blob: dc0ea954ec189f50cd47f058acd6a35497a3c2a0 [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 "SkColorFilter.h"
#include "GrDrawTarget.h"
#include "GrDrawTargetCaps.h"
#include "GrFontScaler.h"
#include "SkGlyphCache.h"
#include "GrGpu.h"
#include "GrIndexBuffer.h"
#include "GrStrokeInfo.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"
SK_CONF_DECLARE(bool, c_DumpFontCache, "gpu.dumpFontCache", false,
"Dump the contents of the font cache before every purge.");
static const int kGlyphCoordsNoColorAttributeIndex = 1;
static const int kGlyphCoordsWithColorAttributeIndex = 2;
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;
namespace {
// position + texture coord
extern const GrVertexAttrib gTextVertexAttribs[] = {
{kVec2f_GrVertexAttribType, 0, kPosition_GrVertexAttribBinding},
{kVec2f_GrVertexAttribType, sizeof(SkPoint) , kEffect_GrVertexAttribBinding}
};
static const size_t kTextVASize = 2 * sizeof(SkPoint);
// position + color + texture coord
extern const GrVertexAttrib gTextVertexWithColorAttribs[] = {
{kVec2f_GrVertexAttribType, 0, kPosition_GrVertexAttribBinding},
{kVec4ub_GrVertexAttribType, sizeof(SkPoint), kColor_GrVertexAttribBinding},
{kVec2f_GrVertexAttribType, sizeof(SkPoint) + sizeof(GrColor), kEffect_GrVertexAttribBinding}
};
static const size_t kTextVAColorSize = 2 * sizeof(SkPoint) + sizeof(GrColor);
};
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;
fGammaTexture = NULL;
fCurrTexture = NULL;
fCurrVertex = 0;
fEffectTextureUniqueID = SK_InvalidUniqueID;
fEffectColor = GrColor_ILLEGAL;
fEffectFlags = 0;
fVertices = NULL;
fMaxVertices = 0;
fVertexBounds.setLargestInverted();
}
GrDistanceFieldTextContext::~GrDistanceFieldTextContext() {
this->flushGlyphs();
SkSafeSetNull(fGammaTexture);
}
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::setupCoverageEffect(const SkColor& filteredColor) {
GrTextureParams params(SkShader::kRepeat_TileMode, GrTextureParams::kBilerp_FilterMode);
GrTextureParams gammaParams(SkShader::kClamp_TileMode, GrTextureParams::kNone_FilterMode);
uint32_t textureUniqueID = fCurrTexture->getUniqueID();
// set up any flags
uint32_t flags = 0;
flags |= fContext->getMatrix().isSimilarity() ? kSimilarity_DistanceFieldEffectFlag : 0;
flags |= fUseLCDText ? kUseLCD_DistanceFieldEffectFlag : 0;
flags |= fUseLCDText && fContext->getMatrix().rectStaysRect() ?
kRectToRect_DistanceFieldEffectFlag : 0;
bool useBGR = SkDeviceProperties::Geometry::kBGR_Layout ==
fDeviceProperties.fGeometry.getLayout();
flags |= fUseLCDText && useBGR ? kBGR_DistanceFieldEffectFlag : 0;
// see if we need to create a new effect
if (textureUniqueID != fEffectTextureUniqueID ||
filteredColor != fEffectColor ||
flags != fEffectFlags) {
if (fUseLCDText) {
GrColor colorNoPreMul = skcolor_to_grcolor_nopremultiply(filteredColor);
fCachedEffect.reset(GrDistanceFieldLCDTextureEffect::Create(fCurrTexture,
params,
fGammaTexture,
gammaParams,
colorNoPreMul,
flags));
} else {
#ifdef SK_GAMMA_APPLY_TO_A8
U8CPU lum = SkColorSpaceLuminance::computeLuminance(fDeviceProperties.fGamma,
filteredColor);
fCachedEffect.reset(GrDistanceFieldTextureEffect::Create(fCurrTexture,
params,
fGammaTexture,
gammaParams,
lum/255.f,
flags));
#else
fCachedEffect.reset(GrDistanceFieldTextureEffect::Create(fCurrTexture,
params, flags));
#endif
}
fEffectTextureUniqueID = textureUniqueID;
fEffectColor = filteredColor;
fEffectFlags = flags;
}
}
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) {
// setup our sampler state for our text texture/atlas
SkASSERT(SkIsAlign4(fCurrVertex));
// get our current color
SkColor filteredColor;
SkColorFilter* colorFilter = fSkPaint.getColorFilter();
if (NULL != colorFilter) {
filteredColor = colorFilter->filterColor(fSkPaint.getColor());
} else {
filteredColor = fSkPaint.getColor();
}
this->setupCoverageEffect(filteredColor);
// Effects could be stored with one of the cache objects (atlas?)
int coordsIdx = drawState->hasColorVertexAttribute() ? kGlyphCoordsWithColorAttributeIndex :
kGlyphCoordsNoColorAttributeIndex;
drawState->addCoverageEffect(fCachedEffect.get(), coordsIdx);
// Set draw state
if (fUseLCDText) {
GrColor colorNoPreMul = skcolor_to_grcolor_nopremultiply(filteredColor);
if (kOne_GrBlendCoeff != fPaint.getSrcBlendCoeff() ||
kISA_GrBlendCoeff != fPaint.getDstBlendCoeff() ||
fPaint.numColorStages()) {
GrPrintf("LCD Text will not draw correctly.\n");
}
SkASSERT(!drawState->hasColorVertexAttribute());
// 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(colorNoPreMul);
drawState->setBlendFunc(kConstC_GrBlendCoeff, kISC_GrBlendCoeff);
} else {
// set back to normal in case we took LCD path previously.
drawState->setBlendFunc(fPaint.getSrcBlendCoeff(), fPaint.getDstBlendCoeff());
// We're using per-vertex color.
SkASSERT(drawState->hasColorVertexAttribute());
}
int nGlyphs = fCurrVertex / 4;
fDrawTarget->setIndexSourceToBuffer(fContext->getQuadIndexBuffer());
fDrawTarget->drawIndexedInstances(kTriangles_GrPrimitiveType,
nGlyphs,
4, 6, &fVertexBounds);
fDrawTarget->resetVertexSource();
fVertices = NULL;
fMaxVertices = 0;
fCurrVertex = 0;
SkSafeSetNull(fCurrTexture);
fVertexBounds.setLargestInverted();
}
}
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);
GrStrokeInfo strokeInfo(SkStrokeRec::kFill_InitStyle);
fContext->drawPath(tmpPaint, *glyph->fPath, strokeInfo);
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();
}
bool useColorVerts = !fUseLCDText;
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;
if (useColorVerts) {
fDrawTarget->drawState()->setVertexAttribs<gTextVertexWithColorAttribs>(
SK_ARRAY_COUNT(gTextVertexWithColorAttribs),
kTextVAColorSize);
} else {
fDrawTarget->drawState()->setVertexAttribs<gTextVertexAttribs>(
SK_ARRAY_COUNT(gTextVertexAttribs),
kTextVASize);
}
bool flush = fDrawTarget->geometryHints(&fMaxVertices, NULL);
if (flush) {
this->flushGlyphs();
fContext->flush();
if (useColorVerts) {
fDrawTarget->drawState()->setVertexAttribs<gTextVertexWithColorAttribs>(
SK_ARRAY_COUNT(gTextVertexWithColorAttribs),
kTextVAColorSize);
} else {
fDrawTarget->drawState()->setVertexAttribs<gTextVertexAttribs>(
SK_ARRAY_COUNT(gTextVertexAttribs),
kTextVASize);
}
}
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,
&fVertices,
NULL);
GrAlwaysAssert(success);
}
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);
SkRect r;
r.fLeft = sx;
r.fTop = sy;
r.fRight = sx + width;
r.fBottom = sy + height;
fVertexBounds.growToInclude(r);
size_t vertSize = fUseLCDText ? (2 * sizeof(SkPoint))
: (2 * sizeof(SkPoint) + sizeof(GrColor));
SkASSERT(vertSize == fDrawTarget->getDrawState().getVertexStride());
SkPoint* positions = reinterpret_cast<SkPoint*>(
reinterpret_cast<intptr_t>(fVertices) + vertSize * fCurrVertex);
positions->setRectFan(r.fLeft, r.fTop, r.fRight, r.fBottom, vertSize);
// The texture coords are last in both the with and without color vertex layouts.
SkPoint* textureCoords = reinterpret_cast<SkPoint*>(
reinterpret_cast<intptr_t>(positions) + vertSize - sizeof(SkPoint));
textureCoords->setRectFan(SkFixedToFloat(texture->normalizeFixedX(tx)),
SkFixedToFloat(texture->normalizeFixedY(ty)),
SkFixedToFloat(texture->normalizeFixedX(tx + tw)),
SkFixedToFloat(texture->normalizeFixedY(ty + th)),
vertSize);
if (useColorVerts) {
if (0xFF == GrColorUnpackA(fPaint.getColor())) {
fDrawTarget->drawState()->setHint(GrDrawState::kVertexColorsAreOpaque_Hint, true);
}
// color comes after position.
GrColor* colors = reinterpret_cast<GrColor*>(positions + 1);
for (int i = 0; i < 4; ++i) {
*colors = fPaint.getColor();
colors = reinterpret_cast<GrColor*>(reinterpret_cast<intptr_t>(colors) + vertSize);
}
}
fCurrVertex += 4;
}
inline void GrDistanceFieldTextContext::init(const GrPaint& paint, const SkPaint& skPaint) {
GrTextContext::init(paint, skPaint);
fStrike = NULL;
fCurrVertex = 0;
fVertices = NULL;
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.setHinting(SkPaint::kNormal_Hinting);
fSkPaint.setSubpixelText(true);
}
inline void GrDistanceFieldTextContext::finish() {
this->flushGlyphs();
GrTextContext::finish();
}
static void setup_gamma_texture(GrContext* context, const SkGlyphCache* cache,
const SkDeviceProperties& deviceProperties,
GrTexture** gammaTexture) {
if (NULL == *gammaTexture) {
int width, height;
size_t size;
#ifdef SK_GAMMA_CONTRAST
SkScalar contrast = SK_GAMMA_CONTRAST;
#else
SkScalar contrast = 0.5f;
#endif
SkScalar paintGamma = deviceProperties.fGamma;
SkScalar deviceGamma = deviceProperties.fGamma;
size = SkScalerContext::GetGammaLUTSize(contrast, paintGamma, deviceGamma,
&width, &height);
SkAutoTArray<uint8_t> data((int)size);
SkScalerContext::GetGammaLUTData(contrast, paintGamma, deviceGamma, data.get());
// TODO: Update this to use the cache rather than directly creating a texture.
GrTextureDesc desc;
desc.fFlags = kDynamicUpdate_GrTextureFlagBit;
desc.fWidth = width;
desc.fHeight = height;
desc.fConfig = kAlpha_8_GrPixelConfig;
*gammaTexture = context->getGpu()->createTexture(desc, NULL, 0);
if (NULL == *gammaTexture) {
return;
}
context->writeTexturePixels(*gammaTexture,
0, 0, width, height,
(*gammaTexture)->config(), data.get(), 0,
GrContext::kDontFlush_PixelOpsFlag);
}
}
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();
SkAutoGlyphCacheNoGamma autoCache(fSkPaint, &fDeviceProperties, NULL);
SkGlyphCache* cache = autoCache.getCache();
GrFontScaler* fontScaler = GetGrFontScaler(cache);
setup_gamma_texture(fContext, cache, fDeviceProperties, &fGammaTexture);
// 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();
SkAutoGlyphCacheNoGamma autoCache(fSkPaint, &fDeviceProperties, NULL);
SkGlyphCache* cache = autoCache.getCache();
GrFontScaler* fontScaler = GetGrFontScaler(cache);
setup_gamma_texture(fContext, cache, fDeviceProperties, &fGammaTexture);
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();
}