samplecode/SampleComplexClip.cpp

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

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 },
};

#define TEST_INVERSE 0

class ComplexClipView : public SkView {
    SkScalar    fWidth;
public:
	ComplexClipView() {
    }
    
protected:
    // overrides from SkEventSink
    virtual bool onQuery(SkEvent* evt) {
        if (SampleCode::TitleQ(*evt)) {
            SampleCode::TitleR(evt, "ComplexClip");
            return true;
        }
        return this->INHERITED::onQuery(evt);
    }
    
    void drawBG(SkCanvas* canvas) {
        canvas->drawColor(SkColorSetRGB(0xA0,0xDD,0xA0));
    }
    
    virtual void onDraw(SkCanvas* canvas) {
        SkPath path;
        path.moveTo(SkIntToScalar(0),   SkIntToScalar(50));
        path.quadTo(SkIntToScalar(0),   SkIntToScalar(0),   SkIntToScalar(50),  SkIntToScalar(0));
        path.lineTo(SkIntToScalar(175), SkIntToScalar(0));
        path.quadTo(SkIntToScalar(200), SkIntToScalar(0),   SkIntToScalar(200), SkIntToScalar(25));
        path.lineTo(SkIntToScalar(200), SkIntToScalar(150));
        path.quadTo(SkIntToScalar(200), SkIntToScalar(200), SkIntToScalar(150), SkIntToScalar(200));
        path.lineTo(SkIntToScalar(0),   SkIntToScalar(200));
        path.close();
        path.moveTo(SkIntToScalar(50),  SkIntToScalar(50));
        path.lineTo(SkIntToScalar(150), SkIntToScalar(50));
        path.lineTo(SkIntToScalar(150), SkIntToScalar(125));
        path.quadTo(SkIntToScalar(150), SkIntToScalar(150), SkIntToScalar(125), SkIntToScalar(150));
        path.lineTo(SkIntToScalar(50),  SkIntToScalar(150));
        path.close();
        path.setFillType(SkPath::kEvenOdd_FillType);
        SkColor pathColor = SK_ColorBLACK;
        SkPaint pathPaint;
        pathPaint.setAntiAlias(true);
        pathPaint.setColor(pathColor);

        SkPath clipA;
        clipA.moveTo(SkIntToScalar(10),  SkIntToScalar(20));
        clipA.lineTo(SkIntToScalar(165), SkIntToScalar(22));
        clipA.lineTo(SkIntToScalar(70),  SkIntToScalar(105));
        clipA.lineTo(SkIntToScalar(165), SkIntToScalar(177));
        clipA.lineTo(SkIntToScalar(-5),  SkIntToScalar(180));
        clipA.close();
        SkColor colorA = SK_ColorCYAN;

        SkPath clipB;
        clipB.moveTo(SkIntToScalar(40),  SkIntToScalar(10));
        clipB.lineTo(SkIntToScalar(190), SkIntToScalar(15));
        clipB.lineTo(SkIntToScalar(195), SkIntToScalar(190));
        clipB.lineTo(SkIntToScalar(40),  SkIntToScalar(185));
        clipB.lineTo(SkIntToScalar(155), SkIntToScalar(100));
        clipB.close();
        SkColor colorB = SK_ColorRED;

        drawBG(canvas);
        SkPaint paint;
        paint.setAntiAlias(true);

        paint.setStyle(SkPaint::kStroke_Style);
        paint.setStrokeWidth(0);

        canvas->translate(SkIntToScalar(10),SkIntToScalar(10));
        canvas->drawPath(path, pathPaint);
        paint.setColor(colorA);
        canvas->drawPath(clipA, paint);
        paint.setColor(colorB);
        canvas->drawPath(clipB, paint);

        static const struct {
            SkRegion::Op fOp;
            const char*  fName;
        } gOps[] = { //extra spaces in names for measureText
            {SkRegion::kIntersect_Op,         "Isect "},
            {SkRegion::kDifference_Op,        "Diff " },
            {SkRegion::kUnion_Op,             "Union "},
            {SkRegion::kXOR_Op,               "Xor "  },
            {SkRegion::kReverseDifference_Op, "RDiff "}
        };

        canvas->translate(0, SkIntToScalar(40));
        canvas->scale(3 * SK_Scalar1 / 4, 3 * SK_Scalar1 / 4);
        canvas->save();

        int invALimit = TEST_INVERSE ? 1 : 2;
        for (int invA = 0; invALimit < 2; ++invA) {
            for (int op = 0; op < SK_ARRAY_COUNT(gOps); ++op) {
                int idx = invA * SK_ARRAY_COUNT(gOps) + op;
                if (!(idx % 3)) {
                    canvas->restore();
                    canvas->translate(0, SkIntToScalar(250));
                    canvas->save();
                }
                canvas->save();
                    // set clip
                    clipA.setFillType(invA ? SkPath::kInverseEvenOdd_FillType :
                                             SkPath::kEvenOdd_FillType);
                    canvas->clipPath(clipA);
                    canvas->clipPath(clipB, gOps[op].fOp);

                    // draw path clipped
                    canvas->drawPath(path, pathPaint);
                canvas->restore();

                // draw path in hairline
                paint.setColor(pathColor);
                canvas->drawPath(path, paint);

                // draw clips in hair line
                paint.setColor(colorA);
                canvas->drawPath(clipA, paint);
                paint.setColor(colorB);
                canvas->drawPath(clipB, paint);

                paint.setTextSize(SkIntToScalar(20));

                SkScalar txtX = SkIntToScalar(55);
                paint.setColor(colorA);
                const char* aTxt = invA ? "InverseA " : "A ";
                canvas->drawText(aTxt, strlen(aTxt), txtX, SkIntToScalar(220), paint);
                txtX += paint.measureText(aTxt, strlen(aTxt));
                paint.setColor(SK_ColorBLACK);
                canvas->drawText(gOps[op].fName, strlen(gOps[op].fName),
                                    txtX, SkIntToScalar(220), paint);
                txtX += paint.measureText(gOps[op].fName, strlen(gOps[op].fName));
                paint.setColor(colorB);
                canvas->drawText("B", 1, txtX, SkIntToScalar(220), paint);

                canvas->translate(SkIntToScalar(250),0);
            }
        }
        canvas->restore();
    }

    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 ComplexClipView; }
static SkViewRegister reg(MyFactory);