third_party/skia/experimental/sktext/src/Paint.h

// Copyright 2021 Google LLC.
#ifndef Painter_DEFINED
#define Painter_DEFINED
#include "experimental/sktext/include/Text.h"
#include "experimental/sktext/include/Types.h"
#include "include/core/SkCanvas.h"

namespace skia {
namespace text {

    struct DecoratedBlock {
        DecoratedBlock(uint32_t count, SkPaint fg, SkPaint bg)
                : charCount(count)
                , foregroundPaint(std::move(fg))
                , backgroundPaint(std::move(bg)) { }
        uint32_t    charCount;
        SkPaint foregroundPaint;
        SkPaint backgroundPaint;
    };

    class TrivialFontChain : public FontChain {
    public:
        TrivialFontChain(const char* ff, SkScalar size, SkFontStyle fontStyle)
                : fTypeface(sk_sp<SkTypeface>(SkFontMgr::RefDefault()->matchFamilyStyle(ff, SkFontStyle::Normal())))
                , fSize(size)
                , fFontStyle(fontStyle) { }
        size_t count() const override { return (size_t)1; }
        sk_sp<SkTypeface> operator[](size_t index) const  override {
            SkASSERT(index == 0);
            return fTypeface;
        }
        float fontSize() const override { return fSize; }
        SkString locale() const override { return SkString("en"); }
        sk_sp<SkTypeface> getTypeface() const { return fTypeface; }
        bool empty() const { return fTypeface == nullptr; }

    private:
        sk_sp<SkTypeface> fTypeface;
        SkScalar fSize;
        SkFontStyle fFontStyle;
    };

    class MultipleFontChain : public FontChain {
    public:
        MultipleFontChain(std::vector<const char*> ffs, SkScalar size, SkFontStyle fontStyle)
                : fSize(size)
                , fFontStyle(fontStyle) {
            for (auto& ff  : ffs) {
                auto typeface = SkFontMgr::RefDefault()->matchFamilyStyle(ff, SkFontStyle::Normal());
                if (typeface != nullptr) {
                    fTypefaces.emplace_back(typeface);
                }
            }
        }
        size_t count() const override { return fTypefaces.size(); }
        sk_sp<SkTypeface> operator[](size_t index) const  override {
            SkASSERT(index < fTypefaces.size());
            return fTypefaces[index];
        }
        float fontSize() const override { return fSize; }
        SkString locale() const override { return SkString("en"); }
        bool empty() const { return fTypefaces.empty(); }

    private:
        std::vector<sk_sp<SkTypeface>> fTypefaces;
        SkScalar fSize;
        SkFontStyle fFontStyle;
    };

    class Paint : public Visitor {
    public:
        void paint(SkCanvas* canvas, SkPoint xy, UnicodeText* unicodeText, WrappedText* wrappedText, SkSpan<DecoratedBlock> decoratedBlocks);
        // Simplification (using default font manager, default font family and default everything possible)
        static bool drawText(std::u16string text, SkCanvas* canvas, SkScalar x, SkScalar y);
        static bool drawText(std::u16string text, SkCanvas* canvas, SkScalar width);
        static bool drawText(std::u16string text, SkCanvas* canvas,
                             TextDirection textDirection, TextAlign textAlign,
                             SkPaint foreground, SkPaint background,
                             const SkString& fontFamily, SkScalar fontSize, SkFontStyle fontStyle,
                             SkScalar x, SkScalar y);
        static bool drawText(std::u16string text, SkCanvas* canvas,
                             TextDirection textDirection, TextAlign textAlign,
                             SkPaint foreground, SkPaint background,
                             const SkString& fontFamily, SkScalar fontSize, SkFontStyle fontStyle,
                             SkSize reqSize, SkScalar x, SkScalar y);

    private:
        static std::unique_ptr<WrappedText> layout(std::u16string text,
                                                   TextDirection textDirection, TextAlign textAlign,
                                                   SkSize reqSize,
                                                   SkSpan<FontBlock> fontBlocks);

        void onGlyphRun(const SkFont& font,
                        DirTextRange dirTextRange,
                        SkRect bounds,
                        TextIndex trailingSpaces,
                        size_t glyphCount,
                        const uint16_t glyphs[],
                        const SkPoint positions[],
                        const TextIndex clusters[]) override;

        // We guarantee that the text range will be inside one of the decorated blocks
        DecoratedBlock findDecoratedBlock(TextRange textRange);

        SkCanvas* fCanvas;
        SkPoint fXY;
        SkSpan<FontBlock> fFontBlocks;
        SkSpan<DecoratedBlock> fDecoratedBlocks;
    };
}  // namespace text
} // namespace skia
#endif // Painter_DEFINED