blob: 0e66101d5ff0d6ca1a3d6d59abb4177f0d263870 [file] [log] [blame]
/*
* Copyright 2020 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "src/text/gpu/SDFTControl.h"
#include "include/core/SkFont.h"
#include "include/core/SkFontTypes.h"
#include "include/core/SkMatrix.h"
#include "include/core/SkPaint.h"
#include "include/core/SkScalar.h"
#include "src/core/SkFontPriv.h"
#include "src/core/SkGlyph.h"
#include "src/core/SkReadBuffer.h"
#include "src/core/SkWriteBuffer.h"
#include <tuple>
struct SkPoint;
namespace sktext::gpu {
#if !defined(SK_DISABLE_SDF_TEXT)
// 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 Control.
static const int kSmallDFFontLimit = 32;
static const int kMediumDFFontLimit = 72;
static const int kLargeDFFontLimit = 162;
#ifdef SK_BUILD_FOR_MAC
static const int kExtraLargeDFFontLimit = 256;
#endif
SkScalar SDFTControl::MinSDFTRange(bool useSDFTForSmallText, SkScalar min) {
if (!useSDFTForSmallText) {
return kLargeDFFontLimit;
}
return min;
}
SDFTControl::SDFTControl(
bool ableToUseSDFT, bool useSDFTForSmallText, bool useSDFTForPerspectiveText,
SkScalar min, SkScalar max)
: fMinDistanceFieldFontSize{MinSDFTRange(useSDFTForSmallText, min)}
, fMaxDistanceFieldFontSize{max}
, fAbleToUseSDFT{ableToUseSDFT}
, fAbleToUsePerspectiveSDFT{useSDFTForPerspectiveText} {
SkASSERT_RELEASE(0 < min && min <= max);
}
#endif // !defined(SK_DISABLE_SDF_TEXT)
bool SDFTControl::isDirect(SkScalar approximateDeviceTextSize, const SkPaint& paint,
const SkMatrix& matrix) const {
#if !defined(SK_DISABLE_SDF_TEXT)
const bool isSDFT = this->isSDFT(approximateDeviceTextSize, paint, matrix);
#else
const bool isSDFT = false;
#endif
return !isSDFT &&
!matrix.hasPerspective() &&
0 < approximateDeviceTextSize &&
approximateDeviceTextSize < SkGlyphDigest::kSkSideTooBigForAtlas;
}
#if !defined(SK_DISABLE_SDF_TEXT)
bool SDFTControl::isSDFT(SkScalar approximateDeviceTextSize, const SkPaint& paint,
const SkMatrix& matrix) const {
const bool wideStroke = paint.getStyle() == SkPaint::kStroke_Style &&
paint.getStrokeWidth() > 0;
return fAbleToUseSDFT &&
paint.getMaskFilter() == nullptr &&
(paint.getStyle() == SkPaint::kFill_Style || wideStroke) &&
0 < approximateDeviceTextSize &&
(fAbleToUsePerspectiveSDFT || !matrix.hasPerspective()) &&
(fMinDistanceFieldFontSize <= approximateDeviceTextSize || matrix.hasPerspective()) &&
approximateDeviceTextSize <= fMaxDistanceFieldFontSize;
}
std::tuple<SkFont, SkScalar, SDFTMatrixRange>
SDFTControl::getSDFFont(const SkFont& font, const SkMatrix& viewMatrix,
const SkPoint& textLoc) const {
SkScalar textSize = font.getSize();
SkScalar scaledTextSize = SkFontPriv::ApproximateTransformedTextSize(font, viewMatrix, textLoc);
if (scaledTextSize <= 0 || SkScalarNearlyEqual(textSize, scaledTextSize)) {
scaledTextSize = textSize;
}
SkFont dfFont{font};
SkScalar dfMaskScaleFloor;
SkScalar dfMaskScaleCeil;
SkScalar dfMaskSize;
if (scaledTextSize <= kSmallDFFontLimit) {
dfMaskScaleFloor = fMinDistanceFieldFontSize;
dfMaskScaleCeil = kSmallDFFontLimit;
dfMaskSize = kSmallDFFontLimit;
} else if (scaledTextSize <= kMediumDFFontLimit) {
dfMaskScaleFloor = kSmallDFFontLimit;
dfMaskScaleCeil = kMediumDFFontLimit;
dfMaskSize = kMediumDFFontLimit;
#ifdef SK_BUILD_FOR_MAC
} else if (scaledTextSize <= kLargeDFFontLimit) {
dfMaskScaleFloor = kMediumDFFontLimit;
dfMaskScaleCeil = kLargeDFFontLimit;
dfMaskSize = kLargeDFFontLimit;
} else {
dfMaskScaleFloor = kLargeDFFontLimit;
dfMaskScaleCeil = fMaxDistanceFieldFontSize;
dfMaskSize = kExtraLargeDFFontLimit;
}
#else
} else {
dfMaskScaleFloor = kMediumDFFontLimit;
dfMaskScaleCeil = fMaxDistanceFieldFontSize;
dfMaskSize = kLargeDFFontLimit;
}
#endif
dfFont.setSize(dfMaskSize);
dfFont.setEdging(SkFont::Edging::kAntiAlias);
dfFont.setForceAutoHinting(false);
dfFont.setHinting(SkFontHinting::kNormal);
// The sub-pixel position will always happen when transforming to the screen.
dfFont.setSubpixel(false);
SkScalar minMatrixScale = dfMaskScaleFloor / textSize,
maxMatrixScale = dfMaskScaleCeil / textSize;
return {dfFont, textSize / dfMaskSize, {minMatrixScale, maxMatrixScale}};
}
bool SDFTMatrixRange::matrixInRange(const SkMatrix& matrix) const {
SkScalar maxScale = matrix.getMaxScale();
return fMatrixMin < maxScale && maxScale <= fMatrixMax;
}
void SDFTMatrixRange::flatten(SkWriteBuffer& buffer) const {
buffer.writeScalar(fMatrixMin);
buffer.writeScalar(fMatrixMax);
}
SDFTMatrixRange SDFTMatrixRange::MakeFromBuffer(SkReadBuffer& buffer) {
SkScalar min = buffer.readScalar();
SkScalar max = buffer.readScalar();
return SDFTMatrixRange{min, max};
}
#endif // !defined(SK_DISABLE_SDF_TEXT)
} // namespace sktext::gpu