skia2/fuzz/FuzzGradients.cpp

/*
 * Copyright 2016 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "Fuzz.h"
#include "SkCanvas.h"
#include "SkGradientShader.h"
#include "SkSurface.h"
#include "SkTLazy.h"

#include <algorithm>

const int MAX_COUNT = 400;

bool makeMatrix(Fuzz* fuzz, SkMatrix* m) {
    SkScalar scaleX, skewX, transX, skewY, scaleY, transY, persp0, persp1, persp2;
    if (!fuzz->next(&scaleX) ||
        !fuzz->next(&skewX)  ||
        !fuzz->next(&transX) ||
        !fuzz->next(&skewY)  ||
        !fuzz->next(&scaleY) ||
        !fuzz->next(&transY) ||
        !fuzz->next(&persp0) ||
        !fuzz->next(&persp1) ||
        !fuzz->next(&persp2)) {
        return false;
    }
    m->setAll(scaleX, skewX, transX, skewY, scaleY, transY, persp0, persp1, persp2);
    return true;
}

bool initGradientParams(Fuzz* fuzz, std::vector<SkColor>* colors,
    std::vector<SkScalar>* pos, SkShader::TileMode* mode) {
    if (fuzz->remaining() < sizeof(uint32_t)) {
        return false;
    }
    uint32_t count = fuzz->nextRangeU(0, MAX_COUNT);

    if (fuzz->remaining() < sizeof(uint32_t)) {
        return false;
    }
    *mode = static_cast<SkShader::TileMode>(fuzz->nextRangeU(0, 3));

    colors->clear();
    pos   ->clear();
    for (uint32_t i = 0; i < count; i++) {
        SkColor c;
        SkScalar s;
        if (!fuzz->next(&c) || !fuzz->next(&s)) {
            return false;
        }
        colors->push_back(c);
        pos   ->push_back(s);
    }
    if (count) {
        std::sort(pos->begin(), pos->end());
        // The order matters.  If count == 1, we want pos == 0.
        (*pos)[count - 1] = 1;
        (*pos)[0]         = 0;
    }
    return true;
}

void fuzzLinearGradient(Fuzz* fuzz) {
        SkScalar a, b, c, d;
        bool useLocalMatrix, useGlobalMatrix;
        if (!fuzz->next(&a)               ||
            !fuzz->next(&b)               ||
            !fuzz->next(&c)               ||
            !fuzz->next(&d)               ||
            !fuzz->next(&useLocalMatrix)  ||
            !fuzz->next(&useGlobalMatrix)) {
            return;
        }
        SkPoint pts[2] = {SkPoint::Make(a,b), SkPoint::Make(c, d)};

        std::vector<SkColor> colors;
        std::vector<SkScalar> pos;
        SkShader::TileMode mode;
        if (!initGradientParams(fuzz, &colors, &pos, &mode)) {
            return;
        }

        SkPaint p;
        uint32_t flags;
        if (!fuzz->next(&flags)) {
            return;
        }

        SkTLazy<SkMatrix> localMatrix;
        if (useLocalMatrix && !makeMatrix(fuzz, localMatrix.init())) {
            return;
        }
        p.setShader(SkGradientShader::MakeLinear(pts, colors.data(), pos.data(),
            colors.size(), mode, flags, localMatrix.getMaybeNull()));

        sk_sp<SkSurface> surface(SkSurface::MakeRasterN32Premul(50, 50));
        if (useGlobalMatrix) {
            SkMatrix gm;
            if (!makeMatrix(fuzz, &gm)) {
                return;
            }
            SkCanvas* c = surface->getCanvas();
            c->setMatrix(gm);
            c->drawPaint(p);
        } else {
            surface->getCanvas()->drawPaint(p);
        }
}

void fuzzRadialGradient(Fuzz* fuzz) {
        SkScalar a, b, radius;
        bool useLocalMatrix, useGlobalMatrix;
        if (!fuzz->next(&a)               ||
            !fuzz->next(&b)               ||
            !fuzz->next(&radius)          ||
            !fuzz->next(&useLocalMatrix)  ||
            !fuzz->next(&useGlobalMatrix)) {
            return;
        }
        SkPoint center = SkPoint::Make(a,b);

        std::vector<SkColor> colors;
        std::vector<SkScalar> pos;
        SkShader::TileMode mode;
        if (!initGradientParams(fuzz, &colors, &pos, &mode)) {
            return;
        }

        SkPaint p;
        uint32_t flags;
        if (!fuzz->next(&flags)) {
            return;
        }

        SkTLazy<SkMatrix> localMatrix;
        if (useLocalMatrix && !makeMatrix(fuzz, localMatrix.init())) {
            return;
        }
        p.setShader(SkGradientShader::MakeRadial(center, radius, colors.data(),
            pos.data(), colors.size(), mode, flags, localMatrix.getMaybeNull()));


        sk_sp<SkSurface> surface(SkSurface::MakeRasterN32Premul(50, 50));
        if (useGlobalMatrix) {
            SkMatrix gm;
            if (!makeMatrix(fuzz, &gm)) {
                return;
            }
            SkCanvas* c = surface->getCanvas();
            c->setMatrix(gm);
            c->drawPaint(p);
        } else {
            surface->getCanvas()->drawPaint(p);
        }
}

void fuzzTwoPointConicalGradient(Fuzz* fuzz) {
        SkScalar a, b, startRadius, c, d, endRadius;
        bool useLocalMatrix, useGlobalMatrix;
        if (!fuzz->next(&a)               ||
            !fuzz->next(&b)               ||
            !fuzz->next(&startRadius)     ||
            !fuzz->next(&c)               ||
            !fuzz->next(&d)               ||
            !fuzz->next(&endRadius)       ||
            !fuzz->next(&useLocalMatrix)  ||
            !fuzz->next(&useGlobalMatrix)) {
            return;
        }
        SkPoint start = SkPoint::Make(a, b);
        SkPoint end = SkPoint::Make(c, d);

        std::vector<SkColor> colors;
        std::vector<SkScalar> pos;
        SkShader::TileMode mode;
        if (!initGradientParams(fuzz, &colors, &pos, &mode)) {
            return;
        }

        SkPaint p;
        uint32_t flags;
        if (!fuzz->next(&flags)) {
            return;
        }

        SkTLazy<SkMatrix> localMatrix;
        if (useLocalMatrix && !makeMatrix(fuzz, localMatrix.init())) {
            return;
        }
        p.setShader(SkGradientShader::MakeTwoPointConical(start, startRadius,
            end, endRadius, colors.data(), pos.data(), colors.size(), mode,
            flags, localMatrix.getMaybeNull()));

        sk_sp<SkSurface> surface(SkSurface::MakeRasterN32Premul(50, 50));
        if (useGlobalMatrix) {
            SkMatrix gm;
            if (!makeMatrix(fuzz, &gm)) {
                return;
            }
            SkCanvas* c = surface->getCanvas();
            c->setMatrix(gm);
            c->drawPaint(p);
        } else {
            surface->getCanvas()->drawPaint(p);
        }
}

void fuzzSweepGradient(Fuzz* fuzz) {
        SkScalar cx, cy;
        bool useLocalMatrix, useGlobalMatrix;
        if (!fuzz->next(&cx)              ||
            !fuzz->next(&cy)              ||
            !fuzz->next(&useLocalMatrix)  ||
            !fuzz->next(&useGlobalMatrix)) {
            return;
        }

        std::vector<SkColor> colors;
        std::vector<SkScalar> pos;
        SkShader::TileMode mode;
        if (!initGradientParams(fuzz, &colors, &pos, &mode)) {
            return;
        }

        SkPaint p;
        if (useLocalMatrix) {
            SkMatrix m;
            if (!makeMatrix(fuzz, &m)) {
                return;
            }
            uint32_t flags;
            if (!fuzz->next(&flags)) {
                return;
            }
            p.setShader(SkGradientShader::MakeSweep(cx, cy, colors.data(),
                pos.data(), colors.size(), flags, &m));
        } else {
            p.setShader(SkGradientShader::MakeSweep(cx, cy, colors.data(),
                pos.data(), colors.size()));
        }


        sk_sp<SkSurface> surface(SkSurface::MakeRasterN32Premul(50, 50));
        if (useGlobalMatrix) {
            SkMatrix gm;
            if (!makeMatrix(fuzz, &gm)) {
                return;
            }
            SkCanvas* c = surface->getCanvas();
            c->setMatrix(gm);
            c->drawPaint(p);
        } else {
            surface->getCanvas()->drawPaint(p);
        }
}

DEF_FUZZ(Gradients, fuzz) {
    uint8_t i;
    if (!fuzz->next(&i)) {
        return;
    }

    switch(i) {
        case 0:
            SkDebugf("LinearGradient\n");
            fuzzLinearGradient(fuzz);
            return;
        case 1:
            SkDebugf("RadialGradient\n");
            fuzzRadialGradient(fuzz);
            return;
        case 2:
            SkDebugf("TwoPointConicalGradient\n");
            fuzzTwoPointConicalGradient(fuzz);
            return;
    }
    SkDebugf("SweepGradient\n");
    fuzzSweepGradient(fuzz);
    return;
}