tools/fonts/TestSVGTypeface.h

/*
 * Copyright 2014 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef TestSVGTypeface_DEFINED
#define TestSVGTypeface_DEFINED

#include "SkFontArguments.h"
#include "SkFontMetrics.h"
#include "SkMutex.h"
#include "SkPaint.h"
#include "SkPathOps.h"
#include "SkPoint.h"
#include "SkRect.h"
#include "SkRefCnt.h"
#include "SkScalar.h"
#include "SkSpan.h"
#include "SkStream.h"
#include "SkString.h"
#include "SkTArray.h"
#include "SkTHash.h"
#include "SkTypeface.h"
#include "SkTypes.h"

#include <memory>

class SkCanvas;
class SkDescriptor;
class SkFontDescriptor;
class SkFontStyle;
class SkGlyph;
class SkPath;
class SkScalerContext;
class SkSVGDOM;
class SkWStream;
struct SkAdvancedTypefaceMetrics;
struct SkScalerContextEffects;
struct SkScalerContextRec;

struct SkSVGTestTypefaceGlyphData {
    const char* fSvgResourcePath;
    SkPoint     fOrigin;  // y-down
    SkScalar    fAdvance;
    SkUnichar   fUnicode;  // TODO: this limits to 1:1
};

class TestSVGTypeface : public SkTypeface {
public:
    TestSVGTypeface(const char*                              name,
                    int                                      upem,
                    const SkFontMetrics&                     metrics,
                    SkSpan<const SkSVGTestTypefaceGlyphData> data,
                    const SkFontStyle&                       style);
    ~TestSVGTypeface() override;
    void getAdvance(SkGlyph* glyph) const;
    void getFontMetrics(SkFontMetrics* metrics) const;

    static sk_sp<TestSVGTypeface> Default();
    static sk_sp<TestSVGTypeface> Planets();
    void                          exportTtxCbdt(SkWStream*, SkSpan<unsigned> strikeSizes) const;
    void                          exportTtxSbix(SkWStream*, SkSpan<unsigned> strikeSizes) const;
    void                          exportTtxColr(SkWStream*) const;
    virtual bool                  getPathOp(SkColor, SkPathOp*) const = 0;

    struct GlyfLayerInfo {
        GlyfLayerInfo(int layerColorIndex, SkIRect bounds)
                : fLayerColorIndex(layerColorIndex), fBounds(bounds) {}
        int     fLayerColorIndex;
        SkIRect fBounds;
    };
    struct GlyfInfo {
        GlyfInfo() : fBounds(SkIRect::MakeEmpty()) {}
        SkIRect                 fBounds;
        SkTArray<GlyfLayerInfo> fLayers;
    };

protected:
    void exportTtxCommon(SkWStream*, const char* type, const SkTArray<GlyfInfo>* = nullptr) const;

    SkScalerContext*                           onCreateScalerContext(const SkScalerContextEffects&,
                                                                     const SkDescriptor* desc) const override;
    void                                       onFilterRec(SkScalerContextRec* rec) const override;
    void                                       getGlyphToUnicodeMap(SkUnichar*) const override;
    std::unique_ptr<SkAdvancedTypefaceMetrics> onGetAdvancedMetrics() const override;

    std::unique_ptr<SkStreamAsset> onOpenStream(int* ttcIndex) const override { return nullptr; }

    sk_sp<SkTypeface> onMakeClone(const SkFontArguments& args) const override {
        return sk_ref_sp(this);
    }

    void onGetFontDescriptor(SkFontDescriptor* desc, bool* isLocal) const override;

    int onCharsToGlyphs(const void* chars,
                        Encoding    encoding,
                        uint16_t    glyphs[],
                        int         glyphCount) const override;

    int onCountGlyphs() const override { return fGlyphCount; }

    int onGetUPEM() const override { return fUpem; }

    void                          onGetFamilyName(SkString* familyName) const override;
    SkTypeface::LocalizedStrings* onCreateFamilyNameIterator() const override;

    int onGetVariationDesignPosition(SkFontArguments::VariationPosition::Coordinate coordinates[],
                                     int coordinateCount) const override {
        return 0;
    }

    int onGetVariationDesignParameters(SkFontParameters::Variation::Axis parameters[],
                                       int parameterCount) const override {
        return 0;
    }

    int onGetTableTags(SkFontTableTag tags[]) const override { return 0; }

    size_t onGetTableData(SkFontTableTag tag,
                          size_t         offset,
                          size_t         length,
                          void*          data) const override {
        return 0;
    }

private:
    struct Glyph {
        Glyph();
        ~Glyph();
        SkPoint     fOrigin;
        SkScalar    fAdvance;
        const char* fResourcePath;

        SkSize size() const;
        void render(SkCanvas*) const;

    private:
        // Lazily parses the SVG from fResourcePath, and manages mutex locking.
        template <typename Fn> void withSVG(Fn&&) const;

        // The mutex guards lazy parsing of the SVG, but also predates that.
        // Must be SkSVGDOM::render() is not thread safe?
        // If not, an SkOnce is enough here.
        mutable SkMutex         fSvgMutex;
        mutable bool            fParsedSvg = false;
        mutable sk_sp<SkSVGDOM> fSvg;
    };

    SkString                         fName;
    int                              fUpem;
    const SkFontMetrics              fFontMetrics;
    std::unique_ptr<Glyph[]>         fGlyphs;
    int                              fGlyphCount;
    SkTHashMap<SkUnichar, SkGlyphID> fCMap;
    friend class SkTestSVGScalerContext;
};

#endif