dstMask.image() += dstMask.fRowBytes * topDiff;
dstMask.bounds().fTop = srcMask.fBounds.fTop;
}
if (srcMask.fBounds.fLeft < dstMask.fBounds.fLeft) {
int32_t leftDiff = dstMask.fBounds.fLeft - srcMask.fBounds.fLeft;
srcMask.image() += leftDiff;
srcMask.bounds().fLeft = dstMask.fBounds.fLeft;
}
if (dstMask.fBounds.fLeft < srcMask.fBounds.fLeft) {
int32_t leftDiff = srcMask.fBounds.fLeft - dstMask.fBounds.fLeft;
dstMask.image() += leftDiff;
dstMask.bounds().fLeft = srcMask.fBounds.fLeft;
}
if (srcMask.fBounds.fBottom < dstMask.fBounds.fBottom) {
dstMask.bounds().fBottom = srcMask.fBounds.fBottom;
}
if (dstMask.fBounds.fBottom < srcMask.fBounds.fBottom) {
srcMask.bounds().fBottom = dstMask.fBounds.fBottom;
}
if (srcMask.fBounds.fRight < dstMask.fBounds.fRight) {
dstMask.bounds().fRight = srcMask.fBounds.fRight;
}
if (dstMask.fBounds.fRight < srcMask.fBounds.fRight) {
srcMask.bounds().fRight = dstMask.fBounds.fRight;
}
SkASSERT(srcMask.fBounds == dstMask.fBounds);
int width = srcMask.fBounds.width();
int height = srcMask.fBounds.height();
int dstRB = dstMask.fRowBytes;
int srcRB = srcMask.fRowBytes;
const uint8_t* src = srcMask.fImage;
uint8_t* dst = dstMask.image();
if (SkMask::k3D_Format == srcMask.fFormat) {
// we have to copy 3 times as much
height *= 3;
}
// If not filling the full original glyph, clear it out first.
if (dstMask.fBounds != origBounds) {
sk_bzero(origGlyph.fImage, origGlyph.fHeight * origGlyph.rowBytes());
}
while (--height >= 0) {
memcpy(dst, src, width);
src += srcRB;
dst += dstRB;
}
}
}
void SkScalerContext::getPath(SkGlyph& glyph, SkArenaAlloc* alloc) {
this->internalGetPath(glyph, alloc);
}
sk_sp<SkDrawable> SkScalerContext::getDrawable(SkGlyph& glyph) {
return this->generateDrawable(glyph);
}
//TODO: make pure virtual
sk_sp<SkDrawable> SkScalerContext::generateDrawable(const SkGlyph&) {
return nullptr;
}
void SkScalerContext::getFontMetrics(SkFontMetrics* fm) {
SkASSERT(fm);
this->generateFontMetrics(fm);
}
///////////////////////////////////////////////////////////////////////////////
void SkScalerContext::internalGetPath(SkGlyph& glyph, SkArenaAlloc* alloc) {
SkASSERT(glyph.fAdvancesBoundsFormatAndInitialPathDone);
if (glyph.setPathHasBeenCalled()) {
return;
}
SkPath path;
SkPath devPath;
bool hairline = false;
SkPackedGlyphID glyphID = glyph.getPackedID();
if (!generatePath(glyph, &path)) {
glyph.setPath(alloc, (SkPath*)nullptr, hairline);
return;
}
if (fRec.fFlags & SkScalerContext::kSubpixelPositioning_Flag) {
SkFixed dx = glyphID.getSubXFixed();
SkFixed dy = glyphID.getSubYFixed();
if (dx | dy) {
path.offset(SkFixedToScalar(dx), SkFixedToScalar(dy));
}
}
if (fRec.fFrameWidth < 0 && fPathEffect == nullptr) {
devPath.swap(path);
} else {
// need the path in user-space, with only the point-size applied
// so that our stroking and effects will operate the same way they
// would if the user had extracted the path themself, and then
// called drawPath
SkPath localPath;
SkMatrix matrix;
SkMatrix inverse;
fRec.getMatrixFrom2x2(&matrix);
if (!matrix.invert(&inverse)) {
glyph.setPath(alloc, &devPath, hairline);
}
path.transform(inverse, &localPath);
// now localPath is only affected by the paint settings, and not the canvas matrix
SkStrokeRec rec(SkStrokeRec::kFill_InitStyle);
if (fRec.fFrameWidth >= 0) {
rec.setStrokeStyle(fRec.fFrameWidth,
SkToBool(fRec.fFlags & kFrameAndFill_Flag));
// glyphs are always closed contours, so cap type is ignored,
// so we just pass something.
rec.setStrokeParams((SkPaint::Cap)fRec.fStrokeCap,
(SkPaint::Join)fRec.fStrokeJoin,
fRec.fMiterLimit);
}
if (fPathEffect) {
SkPath effectPath;
if (fPathEffect->filterPath(&effectPath, localPath, &rec, nullptr, matrix)) {
localPath.swap(effectPath);
}
}
if (rec.needToApply()) {
SkPath strokePath;
if (rec.applyToPath(&strokePath, localPath)) {
localPath.swap(strokePath);
}
}
// The path effect may have modified 'rec', so wait to here to check hairline status.
if (rec.isHairlineStyle()) {
hairline = true;
}
localPath.transform(matrix, &devPath);
}
glyph.setPath(alloc, &devPath, hairline);
}
void SkScalerContextRec::getMatrixFrom2x2(SkMatrix* dst) const {
dst->setAll(fPost2x2[0][0], fPost2x2[0][1], 0,
fPost2x2[1][0], fPost2x2[1][1], 0,
0, 0, 1);
}
void SkScalerContextRec::getLocalMatrix(SkMatrix* m) const {
*m = SkFontPriv::MakeTextMatrix(fTextSize, fPreScaleX, fPreSkewX);
}
void SkScalerContextRec::getSingleMatrix(SkMatrix* m) const {
this->getLocalMatrix(m);
// now concat the device matrix
SkMatrix deviceMatrix;
this->getMatrixFrom2x2(&deviceMatrix);
m->postConcat(deviceMatrix);
}
bool SkScalerContextRec::computeMatrices(PreMatrixScale preMatrixScale, SkVector* s, SkMatrix* sA,
SkMatrix* GsA, SkMatrix* G_inv, SkMatrix* A_out)
{
// A is the 'total' matrix.
SkMatrix A;
this->getSingleMatrix(&A);
// The caller may find the 'total' matrix useful when dealing directly with EM sizes.
if (A_out) {
*A_out = A;
}
// GA is the matrix A with rotation removed.
SkMatrix GA;
bool skewedOrFlipped = A.getSkewX() || A.getSkewY() || A.getScaleX() < 0 || A.getScaleY() < 0;
if (skewedOrFlipped) {
// QR by Givens rotations. G is Q^T and GA is R. G is rotational (no reflections).
// h is where A maps the horizontal baseline.
SkPoint h = SkPoint::Make(SK_Scalar1, 0);
A.mapPoints(&h, 1);
// G is the Givens Matrix for A (rotational matrix where GA[0][1] == 0).
SkMatrix G;
SkComputeGivensRotation(h, &G);
GA = G;
GA.preConcat(A);
// The 'remainingRotation' is G inverse, which is fairly simple since G is 2x2 rotational.
if (G_inv) {
G_inv->setAll(
G.get(SkMatrix::kMScaleX), -G.get(SkMatrix::kMSkewX), G.get(SkMatrix::kMTransX),
-G.get(SkMatrix::kMSkewY), G.get(SkMatrix::kMScaleY), G.get(SkMatrix::kMTransY),
G.get(SkMatrix::kMPersp0), G.get(SkMatrix::kMPersp1), G.get(SkMatrix::kMPersp2));
}
} else {
GA = A;
if (G_inv) {
G_inv->reset();
}
}
// If the 'total' matrix is singular, set the 'scale' to something finite and zero the matrices.
// All underlying ports have issues with zero text size, so use the matricies to zero.
// If one of the scale factors is less than 1/256 then an EM filling square will
// never affect any pixels.
// If there are any nonfinite numbers in the matrix, bail out and set the matrices to zero.
if (SkScalarAbs(GA.get(SkMatrix::kMScaleX)) <= SK_ScalarNearlyZero ||
SkScalarAbs(GA.get(SkMatrix::kMScaleY)) <= SK_ScalarNearlyZero ||
!GA.isFinite())
{
s->fX = SK_Scalar1;
s->fY = SK_Scalar1;
sA->setScale(0, 0);
if (GsA) {
GsA->setScale(0, 0);
}
if (G_inv) {
G_inv->reset();
}
return false;
}
// At this point, given GA, create s.
switch (preMatrixScale) {
case PreMatrixScale::kFull:
s->fX = SkScalarAbs(GA.get(SkMatrix::kMScaleX));
s->fY = SkScalarAbs(GA.get(SkMatrix::kMScaleY));
break;
case PreMatrixScale::kVertical: {
SkScalar yScale = SkScalarAbs(GA.get(SkMatrix::kMScaleY));
s->fX = yScale;
s->fY = yScale;
break;
}
case PreMatrixScale::kVerticalInteger: {
SkScalar realYScale = SkScalarAbs(GA.get(SkMatrix::kMScaleY));
SkScalar intYScale = SkScalarRoundToScalar(realYScale);
if (intYScale == 0) {
intYScale = SK_Scalar1;
}
s->fX = intYScale;
s->fY = intYScale;
break;
}
}
// The 'remaining' matrix sA is the total matrix A without the scale.
if (!skewedOrFlipped && (
(PreMatrixScale::kFull == preMatrixScale) ||
(PreMatrixScale::kVertical == preMatrixScale && A.getScaleX() == A.getScaleY())))
{
// If GA == A and kFull, sA is identity.
// If GA == A and kVertical and A.scaleX == A.scaleY, sA is identity.
sA->reset();
} else if (!skewedOrFlipped && PreMatrixScale::kVertical == preMatrixScale) {
// If GA == A and kVertical, sA.scaleY is SK_Scalar1.
sA->reset();
sA->setScaleX(A.getScaleX() / s->fY);
} else {
// TODO: like kVertical, kVerticalInteger with int scales.
*sA = A;
sA->preScale(SkScalarInvert(s->fX), SkScalarInvert(s->fY));
}
// The 'remainingWithoutRotation' matrix GsA is the non-rotational part of A without the scale.
if (GsA) {
*GsA = GA;
// G is rotational so reorders with the scale.
GsA->preScale(SkScalarInvert(s->fX), SkScalarInvert(s->fY));
}
return true;
}
SkAxisAlignment SkScalerContext::computeAxisAlignmentForHText() const {
return fRec.computeAxisAlignmentForHText();
}
SkAxisAlignment SkScalerContextRec::computeAxisAlignmentForHText() const {
// Why fPost2x2 can be used here.
// getSingleMatrix multiplies in getLocalMatrix, which consists of
// * fTextSize (a scale, which has no effect)
// * fPreScaleX (a scale in x, which has no effect)
// * fPreSkewX (has no effect, but would on vertical text alignment).
// In other words, making the text bigger, stretching it along the
// horizontal axis, or fake italicizing it does not move the baseline.
if (!SkToBool(fFlags & SkScalerContext::kBaselineSnap_Flag)) {
return SkAxisAlignment::kNone;
}
if (0 == fPost2x2[1][0]) {
// The x axis is mapped onto the x axis.
return SkAxisAlignment::kX;
}
if (0 == fPost2x2[0][0]) {
// The x axis is mapped onto the y axis.
return SkAxisAlignment::kY;
}
return SkAxisAlignment::kNone;
}
void SkScalerContextRec::setLuminanceColor(SkColor c) {
fLumBits = SkMaskGamma::CanonicalColor(
SkColorSetRGB(SkColorGetR(c), SkColorGetG(c), SkColorGetB(c)));
}
/*
* Return the scalar with only limited fractional precision. Used to consolidate matrices
* that vary only slightly when we create our key into the font cache, since the font scaler
* typically returns the same looking resuts for tiny changes in the matrix.
*/
static SkScalar sk_relax(SkScalar x) {
SkScalar n = SkScalarRoundToScalar(x * 1024);
return n / 1024.0f;
}
static SkMask::Format compute_mask_format(const SkFont& font) {
switch (font.getEdging()) {
case SkFont::Edging::kAlias:
return SkMask::kBW_Format;
case SkFont::Edging::kAntiAlias:
return SkMask::kA8_Format;
case SkFont::Edging::kSubpixelAntiAlias:
return SkMask::kLCD16_Format;
}
SkASSERT(false);
return SkMask::kA8_Format;
}
// Beyond this size, LCD doesn't appreciably improve quality, but it always
// cost more RAM and draws slower, so we set a cap.
#ifndef SK_MAX_SIZE_FOR_LCDTEXT
#define SK_MAX_SIZE_FOR_LCDTEXT 48
#endif
const SkScalar gMaxSize2ForLCDText = SK_MAX_SIZE_FOR_LCDTEXT * SK_MAX_SIZE_FOR_LCDTEXT;
static bool too_big_for_lcd(const SkScalerContextRec& rec, bool checkPost2x2) {
if (checkPost2x2) {
SkScalar area = rec.fPost2x2[0][0] * rec.fPost2x2[1][1] -
rec.fPost2x2[1][0] * rec.fPost2x2[0][1];
area *= rec.fTextSize * rec.fTextSize;
return area > gMaxSize2ForLCDText;
} else {
return rec.fTextSize > SK_MAX_SIZE_FOR_LCDTEXT;
}
}
// The only reason this is not file static is because it needs the context of SkScalerContext to
// access SkPaint::computeLuminanceColor.
void SkScalerContext::MakeRecAndEffects(const SkFont& font, const SkPaint& paint,
const SkSurfaceProps& surfaceProps,
SkScalerContextFlags scalerContextFlags,
const SkMatrix& deviceMatrix,
SkScalerContextRec* rec,
SkScalerContextEffects* effects) {
SkASSERT(!deviceMatrix.hasPerspective());
sk_bzero(rec, sizeof(SkScalerContextRec));
SkTypeface* typeface = font.getTypeface();
rec->fTypefaceID = typeface->uniqueID();
rec->fTextSize = font.getSize();
rec->fPreScaleX = font.getScaleX();
rec->fPreSkewX = font.getSkewX();
bool checkPost2x2 = false;
const SkMatrix::TypeMask mask = deviceMatrix.getType();
if (mask & SkMatrix::kScale_Mask) {
rec->fPost2x2[0][0] = sk_relax(deviceMatrix.getScaleX());
rec->fPost2x2[1][1] = sk_relax(deviceMatrix.getScaleY());
checkPost2x2 = true;
} else {
rec->fPost2x2[0][0] = rec->fPost2x2[1][1] = SK_Scalar1;
}
if (mask & SkMatrix::kAffine_Mask) {
rec->fPost2x2[0][1] = sk_relax(deviceMatrix.getSkewX());
rec->fPost2x2[1][0] = sk_relax(deviceMatrix.getSkewY());
checkPost2x2 = true;
} else {
rec->fPost2x2[0][1] = rec->fPost2x2[1][0] = 0;
}
SkPaint::Style style = paint.getStyle();
SkScalar strokeWidth = paint.getStrokeWidth();
unsigned flags = 0;
if (font.isEmbolden()) {
#ifdef SK_USE_FREETYPE_EMBOLDEN
flags |= SkScalerContext::kEmbolden_Flag;
#else
SkScalar fakeBoldScale = SkScalarInterpFunc(font.getSize(),
kStdFakeBoldInterpKeys,
kStdFakeBoldInterpValues,
kStdFakeBoldInterpLength);
SkScalar extra = font.getSize() * fakeBoldScale;
if (style == SkPaint::kFill_Style) {
style = SkPaint::kStrokeAndFill_Style;
strokeWidth = extra; // ignore paint's strokeWidth if it was "fill"
} else {
strokeWidth += extra;
}
#endif
}
if (style != SkPaint::kFill_Style && strokeWidth >= 0) {
rec->fFrameWidth = strokeWidth;
rec->fMiterLimit = paint.getStrokeMiter();
rec->fStrokeJoin = SkToU8(paint.getStrokeJoin());
rec->fStrokeCap = SkToU8(paint.getStrokeCap());
if (style == SkPaint::kStrokeAndFill_Style) {
flags |= SkScalerContext::kFrameAndFill_Flag;
}
} else {
rec->fFrameWidth = -1;
rec->fMiterLimit = 0;
rec->fStrokeJoin = 0;
rec->fStrokeCap = 0;
}
rec->fMaskFormat = compute_mask_format(font);
if (SkMask::kLCD16_Format == rec->fMaskFormat) {
if (too_big_for_lcd(*rec, checkPost2x2)) {
rec->fMaskFormat = SkMask::kA8_Format;
flags |= SkScalerContext::kGenA8FromLCD_Flag;
} else {
SkPixelGeometry geometry = surfaceProps.pixelGeometry();
switch (geometry) {
case kUnknown_SkPixelGeometry:
// eeek, can't support LCD
rec->fMaskFormat = SkMask::kA8_Format;
flags |= SkScalerContext::kGenA8FromLCD_Flag;
break;
case kRGB_H_SkPixelGeometry:
// our default, do nothing.
break;
case kBGR_H_SkPixelGeometry:
flags |= SkScalerContext::kLCD_BGROrder_Flag;
break;
case kRGB_V_SkPixelGeometry:
flags |= SkScalerContext::kLCD_Vertical_Flag;
break;
case kBGR_V_SkPixelGeometry:
flags |= SkScalerContext::kLCD_Vertical_Flag;
flags |= SkScalerContext::kLCD_BGROrder_Flag;
break;
}
}
}
if (font.isEmbeddedBitmaps()) {
flags |= SkScalerContext::kEmbeddedBitmapText_Flag;
}
if (font.isSubpixel()) {
flags |= SkScalerContext::kSubpixelPositioning_Flag;
}
if (font.isForceAutoHinting()) {
flags |= SkScalerContext::kForceAutohinting_Flag;
}
if (font.isLinearMetrics()) {
flags |= SkScalerContext::kLinearMetrics_Flag;
}
if (font.isBaselineSnap()) {
flags |= SkScalerContext::kBaselineSnap_Flag;
}
if (typeface->glyphMaskNeedsCurrentColor()) {
flags |= SkScalerContext::kNeedsForegroundColor_Flag;
rec->fForegroundColor = paint.getColor();
}
rec->fFlags = SkToU16(flags);
// these modify fFlags, so do them after assigning fFlags
rec->setHinting(font.getHinting());
rec->setLuminanceColor(SkPaintPriv::ComputeLuminanceColor(paint));
// For now always set the paint gamma equal to the device gamma.
// The math in SkMaskGamma can handle them being different,
// but it requires superluminous masks when
// Ex : deviceGamma(x) < paintGamma(x) and x is sufficiently large.
rec->setDeviceGamma(surfaceProps.textGamma());
rec->setPaintGamma(surfaceProps.textGamma());
rec->setContrast(surfaceProps.textContrast());
if (!SkToBool(scalerContextFlags & SkScalerContextFlags::kFakeGamma)) {
rec->ignoreGamma();
}
if (!SkToBool(scalerContextFlags & SkScalerContextFlags::kBoostContrast)) {
rec->setContrast(0);
}
new (effects) SkScalerContextEffects{paint};
}
SkDescriptor* SkScalerContext::CreateDescriptorAndEffectsUsingPaint(
const SkFont& font, const SkPaint& paint, const SkSurfaceProps& surfaceProps,
SkScalerContextFlags scalerContextFlags, const SkMatrix& deviceMatrix, SkAutoDescriptor* ad,
SkScalerContextEffects* effects)
{
SkScalerContextRec rec;
MakeRecAndEffects(font, paint, surfaceProps, scalerContextFlags, deviceMatrix, &rec, effects);
return AutoDescriptorGivenRecAndEffects(rec, *effects, ad);
}
static size_t calculate_size_and_flatten(const SkScalerContextRec& rec,
const SkScalerContextEffects& effects,
SkBinaryWriteBuffer* effectBuffer) {
size_t descSize = sizeof(rec);
int entryCount = 1;
if (effects.fPathEffect || effects.fMaskFilter) {
if (effects.fPathEffect) { effectBuffer->writeFlattenable(effects.fPathEffect); }
if (effects.fMaskFilter) { effectBuffer->writeFlattenable(effects.fMaskFilter); }
entryCount += 1;
descSize += effectBuffer->bytesWritten();
}
descSize += SkDescriptor::ComputeOverhead(entryCount);
return descSize;
}
static void generate_descriptor(const SkScalerContextRec& rec,
const SkBinaryWriteBuffer& effectBuffer,
SkDescriptor* desc) {
desc->addEntry(kRec_SkDescriptorTag, sizeof(rec), &rec);
if (effectBuffer.bytesWritten() > 0) {
effectBuffer.writeToMemory(desc->addEntry(kEffects_SkDescriptorTag,
effectBuffer.bytesWritten(),
nullptr));
}
desc->computeChecksum();
}
SkDescriptor* SkScalerContext::AutoDescriptorGivenRecAndEffects(
const SkScalerContextRec& rec,
const SkScalerContextEffects& effects,
SkAutoDescriptor* ad)
{
SkBinaryWriteBuffer buf({});
ad->reset(calculate_size_and_flatten(rec, effects, &buf));
generate_descriptor(rec, buf, ad->getDesc());
return ad->getDesc();
}
std::unique_ptr<SkDescriptor> SkScalerContext::DescriptorGivenRecAndEffects(
const SkScalerContextRec& rec,
const SkScalerContextEffects& effects)
{
SkBinaryWriteBuffer buf({});
auto desc = SkDescriptor::Alloc(calculate_size_and_flatten(rec, effects, &buf));
generate_descriptor(rec, buf, desc.get());
return desc;
}
void SkScalerContext::DescriptorBufferGiveRec(const SkScalerContextRec& rec, void* buffer) {
generate_descriptor(rec, SkBinaryWriteBuffer({}), (SkDescriptor*)buffer);
}
bool SkScalerContext::CheckBufferSizeForRec(const SkScalerContextRec& rec,
const SkScalerContextEffects& effects,
size_t size) {
SkBinaryWriteBuffer buf({});
return size >= calculate_size_and_flatten(rec, effects, &buf);
}
std::unique_ptr<SkScalerContext> SkScalerContext::MakeEmpty(
sk_sp<SkTypeface> typeface, const SkScalerContextEffects& effects,
const SkDescriptor* desc) {
class SkScalerContext_Empty : public SkScalerContext {
public:
SkScalerContext_Empty(sk_sp<SkTypeface> typeface, const SkScalerContextEffects& effects,
const SkDescriptor* desc)
: SkScalerContext(std::move(typeface), effects, desc) {}
protected:
GlyphMetrics generateMetrics(const SkGlyph& glyph, SkArenaAlloc*) override {
return {glyph.maskFormat()};
}
void generateImage(const SkGlyph&, void*) override {}
bool generatePath(const SkGlyph& glyph, SkPath* path) override {
path->reset();
return false;
}
void generateFontMetrics(SkFontMetrics* metrics) override {
if (metrics) {
sk_bzero(metrics, sizeof(*metrics));
}
}
};
return std::make_unique<SkScalerContext_Empty>(std::move(typeface), effects, desc);
}