const ResizeFilter *magick_unused(resize_filter))
{
/*
- Blackman: 2rd Order cosine windowing function:
+ Blackman: 2nd order cosine windowing function:
0.42 + 0.5 cos(pi x) + 0.08 cos(2pi x)
- Refactored by Chantal Racette and Nicolas Robidoux so it needs
- only one trig call and five flops.
+
+ Refactored by Chantal Racette and Nicolas Robidoux to one trig call and
+ five flops.
*/
const double alpha = cos(MagickPI*(double) x);
return(0.34+alpha*(0.5+alpha*0.16));
static MagickRealType Sinc(const MagickRealType x,
const ResizeFilter *magick_unused(resize_filter))
{
- MagickRealType
- p,
- xx;
-
- if (fabs((double) x) > 4.0)
- return(sin(MagickPI*(double) x)/(MagickPI*x));
- /*
- Approximations of the sinc function over the interval [-4,4] constructed
- by Nicolas Robidoux with the assistance of Chantal Racette with funding
- from the Natural Sciences and Engineering Research Council of Canada.
- */
- xx=x*x;
-#if MAGICKCORE_QUANTUM_DEPTH <= 16
+ const double xd = x;
+ if (fabs(xd) > 4.0)
+ return(sin(MagickPI*xd)/(MagickPI*x));
{
/*
- Approximation with maximum relative error 6.3e-6 < 1/2^17.
+ Approximations of the sinc function over the interval [-4,4]
+ constructed by Nicolas Robidoux and Chantal Racette with funding
+ from the Natural Sciences and Engineering Research Council of
+ Canada.
+ */
+ const MagickRealType xx = x*x;
+#if MAGICKCORE_QUANTUM_DEPTH <= 8
+ /*
+ Maximum relative error 8.9e-4 < 1/2^10.
+ */
+ const MagickRealType c0 = 0.173456131023616172130931138332417073143e-2L;
+ const MagickRealType c1 = -0.380364743836376263041954887553883370815e-3L;
+ const MagickRealType c2 = 0.374219191965003105059092491853033171168e-4L;
+ const MagickRealType c3 = -0.207789976431855699043820493597151957343e-5L;
+ const MagickRealType c4 = 0.643040460008483757431732461799962454945e-7L;
+ const MagickRealType c5 = -0.865087318355486581259138486910631069838e-9L;
+ const MagickRealType p = c0+xx*(c1+xx*(c2+xx*(c3+xx*(c4+xx*c5))));
+#elif MAGICKCORE_QUANTUM_DEPTH <= 16
+ /*
+ Maximum relative error 6.3e-6 < 1/2^17.
*/
const MagickRealType c0 = 0.173610016489197553621906385078711564924e-2L;
const MagickRealType c1 = -0.384186115075660162081071290162149315834e-3L;
const MagickRealType c5 = -0.324874073895735800961260474028013982211e-8L;
const MagickRealType c6 = 0.628155216606695311524920882748052490116e-10L;
const MagickRealType c7 = -0.586110644039348333520104379959307242711e-12L;
- p=c0+xx*(c1+xx*(c2+xx*(c3+xx*(c4+xx*(c5+xx*(c6+xx*c7))))));
- }
+ const MagickRealType p = c0+xx*(c1+xx*(c2+xx*(c3+xx*(c4+xx*(c5+xx*
+ (c6+xx*c7))))));
#else
- {
/*
- Approximation with maximum relative error of 4.1e-11 < 1/2^33.
+ Maximum relative error 4.1e-11 < 1/2^34.
*/
const MagickRealType c0 = 0.173611111104053387736747210985091995555e-2L;
const MagickRealType c1 = -0.384241241675270460704990597975054901693e-3L;
const MagickRealType c9 = -0.500117812133871122182855704211250504815e-15L;
const MagickRealType c10 = 0.506270333308352987196209731044295839327e-17L;
const MagickRealType c11 = -0.277631746025848834036870351854616274324e-19L;
- p=c0+xx*(c1+xx*(c2+xx*(c3+xx*(c4+xx*(c5+xx*(c6+xx*(c7+xx*(c8+xx*(c9+xx*
- (c10+xx*c11))))))))));
- }
+ const MagickRealType p = c0+xx*(c1+xx*(c2+xx*(c3+xx*(c4+xx*(c5+xx*(c6+xx*
+ (c7+xx*(c8+xx*(c9+xx*(c10+xx*c11))))))))));
#endif
- return((xx-1.0)*(xx-4.0)*(xx-9.0)*(xx-16.0)*p);
+ return((xx-1.0)*(xx-4.0)*(xx-9.0)*(xx-16.0)*p);
+ }
}
static MagickRealType Triangle(const MagickRealType x,
const ResizeFilter *magick_unused(resize_filter))
{
/*
- 1rd order (linear) B-Spline, bilinear interpolation, Tent 1D filter, or a
+ 1st order (linear) B-Spline, bilinear interpolation, Tent 1D filter, or a
Bartlett 2D Cone filter.
*/
if (x < 1.0)