skia/src/samplecode/SampleStrokePath.cpp

#include "SampleCode.h"
#include "SkCanvas.h"
#include "SkParsePath.h"
#include "SkPath.h"
#include "SkRandom.h"
#include "SkView.h"

#include "SkBlurMaskFilter.h"

#if 0
#include "SkBlurMask.h"
static void test_blur() {
    uint8_t cell[9];
    memset(cell, 0xFF, sizeof(cell));
    SkMask src;
    src.fImage = cell;
    src.fFormat = SkMask::kA8_Format;
    SkMask dst;

    for (int y = 1; y <= 3; y++) {
        for (int x = 1; x <= 3; x++) {
            src.fBounds.set(0, 0, x, y);
            src.fRowBytes = src.fBounds.width();
            
            SkScalar radius = 1.f;

            printf("src [%d %d %d %d] radius %g\n", src.fBounds.fLeft, src.fBounds.fTop,
                   src.fBounds.fRight, src.fBounds.fBottom, radius);

            SkBlurMask::Blur(&dst, src, radius, SkBlurMask::kNormal_Style);
            uint8_t* dstPtr = dst.fImage;

            for (int y = 0; y < dst.fBounds.height(); y++) {
                for (int x = 0; x < dst.fBounds.width(); x++) {
                    printf(" %02X", dstPtr[x]);
                }
                printf("\n");
                dstPtr += dst.fRowBytes;
            }
        }
    }
}
#endif

static void scale_to_width(SkPath* path, SkScalar dstWidth) {
    const SkRect& bounds = path->getBounds();
    SkScalar scale = dstWidth / bounds.width();
    SkMatrix matrix;

    matrix.setScale(scale, scale);
    path->transform(matrix);
}

static const struct {
    SkPaint::Style  fStyle;
    SkPaint::Join   fJoin;
    int             fStrokeWidth;
} gRec[] = {
    { SkPaint::kFill_Style,             SkPaint::kMiter_Join,   0 },
    { SkPaint::kStroke_Style,           SkPaint::kMiter_Join,   0 },
    { SkPaint::kStroke_Style,           SkPaint::kMiter_Join,   10 },
    { SkPaint::kStrokeAndFill_Style,    SkPaint::kMiter_Join,   10 },
};

class StrokePathView : public SkView {
    SkScalar    fWidth;
    SkPath      fPath;
public:
	StrokePathView() {
//        test_blur();
        fWidth = SkIntToScalar(120);

#if 0
        const char str[] =
            "M 0, 3"
            "C 10, -10, 30, -10, 0, 28"
            "C -30, -10, -10, -10, 0, 3"
            "Z";
        SkParsePath::FromSVGString(str, &fPath);
#else
        fPath.addCircle(0, 0, SkIntToScalar(50), SkPath::kCW_Direction);
        fPath.addCircle(0, SkIntToScalar(-50), SkIntToScalar(30), SkPath::kCW_Direction);
#endif
        
        scale_to_width(&fPath, fWidth);
        const SkRect& bounds = fPath.getBounds();
        fPath.offset(-bounds.fLeft, -bounds.fTop);
    }
    
protected:
    // overrides from SkEventSink
    virtual bool onQuery(SkEvent* evt) {
        if (SampleCode::TitleQ(*evt)) {
            SampleCode::TitleR(evt, "StrokePath");
            return true;
        }
        return this->INHERITED::onQuery(evt);
    }
    
    void drawBG(SkCanvas* canvas) {
        canvas->drawColor(0xFFDDDDDD);
    }
    
    SkRandom rand;
    
    void drawSet(SkCanvas* canvas, SkPaint* paint) {
        SkAutoCanvasRestore acr(canvas, true);

        for (size_t i = 0; i < SK_ARRAY_COUNT(gRec); i++) {
            paint->setStyle(gRec[i].fStyle);
            paint->setStrokeJoin(gRec[i].fJoin);
            paint->setStrokeWidth(SkIntToScalar(gRec[i].fStrokeWidth));
            canvas->drawPath(fPath, *paint);
            canvas->translate(fWidth * 5 / 4, 0);
        }
    }

    virtual void onDraw(SkCanvas* canvas) {
        drawBG(canvas);
        //return;
        canvas->translate(SkIntToScalar(10), SkIntToScalar(10));

        SkPaint paint;
        paint.setAntiAlias(true);
        
        if (true) {
            canvas->drawColor(SK_ColorBLACK);

            paint.setTextSize(24);
            paint.setColor(SK_ColorWHITE);
            canvas->translate(10, 30);

            static const SkBlurMaskFilter::BlurStyle gStyle[] = {
                SkBlurMaskFilter::kNormal_BlurStyle,
                SkBlurMaskFilter::kInner_BlurStyle,
                SkBlurMaskFilter::kOuter_BlurStyle,
                SkBlurMaskFilter::kSolid_BlurStyle,
            };
            for (int x = 0; x < 5; x++) {
                SkMaskFilter* mf;
                SkScalar radius = 4;
                for (int y = 0; y < 10; y++) {
                    if (x) {
                        mf = SkBlurMaskFilter::Create(radius, gStyle[x - 1]);
                        paint.setMaskFilter(mf)->unref();
                    }
                    canvas->drawText("Title Bar", 9, x*100, y*30, paint);
                    radius *= 0.75f;
                }
                
            }
            return;
        }

        paint.setColor(SK_ColorBLUE);

#if 1
        SkPath p;
        float r = rand.nextUScalar1() + 0.5f;
        SkScalar x = 0, y = 0;
        p.moveTo(x, y);
#if 0
        p.cubicTo(x-75*r, y+75*r, x-40*r, y+125*r, x, y+85*r);
        p.cubicTo(x+40*r, y+125*r, x+75*r, y+75*r, x, y);
#else
        p.cubicTo(x+75*r, y+75*r, x+40*r, y+125*r, x, y+85*r);
        p.cubicTo(x-40*r, y+125*r, x-75*r, y+75*r, x, y);
#endif
        p.close();
        fPath = p;
        fPath.offset(100, 0);
#endif
        
        fPath.setFillType(SkPath::kWinding_FillType);
        drawSet(canvas, &paint);
        
        canvas->translate(0, fPath.getBounds().height() * 5 / 4);
        fPath.setFillType(SkPath::kEvenOdd_FillType);
        drawSet(canvas, &paint);
    }

    virtual SkView::Click* onFindClickHandler(SkScalar x, SkScalar y) {
        this->inval(NULL);
        return this->INHERITED::onFindClickHandler(x, y);
    }
private:
    typedef SkView INHERITED;
};

//////////////////////////////////////////////////////////////////////////////

static SkView* MyFactory() { return new StrokePathView; }
static SkViewRegister reg(MyFactory);