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/* libs/graphics/sgl/SkScalerContext.cpp
**
** Copyright 2006, The Android Open Source Project
**
** Licensed under the Apache License, Version 2.0 (the "License");
** you may not use this file except in compliance with the License.
** You may obtain a copy of the License at
**
** http://www.apache.org/licenses/LICENSE-2.0
**
** Unless required by applicable law or agreed to in writing, software
** distributed under the License is distributed on an "AS IS" BASIS,
** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
** See the License for the specific language governing permissions and
** limitations under the License.
*/
#include "SkScalerContext.h"
#include "SkColorPriv.h"
#include "SkDescriptor.h"
#include "SkDraw.h"
#include "SkFontHost.h"
#include "SkMaskFilter.h"
#include "SkPathEffect.h"
#include "SkRasterizer.h"
#include "SkRegion.h"
#include "SkStroke.h"
#include "SkThread.h"
#define ComputeBWRowBytes(width) (((unsigned)(width) + 7) >> 3)
static const uint8_t* gBlackGammaTable;
static const uint8_t* gWhiteGammaTable;
void SkGlyph::toMask(SkMask* mask) const {
SkASSERT(mask);
mask->fImage = (uint8_t*)fImage;
mask->fBounds.set(fLeft, fTop, fLeft + fWidth, fTop + fHeight);
mask->fRowBytes = this->rowBytes();
mask->fFormat = static_cast<SkMask::Format>(fMaskFormat);
}
size_t SkGlyph::computeImageSize() const {
const size_t size = this->rowBytes() * fHeight;
switch (fMaskFormat) {
case SkMask::kHorizontalLCD_Format:
return SkAlign4(size) + sizeof(uint32_t) * ((fWidth + 2) * fHeight);
case SkMask::kVerticalLCD_Format:
return SkAlign4(size) + sizeof(uint32_t) * (fWidth * (fHeight + 2));
case SkMask::k3D_Format:
return 3 * size;
default:
return size;
}
}
void SkGlyph::zeroMetrics() {
fAdvanceX = 0;
fAdvanceY = 0;
fWidth = 0;
fHeight = 0;
fTop = 0;
fLeft = 0;
fRsbDelta = 0;
fLsbDelta = 0;
}
void SkGlyph::expandA8ToLCD() const {
SkASSERT(fMaskFormat == SkMask::kHorizontalLCD_Format ||
fMaskFormat == SkMask::kVerticalLCD_Format);
#if defined(SK_SUPPORT_LCDTEXT)
uint8_t* input = reinterpret_cast<uint8_t*>(fImage);
uint32_t* output = reinterpret_cast<uint32_t*>(input + SkAlign4(rowBytes() * fHeight));
if (fMaskFormat == SkMask::kHorizontalLCD_Format) {
for (unsigned y = 0; y < fHeight; ++y) {
const uint8_t* inputRow = input;
*output++ = 0; // make the extra column on the left clear
for (unsigned x = 0; x < fWidth; ++x) {
const uint8_t alpha = *inputRow++;
*output++ = SkPackARGB32(alpha, alpha, alpha, alpha);
}
*output++ = 0;
input += rowBytes();
}
} else {
const unsigned outputRowBytes = sizeof(uint32_t) * fWidth;
memset(output, 0, outputRowBytes);
output += fWidth;
for (unsigned y = 0; y < fHeight; ++y) {
const uint8_t* inputRow = input;
for (unsigned x = 0; x < fWidth; ++x) {
const uint8_t alpha = *inputRow++;
*output++ = SkPackARGB32(alpha, alpha, alpha, alpha);
}
input += rowBytes();
}
memset(output, 0, outputRowBytes);
output += fWidth;
}
#else
#endif
}
///////////////////////////////////////////////////////////////////////////////
#ifdef SK_DEBUG
#define DUMP_RECx
#endif
static SkFlattenable* load_flattenable(const SkDescriptor* desc, uint32_t tag) {
SkFlattenable* obj = NULL;
uint32_t len;
const void* data = desc->findEntry(tag, &len);
if (data) {
SkFlattenableReadBuffer buffer(data, len);
obj = buffer.readFlattenable();
SkASSERT(buffer.offset() == buffer.size());
}
return obj;
}
SkScalerContext::SkScalerContext(const SkDescriptor* desc)
: fPathEffect(NULL), fMaskFilter(NULL)
{
static bool gHaveGammaTables;
if (!gHaveGammaTables) {
const uint8_t* tables[2];
SkFontHost::GetGammaTables(tables);
gBlackGammaTable = tables[0];
gWhiteGammaTable = tables[1];
gHaveGammaTables = true;
}
fBaseGlyphCount = 0;
fNextContext = NULL;
const Rec* rec = (const Rec*)desc->findEntry(kRec_SkDescriptorTag, NULL);
SkASSERT(rec);
fRec = *rec;
#ifdef DUMP_REC
desc->assertChecksum();
SkDebugf("SkScalarContext checksum %x count %d length %d\n",
desc->getChecksum(), desc->getCount(), desc->getLength());
SkDebugf(" textsize %g prescale %g preskew %g post [%g %g %g %g]\n",
rec->fTextSize, rec->fPreScaleX, rec->fPreSkewX, rec->fPost2x2[0][0],
rec->fPost2x2[0][1], rec->fPost2x2[1][0], rec->fPost2x2[1][1]);
SkDebugf(" frame %g miter %g hints %d framefill %d format %d join %d\n",
rec->fFrameWidth, rec->fMiterLimit, rec->fHints, rec->fFrameAndFill,
rec->fMaskFormat, rec->fStrokeJoin);
SkDebugf(" pathEffect %x maskFilter %x\n",
desc->findEntry(kPathEffect_SkDescriptorTag, NULL),
desc->findEntry(kMaskFilter_SkDescriptorTag, NULL));
#endif
fPathEffect = (SkPathEffect*)load_flattenable(desc, kPathEffect_SkDescriptorTag);
fMaskFilter = (SkMaskFilter*)load_flattenable(desc, kMaskFilter_SkDescriptorTag);
fRasterizer = (SkRasterizer*)load_flattenable(desc, kRasterizer_SkDescriptorTag);
}
SkScalerContext::~SkScalerContext() {
SkDELETE(fNextContext);
SkSafeUnref(fPathEffect);
SkSafeUnref(fMaskFilter);
SkSafeUnref(fRasterizer);
}
static SkScalerContext* allocNextContext(const SkScalerContext::Rec& rec) {
// fonthost will determine the next possible font to search, based
// on the current font in fRec. It will return NULL if ctx is our
// last font that can be searched (i.e. ultimate fallback font)
uint32_t newFontID = SkFontHost::NextLogicalFont(rec.fFontID, rec.fOrigFontID);
if (0 == newFontID) {
return NULL;
}
SkAutoDescriptor ad(sizeof(rec) + SkDescriptor::ComputeOverhead(1));
SkDescriptor* desc = ad.getDesc();
desc->init();
SkScalerContext::Rec* newRec =
(SkScalerContext::Rec*)desc->addEntry(kRec_SkDescriptorTag,
sizeof(rec), &rec);
newRec->fFontID = newFontID;
desc->computeChecksum();
return SkFontHost::CreateScalerContext(desc);
}
/* Return the next context, creating it if its not already created, but return
NULL if the fonthost says there are no more fonts to fallback to.
*/
SkScalerContext* SkScalerContext::getNextContext() {
SkScalerContext* next = fNextContext;
// if next is null, then either it isn't cached yet, or we're at the
// end of our possible chain
if (NULL == next) {
next = allocNextContext(fRec);
if (NULL == next) {
return NULL;
}
// next's base is our base + our local count
next->setBaseGlyphCount(fBaseGlyphCount + this->getGlyphCount());
// cache the answer
fNextContext = next;
}
return next;
}
SkScalerContext* SkScalerContext::getGlyphContext(const SkGlyph& glyph) {
unsigned glyphID = glyph.getGlyphID();
SkScalerContext* ctx = this;
for (;;) {
unsigned count = ctx->getGlyphCount();
if (glyphID < count) {
break;
}
glyphID -= count;
ctx = ctx->getNextContext();
if (NULL == ctx) {
SkDebugf("--- no context for glyph %x\n", glyph.getGlyphID());
// just return the original context (this)
return this;
}
}
return ctx;
}
/* This loops through all available fallback contexts (if needed) until it
finds some context that can handle the unichar. If all fail, returns 0
*/
uint16_t SkScalerContext::charToGlyphID(SkUnichar uni) {
SkScalerContext* ctx = this;
unsigned glyphID;
for (;;) {
glyphID = ctx->generateCharToGlyph(uni);
if (glyphID) {
break; // found it
}
ctx = ctx->getNextContext();
if (NULL == ctx) {
return 0; // no more contexts, return missing glyph
}
}
// add the ctx's base, making glyphID unique for chain of contexts
glyphID += ctx->fBaseGlyphCount;
// check for overflow of 16bits, since our glyphID cannot exceed that
if (glyphID > 0xFFFF) {
glyphID = 0;
}
return SkToU16(glyphID);
}
SkUnichar SkScalerContext::glyphIDToChar(uint16_t glyphID) {
SkScalerContext* ctx = this;
unsigned rangeEnd = 0;
do {
unsigned rangeStart = rangeEnd;
rangeEnd += ctx->getGlyphCount();
if (rangeStart <= glyphID && glyphID < rangeEnd) {
return ctx->generateGlyphToChar(glyphID - rangeStart);
}
ctx = ctx->getNextContext();
} while (NULL != ctx);
return 0;
}
void SkScalerContext::getAdvance(SkGlyph* glyph) {
// mark us as just having a valid advance
glyph->fMaskFormat = MASK_FORMAT_JUST_ADVANCE;
// we mark the format before making the call, in case the impl
// internally ends up calling its generateMetrics, which is OK
// albeit slower than strictly necessary
this->getGlyphContext(*glyph)->generateAdvance(glyph);
}
void SkScalerContext::getMetrics(SkGlyph* glyph) {
this->getGlyphContext(*glyph)->generateMetrics(glyph);
// for now we have separate cache entries for devkerning on and off
// in the future we might share caches, but make our measure/draw
// code make the distinction. Thus we zap the values if the caller
// has not asked for them.
if ((fRec.fFlags & SkScalerContext::kDevKernText_Flag) == 0) {
// no devkern, so zap the fields
glyph->fLsbDelta = glyph->fRsbDelta = 0;
}
// if either dimension is empty, zap the image bounds of the glyph
if (0 == glyph->fWidth || 0 == glyph->fHeight) {
glyph->fWidth = 0;
glyph->fHeight = 0;
glyph->fTop = 0;
glyph->fLeft = 0;
glyph->fMaskFormat = 0;
return;
}
if (fRec.fFrameWidth > 0 || fPathEffect != NULL || fRasterizer != NULL) {
SkPath devPath, fillPath;
SkMatrix fillToDevMatrix;
this->internalGetPath(*glyph, &fillPath, &devPath, &fillToDevMatrix);
if (fRasterizer) {
SkMask mask;
if (fRasterizer->rasterize(fillPath, fillToDevMatrix, NULL,
fMaskFilter, &mask,
SkMask::kJustComputeBounds_CreateMode)) {
glyph->fLeft = mask.fBounds.fLeft;
glyph->fTop = mask.fBounds.fTop;
glyph->fWidth = SkToU16(mask.fBounds.width());
glyph->fHeight = SkToU16(mask.fBounds.height());
} else {
goto SK_ERROR;
}
} else {
// just use devPath
SkIRect ir;
devPath.getBounds().roundOut(&ir);
if (ir.isEmpty() || !ir.is16Bit()) {
goto SK_ERROR;
}
glyph->fLeft = ir.fLeft;
glyph->fTop = ir.fTop;
glyph->fWidth = SkToU16(ir.width());
glyph->fHeight = SkToU16(ir.height());
}
}
if (SkMask::kARGB32_Format != glyph->fMaskFormat) {
glyph->fMaskFormat = fRec.fMaskFormat;
}
if (fMaskFilter) {
SkMask src, dst;
SkMatrix matrix;
glyph->toMask(&src);
fRec.getMatrixFrom2x2(&matrix);
src.fImage = NULL; // only want the bounds from the filter
if (fMaskFilter->filterMask(&dst, src, matrix, NULL)) {
SkASSERT(dst.fImage == NULL);
glyph->fLeft = dst.fBounds.fLeft;
glyph->fTop = dst.fBounds.fTop;
glyph->fWidth = SkToU16(dst.fBounds.width());
glyph->fHeight = SkToU16(dst.fBounds.height());
glyph->fMaskFormat = dst.fFormat;
}
}
return;
SK_ERROR:
// draw nothing 'cause we failed
glyph->fLeft = 0;
glyph->fTop = 0;
glyph->fWidth = 0;
glyph->fHeight = 0;
// put a valid value here, in case it was earlier set to
// MASK_FORMAT_JUST_ADVANCE
glyph->fMaskFormat = fRec.fMaskFormat;
}
void SkScalerContext::getImage(const SkGlyph& origGlyph) {
const SkGlyph* glyph = &origGlyph;
SkGlyph tmpGlyph;
if (fMaskFilter) { // restore the prefilter bounds
tmpGlyph.init(origGlyph.fID);
// need the original bounds, sans our maskfilter
SkMaskFilter* mf = fMaskFilter;
fMaskFilter = NULL; // temp disable
this->getMetrics(&tmpGlyph);
fMaskFilter = mf; // restore
tmpGlyph.fImage = origGlyph.fImage;
// we need the prefilter bounds to be <= filter bounds
SkASSERT(tmpGlyph.fWidth <= origGlyph.fWidth);
SkASSERT(tmpGlyph.fHeight <= origGlyph.fHeight);
glyph = &tmpGlyph;
}
if (fRec.fFrameWidth > 0 || fPathEffect != NULL || fRasterizer != NULL) {
SkPath devPath, fillPath;
SkMatrix fillToDevMatrix;
this->internalGetPath(*glyph, &fillPath, &devPath, &fillToDevMatrix);
const bool lcdMode = fRec.fMaskFormat == SkMask::kHorizontalLCD_Format ||
fRec.fMaskFormat == SkMask::kVerticalLCD_Format;
if (fRasterizer) {
SkMask mask;
glyph->toMask(&mask);
mask.fFormat = SkMask::kA8_Format;
sk_bzero(glyph->fImage, mask.computeImageSize());
if (!fRasterizer->rasterize(fillPath, fillToDevMatrix, NULL,
fMaskFilter, &mask,
SkMask::kJustRenderImage_CreateMode)) {
return;
}
} else {
SkBitmap bm;
SkBitmap::Config config;
SkMatrix matrix;
SkRegion clip;
SkPaint paint;
SkDraw draw;
if (SkMask::kA8_Format == fRec.fMaskFormat || lcdMode) {
config = SkBitmap::kA8_Config;
paint.setAntiAlias(true);
} else {
SkASSERT(SkMask::kBW_Format == fRec.fMaskFormat);
config = SkBitmap::kA1_Config;
paint.setAntiAlias(false);
}
clip.setRect(0, 0, glyph->fWidth, glyph->fHeight);
matrix.setTranslate(-SkIntToScalar(glyph->fLeft),
-SkIntToScalar(glyph->fTop));
bm.setConfig(config, glyph->fWidth, glyph->fHeight,
glyph->rowBytes());
bm.setPixels(glyph->fImage);
sk_bzero(glyph->fImage, bm.height() * bm.rowBytes());
draw.fClip = &clip;
draw.fMatrix = &matrix;
draw.fBitmap = &bm;
draw.fBounder = NULL;
draw.drawPath(devPath, paint);
}
if (lcdMode) {
glyph->expandA8ToLCD();
}
} else {
this->getGlyphContext(*glyph)->generateImage(*glyph);
}
if (fMaskFilter) {
SkMask srcM, dstM;
SkMatrix matrix;
// the src glyph image shouldn't be 3D
SkASSERT(SkMask::k3D_Format != glyph->fMaskFormat);
glyph->toMask(&srcM);
fRec.getMatrixFrom2x2(&matrix);
if (fMaskFilter->filterMask(&dstM, srcM, matrix, NULL)) {
int width = SkFastMin32(origGlyph.fWidth, dstM.fBounds.width());
int height = SkFastMin32(origGlyph.fHeight, dstM.fBounds.height());
int dstRB = origGlyph.rowBytes();
int srcRB = dstM.fRowBytes;
const uint8_t* src = (const uint8_t*)dstM.fImage;
uint8_t* dst = (uint8_t*)origGlyph.fImage;
if (SkMask::k3D_Format == dstM.fFormat) {
// we have to copy 3 times as much
height *= 3;
}
// clean out our glyph, since it may be larger than dstM
//sk_bzero(dst, height * dstRB);
while (--height >= 0) {
memcpy(dst, src, width);
src += srcRB;
dst += dstRB;
}
SkMask::FreeImage(dstM.fImage);
}
}
// check to see if we should filter the alpha channel
if (NULL == fMaskFilter &&
fRec.fMaskFormat != SkMask::kBW_Format &&
fRec.fMaskFormat != SkMask::kLCD16_Format &&
(fRec.fFlags & (kGammaForBlack_Flag | kGammaForWhite_Flag)) != 0)
{
const uint8_t* table = (fRec.fFlags & kGammaForBlack_Flag) ? gBlackGammaTable : gWhiteGammaTable;
if (NULL != table) {
uint8_t* dst = (uint8_t*)origGlyph.fImage;
unsigned rowBytes = origGlyph.rowBytes();
for (int y = origGlyph.fHeight - 1; y >= 0; --y) {
for (int x = origGlyph.fWidth - 1; x >= 0; --x) {
dst[x] = table[dst[x]];
}
dst += rowBytes;
}
}
}
}
void SkScalerContext::getPath(const SkGlyph& glyph, SkPath* path) {
this->internalGetPath(glyph, NULL, path, NULL);
}
void SkScalerContext::getFontMetrics(SkPaint::FontMetrics* mx,
SkPaint::FontMetrics* my) {
this->generateFontMetrics(mx, my);
}
SkUnichar SkScalerContext::generateGlyphToChar(uint16_t glyph) {
return 0;
}
///////////////////////////////////////////////////////////////////////////////
void SkScalerContext::internalGetPath(const SkGlyph& glyph, SkPath* fillPath,
SkPath* devPath, SkMatrix* fillToDevMatrix) {
SkPath path;
this->getGlyphContext(glyph)->generatePath(glyph, &path);
if (fRec.fFrameWidth > 0 || fPathEffect != NULL) {
// 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, inverse;
fRec.getMatrixFrom2x2(&matrix);
matrix.invert(&inverse);
path.transform(inverse, &localPath);
// now localPath is only affected by the paint settings, and not the canvas matrix
SkScalar width = fRec.fFrameWidth;
if (fPathEffect) {
SkPath effectPath;
if (fPathEffect->filterPath(&effectPath, localPath, &width)) {
localPath.swap(effectPath);
}
}
if (width > 0) {
SkStroke stroker;
SkPath outline;
stroker.setWidth(width);
stroker.setMiterLimit(fRec.fMiterLimit);
stroker.setJoin((SkPaint::Join)fRec.fStrokeJoin);
stroker.setDoFill(SkToBool(fRec.fFlags & kFrameAndFill_Flag));
stroker.strokePath(localPath, &outline);
localPath.swap(outline);
}
// now return stuff to the caller
if (fillToDevMatrix) {
*fillToDevMatrix = matrix;
}
if (devPath) {
localPath.transform(matrix, devPath);
}
if (fillPath) {
fillPath->swap(localPath);
}
} else { // nothing tricky to do
if (fillToDevMatrix) {
fillToDevMatrix->reset();
}
if (devPath) {
if (fillPath == NULL) {
devPath->swap(path);
} else {
*devPath = path;
}
}
if (fillPath) {
fillPath->swap(path);
}
}
if (devPath) {
devPath->updateBoundsCache();
}
if (fillPath) {
fillPath->updateBoundsCache();
}
}
void SkScalerContext::Rec::getMatrixFrom2x2(SkMatrix* dst) const {
dst->reset();
dst->setScaleX(fPost2x2[0][0]);
dst->setSkewX( fPost2x2[0][1]);
dst->setSkewY( fPost2x2[1][0]);
dst->setScaleY(fPost2x2[1][1]);
}
void SkScalerContext::Rec::getLocalMatrix(SkMatrix* m) const {
m->setScale(SkScalarMul(fTextSize, fPreScaleX), fTextSize);
if (fPreSkewX) {
m->postSkew(fPreSkewX, 0);
}
}
void SkScalerContext::Rec::getSingleMatrix(SkMatrix* m) const {
this->getLocalMatrix(m);
// now concat the device matrix
SkMatrix deviceMatrix;
this->getMatrixFrom2x2(&deviceMatrix);
m->postConcat(deviceMatrix);
}
///////////////////////////////////////////////////////////////////////////////
#include "SkFontHost.h"
class SkScalerContext_Empty : public SkScalerContext {
public:
SkScalerContext_Empty(const SkDescriptor* desc) : SkScalerContext(desc) {}
protected:
virtual unsigned generateGlyphCount() {
return 0;
}
virtual uint16_t generateCharToGlyph(SkUnichar uni) {
return 0;
}
virtual void generateAdvance(SkGlyph* glyph) {
glyph->zeroMetrics();
}
virtual void generateMetrics(SkGlyph* glyph) {
glyph->zeroMetrics();
}
virtual void generateImage(const SkGlyph& glyph) {}
virtual void generatePath(const SkGlyph& glyph, SkPath* path) {}
virtual void generateFontMetrics(SkPaint::FontMetrics* mx,
SkPaint::FontMetrics* my) {
if (mx) {
sk_bzero(mx, sizeof(*mx));
}
if (my) {
sk_bzero(my, sizeof(*my));
}
}
};
extern SkScalerContext* SkCreateColorScalerContext(const SkDescriptor* desc);
SkScalerContext* SkScalerContext::Create(const SkDescriptor* desc) {
SkScalerContext* c = NULL; //SkCreateColorScalerContext(desc);
if (NULL == c) {
c = SkFontHost::CreateScalerContext(desc);
}
if (NULL == c) {
c = SkNEW_ARGS(SkScalerContext_Empty, (desc));
}
return c;
}