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* Copyright 2019 Google Inc.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
#ifndef SkStrikeInterface_DEFINED
#define SkStrikeInterface_DEFINED
#include "include/core/SkPaint.h"
#include "include/core/SkPoint.h"
#include "include/core/SkTypes.h"
#include "src/core/SkGlyph.h"
#include "src/core/SkSpan.h"
#include <memory>
class SkDescriptor;
class SkGlyph;
class SkMaskFilter;
class SkPathEffect;
class SkTypeface;
// TODO: rename SkScalerContextEffects -> SkStrikeEffects
struct SkScalerContextEffects {
SkScalerContextEffects() : fPathEffect(nullptr), fMaskFilter(nullptr) {}
SkScalerContextEffects(SkPathEffect* pe, SkMaskFilter* mf)
: fPathEffect(pe), fMaskFilter(mf) {}
explicit SkScalerContextEffects(const SkPaint& paint)
: fPathEffect(paint.getPathEffect())
, fMaskFilter(paint.getMaskFilter()) {}
SkPathEffect* fPathEffect;
SkMaskFilter* fMaskFilter;
struct SkGlyphPos {
size_t index;
const SkGlyph* glyph;
SkPoint position;
struct SkPathPos {
const SkPath* path;
SkPoint position;
class SkStrikeInterface {
virtual ~SkStrikeInterface() = default;
virtual const SkDescriptor& getDescriptor() const = 0;
enum PreparationDetail {
// prepareForDrawing takes glyphIDs, and position, and returns a list of SkGlyphs and
// positions where all the data to draw the glyph has been created. The maxDimension
// parameter determines if the mask/SDF version will be created, or an alternate drawing
// format should be used. For path-only drawing set maxDimension to 0, and for bitmap-device
// drawing (where there is no upper limit to the glyph in the cache) use INT_MAX.
// * PreparationDetail determines, in the mask case, if the mask/SDF should be generated.
// This does not affect the path or fallback cases.
virtual SkSpan<const SkGlyphPos>
prepareForDrawing(const SkPackedGlyphID packedGlyphIDs[],
const SkPoint positions[],
size_t n,
int maxDimension,
PreparationDetail detail,
SkGlyphPos results[]) = 0;
// rounding() and subpixelMask are used to calculate the subpixel position of a glyph.
// The per component (x or y) calculation is:
// subpixelOffset = (floor((viewportPosition + rounding) & mask) >> 14) & 3
// where mask is either 0 or ~0, and rounding is either
// 1/2 for non-subpixel or 1/8 for subpixel.
virtual SkVector rounding() const = 0;
virtual SkIPoint subpixelMask() const = 0;
// Used with SkScopedStrike to take action at the end of a scope.
virtual void onAboutToExitScope() = 0;
struct Deleter {
void operator()(SkStrikeInterface* ptr) const {
using SkScopedStrike = std::unique_ptr<SkStrikeInterface, SkStrikeInterface::Deleter>;
class SkStrikeCacheInterface {
virtual ~SkStrikeCacheInterface() = default;
virtual SkScopedStrike findOrCreateScopedStrike(const SkDescriptor& desc,
const SkScalerContextEffects& effects,
const SkTypeface& typeface) = 0;
#endif //SkStrikeInterface_DEFINED