const ResizeFilter *magick_unused(resize_filter))
{
/*
- 1D Gaussian with sigm=1/2
- exp(-2 x^2)/sqrt(pi/2))
+ Normalized Gaussian with variance 1/2 (by default):
+ 1/sqrt(2 pi sigma^2) exp(-x^2/(2 sigma^2))
*/
- const MagickRealType alpha = 2.0/MagickSQ2PI;
- return(exp(-(double)(2.0*x*x))*alpha);
+ #define MagickGAUSSIANSIGMAL 0.5L
+ /*
+ Change the value of MagickGAUSSIANSIGMAL if you want to override
+ the default.
+ */
+ const MagickRealType sigma2 = MagickGAUSSIANSIGMAL*MagickGAUSSIANSIGMAL;
+ const MagickRealType alpha = -1.0/(2.0*sigma2);
+ const MagickRealType normalizer = sqrt((double) (1.0/(2.0*MagickPIL*sigma2)));
+ return(normalizer*exp((double) (alpha*x*x)));
}
static MagickRealType Hanning(const MagickRealType x,
const MagickRealType c14 = 0.374841980075726557899013574367932640586e-25L;
const MagickRealType c15 = -0.138632329047117683500928913798808544919e-27L;
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+xx*(c12+xx*(c13+xx*(c14+xx*15
+ (c7+xx*(c8+xx*(c9+xx*(c10+xx*(c11+xx*(c12+xx*(c13+xx*(c14+xx*c15
))))))))))))));
#endif
return((xx-1.0)*(xx-4.0)*(xx-9.0)*(xx-16.0)*p);
% Blackman Hanning Hamming
% Kaiser Lanczos (Sinc)
%
-% Polynomial Approximations (high precision fast versions)
-% SincPolynomial
-%
% FIR filters are used as is, and are limited by that filters support window
% (unless over-ridden). 'Gaussian' while classed as an IIR filter, is also
% simply clipped by its support size (1.5).
% recommended as it removes the correct filter selection for different
% filtering image operations. Selecting a window filtering method is better.
%
-% Lanczos is a special case of a Sinc windowed Sinc, but defaulting to
-% a 3 lobe support, rather that the default 4 lobe support of the others.
+% Lanczos is purely special case of a Sinc windowed Sinc, but defaulting to
+% a 3 lobe support, rather that the default 4 lobe support.
%
% Special options can be used to override specific, or all the filter
% settings. However doing so is not advisible unless you have expert
% used for simple filters like FIR filters, and the Gaussian Filter.
% This will override any 'filter:lobes' option.
%
-% "filter:win-support" Scale windowing function to this size instead.
-% This causes the windowing (or self-windowing Lagrange filter) to act
-% is if the support window it much much larger than what is actually
-% supplied to the calling operator. The filter however is still
-% clipped to the real support size given, by the support range suppiled
-% to the caller. If unset this will equal the normal filter support
-% size.
-%
% "filter:blur" Scale the filter and support window by this amount.
% A value >1 will generally result in a more burred image with
% more ringing effects, while a value <1 will sharpen the
% resulting image with more aliasing and Morie effects.
%
+% "filter:win-support" Scale windowing function to this size instead.
+% This causes the windowing (or self-windowing Lagrange filter)
+% to act is if the support winodw it much much larger than what
+% is actually supplied to the calling operator. The filter however
+% is still clipped to the real support size given. If unset this
+% will equal the normal filter support size.
+%
% "filter:b"
% "filter:c" Override the preset B,C values for a Cubic type of filter
% If only one of these are given it is assumes to be a 'Keys'
% type of filter such that B+2C=1, where Keys 'alpha' value = C
%
-% "filter:verbose" Output the exact results of the filter selections
-% made, as well as plotting data for graphing the resulting filter
-% over support range (blur adjusted).
+% "filter:verbose" Output verbose plotting data for graphing the
+% resulting filter over the whole support range (with blur effect).
%
% Set a true un-windowed Sinc filter with 10 lobes (very slow)
% -set option:filter:filter Sinc
% o image: the image.
%
% o filter: the filter type, defining a preset filter, window and support.
-% The artifact settings listed above will override those selections.
%
% o blur: blur the filter by this amount, use 1.0 if unknown. Image
-% artifact "filter:blur" will override this internal usage.
+% artifact "filter:blur" will override this old usage
%
% o radial: 1D orthogonal filter (Sinc) or 2D radial filter (Bessel)
%
/*
Report Filter Details
*/
- support = GetResizeFilterSupport(resize_filter); /* support range */
+ support=GetResizeFilterSupport(resize_filter); /* support range */
(void) fprintf(stdout,"#\n# Resize Filter (for graphing)\n#\n");
(void) fprintf(stdout,"# filter = %s\n",
- MagickOptionToMnemonic(MagickFilterOptions, filter_type) );
+ MagickOptionToMnemonic(MagickFilterOptions,filter_type));
(void) fprintf(stdout,"# window = %s\n",
- MagickOptionToMnemonic(MagickFilterOptions, window_type) );
+ MagickOptionToMnemonic(MagickFilterOptions,window_type));
(void) fprintf(stdout,"# support = %.*g\n",
- GetMagickPrecision(),resize_filter->support );
+ GetMagickPrecision(),(double) resize_filter->support);
(void) fprintf(stdout,"# win-support = %.*g\n",
- GetMagickPrecision(),resize_filter->window_support );
+ GetMagickPrecision(),(double) resize_filter->window_support);
(void) fprintf(stdout,"# blur = %.*g\n",
- GetMagickPrecision(),resize_filter->blur );
+ GetMagickPrecision(),(double) resize_filter->blur);
(void) fprintf(stdout,"# blurred_support = %.*g\n",
- GetMagickPrecision(),support);
+ GetMagickPrecision(),(double) support);
(void) fprintf(stdout,"# B,C = %.*g,%.*g\n",
- GetMagickPrecision(),B, GetMagickPrecision(),C);
+ GetMagickPrecision(),B,GetMagickPrecision(),(double) C);
(void) fprintf(stdout,"#\n");
/*
Output values of resulting filter graph -- for graphing filter result.
projects / imagemagick / commitdiff