ClipSuperRRect Class Reference

Inheritance diagram for ClipSuperRRect:

Public Member Functions
	ClipSuperRRect (const char *name, float power)
void	drawSuperRRect (SkCanvas *canvas, const SkRect &superRRect, float radX, float radY, SkColor color)
void	onDraw (SkCanvas *canvas) override
Public Member Functions inherited from RuntimeShaderGM
	RuntimeShaderGM (const char *name, SkISize size, const char *sksl, uint32_t flags=0)
void	onOnceBeforeDraw () override
bool	runAsBench () const override
SkString	getName () const override
SkISize	getISize () override
bool	onAnimate (double nanos) override
Public Member Functions inherited from skiagm::GM
	GM (SkColor backgroundColor=SK_ColorWHITE)
virtual	~GM ()
void	setMode (Mode mode)
Mode	getMode () const
DrawResult	gpuSetup (SkCanvas *, SkString *errorMsg, GraphiteTestContext *=nullptr)
void	gpuTeardown ()
void	onceBeforeDraw ()
DrawResult	draw (SkCanvas *canvas)
DrawResult	draw (SkCanvas *, SkString *errorMsg)
void	drawBackground (SkCanvas *)
DrawResult	drawContent (SkCanvas *canvas)
DrawResult	drawContent (SkCanvas *, SkString *errorMsg)
SkScalar	width ()
SkScalar	height ()
SkColor	getBGColor () const
void	setBGColor (SkColor)
void	drawSizeBounds (SkCanvas *, SkColor)
bool	animate (double)
virtual bool	onChar (SkUnichar)
bool	getControls (SkMetaData *controls)
void	setControls (const SkMetaData &controls)
virtual void	modifyGrContextOptions (GrContextOptions *)
virtual void	modifyGraphiteContextOptions (skgpu::graphite::ContextOptions *) const
virtual bool	isBazelOnly () const
virtual std::map< std::string, std::string >	getGoldKeys () const

Additional Inherited Members
Public Types inherited from skiagm::GM
enum	Mode { kGM_Mode , kSample_Mode , kBench_Mode }
using	DrawResult = skiagm::DrawResult
using	GraphiteTestContext = skiatest::graphite::GraphiteTestContext
Static Public Attributes inherited from skiagm::GM
static constexpr char	kErrorMsg_DrawSkippedGpuOnly []
Protected Member Functions inherited from skiagm::GM
virtual DrawResult	onGpuSetup (SkCanvas *, SkString *, GraphiteTestContext *)
virtual void	onGpuTeardown ()
virtual DrawResult	onDraw (SkCanvas *, SkString *errorMsg)
virtual bool	onGetControls (SkMetaData *)
virtual void	onSetControls (const SkMetaData &)
GraphiteTestContext *	graphiteTestContext () const
Protected Attributes inherited from RuntimeShaderGM
SkString	fName
SkISize	fSize
uint32_t	fFlags
float	fSecs = 0.0f
SkString	fSkSL
sk_sp< SkRuntimeEffect >	fEffect

Detailed Description

Definition at line 441 of file runtimeshader.cpp.

Constructor & Destructor Documentation

ClipSuperRRect()

ClipSuperRRect::ClipSuperRRect ( const char *  name, float  power  )

inline

Definition at line 443 of file runtimeshader.cpp.

                                                  : RuntimeShaderGM(name, {500, 500}, R"(
        uniform float power_minus1;
        uniform float2 stretch_factor;
        uniform float2x2 derivatives;
        half4 main(float2 xy) {
            xy = max(abs(xy) + stretch_factor, 0);
            float2 exp_minus1 = pow(xy, power_minus1.xx);  // If power == 3.5: xy * xy * sqrt(xy)
            float f = dot(exp_minus1, xy) - 1;  // f = x^n + y^n - 1
            float2 grad = exp_minus1 * derivatives;
            float fwidth = abs(grad.x) + abs(grad.y) + 1e-12;  // 1e-12 to avoid a divide by zero.
            return half4(saturate(.5 - f/fwidth)); // Approx coverage by riding the gradient to f=0.
        }
    )"), fPower(power) {}

Member Function Documentation

drawSuperRRect()

void ClipSuperRRect::drawSuperRRect ( SkCanvas *  canvas, const SkRect &  superRRect, float  radX, float  radY, SkColor  color  )

inline

Definition at line 457 of file runtimeshader.cpp.

                                       {
        SkPaint paint;
        paint.setColor(color);
 
        if (fPower == 2) {
            // Draw a normal round rect for the sake of testing.
            SkRRect rrect = SkRRect::MakeRectXY(superRRect, radX, radY);
            paint.setAntiAlias(true);
            canvas->drawRRect(rrect, paint);
            return;
        }
 
        SkRuntimeShaderBuilder builder(fEffect);
        builder.uniform("power_minus1") = fPower - 1;
 
        // Size the corners such that the "apex" of our "super" rounded corner is in the same
        // location that the apex of a circular rounded corner would be with the given radii. We
        // define the apex as the point on the rounded corner that is 45 degrees between the
        // horizontal and vertical edges.
        float scale = (1 - SK_ScalarRoot2Over2) / (1 - exp2f(-1/fPower));
        float cornerWidth = radX * scale;
        float cornerHeight = radY * scale;
        cornerWidth = std::min(cornerWidth, superRRect.width() * .5f);
        cornerHeight = std::min(cornerHeight, superRRect.height() * .5f);
        // The stretch factor controls how long the flat edge should be between rounded corners.
        builder.uniform("stretch_factor") = SkV2{1 - superRRect.width()*.5f / cornerWidth,
                                                 1 - superRRect.height()*.5f / cornerHeight};
 
        // Calculate a 2x2 "derivatives" matrix that the shader will use to find the gradient.
        //
        //     f = s^n + t^n - 1   [s,t are "super" rounded corner coords in normalized 0..1 space]
        //
        //     gradient = [df/dx  df/dy] = [ns^(n-1)  nt^(n-1)] * |ds/dx  ds/dy|
        //                                                        |dt/dx  dt/dy|
        //
        //              = [s^(n-1)  t^(n-1)] * |n  0| * |ds/dx  ds/dy|
        //                                     |0  n|   |dt/dx  dt/dy|
        //
        //              = [s^(n-1)  t^(n-1)] * |2n/cornerWidth   0| * mat2x2(canvasMatrix)^-1
        //                                     |0  2n/cornerHeight|
        //
        //              = [s^(n-1)  t^(n-1)] * "derivatives"
        //
        const SkMatrix& M = canvas->getTotalMatrix();
        float a=M.getScaleX(), b=M.getSkewX(), c=M.getSkewY(), d=M.getScaleY();
        float determinant = a*d - b*c;
        float dx = fPower / (cornerWidth * determinant);
        float dy = fPower / (cornerHeight * determinant);
        builder.uniform("derivatives") = SkV4{d*dx, -c*dy, -b*dx, a*dy};
 
        // This matrix will be inverted by the effect system, giving a matrix that converts local
        // coordinates to (almost) coner coordinates. To get the rest of the way to the nearest
        // corner's space, the shader will have to take the absolute value, add the stretch_factor,
        // then clamp above zero.
        SkMatrix cornerToLocal;
        cornerToLocal.setScaleTranslate(cornerWidth, cornerHeight, superRRect.centerX(),
                                        superRRect.centerY());
        canvas->clipShader(builder.makeShader(&cornerToLocal));
 
        // Bloat the outer edges of the rect we will draw so it contains all the antialiased pixels.
        // Bloat by a full pixel instead of half in case Skia is in a mode that draws this rect with
        // unexpected AA of its own.
        float inverseDet = 1 / fabsf(determinant);
        float bloatX = (fabsf(d) + fabsf(c)) * inverseDet;
        float bloatY = (fabsf(b) + fabsf(a)) * inverseDet;
        canvas->drawRect(superRRect.makeOutset(bloatX, bloatY), paint);
    }

onDraw()

void ClipSuperRRect::onDraw ( SkCanvas *  canvas )

inlineoverridevirtual

Reimplemented from skiagm::GM.

Definition at line 526 of file runtimeshader.cpp.

                                           {
        SkRandom rand(2);
 
        canvas->save();
        canvas->translate(canvas->imageInfo().width() / 2.f, canvas->imageInfo().height() / 2.f);
 
        canvas->save();
        canvas->rotate(21);
        this->drawSuperRRect(canvas, SkRect::MakeXYWH(-5, 25, 175, 100), 50, 30,
                             rand.nextU() | 0xff808080);
        canvas->restore();
 
        canvas->save();
        canvas->rotate(94);
        this->drawSuperRRect(canvas, SkRect::MakeXYWH(95, 75, 125, 100), 30, 30,
                             rand.nextU() | 0xff808080);
        canvas->restore();
 
        canvas->save();
        canvas->rotate(132);
        this->drawSuperRRect(canvas, SkRect::MakeXYWH(0, 75, 150, 100), 40, 30,
                             rand.nextU() | 0xff808080);
        canvas->restore();
 
        canvas->save();
        canvas->rotate(282);
        this->drawSuperRRect(canvas, SkRect::MakeXYWH(15, -20, 100, 100), 20, 20,
                             rand.nextU() | 0xff808080);
        canvas->restore();
 
        canvas->save();
        canvas->rotate(0);
        this->drawSuperRRect(canvas, SkRect::MakeXYWH(140, -50, 90, 110), 25, 25,
                             rand.nextU() | 0xff808080);
        canvas->restore();
 
        canvas->save();
        canvas->rotate(-35);
        this->drawSuperRRect(canvas, SkRect::MakeXYWH(160, -60, 60, 90), 18, 18,
                             rand.nextU() | 0xff808080);
        canvas->restore();
 
        canvas->save();
        canvas->rotate(65);
        this->drawSuperRRect(canvas, SkRect::MakeXYWH(220, -120, 60, 90), 18, 18,
                             rand.nextU() | 0xff808080);
        canvas->restore();
 
        canvas->save();
        canvas->rotate(265);
        this->drawSuperRRect(canvas, SkRect::MakeXYWH(150, -129, 80, 160), 24, 39,
                             rand.nextU() | 0xff808080);
        canvas->restore();
 
        canvas->restore();
    }

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

• third_party/skia/gm/runtimeshader.cpp