void SkMatrix3D::setRotateZ(SkScalar degZ) {
SkScalar s, c;
s = SkScalarSinCos(SkDegreesToRadians(degZ), &c);
this->setRow(0, c, -s, 0);
this->setRow(1, s, c, 0);
this->setRow(2, 0, 0, SK_Scalar1);
}
void SkColorMatrix::setRotate(Axis axis, SkScalar degrees)
{
SkScalar S, C;
S = SkScalarSinCos(SkDegreesToRadians(degrees), &C);
this->setSinCos(axis, S, C);
}
void SkMatrix3D::setRotateY(SkScalar degY) {
SkScalar s, c;
s = SkScalarSinCos(SkDegreesToRadians(degY), &c);
this->setRow(0, c, 0, -s);
this->setRow(1, 0, SK_Scalar1, 0);
this->setRow(2, s, 0, c);
}
static void create_ngon(int n, SkPoint* pts, SkScalar width, SkScalar height) {
float angleStep = 360.0f / n, angle = 0.0f, sin, cos;
if ((n % 2) == 1) {
angle = angleStep/2.0f;
}
for (int i = 0; i < n; ++i) {
sin = SkScalarSinCos(SkDegreesToRadians(angle), &cos);
pts[i].fX = -sin * width;
pts[i].fY = cos * height;
angle += angleStep;
}
}
static void test_matrix_decomposition(skiatest::Reporter* reporter) {
SkMatrix mat;
SkScalar rotation0, scaleX, scaleY, rotation1;
const float kRotation0 = 15.5f;
const float kRotation1 = -50.f;
const float kScale0 = 5000.f;
const float kScale1 = 0.001f;
// identity
mat.reset();
REPORTER_ASSERT(reporter, SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1));
REPORTER_ASSERT(reporter, SkScalarNearlyZero(rotation0));
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleX, SK_Scalar1));
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleY, SK_Scalar1));
REPORTER_ASSERT(reporter, SkScalarNearlyZero(rotation1));
// make sure it doesn't crash if we pass in NULLs
REPORTER_ASSERT(reporter, SkDecomposeUpper2x2(mat, NULL, NULL, NULL, NULL));
// rotation only
mat.setRotate(kRotation0);
REPORTER_ASSERT(reporter, SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1));
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(rotation0, SkDegreesToRadians(kRotation0)));
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleX, SK_Scalar1));
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleY, SK_Scalar1));
REPORTER_ASSERT(reporter, SkScalarNearlyZero(rotation1));
// uniform scale only
mat.setScale(kScale0, kScale0);
REPORTER_ASSERT(reporter, SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1));
REPORTER_ASSERT(reporter, SkScalarNearlyZero(rotation0));
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleX, kScale0));
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleY, kScale0));
REPORTER_ASSERT(reporter, SkScalarNearlyZero(rotation1));
// anisotropic scale only
mat.setScale(kScale1, kScale0);
REPORTER_ASSERT(reporter, SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1));
REPORTER_ASSERT(reporter, SkScalarNearlyZero(rotation0));
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleX, kScale1));
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleY, kScale0));
REPORTER_ASSERT(reporter, SkScalarNearlyZero(rotation1));
// rotation then uniform scale
mat.setRotate(kRotation1);
mat.postScale(kScale0, kScale0);
REPORTER_ASSERT(reporter, SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1));
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(rotation0, SkDegreesToRadians(kRotation1)));
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleX, kScale0));
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleY, kScale0));
REPORTER_ASSERT(reporter, SkScalarNearlyZero(rotation1));
// uniform scale then rotation
mat.setScale(kScale0, kScale0);
mat.postRotate(kRotation1);
REPORTER_ASSERT(reporter, SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1));
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(rotation0, SkDegreesToRadians(kRotation1)));
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleX, kScale0));
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleY, kScale0));
REPORTER_ASSERT(reporter, SkScalarNearlyZero(rotation1));
// rotation then uniform scale+reflection
mat.setRotate(kRotation0);
mat.postScale(kScale1, -kScale1);
REPORTER_ASSERT(reporter, SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1));
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(rotation0, SkDegreesToRadians(kRotation0)));
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleX, kScale1));
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleY, -kScale1));
REPORTER_ASSERT(reporter, SkScalarNearlyZero(rotation1));
// uniform scale+reflection, then rotate
mat.setScale(kScale0, -kScale0);
mat.postRotate(kRotation1);
REPORTER_ASSERT(reporter, SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1));
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(rotation0, SkDegreesToRadians(-kRotation1)));
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleX, kScale0));
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleY, -kScale0));
REPORTER_ASSERT(reporter, SkScalarNearlyZero(rotation1));
// rotation then anisotropic scale
mat.setRotate(kRotation1);
mat.postScale(kScale1, kScale0);
REPORTER_ASSERT(reporter, SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1));
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(rotation0, SkDegreesToRadians(kRotation1)));
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleX, kScale1));
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleY, kScale0));
REPORTER_ASSERT(reporter, SkScalarNearlyZero(rotation1));
// anisotropic scale then rotation
mat.setScale(kScale1, kScale0);
mat.postRotate(kRotation0);
REPORTER_ASSERT(reporter, SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1));
REPORTER_ASSERT(reporter, SkScalarNearlyZero(rotation0));
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleX, kScale1));
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleY, kScale0));
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(rotation1, SkDegreesToRadians(kRotation0)));
// rotation, uniform scale, then different rotation
mat.setRotate(kRotation1);
mat.postScale(kScale0, kScale0);
mat.postRotate(kRotation0);
REPORTER_ASSERT(reporter, SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1));
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(rotation0,
SkDegreesToRadians(kRotation0 + kRotation1)));
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleX, kScale0));
REPORTER_ASSERT(reporter, SkScalarNearlyEqual(scaleY, kScale0));
REPORTER_ASSERT(reporter, SkScalarNearlyZero(rotation1));
// rotation, anisotropic scale, then different rotation
mat.setRotate(kRotation0);
mat.postScale(kScale1, kScale0);
mat.postRotate(kRotation1);
REPORTER_ASSERT(reporter, SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1));
// Because of the shear/skew we won't get the same results, so we need to multiply it out.
// Generating the matrices requires doing a radian-to-degree calculation, then degree-to-radian
// calculation (in setRotate()), which adds error, so this just computes the matrix elements
// directly.
SkScalar c0;
SkScalar s0 = SkScalarSinCos(rotation0, &c0);
SkScalar c1;
SkScalar s1 = SkScalarSinCos(rotation1, &c1);
// We do a relative check here because large scale factors cause problems with an absolute check
REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMScaleX],
scaleX*c0*c1 - scaleY*s0*s1));
REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMSkewX],
-scaleX*s0*c1 - scaleY*c0*s1));
REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMSkewY],
scaleX*c0*s1 + scaleY*s0*c1));
REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMScaleY],
-scaleX*s0*s1 + scaleY*c0*c1));
// try some random matrices
SkMWCRandom rand;
for (int m = 0; m < 1000; ++m) {
SkScalar rot0 = rand.nextRangeF(-SK_ScalarPI, SK_ScalarPI);
SkScalar sx = rand.nextRangeF(-3000.f, 3000.f);
SkScalar sy = rand.nextRangeF(-3000.f, 3000.f);
SkScalar rot1 = rand.nextRangeF(-SK_ScalarPI, SK_ScalarPI);
mat.setRotate(rot0);
mat.postScale(sx, sy);
mat.postRotate(rot1);
if (SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1)) {
SkScalar c0;
SkScalar s0 = SkScalarSinCos(rotation0, &c0);
SkScalar c1;
SkScalar s1 = SkScalarSinCos(rotation1, &c1);
REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMScaleX],
scaleX*c0*c1 - scaleY*s0*s1));
REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMSkewX],
-scaleX*s0*c1 - scaleY*c0*s1));
REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMSkewY],
scaleX*c0*s1 + scaleY*s0*c1));
REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMScaleY],
-scaleX*s0*s1 + scaleY*c0*c1));
} else {
// if the matrix is degenerate, the basis vectors should be near-parallel or near-zero
SkScalar perpdot = mat[SkMatrix::kMScaleX]*mat[SkMatrix::kMScaleY] -
mat[SkMatrix::kMSkewX]*mat[SkMatrix::kMSkewY];
REPORTER_ASSERT(reporter, SkScalarNearlyZero(perpdot));
}
}
// translation shouldn't affect this
mat.postTranslate(-1000.f, 1000.f);
REPORTER_ASSERT(reporter, SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1));
s0 = SkScalarSinCos(rotation0, &c0);
s1 = SkScalarSinCos(rotation1, &c1);
REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMScaleX],
scaleX*c0*c1 - scaleY*s0*s1));
REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMSkewX],
-scaleX*s0*c1 - scaleY*c0*s1));
REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMSkewY],
scaleX*c0*s1 + scaleY*s0*c1));
REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMScaleY],
-scaleX*s0*s1 + scaleY*c0*c1));
// perspective shouldn't affect this
mat[SkMatrix::kMPersp0] = 12.f;
mat[SkMatrix::kMPersp1] = 4.f;
mat[SkMatrix::kMPersp2] = 1872.f;
REPORTER_ASSERT(reporter, SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1));
s0 = SkScalarSinCos(rotation0, &c0);
s1 = SkScalarSinCos(rotation1, &c1);
REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMScaleX],
scaleX*c0*c1 - scaleY*s0*s1));
REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMSkewX],
-scaleX*s0*c1 - scaleY*c0*s1));
REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMSkewY],
scaleX*c0*s1 + scaleY*s0*c1));
REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMScaleY],
-scaleX*s0*s1 + scaleY*c0*c1));
// rotation, anisotropic scale + reflection, then different rotation
mat.setRotate(kRotation0);
mat.postScale(-kScale1, kScale0);
mat.postRotate(kRotation1);
REPORTER_ASSERT(reporter, SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1));
s0 = SkScalarSinCos(rotation0, &c0);
s1 = SkScalarSinCos(rotation1, &c1);
REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMScaleX],
scaleX*c0*c1 - scaleY*s0*s1));
REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMSkewX],
-scaleX*s0*c1 - scaleY*c0*s1));
REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMSkewY],
scaleX*c0*s1 + scaleY*s0*c1));
REPORTER_ASSERT(reporter, scalar_nearly_equal_relative(mat[SkMatrix::kMScaleY],
-scaleX*s0*s1 + scaleY*c0*c1));
// degenerate matrices
// mostly zero entries
mat.reset();
mat[SkMatrix::kMScaleX] = 0.f;
REPORTER_ASSERT(reporter, !SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1));
mat.reset();
mat[SkMatrix::kMScaleY] = 0.f;
REPORTER_ASSERT(reporter, !SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1));
mat.reset();
// linearly dependent entries
mat[SkMatrix::kMScaleX] = 1.f;
mat[SkMatrix::kMSkewX] = 2.f;
mat[SkMatrix::kMSkewY] = 4.f;
mat[SkMatrix::kMScaleY] = 8.f;
REPORTER_ASSERT(reporter, !SkDecomposeUpper2x2(mat, &rotation0, &scaleX, &scaleY, &rotation1));
}
static SkPoint unit_vec(int degrees) {
SkScalar rad = SkDegreesToRadians(SkIntToScalar(degrees));
SkScalar s, c;
s = SkScalarSinCos(rad, &c);
return SkPoint::Make(c, s);
}
virtual void onDraw(SkCanvas* canvas) {
if (!fInitialized) {
make_bitmap();
fInitialized = true;
}
canvas->clear(0xFF101010);
SkPaint checkPaint;
checkPaint.setColor(0xFF202020);
for (int y = 0; y < HEIGHT; y += 16) {
for (int x = 0; x < WIDTH; x += 16) {
canvas->save();
canvas->translate(SkIntToScalar(x), SkIntToScalar(y));
canvas->drawRect(SkRect::MakeXYWH(8, 0, 8, 8), checkPaint);
canvas->drawRect(SkRect::MakeXYWH(0, 8, 8, 8), checkPaint);
canvas->restore();
}
}
SkPoint3 pointLocation(0, 0, SkIntToScalar(10));
SkScalar azimuthRad = SkDegreesToRadians(SkIntToScalar(225));
SkScalar elevationRad = SkDegreesToRadians(SkIntToScalar(5));
SkPoint3 distantDirection(SkScalarMul(SkScalarCos(azimuthRad), SkScalarCos(elevationRad)),
SkScalarMul(SkScalarSin(azimuthRad), SkScalarCos(elevationRad)),
SkScalarSin(elevationRad));
SkPoint3 spotLocation(SkIntToScalar(-10), SkIntToScalar(-10), SkIntToScalar(20));
SkPoint3 spotTarget(SkIntToScalar(40), SkIntToScalar(40), 0);
SkScalar spotExponent = SK_Scalar1;
SkScalar cutoffAngle = SkIntToScalar(15);
SkScalar kd = SkIntToScalar(2);
SkScalar ks = SkIntToScalar(1);
SkScalar shininess = SkIntToScalar(8);
SkScalar surfaceScale = SkIntToScalar(1);
SkColor white(0xFFFFFFFF);
SkPaint paint;
SkImageFilter::CropRect cropRect(SkRect::MakeXYWH(20, 10, 60, 65));
int y = 0;
for (int i = 0; i < 2; i++) {
const SkImageFilter::CropRect* cr = (i == 0) ? NULL : &cropRect;
paint.setImageFilter(SkLightingImageFilter::CreatePointLitDiffuse(pointLocation, white, surfaceScale, kd, NULL, cr))->unref();
drawClippedBitmap(canvas, paint, 0, y);
paint.setImageFilter(SkLightingImageFilter::CreateDistantLitDiffuse(distantDirection, white, surfaceScale, kd, NULL, cr))->unref();
drawClippedBitmap(canvas, paint, 110, y);
paint.setImageFilter(SkLightingImageFilter::CreateSpotLitDiffuse(spotLocation, spotTarget, spotExponent, cutoffAngle, white, surfaceScale, kd, NULL, cr))->unref();
drawClippedBitmap(canvas, paint, 220, y);
y += 110;
paint.setImageFilter(SkLightingImageFilter::CreatePointLitSpecular(pointLocation, white, surfaceScale, ks, shininess, NULL, cr))->unref();
drawClippedBitmap(canvas, paint, 0, y);
paint.setImageFilter(SkLightingImageFilter::CreateDistantLitSpecular(distantDirection, white, surfaceScale, ks, shininess, NULL, cr))->unref();
drawClippedBitmap(canvas, paint, 110, y);
paint.setImageFilter(SkLightingImageFilter::CreateSpotLitSpecular(spotLocation, spotTarget, spotExponent, cutoffAngle, white, surfaceScale, ks, shininess, NULL, cr))->unref();
drawClippedBitmap(canvas, paint, 220, y);
y += 110;
}
}
void onOnceBeforeDraw() override {
{
SkPath* lineAnglesPath = &fPaths.push_back();
enum {
kNumAngles = 15,
kRadius = 40,
};
for (int i = 0; i < kNumAngles; ++i) {
SkScalar angle = SK_ScalarPI * SkIntToScalar(i) / kNumAngles;
SkScalar x = kRadius * SkScalarCos(angle);
SkScalar y = kRadius * SkScalarSin(angle);
lineAnglesPath->moveTo(x, y);
lineAnglesPath->lineTo(-x, -y);
}
}
{
SkPath* kindaTightQuad = &fPaths.push_back();
kindaTightQuad->moveTo(0, -10 * SK_Scalar1);
kindaTightQuad->quadTo(SkIntToScalar(100), SkIntToScalar(100), -10 * SK_Scalar1, 0);
}
{
SkPath* tightQuad = &fPaths.push_back();
tightQuad->moveTo(0, -5 * SK_Scalar1);
tightQuad->quadTo(SkIntToScalar(100), SkIntToScalar(100), -5 * SK_Scalar1, 0);
}
{
SkPath* tighterQuad = &fPaths.push_back();
tighterQuad->moveTo(0, -2 * SK_Scalar1);
tighterQuad->quadTo(SkIntToScalar(100), SkIntToScalar(100), -2 * SK_Scalar1, 0);
}
{
SkPath* unevenTighterQuad = &fPaths.push_back();
unevenTighterQuad->moveTo(0, -1 * SK_Scalar1);
SkPoint p;
p.set(-2 * SK_Scalar1 + 3 * SkIntToScalar(102) / 4, SkIntToScalar(75));
unevenTighterQuad->quadTo(SkIntToScalar(100), SkIntToScalar(100), p.fX, p.fY);
}
{
SkPath* reallyTightQuad = &fPaths.push_back();
reallyTightQuad->moveTo(0, -1 * SK_Scalar1);
reallyTightQuad->quadTo(SkIntToScalar(100), SkIntToScalar(100), -1 * SK_Scalar1, 0);
}
{
SkPath* closedQuad = &fPaths.push_back();
closedQuad->moveTo(0, -0);
closedQuad->quadTo(SkIntToScalar(100), SkIntToScalar(100), 0, 0);
}
{
SkPath* unevenClosedQuad = &fPaths.push_back();
unevenClosedQuad->moveTo(0, -0);
unevenClosedQuad->quadTo(SkIntToScalar(100), SkIntToScalar(100),
SkIntToScalar(75), SkIntToScalar(75));
}
// Two problem cases for gpu hairline renderer found by shapeops testing. These used
// to assert that the computed bounding box didn't contain all the vertices.
{
SkPath* problem1 = &fPaths.push_back();
problem1->moveTo(SkIntToScalar(4), SkIntToScalar(6));
problem1->cubicTo(SkIntToScalar(5), SkIntToScalar(6),
SkIntToScalar(5), SkIntToScalar(4),
SkIntToScalar(4), SkIntToScalar(0));
problem1->close();
}
{
SkPath* problem2 = &fPaths.push_back();
problem2->moveTo(SkIntToScalar(5), SkIntToScalar(1));
problem2->lineTo(4.32787323f, 1.67212653f);
problem2->cubicTo(2.75223875f, 3.24776125f,
3.00581908f, 4.51236057f,
3.7580452f, 4.37367964f);
problem2->cubicTo(4.66472578f, 3.888381f,
5.f, 2.875f,
5.f, 1.f);
problem2->close();
}
// Three paths that show the same bug (missing end caps)
{
// A caret (crbug.com/131770)
SkPath* bug0 = &fPaths.push_back();
bug0->moveTo(6.5f,5.5f);
bug0->lineTo(3.5f,0.5f);
bug0->moveTo(0.5f,5.5f);
bug0->lineTo(3.5f,0.5f);
}
{
// An X (crbug.com/137317)
SkPath* bug1 = &fPaths.push_back();
bug1->moveTo(1, 1);
bug1->lineTo(6, 6);
bug1->moveTo(1, 6);
bug1->lineTo(6, 1);
}
{
// A right angle (crbug.com/137465 and crbug.com/256776)
SkPath* bug2 = &fPaths.push_back();
bug2->moveTo(5.5f, 5.5f);
bug2->lineTo(5.5f, 0.5f);
bug2->lineTo(0.5f, 0.5f);
}
{
// Arc example to test imperfect truncation bug (crbug.com/295626)
static const SkScalar kRad = SkIntToScalar(2000);
static const SkScalar kStartAngle = 262.59717f;
static const SkScalar kSweepAngle = SkScalarHalf(17.188717f);
SkPath* bug = &fPaths.push_back();
// Add a circular arc
SkRect circle = SkRect::MakeLTRB(-kRad, -kRad, kRad, kRad);
bug->addArc(circle, kStartAngle, kSweepAngle);
// Now add the chord that should cap the circular arc
SkScalar cosV, sinV = SkScalarSinCos(SkDegreesToRadians(kStartAngle), &cosV);
SkPoint p0 = SkPoint::Make(kRad * cosV, kRad * sinV);
sinV = SkScalarSinCos(SkDegreesToRadians(kStartAngle + kSweepAngle), &cosV);
SkPoint p1 = SkPoint::Make(kRad * cosV, kRad * sinV);
bug->moveTo(p0);
bug->lineTo(p1);
}
}
static SkPoint unit_vec(int degrees) {
SkScalar rad = SkDegreesToRadians(SkIntToScalar(degrees));
return SkPoint::Make(SkScalarCos(rad), SkScalarSin(rad));
}
