SampleFitCubicToCircle Class Reference

Inheritance diagram for SampleFitCubicToCircle:

Classes
class	Click

Public Member Functions
	SampleFitCubicToCircle ()
void	load (SkScalar w, SkScalar h) override
void	draw (SkCanvas *) override
bool	onChar (SkUnichar) override
Public Member Functions inherited from ClickHandlerSlide
bool	onMouse (SkScalar x, SkScalar y, skui::InputState clickState, skui::ModifierKey modifierKeys) final
Public Member Functions inherited from Slide
virtual SkISize	getDimensions () const
virtual void	gpuTeardown ()
virtual bool	animate (double nanos)
virtual void	resize (SkScalar winWidth, SkScalar winHeight)
virtual void	unload ()
virtual bool	onGetControls (SkMetaData *)
virtual void	onSetControls (const SkMetaData &)
const SkString &	getName ()
Public Member Functions inherited from SkRefCntBase
	SkRefCntBase ()
virtual	~SkRefCntBase ()
bool	unique () const
void	ref () const
void	unref () const

Protected Member Functions
Click *	onFindClickHandler (SkScalar x, SkScalar y, skui::ModifierKey) override
bool	onClick (Click *) override
Protected Member Functions inherited from ClickHandlerSlide
virtual bool	onClick (Click *)=0

Additional Inherited Members
Protected Attributes inherited from Slide
SkString	fName

Detailed Description

Definition at line 39 of file FitCubicToCircleSlide.cpp.

Constructor & Destructor Documentation

SampleFitCubicToCircle()

SampleFitCubicToCircle::SampleFitCubicToCircle ( )

inline

Definition at line 41 of file FitCubicToCircleSlide.cpp.

{ fName = "FitCubicToCircle"; }

Member Function Documentation

draw()

void SampleFitCubicToCircle::draw ( SkCanvas *  canvas )

overridevirtual

Implements Slide.

Definition at line 157 of file FitCubicToCircleSlide.cpp.

                                                  {
    canvas->clear(SK_ColorBLACK);
 
    SkPaint circlePaint;
    circlePaint.setColor(0x80ffffff);
    circlePaint.setStyle(SkPaint::kStroke_Style);
    circlePaint.setStrokeWidth(0);
    circlePaint.setAntiAlias(true);
    canvas->drawArc(SkRect::MakeXYWH(kCenterX - kRadius, kCenterY - kRadius, kRadius * 2,
                                     kRadius * 2), 0, 360, false, circlePaint);
 
    SkPaint cubicPaint;
    cubicPaint.setColor(SK_ColorGREEN);
    cubicPaint.setStyle(SkPaint::kStroke_Style);
    cubicPaint.setStrokeWidth(10);
    cubicPaint.setAntiAlias(true);
    SkPath cubicPath;
    cubicPath.moveTo(fCubicX[0], fCubicY[0]);
    cubicPath.cubicTo(fCubicX[1], fCubicY[1], fCubicX[2], fCubicY[2], fCubicX[3], fCubicY[3]);
    canvas->drawPath(cubicPath, cubicPaint);
 
    SkPaint endpointsPaint;
    endpointsPaint.setColor(SK_ColorBLUE);
    endpointsPaint.setStrokeWidth(8);
    endpointsPaint.setAntiAlias(true);
    SkPoint points[2] = {{(float)fCubicX[0], (float)fCubicY[0]},
                         {(float)fCubicX[3], (float)fCubicY[3]}};
    canvas->drawPoints(SkCanvas::kPoints_PointMode, 2, points, endpointsPaint);
 
    SkPaint textPaint;
    textPaint.setColor(SK_ColorWHITE);
    constexpr static float kInfoTextSize = 16;
    SkFont font(ToolUtils::DefaultTypeface(), kInfoTextSize);
    int infoY = 10 + kInfoTextSize;
    for (const SkString& infoString : fInfoStrings) {
        canvas->drawString(infoString.c_str(), 10, infoY, font, textPaint);
        infoY += kInfoTextSize * 3/2;
    }
}

load()

void SampleFitCubicToCircle::load ( SkScalar  w, SkScalar  h  )

inlineoverridevirtual

Reimplemented from Slide.

Definition at line 42 of file FitCubicToCircleSlide.cpp.

{ this->fitCubic(); }

onChar()

bool SampleFitCubicToCircle::onChar ( SkUnichar  unichar )

overridevirtual

Reimplemented from Slide.

Definition at line 238 of file FitCubicToCircleSlide.cpp.

                                                     {
    if (unichar == 'E') {
        constexpr static double kMaxErrorT = 0.21132486540519;  // Always the same.
        // Split the arc in half until error =~0, and report the improvement after each halving.
        double lastError = -1;
        for (double theta = fTheta; lastError != 0; theta /= 2) {
            double rads = theta * M_PI/180;
            std::array<double, 4> X, Y;
            fit_cubic_to_unit_circle(1, 0, std::cos(rads), std::sin(rads), &X, &Y);
            auto [x, dx, ddx] = eval_cubic(X.data(), kMaxErrorT);
            auto [y, dy, ddy] = eval_cubic(Y.data(), kMaxErrorT);
            double error = std::sqrt(x*x + y*y) * kRadius - kRadius;
            if ((float)error <= 0) {
                error = 0;
            }
            SkDebugf("%6.2f degrees:   error= %10.5gpx", theta, error);
            if (lastError > 0) {
                SkDebugf(" (%17.14fx improvement)", lastError / error);
            }
            SkDebugf("\n");
            lastError = error;
        }
        return true;
    }
    return false;
}

onClick()

bool SampleFitCubicToCircle::onClick ( Click *  )

overrideprotected

Definition at line 232 of file FitCubicToCircleSlide.cpp.

                                                                  {
    Click* myClick = (Click*)click;
    myClick->doClick(this);
    return true;
}

onFindClickHandler()

ClickHandlerSlide::Click * SampleFitCubicToCircle::onFindClickHandler ( SkScalar  x, SkScalar  y, skui::ModifierKey  modi  )

overrideprotectedvirtual

Return a Click object to handle the click. onClick will be called repeatedly with the latest mouse state tracked on the Click object until it returns false.

Implements ClickHandlerSlide.

Definition at line 219 of file FitCubicToCircleSlide.cpp.

                                                                                      {
    double dx0 = x - fCubicX[0];
    double dy0 = y - fCubicY[0];
    double dx3 = x - fCubicX[3];
    double dy3 = y - fCubicY[3];
    if (dx0*dx0 + dy0*dy0 < dx3*dx3 + dy3*dy3) {
        return new Click(0);
    } else {
        return new Click(1);
    }
}

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The documentation for this class was generated from the following file:

• third_party/skia/tools/viewer/FitCubicToCircleSlide.cpp