skia/renderer/src/skia_renderer.cpp

#include "skia_renderer.hpp"
#include "SkData.h"
#include "SkGradientShader.h"
#include "SkPath.h"
#include "SkVertices.h"
#include "rive/math/vec2d.hpp"
#include "rive/shapes/paint/color.hpp"
#include "to_skia.hpp"

using namespace rive;

class SkiaBuffer : public RenderBuffer {
    const size_t m_ElemSize;
    void* m_Buffer;

public:
    SkiaBuffer(const void* src, size_t count, size_t elemSize) :
        RenderBuffer(count), m_ElemSize(elemSize) {
        size_t bytes = count * elemSize;
        m_Buffer = malloc(bytes);
        memcpy(m_Buffer, src, bytes);
    }

    ~SkiaBuffer() { free(m_Buffer); }

    const float* f32s() const {
        assert(m_ElemSize == sizeof(float));
        return static_cast<const float*>(m_Buffer);
    }

    const uint16_t* u16s() const {
        assert(m_ElemSize == sizeof(uint16_t));
        return static_cast<const uint16_t*>(m_Buffer);
    }

    const SkPoint* points() const { return reinterpret_cast<const SkPoint*>(this->f32s()); }

    static const SkiaBuffer* Cast(const RenderBuffer* buffer) {
        return reinterpret_cast<const SkiaBuffer*>(buffer);
    }
};

template <typename T> rcp<RenderBuffer> make_buffer(Span<T> span) {
    return rcp<RenderBuffer>(new SkiaBuffer(span.data(), span.size(), sizeof(T)));
}

class SkiaRenderShader : public RenderShader {
public:
    SkiaRenderShader(sk_sp<SkShader> sh) : shader(std::move(sh)) {}

    sk_sp<SkShader> shader;
};

void SkiaRenderPath::fillRule(FillRule value) { m_Path.setFillType(ToSkia::convert(value)); }

void SkiaRenderPath::reset() { m_Path.reset(); }
void SkiaRenderPath::addRenderPath(RenderPath* path, const Mat2D& transform) {
    m_Path.addPath(reinterpret_cast<SkiaRenderPath*>(path)->m_Path, ToSkia::convert(transform));
}

void SkiaRenderPath::moveTo(float x, float y) { m_Path.moveTo(x, y); }
void SkiaRenderPath::lineTo(float x, float y) { m_Path.lineTo(x, y); }
void SkiaRenderPath::cubicTo(float ox, float oy, float ix, float iy, float x, float y) {
    m_Path.cubicTo(ox, oy, ix, iy, x, y);
}
void SkiaRenderPath::close() { m_Path.close(); }

SkiaRenderPaint::SkiaRenderPaint() { m_Paint.setAntiAlias(true); }

void SkiaRenderPaint::style(RenderPaintStyle style) {
    switch (style) {
        case RenderPaintStyle::fill:
            m_Paint.setStyle(SkPaint::Style::kFill_Style);
            break;
        case RenderPaintStyle::stroke:
            m_Paint.setStyle(SkPaint::Style::kStroke_Style);
            break;
    }
}
void SkiaRenderPaint::color(unsigned int value) { m_Paint.setColor(value); }
void SkiaRenderPaint::thickness(float value) { m_Paint.setStrokeWidth(value); }
void SkiaRenderPaint::join(StrokeJoin value) { m_Paint.setStrokeJoin(ToSkia::convert(value)); }
void SkiaRenderPaint::cap(StrokeCap value) { m_Paint.setStrokeCap(ToSkia::convert(value)); }

void SkiaRenderPaint::blendMode(BlendMode value) { m_Paint.setBlendMode(ToSkia::convert(value)); }

void SkiaRenderPaint::shader(rcp<RenderShader> rsh) {
    SkiaRenderShader* sksh = (SkiaRenderShader*)rsh.get();
    m_Paint.setShader(sksh ? sksh->shader : nullptr);
}

void SkiaRenderer::save() { m_Canvas->save(); }
void SkiaRenderer::restore() { m_Canvas->restore(); }
void SkiaRenderer::transform(const Mat2D& transform) {
    m_Canvas->concat(ToSkia::convert(transform));
}
void SkiaRenderer::drawPath(RenderPath* path, RenderPaint* paint) {
    m_Canvas->drawPath(reinterpret_cast<SkiaRenderPath*>(path)->path(),
                       reinterpret_cast<SkiaRenderPaint*>(paint)->paint());
}

void SkiaRenderer::clipPath(RenderPath* path) {
    m_Canvas->clipPath(reinterpret_cast<SkiaRenderPath*>(path)->path(), true);
}

void SkiaRenderer::drawImage(const RenderImage* image, BlendMode blendMode, float opacity) {
    SkPaint paint;
    paint.setAlphaf(opacity);
    paint.setBlendMode(ToSkia::convert(blendMode));
    auto skiaImage = reinterpret_cast<const SkiaRenderImage*>(image);
    SkSamplingOptions sampling(SkFilterMode::kLinear);
    m_Canvas->drawImage(skiaImage->skImage(), 0.0f, 0.0f, sampling, &paint);
}

#define SKIA_BUG_13047

void SkiaRenderer::drawImageMesh(const RenderImage* image,
                                 rcp<RenderBuffer> vertices,
                                 rcp<RenderBuffer> uvCoords,
                                 rcp<RenderBuffer> indices,
                                 BlendMode blendMode,
                                 float opacity) {
    // need our vertices and uvs to agree
    assert(vertices->count() == uvCoords->count());
    // vertices and uvs are arrays of floats, so we need their counts to be
    // even, since we treat them as arrays of points
    assert((vertices->count() & 1) == 0);

    const int vertexCount = vertices->count() >> 1;

    SkMatrix scaleM;

    const SkPoint* uvs = SkiaBuffer::Cast(uvCoords.get())->points();

#ifdef SKIA_BUG_13047
    // The local matrix is ignored for drawVertices, so we have to manually scale
    // the UVs to match Skia's convention...
    std::vector<SkPoint> scaledUVs(vertexCount);
    for (int i = 0; i < vertexCount; ++i) {
        scaledUVs[i] = {uvs[i].fX * image->width(), uvs[i].fY * image->height()};
    }
    uvs = scaledUVs.data();
#else
    // We do this because our UVs are normalized, but Skia expects them to be
    // sized to the shader (i.e. 0..width, 0..height).
    // To accomdate this, we effectively scaling the image down to 0..1 to
    // match the scale of the UVs.
    scaleM = SkMatrix::Scale(2.0f / image->width(), 2.0f / image->height());
#endif

    auto skiaImage = reinterpret_cast<const SkiaRenderImage*>(image)->skImage();
    const SkSamplingOptions sampling(SkFilterMode::kLinear);
    auto shader = skiaImage->makeShader(SkTileMode::kClamp, SkTileMode::kClamp, sampling, &scaleM);

    SkPaint paint;
    paint.setAlphaf(opacity);
    paint.setBlendMode(ToSkia::convert(blendMode));
    paint.setShader(shader);

    const SkColor* no_colors = nullptr;
    auto vertexMode = SkVertices::kTriangles_VertexMode;
    // clang-format off
    auto vt = SkVertices::MakeCopy(vertexMode,
                                   vertexCount,
                                   SkiaBuffer::Cast(vertices.get())->points(),
                                   uvs,
                                   no_colors,
                                   indices->count(),
                                   SkiaBuffer::Cast(indices.get())->u16s());
    // clang-format on

    // The blend mode is ignored if we don't have colors && uvs
    m_Canvas->drawVertices(vt, SkBlendMode::kModulate, paint);
}

bool SkiaRenderImage::decode(Span<const uint8_t> encodedData) {

    sk_sp<SkData> data = SkData::MakeWithoutCopy(encodedData.data(), encodedData.size());
    m_SkImage = SkImage::MakeFromEncoded(data);

    // Our optimized skia buld seems to have broken lazy-image decode.
    // As a work-around for now, force the image to be decoded.
    if (m_SkImage) {
        m_SkImage = m_SkImage->makeRasterImage();
    }

    if (m_SkImage) {
        m_Width = m_SkImage->width();
        m_Height = m_SkImage->height();
        return true;
    }
    return false;
}

rcp<RenderShader>
SkiaRenderImage::makeShader(RenderTileMode tx, RenderTileMode ty, const Mat2D* localMatrix) const {
    const SkMatrix lm = localMatrix ? ToSkia::convert(*localMatrix) : SkMatrix();
    const SkSamplingOptions options(SkFilterMode::kLinear);
    auto sh = m_SkImage->makeShader(ToSkia::convert(tx), ToSkia::convert(ty), options, &lm);
    return rcp<RenderShader>(new SkiaRenderShader(std::move(sh)));
}

namespace rive {
    rcp<RenderBuffer> makeBufferU16(Span<const uint16_t> data) { return make_buffer(data); }
    rcp<RenderBuffer> makeBufferU32(Span<const uint32_t> data) { return make_buffer(data); }
    rcp<RenderBuffer> makeBufferF32(Span<const float> data) { return make_buffer(data); }

    RenderPath*
    makeRenderPath(Span<const Vec2D> points, Span<const uint8_t> verbs, FillRule fillrule) {
        return new SkiaRenderPath(SkPath::Make((const SkPoint*)points.data(),
                                               points.size(),
                                               verbs.data(),
                                               verbs.size(),
                                               nullptr,
                                               0, // conics
                                               ToSkia::convert(fillrule),
                                               false));
    }

    RenderPath* makeRenderPath() { return new SkiaRenderPath(); }
    RenderPaint* makeRenderPaint() { return new SkiaRenderPaint(); }
    RenderImage* makeRenderImage() { return new SkiaRenderImage(); }

    rcp<RenderShader> makeLinearGradient(float sx,
                                         float sy,
                                         float ex,
                                         float ey,
                                         const ColorInt colors[],
                                         const float stops[],
                                         int count,
                                         RenderTileMode mode,
                                         const Mat2D* localm) {
        const SkPoint pts[] = {{sx, sy}, {ex, ey}};
        const SkMatrix lm = localm ? ToSkia::convert(*localm) : SkMatrix();
        auto sh = SkGradientShader::MakeLinear(
            pts, (const SkColor*)colors, stops, count, ToSkia::convert(mode), 0, &lm);
        return rcp<RenderShader>(new SkiaRenderShader(std::move(sh)));
    }

    rcp<RenderShader> makeRadialGradient(float cx,
                                         float cy,
                                         float radius,
                                         const ColorInt colors[],
                                         const float stops[],
                                         int count,
                                         RenderTileMode mode,
                                         const Mat2D* localm) {
        const SkMatrix lm = localm ? ToSkia::convert(*localm) : SkMatrix();
        auto sh = SkGradientShader::MakeRadial(
            {cx, cy}, radius, (const SkColor*)colors, stops, count, ToSkia::convert(mode), 0, &lm);
        return rcp<RenderShader>(new SkiaRenderShader(std::move(sh)));
    }

    rcp<RenderShader> makeSweepGradient(float cx,
                                        float cy,
                                        const ColorInt colors[],
                                        const float stops[],
                                        int count,
                                        RenderTileMode mode,
                                        const Mat2D* localm) {
        const SkMatrix lm = localm ? ToSkia::convert(*localm) : SkMatrix();
        auto sh = SkGradientShader::MakeSweep(cx, cy, (const SkColor*)colors, stops, count, 0, &lm);
        return rcp<RenderShader>(new SkiaRenderShader(std::move(sh)));
    }
} // namespace rive