386         v->codeAppendf(    "%s.xy = float2(0, coverage);", arcCoord.vsOut());  in onEmitCode()
394         v->codeAppendf(    "%s.xy = float2(arccoord.x+1, arccoord.y);", arcCoord.vsOut());  in onEmitCode()
397             v->codeAppendf("float2x2 derivatives = inverse(skewmatrix);");  in onEmitCode()
398             v->codeAppendf("%s.zw = derivatives * (arccoord/radii * 2);", arcCoord.vsOut());  in onEmitCode()
405         f->codeAppendf("float x_plus_1=%s.x, y=%s.y;", arcCoord.fsIn(), arcCoord.fsIn());  in onEmitCode()
406         f->codeAppendf("half coverage;");  in onEmitCode()
407         f->codeAppendf("if (0 == x_plus_1) {");  in onEmitCode()
408         f->codeAppendf(    "coverage = y;");  // We are a non-arc pixel (i.e., linear coverage).  in onEmitCode()
409         f->codeAppendf("} else {");  in onEmitCode()
410         f->codeAppendf(    "float fn = x_plus_1 * (x_plus_1 - 2);");  // fn = (x+1)*(x-1) = x^2-1  in onEmitCode()
411         f->codeAppendf(    "fn = fma(y,y, fn);");  // fn = x^2 + y^2 - 1  in onEmitCode()
413             f->codeAppendf("float fnwidth = fwidth(fn);");  in onEmitCode()
416             f->codeAppendf("float gx=%s.z, gy=%s.w;", arcCoord.fsIn(), arcCoord.fsIn());  in onEmitCode()
417             f->codeAppendf("float fnwidth = abs(gx) + abs(gy);");  in onEmitCode()
419         f->codeAppendf(    "half d = fn/fnwidth;");  in onEmitCode()
420         f->codeAppendf(    "coverage = clamp(.5 - d, 0, 1);");  in onEmitCode()
421         f->codeAppendf("}");  in onEmitCode()
422         f->codeAppendf("%s = half4(coverage);", args.fOutputCoverage);  in onEmitCode()