samplecode/SampleConcavePaths.cpp

#include "SampleCode.h"
#include "SkView.h"
#include "SkCanvas.h"
#include "SkGradientShader.h"
#include "SkGraphics.h"
#include "SkImageDecoder.h"
#include "SkPath.h"
#include "SkRegion.h"
#include "SkShader.h"
#include "SkUtils.h"
#include "SkXfermode.h"
#include "SkColorPriv.h"
#include "SkColorFilter.h"
#include "SkParsePath.h"
#include "SkTime.h"
#include "SkTypeface.h"

#include "SkGeometry.h"

class ConcavePathView : public SampleView {
public:
	ConcavePathView() {}
    
protected:
    // overrides from SkEventSink
    virtual bool onQuery(SkEvent* evt) {
        if (SampleCode::TitleQ(*evt)) {
            SampleCode::TitleR(evt, "ConcavePaths");
            return true;
        }
        return this->INHERITED::onQuery(evt);
    }
    
    virtual void onDrawContent(SkCanvas* canvas) {        
        SkPaint paint;
        
        paint.setAntiAlias(true);
        paint.setStyle(SkPaint::kFill_Style);

        // Concave test
        if (1) {
            SkPath path;
            canvas->translate(0, 0);
            path.moveTo(SkIntToScalar(20), SkIntToScalar(20));
            path.lineTo(SkIntToScalar(80), SkIntToScalar(20));
            path.lineTo(SkIntToScalar(30), SkIntToScalar(30));
            path.lineTo(SkIntToScalar(20), SkIntToScalar(80));
            canvas->drawPath(path, paint);
        }
        // Reverse concave test
        if (1) {
            SkPath path;
            canvas->save();
            canvas->translate(100, 0);
            path.moveTo(SkIntToScalar(20), SkIntToScalar(20));
            path.lineTo(SkIntToScalar(20), SkIntToScalar(80));
            path.lineTo(SkIntToScalar(30), SkIntToScalar(30));
            path.lineTo(SkIntToScalar(80), SkIntToScalar(20));
            canvas->drawPath(path, paint);
            canvas->restore();
        }
        // Bowtie (intersection)
        if (1) {
            SkPath path;
            canvas->save();
            canvas->translate(200, 0);
            path.moveTo(SkIntToScalar(20), SkIntToScalar(20));
            path.lineTo(SkIntToScalar(80), SkIntToScalar(80));
            path.lineTo(SkIntToScalar(80), SkIntToScalar(20));
            path.lineTo(SkIntToScalar(20), SkIntToScalar(80));
            canvas->drawPath(path, paint);
            canvas->restore();
        }
        // "fake" bowtie (concave, but no intersection)
        if (1) {
            SkPath path;
            canvas->save();
            canvas->translate(300, 0);
            path.moveTo(SkIntToScalar(20), SkIntToScalar(20));
            path.lineTo(SkIntToScalar(50), SkIntToScalar(40));
            path.lineTo(SkIntToScalar(80), SkIntToScalar(20));
            path.lineTo(SkIntToScalar(80), SkIntToScalar(80));
            path.lineTo(SkIntToScalar(50), SkIntToScalar(60));
            path.lineTo(SkIntToScalar(20), SkIntToScalar(80));
            canvas->drawPath(path, paint);
            canvas->restore();
        }
        // Fish test (intersection/concave)
        if (1) {
            SkPath path;
            canvas->save();
            canvas->translate(0, 100);
            path.moveTo(SkIntToScalar(20), SkIntToScalar(20));
            path.lineTo(SkIntToScalar(80), SkIntToScalar(80));
            path.lineTo(SkIntToScalar(70), SkIntToScalar(50));
            path.lineTo(SkIntToScalar(80), SkIntToScalar(20));
            path.lineTo(SkIntToScalar(20), SkIntToScalar(80));
            path.lineTo(SkIntToScalar(0), SkIntToScalar(50));
            canvas->drawPath(path, paint);
            canvas->restore();
        }
        // Collinear test
        if (1) {
            SkPath path;
            canvas->save();
            canvas->translate(100, 100);
            path.moveTo(SkIntToScalar(20), SkIntToScalar(20));
            path.lineTo(SkIntToScalar(50), SkIntToScalar(20));
            path.lineTo(SkIntToScalar(80), SkIntToScalar(20));
            path.lineTo(SkIntToScalar(50), SkIntToScalar(80));
            canvas->drawPath(path, paint);
            canvas->restore();
        }
        // Hole test
        if (1) {
            SkPath path;
            canvas->save();
            canvas->translate(200, 100);
            path.moveTo(SkIntToScalar(20), SkIntToScalar(20));
            path.lineTo(SkIntToScalar(80), SkIntToScalar(20));
            path.lineTo(SkIntToScalar(80), SkIntToScalar(80));
            path.lineTo(SkIntToScalar(20), SkIntToScalar(80));
            path.moveTo(SkIntToScalar(30), SkIntToScalar(30));
            path.lineTo(SkIntToScalar(30), SkIntToScalar(70));
            path.lineTo(SkIntToScalar(70), SkIntToScalar(70));
            path.lineTo(SkIntToScalar(70), SkIntToScalar(30));
            canvas->drawPath(path, paint);
            canvas->restore();
        }
    }
    
    virtual SkView::Click* onFindClickHandler(SkScalar x, SkScalar y) {
        this->inval(NULL);
        return this->INHERITED::onFindClickHandler(x, y);
    }
    
private:
    typedef SampleView INHERITED;
};

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

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