| /* |
| * Copyright 2015 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #include "GrTextContext.h" |
| |
| #include "GrCaps.h" |
| #include "GrContext.h" |
| #include "GrRecordingContextPriv.h" |
| #include "GrSDFMaskFilter.h" |
| #include "GrTextBlobCache.h" |
| #include "SkDistanceFieldGen.h" |
| #include "SkDraw.h" |
| #include "SkDrawProcs.h" |
| #include "SkGlyphRun.h" |
| #include "SkGr.h" |
| #include "SkGraphics.h" |
| #include "SkMakeUnique.h" |
| #include "SkMaskFilterBase.h" |
| #include "SkPaintPriv.h" |
| #include "SkTo.h" |
| #include "ops/GrMeshDrawOp.h" |
| |
| // DF sizes and thresholds for usage of the small and medium sizes. For example, above |
| // kSmallDFFontLimit we will use the medium size. The large size is used up until the size at |
| // which we switch over to drawing as paths as controlled by Options. |
| static const int kSmallDFFontSize = 32; |
| static const int kSmallDFFontLimit = 32; |
| static const int kMediumDFFontSize = 72; |
| static const int kMediumDFFontLimit = 72; |
| static const int kLargeDFFontSize = 162; |
| |
| static const int kDefaultMinDistanceFieldFontSize = 18; |
| #ifdef SK_BUILD_FOR_ANDROID |
| static const int kDefaultMaxDistanceFieldFontSize = 384; |
| #else |
| static const int kDefaultMaxDistanceFieldFontSize = 2 * kLargeDFFontSize; |
| #endif |
| |
| GrTextContext::GrTextContext(const Options& options) |
| : fDistanceAdjustTable(new GrDistanceFieldAdjustTable), fOptions(options) { |
| SanitizeOptions(&fOptions); |
| } |
| |
| std::unique_ptr<GrTextContext> GrTextContext::Make(const Options& options) { |
| return std::unique_ptr<GrTextContext>(new GrTextContext(options)); |
| } |
| |
| SkColor GrTextContext::ComputeCanonicalColor(const SkPaint& paint, bool lcd) { |
| SkColor canonicalColor = SkPaintPriv::ComputeLuminanceColor(paint); |
| if (lcd) { |
| // This is the correct computation, but there are tons of cases where LCD can be overridden. |
| // For now we just regenerate if any run in a textblob has LCD. |
| // TODO figure out where all of these overrides are and see if we can incorporate that logic |
| // at a higher level *OR* use sRGB |
| SkASSERT(false); |
| //canonicalColor = SkMaskGamma::CanonicalColor(canonicalColor); |
| } else { |
| // A8, though can have mixed BMP text but it shouldn't matter because BMP text won't have |
| // gamma corrected masks anyways, nor color |
| U8CPU lum = SkComputeLuminance(SkColorGetR(canonicalColor), |
| SkColorGetG(canonicalColor), |
| SkColorGetB(canonicalColor)); |
| // reduce to our finite number of bits |
| canonicalColor = SkMaskGamma::CanonicalColor(SkColorSetRGB(lum, lum, lum)); |
| } |
| return canonicalColor; |
| } |
| |
| SkScalerContextFlags GrTextContext::ComputeScalerContextFlags( |
| const GrColorSpaceInfo& colorSpaceInfo) { |
| // If we're doing linear blending, then we can disable the gamma hacks. |
| // Otherwise, leave them on. In either case, we still want the contrast boost: |
| // TODO: Can we be even smarter about mask gamma based on the dest transfer function? |
| if (colorSpaceInfo.isLinearlyBlended()) { |
| return SkScalerContextFlags::kBoostContrast; |
| } else { |
| return SkScalerContextFlags::kFakeGammaAndBoostContrast; |
| } |
| } |
| |
| void GrTextContext::SanitizeOptions(Options* options) { |
| if (options->fMaxDistanceFieldFontSize < 0.f) { |
| options->fMaxDistanceFieldFontSize = kDefaultMaxDistanceFieldFontSize; |
| } |
| if (options->fMinDistanceFieldFontSize < 0.f) { |
| options->fMinDistanceFieldFontSize = kDefaultMinDistanceFieldFontSize; |
| } |
| } |
| |
| bool GrTextContext::CanDrawAsDistanceFields(const SkPaint& paint, const SkFont& font, |
| const SkMatrix& viewMatrix, |
| const SkSurfaceProps& props, |
| bool contextSupportsDistanceFieldText, |
| const Options& options) { |
| if (!viewMatrix.hasPerspective()) { |
| SkScalar maxScale = viewMatrix.getMaxScale(); |
| SkScalar scaledTextSize = maxScale * font.getSize(); |
| // Hinted text looks far better at small resolutions |
| // Scaling up beyond 2x yields undesireable artifacts |
| if (scaledTextSize < options.fMinDistanceFieldFontSize || |
| scaledTextSize > options.fMaxDistanceFieldFontSize) { |
| return false; |
| } |
| |
| bool useDFT = props.isUseDeviceIndependentFonts(); |
| #if SK_FORCE_DISTANCE_FIELD_TEXT |
| useDFT = true; |
| #endif |
| |
| if (!useDFT && scaledTextSize < kLargeDFFontSize) { |
| return false; |
| } |
| } |
| |
| // mask filters modify alpha, which doesn't translate well to distance |
| if (paint.getMaskFilter() || !contextSupportsDistanceFieldText) { |
| return false; |
| } |
| |
| // TODO: add some stroking support |
| if (paint.getStyle() != SkPaint::kFill_Style) { |
| return false; |
| } |
| |
| return true; |
| } |
| |
| SkScalar scaled_text_size(const SkScalar textSize, const SkMatrix& viewMatrix) { |
| SkScalar scaledTextSize = textSize; |
| |
| if (viewMatrix.hasPerspective()) { |
| // for perspective, we simply force to the medium size |
| // TODO: compute a size based on approximate screen area |
| scaledTextSize = kMediumDFFontLimit; |
| } else { |
| SkScalar maxScale = viewMatrix.getMaxScale(); |
| // if we have non-unity scale, we need to choose our base text size |
| // based on the SkPaint's text size multiplied by the max scale factor |
| // TODO: do we need to do this if we're scaling down (i.e. maxScale < 1)? |
| if (maxScale > 0 && !SkScalarNearlyEqual(maxScale, SK_Scalar1)) { |
| scaledTextSize *= maxScale; |
| } |
| } |
| |
| return scaledTextSize; |
| } |
| |
| SkFont GrTextContext::InitDistanceFieldFont(const SkFont& font, |
| const SkMatrix& viewMatrix, |
| const Options& options, |
| SkScalar* textRatio) { |
| SkScalar textSize = font.getSize(); |
| SkScalar scaledTextSize = scaled_text_size(textSize, viewMatrix); |
| |
| SkFont dfFont{font}; |
| |
| if (scaledTextSize <= kSmallDFFontLimit) { |
| *textRatio = textSize / kSmallDFFontSize; |
| dfFont.setSize(SkIntToScalar(kSmallDFFontSize)); |
| } else if (scaledTextSize <= kMediumDFFontLimit) { |
| *textRatio = textSize / kMediumDFFontSize; |
| dfFont.setSize(SkIntToScalar(kMediumDFFontSize)); |
| } else { |
| *textRatio = textSize / kLargeDFFontSize; |
| dfFont.setSize(SkIntToScalar(kLargeDFFontSize)); |
| } |
| |
| dfFont.setEdging(SkFont::Edging::kAntiAlias); |
| dfFont.setForceAutoHinting(false); |
| dfFont.setHinting(kNormal_SkFontHinting); |
| dfFont.setSubpixel(true); |
| return dfFont; |
| } |
| |
| std::pair<SkScalar, SkScalar> GrTextContext::InitDistanceFieldMinMaxScale( |
| SkScalar textSize, |
| const SkMatrix& viewMatrix, |
| const GrTextContext::Options& options) { |
| |
| SkScalar scaledTextSize = scaled_text_size(textSize, viewMatrix); |
| |
| // We have three sizes of distance field text, and within each size 'bucket' there is a floor |
| // and ceiling. A scale outside of this range would require regenerating the distance fields |
| SkScalar dfMaskScaleFloor; |
| SkScalar dfMaskScaleCeil; |
| if (scaledTextSize <= kSmallDFFontLimit) { |
| dfMaskScaleFloor = options.fMinDistanceFieldFontSize; |
| dfMaskScaleCeil = kSmallDFFontLimit; |
| } else if (scaledTextSize <= kMediumDFFontLimit) { |
| dfMaskScaleFloor = kSmallDFFontLimit; |
| dfMaskScaleCeil = kMediumDFFontLimit; |
| } else { |
| dfMaskScaleFloor = kMediumDFFontLimit; |
| dfMaskScaleCeil = options.fMaxDistanceFieldFontSize; |
| } |
| |
| // Because there can be multiple runs in the blob, we want the overall maxMinScale, and |
| // minMaxScale to make regeneration decisions. Specifically, we want the maximum minimum scale |
| // we can tolerate before we'd drop to a lower mip size, and the minimum maximum scale we can |
| // tolerate before we'd have to move to a large mip size. When we actually test these values |
| // we look at the delta in scale between the new viewmatrix and the old viewmatrix, and test |
| // against these values to decide if we can reuse or not(ie, will a given scale change our mip |
| // level) |
| SkASSERT(dfMaskScaleFloor <= scaledTextSize && scaledTextSize <= dfMaskScaleCeil); |
| |
| return std::make_pair(dfMaskScaleFloor / scaledTextSize, dfMaskScaleCeil / scaledTextSize); |
| } |
| |
| SkPaint GrTextContext::InitDistanceFieldPaint(const SkPaint& paint) { |
| SkPaint dfPaint{paint}; |
| dfPaint.setMaskFilter(GrSDFMaskFilter::Make()); |
| return dfPaint; |
| } |
| |
| /////////////////////////////////////////////////////////////////////////////////////////////////// |
| |
| #if GR_TEST_UTILS |
| |
| #include "GrRenderTargetContext.h" |
| |
| GR_DRAW_OP_TEST_DEFINE(GrAtlasTextOp) { |
| static uint32_t gContextID = SK_InvalidGenID; |
| static std::unique_ptr<GrTextContext> gTextContext; |
| static SkSurfaceProps gSurfaceProps(SkSurfaceProps::kLegacyFontHost_InitType); |
| |
| if (context->priv().contextID() != gContextID) { |
| gContextID = context->priv().contextID(); |
| gTextContext = GrTextContext::Make(GrTextContext::Options()); |
| } |
| |
| const GrBackendFormat format = |
| context->priv().caps()->getBackendFormatFromColorType(kRGBA_8888_SkColorType); |
| |
| // Setup dummy SkPaint / GrPaint / GrRenderTargetContext |
| sk_sp<GrRenderTargetContext> rtc(context->priv().makeDeferredRenderTargetContext( |
| format, SkBackingFit::kApprox, 1024, 1024, kRGBA_8888_GrPixelConfig, nullptr)); |
| |
| SkMatrix viewMatrix = GrTest::TestMatrixInvertible(random); |
| |
| SkPaint skPaint; |
| skPaint.setColor(random->nextU()); |
| |
| SkFont font; |
| if (random->nextBool()) { |
| font.setEdging(SkFont::Edging::kSubpixelAntiAlias); |
| } else { |
| font.setEdging(random->nextBool() ? SkFont::Edging::kAntiAlias : SkFont::Edging::kAlias); |
| } |
| font.setSubpixel(random->nextBool()); |
| |
| const char* text = "The quick brown fox jumps over the lazy dog."; |
| |
| // create some random x/y offsets, including negative offsets |
| static const int kMaxTrans = 1024; |
| int xPos = (random->nextU() % 2) * 2 - 1; |
| int yPos = (random->nextU() % 2) * 2 - 1; |
| int xInt = (random->nextU() % kMaxTrans) * xPos; |
| int yInt = (random->nextU() % kMaxTrans) * yPos; |
| |
| return gTextContext->createOp_TestingOnly(context, gTextContext.get(), rtc.get(), |
| skPaint, font, viewMatrix, text, xInt, yInt); |
| } |
| |
| #endif |