shaderpath.cpp

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/*
 * Copyright 2011 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
 
#include "gm/gm.h"
#include "include/core/SkBitmap.h"
#include "include/core/SkCanvas.h"
#include "include/core/SkColor.h"
#include "include/core/SkFont.h"
#include "include/core/SkFontTypes.h"
#include "include/core/SkMatrix.h"
#include "include/core/SkPaint.h"
#include "include/core/SkPath.h"
#include "include/core/SkPoint.h"
#include "include/core/SkScalar.h"
#include "include/core/SkShader.h"
#include "include/core/SkSize.h"
#include "include/core/SkString.h"
#include "include/core/SkTileMode.h"
#include "include/core/SkTypes.h"
#include "include/effects/SkGradientShader.h"
#include "tools/ToolUtils.h"
 
#include <string.h>
 
namespace skiagm {
 
static void makebm(SkBitmap* bm, int w, int h) {
    bm->allocN32Pixels(w, h);
    bm->eraseColor(SK_ColorTRANSPARENT);
 
    SkCanvas    canvas(*bm);
    SkScalar    s = SkIntToScalar(std::min(w, h));
    const SkPoint     kPts0[] = { { 0, 0 }, { s, s } };
    const SkPoint     kPts1[] = { { s/2, 0 }, { s/2, s } };
    const SkScalar    kPos[] = { 0, SK_Scalar1/2, SK_Scalar1 };
    const SkColor kColors0[] = {0x80F00080, 0xF0F08000, 0x800080F0 };
    const SkColor kColors1[] = {0xF08000F0, 0x8080F000, 0xF000F080 };
 
 
    SkPaint     paint;
 
    paint.setShader(SkGradientShader::MakeLinear(kPts0, kColors0, kPos,
                    std::size(kColors0), SkTileMode::kClamp));
    canvas.drawPaint(paint);
    paint.setShader(SkGradientShader::MakeLinear(kPts1, kColors1, kPos,
                    std::size(kColors1), SkTileMode::kClamp));
    canvas.drawPaint(paint);
}
 
///////////////////////////////////////////////////////////////////////////////
 
struct LabeledMatrix {
    SkMatrix    fMatrix;
    const char* fLabel;
};
 
constexpr int kPointSize = 300;
 
class ShaderPathGM : public GM {
public:
    ShaderPathGM() {
        this->setBGColor(0xFFDDDDDD);
    }
 
protected:
    SkString getName() const override { return SkString("shaderpath"); }
 
    SkISize getISize() override { return SkISize::Make(820, 930); }
 
    void onOnceBeforeDraw() override {
        makebm(&fBmp, kPointSize / 4, kPointSize / 4);
    }
 
    void onDraw(SkCanvas* canvas) override {
 
        SkPaint bmpPaint;
        bmpPaint.setAntiAlias(true);
        bmpPaint.setAlphaf(0.5f);
        SkSamplingOptions sampling(SkFilterMode::kLinear);
 
        canvas->drawImage(fBmp.asImage(), 5.f, 5.f, sampling, &bmpPaint);
 
        SkPaint outlinePaint;
        outlinePaint.setStyle(SkPaint::kStroke_Style);
        outlinePaint.setStrokeWidth(0.f);
 
        canvas->translate(15.f, 15.f);
        canvas->scale(2.f, 2.f);
 
        constexpr SkTileMode kTileModes[] = {
            SkTileMode::kRepeat,
            SkTileMode::kMirror,
        };
 
        // position the baseline of the first path
        canvas->translate(0.f, 2.25);
 
        SkPath path;
        path.moveTo(0, 40).cubicTo(10, 70, 20, 10, 30, 40);
 
        canvas->save();
        int i = 0;
        for (size_t tm0 = 0; tm0 < std::size(kTileModes); ++tm0) {
            for (size_t tm1 = 0; tm1 < std::size(kTileModes); ++tm1) {
                SkMatrix localM;
                localM.setTranslate(5.f, 5.f);
                localM.postRotate(20);
                localM.postScale(1.15f, .85f);
 
                SkPaint fillPaint;
                fillPaint.setAntiAlias(true);
                fillPaint.setShader(fBmp.makeShader(kTileModes[tm0], kTileModes[tm1],
                                                    sampling, localM));
 
                canvas->drawPath(path, fillPaint);
                canvas->drawPath(path, outlinePaint);
                canvas->translate(50.f, 0.f);
                ++i;
                if (!(i % 2)) {
                    canvas->restore();
                    canvas->translate(0, 22.5f);
                    canvas->save();
                }
            }
        }
        canvas->restore();
    }
 
private:
    SkBitmap fBmp;
    using INHERITED = GM;
};
 
///////////////////////////////////////////////////////////////////////////////
 
DEF_GM( return new ShaderPathGM; )
}  // namespace skiagm