blob: 2d2f9a14432dd7aae4a719e6469858f30bb8ef84 [file] [log] [blame]
/*
* Copyright 2013 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "GrDistanceFieldTextContext.h"
#include "GrAtlas.h"
#include "GrDrawTarget.h"
#include "GrDrawTargetCaps.h"
#include "GrFontScaler.h"
#include "SkGlyphCache.h"
#include "GrIndexBuffer.h"
#include "GrTextStrike.h"
#include "GrTextStrike_impl.h"
#include "SkDistanceFieldGen.h"
#include "SkDraw.h"
#include "SkGpuDevice.h"
#include "SkPath.h"
#include "SkRTConf.h"
#include "SkStrokeRec.h"
#include "effects/GrDistanceFieldTextureEffect.h"
static const int kGlyphCoordsAttributeIndex = 1;
static const int kSmallDFFontSize = 32;
static const int kSmallDFFontLimit = 32;
static const int kMediumDFFontSize = 64;
static const int kMediumDFFontLimit = 64;
static const int kLargeDFFontSize = 128;
SK_CONF_DECLARE(bool, c_DumpFontCache, "gpu.dumpFontCache", false,
"Dump the contents of the font cache before every purge.");
GrDistanceFieldTextContext::GrDistanceFieldTextContext(GrContext* context,
const SkDeviceProperties& properties,
bool enable)
: GrTextContext(context, properties) {
#if SK_FORCE_DISTANCEFIELD_FONTS
fEnableDFRendering = true;
#else
fEnableDFRendering = enable;
#endif
fStrike = NULL;
fCurrTexture = NULL;
fCurrVertex = 0;
fVertices = NULL;
fMaxVertices = 0;
}
GrDistanceFieldTextContext::~GrDistanceFieldTextContext() {
this->flushGlyphs();
}
bool GrDistanceFieldTextContext::canDraw(const SkPaint& paint) {
if (!fEnableDFRendering && !paint.isDistanceFieldTextTEMP()) {
return false;
}
// rasterizers and mask filters modify alpha, which doesn't
// translate well to distance
if (paint.getRasterizer() || paint.getMaskFilter() ||
!fContext->getTextTarget()->caps()->shaderDerivativeSupport()) {
return false;
}
// TODO: add some stroking support
if (paint.getStyle() != SkPaint::kFill_Style) {
return false;
}
// TODO: choose an appropriate maximum scale for distance fields and
// enable perspective
if (SkDraw::ShouldDrawTextAsPaths(paint, fContext->getMatrix())) {
return false;
}
// distance fields cannot represent color fonts
SkScalerContext::Rec rec;
SkScalerContext::MakeRec(paint, &fDeviceProperties, NULL, &rec);
return rec.getFormat() != SkMask::kARGB32_Format;
}
static inline GrColor skcolor_to_grcolor_nopremultiply(SkColor c) {
unsigned r = SkColorGetR(c);
unsigned g = SkColorGetG(c);
unsigned b = SkColorGetB(c);
return GrColorPackRGBA(r, g, b, 0xff);
}
void GrDistanceFieldTextContext::flushGlyphs() {
if (NULL == fDrawTarget) {
return;
}
GrDrawState* drawState = fDrawTarget->drawState();
GrDrawState::AutoRestoreEffects are(drawState);
drawState->setFromPaint(fPaint, fContext->getMatrix(), fContext->getRenderTarget());
if (fCurrVertex > 0) {
fContext->getFontCache()->updateTextures();
// setup our sampler state for our text texture/atlas
SkASSERT(SkIsAlign4(fCurrVertex));
SkASSERT(fCurrTexture);
GrTextureParams params(SkShader::kRepeat_TileMode, GrTextureParams::kBilerp_FilterMode);
// Effects could be stored with one of the cache objects (atlas?)
if (fUseLCDText) {
bool useBGR = SkDeviceProperties::Geometry::kBGR_Layout ==
fDeviceProperties.fGeometry.getLayout();
drawState->addCoverageEffect(GrDistanceFieldLCDTextureEffect::Create(
fCurrTexture,
params,
fContext->getMatrix().rectStaysRect() &&
fContext->getMatrix().isSimilarity(),
useBGR),
kGlyphCoordsAttributeIndex)->unref();
if (kOne_GrBlendCoeff != fPaint.getSrcBlendCoeff() ||
kISA_GrBlendCoeff != fPaint.getDstBlendCoeff() ||
fPaint.numColorStages()) {
GrPrintf("LCD Text will not draw correctly.\n");
}
// We don't use the GrPaint's color in this case because it's been premultiplied by
// alpha. Instead we feed in a non-premultiplied color, and multiply its alpha by
// the mask texture color. The end result is that we get
// mask*paintAlpha*paintColor + (1-mask*paintAlpha)*dstColor
int a = SkColorGetA(fSkPaint.getColor());
// paintAlpha
drawState->setColor(SkColorSetARGB(a, a, a, a));
// paintColor
drawState->setBlendConstant(skcolor_to_grcolor_nopremultiply(fSkPaint.getColor()));
drawState->setBlendFunc(kConstC_GrBlendCoeff, kISC_GrBlendCoeff);
} else {
drawState->addCoverageEffect(GrDistanceFieldTextureEffect::Create(fCurrTexture, params,
fContext->getMatrix().isSimilarity()),
kGlyphCoordsAttributeIndex)->unref();
// set back to normal in case we took LCD path previously.
drawState->setBlendFunc(fPaint.getSrcBlendCoeff(), fPaint.getDstBlendCoeff());
drawState->setColor(fPaint.getColor());
}
int nGlyphs = fCurrVertex / 4;
fDrawTarget->setIndexSourceToBuffer(fContext->getQuadIndexBuffer());
fDrawTarget->drawIndexedInstances(kTriangles_GrPrimitiveType,
nGlyphs,
4, 6);
fDrawTarget->resetVertexSource();
fVertices = NULL;
fMaxVertices = 0;
fCurrVertex = 0;
SkSafeSetNull(fCurrTexture);
}
}
namespace {
// position + texture coord
extern const GrVertexAttrib gTextVertexAttribs[] = {
{kVec2f_GrVertexAttribType, 0, kPosition_GrVertexAttribBinding},
{kVec2f_GrVertexAttribType, sizeof(SkPoint), kEffect_GrVertexAttribBinding}
};
};
void GrDistanceFieldTextContext::drawPackedGlyph(GrGlyph::PackedID packed,
SkFixed vx, SkFixed vy,
GrFontScaler* scaler) {
if (NULL == fDrawTarget) {
return;
}
if (NULL == fStrike) {
fStrike = fContext->getFontCache()->getStrike(scaler, true);
}
GrGlyph* glyph = fStrike->getGlyph(packed, scaler);
if (NULL == glyph || glyph->fBounds.isEmpty()) {
return;
}
SkScalar sx = SkFixedToScalar(vx);
SkScalar sy = SkFixedToScalar(vy);
/*
// not valid, need to find a different solution for this
vx += SkIntToFixed(glyph->fBounds.fLeft);
vy += SkIntToFixed(glyph->fBounds.fTop);
// keep them as ints until we've done the clip-test
GrFixed width = glyph->fBounds.width();
GrFixed height = glyph->fBounds.height();
// check if we clipped out
if (true || NULL == glyph->fPlot) {
int x = vx >> 16;
int y = vy >> 16;
if (fClipRect.quickReject(x, y, x + width, y + height)) {
// SkCLZ(3); // so we can set a break-point in the debugger
return;
}
}
*/
if (NULL == glyph->fPlot) {
if (fStrike->addGlyphToAtlas(glyph, scaler)) {
goto HAS_ATLAS;
}
// try to clear out an unused plot before we flush
if (fContext->getFontCache()->freeUnusedPlot(fStrike) &&
fStrike->addGlyphToAtlas(glyph, scaler)) {
goto HAS_ATLAS;
}
if (c_DumpFontCache) {
#ifdef SK_DEVELOPER
fContext->getFontCache()->dump();
#endif
}
// before we purge the cache, we must flush any accumulated draws
this->flushGlyphs();
fContext->flush();
// we should have an unused plot now
if (fContext->getFontCache()->freeUnusedPlot(fStrike) &&
fStrike->addGlyphToAtlas(glyph, scaler)) {
goto HAS_ATLAS;
}
if (NULL == glyph->fPath) {
SkPath* path = SkNEW(SkPath);
if (!scaler->getGlyphPath(glyph->glyphID(), path)) {
// flag the glyph as being dead?
delete path;
return;
}
glyph->fPath = path;
}
GrContext::AutoMatrix am;
SkMatrix ctm;
ctm.setScale(fTextRatio, fTextRatio);
ctm.postTranslate(sx, sy);
GrPaint tmpPaint(fPaint);
am.setPreConcat(fContext, ctm, &tmpPaint);
SkStrokeRec stroke(SkStrokeRec::kFill_InitStyle);
fContext->drawPath(tmpPaint, *glyph->fPath, stroke);
return;
}
HAS_ATLAS:
SkASSERT(glyph->fPlot);
GrDrawTarget::DrawToken drawToken = fDrawTarget->getCurrentDrawToken();
glyph->fPlot->setDrawToken(drawToken);
GrTexture* texture = glyph->fPlot->texture();
SkASSERT(texture);
if (fCurrTexture != texture || fCurrVertex + 4 > fMaxVertices) {
this->flushGlyphs();
fCurrTexture = texture;
fCurrTexture->ref();
}
if (NULL == fVertices) {
// If we need to reserve vertices allow the draw target to suggest
// a number of verts to reserve and whether to perform a flush.
fMaxVertices = kMinRequestedVerts;
fDrawTarget->drawState()->setVertexAttribs<gTextVertexAttribs>(
SK_ARRAY_COUNT(gTextVertexAttribs));
bool flush = fDrawTarget->geometryHints(&fMaxVertices, NULL);
if (flush) {
this->flushGlyphs();
fContext->flush();
fDrawTarget->drawState()->setVertexAttribs<gTextVertexAttribs>(
SK_ARRAY_COUNT(gTextVertexAttribs));
}
fMaxVertices = kDefaultRequestedVerts;
// ignore return, no point in flushing again.
fDrawTarget->geometryHints(&fMaxVertices, NULL);
int maxQuadVertices = 4 * fContext->getQuadIndexBuffer()->maxQuads();
if (fMaxVertices < kMinRequestedVerts) {
fMaxVertices = kDefaultRequestedVerts;
} else if (fMaxVertices > maxQuadVertices) {
// don't exceed the limit of the index buffer
fMaxVertices = maxQuadVertices;
}
bool success = fDrawTarget->reserveVertexAndIndexSpace(fMaxVertices,
0,
GrTCast<void**>(&fVertices),
NULL);
GrAlwaysAssert(success);
SkASSERT(2*sizeof(SkPoint) == fDrawTarget->getDrawState().getVertexSize());
}
SkScalar dx = SkIntToScalar(glyph->fBounds.fLeft + SK_DistanceFieldInset);
SkScalar dy = SkIntToScalar(glyph->fBounds.fTop + SK_DistanceFieldInset);
SkScalar width = SkIntToScalar(glyph->fBounds.width() - 2*SK_DistanceFieldInset);
SkScalar height = SkIntToScalar(glyph->fBounds.height() - 2*SK_DistanceFieldInset);
SkScalar scale = fTextRatio;
dx *= scale;
dy *= scale;
sx += dx;
sy += dy;
width *= scale;
height *= scale;
SkFixed tx = SkIntToFixed(glyph->fAtlasLocation.fX + SK_DistanceFieldInset);
SkFixed ty = SkIntToFixed(glyph->fAtlasLocation.fY + SK_DistanceFieldInset);
SkFixed tw = SkIntToFixed(glyph->fBounds.width() - 2*SK_DistanceFieldInset);
SkFixed th = SkIntToFixed(glyph->fBounds.height() - 2*SK_DistanceFieldInset);
static const size_t kVertexSize = 2 * sizeof(SkPoint);
fVertices[2*fCurrVertex].setRectFan(sx,
sy,
sx + width,
sy + height,
kVertexSize);
fVertices[2*fCurrVertex+1].setRectFan(SkFixedToFloat(texture->normalizeFixedX(tx)),
SkFixedToFloat(texture->normalizeFixedY(ty)),
SkFixedToFloat(texture->normalizeFixedX(tx + tw)),
SkFixedToFloat(texture->normalizeFixedY(ty + th)),
kVertexSize);
fCurrVertex += 4;
}
inline void GrDistanceFieldTextContext::init(const GrPaint& paint, const SkPaint& skPaint) {
GrTextContext::init(paint, skPaint);
fStrike = NULL;
fCurrTexture = NULL;
fCurrVertex = 0;
fVertices = NULL;
fMaxVertices = 0;
if (fSkPaint.getTextSize() <= kSmallDFFontLimit) {
fTextRatio = fSkPaint.getTextSize()/kSmallDFFontSize;
fSkPaint.setTextSize(SkIntToScalar(kSmallDFFontSize));
} else if (fSkPaint.getTextSize() <= kMediumDFFontLimit) {
fTextRatio = fSkPaint.getTextSize()/kMediumDFFontSize;
fSkPaint.setTextSize(SkIntToScalar(kMediumDFFontSize));
} else {
fTextRatio = fSkPaint.getTextSize()/kLargeDFFontSize;
fSkPaint.setTextSize(SkIntToScalar(kLargeDFFontSize));
}
fUseLCDText = fSkPaint.isLCDRenderText();
fSkPaint.setLCDRenderText(false);
fSkPaint.setAutohinted(false);
fSkPaint.setSubpixelText(true);
}
inline void GrDistanceFieldTextContext::finish() {
flushGlyphs();
GrTextContext::finish();
}
void GrDistanceFieldTextContext::drawText(const GrPaint& paint, const SkPaint& skPaint,
const char text[], size_t byteLength,
SkScalar x, SkScalar y) {
SkASSERT(byteLength == 0 || text != NULL);
// nothing to draw or can't draw
if (text == NULL || byteLength == 0 /* no raster clip? || fRC->isEmpty()*/
|| fSkPaint.getRasterizer()) {
return;
}
this->init(paint, skPaint);
SkScalar sizeRatio = fTextRatio;
SkDrawCacheProc glyphCacheProc = fSkPaint.getDrawCacheProc();
SkAutoGlyphCache autoCache(fSkPaint, &fDeviceProperties, NULL);
SkGlyphCache* cache = autoCache.getCache();
GrFontScaler* fontScaler = GetGrFontScaler(cache);
// need to measure first
// TODO - generate positions and pre-load cache as well?
const char* stop = text + byteLength;
if (fSkPaint.getTextAlign() != SkPaint::kLeft_Align) {
SkFixed stopX = 0;
SkFixed stopY = 0;
const char* textPtr = text;
while (textPtr < stop) {
// don't need x, y here, since all subpixel variants will have the
// same advance
const SkGlyph& glyph = glyphCacheProc(cache, &textPtr, 0, 0);
stopX += glyph.fAdvanceX;
stopY += glyph.fAdvanceY;
}
SkASSERT(textPtr == stop);
SkScalar alignX = SkFixedToScalar(stopX)*sizeRatio;
SkScalar alignY = SkFixedToScalar(stopY)*sizeRatio;
if (fSkPaint.getTextAlign() == SkPaint::kCenter_Align) {
alignX = SkScalarHalf(alignX);
alignY = SkScalarHalf(alignY);
}
x -= alignX;
y -= alignY;
}
SkFixed fx = SkScalarToFixed(x);
SkFixed fy = SkScalarToFixed(y);
SkFixed fixedScale = SkScalarToFixed(sizeRatio);
while (text < stop) {
const SkGlyph& glyph = glyphCacheProc(cache, &text, 0, 0);
if (glyph.fWidth) {
this->drawPackedGlyph(GrGlyph::Pack(glyph.getGlyphID(),
glyph.getSubXFixed(),
glyph.getSubYFixed()),
fx,
fy,
fontScaler);
}
fx += SkFixedMul_portable(glyph.fAdvanceX, fixedScale);
fy += SkFixedMul_portable(glyph.fAdvanceY, fixedScale);
}
this->finish();
}
void GrDistanceFieldTextContext::drawPosText(const GrPaint& paint, const SkPaint& skPaint,
const char text[], size_t byteLength,
const SkScalar pos[], SkScalar constY,
int scalarsPerPosition) {
SkASSERT(byteLength == 0 || text != NULL);
SkASSERT(1 == scalarsPerPosition || 2 == scalarsPerPosition);
// nothing to draw
if (text == NULL || byteLength == 0 /* no raster clip? || fRC->isEmpty()*/) {
return;
}
this->init(paint, skPaint);
SkDrawCacheProc glyphCacheProc = fSkPaint.getDrawCacheProc();
SkAutoGlyphCache autoCache(fSkPaint, &fDeviceProperties, NULL);
SkGlyphCache* cache = autoCache.getCache();
GrFontScaler* fontScaler = GetGrFontScaler(cache);
const char* stop = text + byteLength;
if (SkPaint::kLeft_Align == fSkPaint.getTextAlign()) {
while (text < stop) {
// the last 2 parameters are ignored
const SkGlyph& glyph = glyphCacheProc(cache, &text, 0, 0);
if (glyph.fWidth) {
SkScalar x = pos[0];
SkScalar y = scalarsPerPosition == 1 ? constY : pos[1];
this->drawPackedGlyph(GrGlyph::Pack(glyph.getGlyphID(),
glyph.getSubXFixed(),
glyph.getSubYFixed()),
SkScalarToFixed(x),
SkScalarToFixed(y),
fontScaler);
}
pos += scalarsPerPosition;
}
} else {
int alignShift = SkPaint::kCenter_Align == fSkPaint.getTextAlign() ? 1 : 0;
while (text < stop) {
// the last 2 parameters are ignored
const SkGlyph& glyph = glyphCacheProc(cache, &text, 0, 0);
if (glyph.fWidth) {
SkScalar x = pos[0];
SkScalar y = scalarsPerPosition == 1 ? constY : pos[1];
this->drawPackedGlyph(GrGlyph::Pack(glyph.getGlyphID(),
glyph.getSubXFixed(),
glyph.getSubYFixed()),
SkScalarToFixed(x) - (glyph.fAdvanceX >> alignShift),
SkScalarToFixed(y) - (glyph.fAdvanceY >> alignShift),
fontScaler);
}
pos += scalarsPerPosition;
}
}
this->finish();
}