for (i=0; i < (ssize_t) image->colors; i++)
{
/*
- Apply transfer function to colormap.
+ Apply transfer function to colormap.
*/
double
- luma;
+ luma;
luma=0.21267*image->colormap[i].red+0.71526*image->colormap[i].green+
- 0.07217*image->colormap[i].blue;
+ 0.07217*image->colormap[i].blue;
image->colormap[i].red=luma+color_correction.saturation*cdl_map[
- ScaleQuantumToMap(ClampToQuantum(image->colormap[i].red))].red-luma;
+ ScaleQuantumToMap(ClampToQuantum(image->colormap[i].red))].red-luma;
image->colormap[i].green=luma+color_correction.saturation*cdl_map[
ScaleQuantumToMap(ClampToQuantum(image->colormap[i].green))].green-luma;
image->colormap[i].blue=luma+color_correction.saturation*cdl_map[
Contrast enhance colormap.
*/
for (i=0; i < (ssize_t) image->colors; i++)
- Contrast(sign,&image->colormap[i].red,&image->colormap[i].green,
- &image->colormap[i].blue);
+ {
+ double
+ blue,
+ green,
+ red;
+
+ Contrast(sign,&red,&green,&blue);
+ image->colormap[i].red=(MagickRealType) red;
+ image->colormap[i].red=(MagickRealType) red;
+ image->colormap[i].red=(MagickRealType) red;
+ }
}
/*
Contrast enhance image.
{
#define EnhancePixel(weight) \
mean=((double) r[i]+GetPixelChannel(enhance_image,channel,q))/2.0; \
- distance=(double) r[i]-(double) GetPixelChannel( \
- enhance_image,channel,q); \
- distance_squared=QuantumScale*(2.0*((double) QuantumRange+1.0)+ \
- mean)*distance*distance; \
- if (distance_squared < ((double) QuantumRange*(double) \
- QuantumRange/25.0f)) \
+ distance=(double) r[i]-(double) GetPixelChannel(enhance_image,channel,q); \
+ distance_squared=QuantumScale*(2.0*((double) QuantumRange+1.0)+mean)* \
+ distance*distance; \
+ if (distance_squared < ((double) QuantumRange*(double) QuantumRange/25.0f)) \
{ \
aggregate+=(weight)*r[i]; \
total_weight+=(weight); \
for (i=0; i < (ssize_t) image->colors; i++)
{
/*
- Gamma-correct colormap.
+ Gamma-correct colormap.
*/
if ((GetPixelRedTraits(image) & UpdatePixelTrait) != 0)
- image->colormap[i].red=(double) gamma_map[
+ image->colormap[i].red=(double) gamma_map[
ScaleQuantumToMap(ClampToQuantum(image->colormap[i].red))];
if ((GetPixelGreenTraits(image) & UpdatePixelTrait) != 0)
image->colormap[i].green=(double) gamma_map[
for (i=0; i < (ssize_t) image->colors; i++)
{
/*
- Negate colormap.
+ Negate colormap.
*/
if (grayscale != MagickFalse)
- if ((image->colormap[i].red != image->colormap[i].green) ||
- (image->colormap[i].green != image->colormap[i].blue))
- continue;
+ if ((image->colormap[i].red != image->colormap[i].green) ||
+ (image->colormap[i].green != image->colormap[i].blue))
+ continue;
if ((GetPixelRedTraits(image) & UpdatePixelTrait) != 0)
- image->colormap[i].red=QuantumRange-image->colormap[i].red;
+ image->colormap[i].red=QuantumRange-image->colormap[i].red;
if ((GetPixelGreenTraits(image) & UpdatePixelTrait) != 0)
- image->colormap[i].green=QuantumRange-image->colormap[i].green;
+ image->colormap[i].green=QuantumRange-image->colormap[i].green;
if ((GetPixelBlueTraits(image) & UpdatePixelTrait) != 0)
- image->colormap[i].blue=QuantumRange-image->colormap[i].blue;
+ image->colormap[i].blue=QuantumRange-image->colormap[i].blue;
}
/*
Negate image.
Negate image.
*/
#if defined(MAGICKCORE_OPENMP_SUPPORT)
- #pragma omp parallel for schedule(static) shared(progress,status) \
+ #pragma omp parallel for schedule(static,4) shared(progress,status) \
dynamic_number_threads(image,image->columns,image->rows,1)
#endif
for (y=0; y < (ssize_t) image->rows; y++)
% o exception: return any errors or warnings in this structure.
%
*/
-MagickExport MagickBooleanType SigmoidalContrastImage(Image *image,
- const MagickBooleanType sharpen,const double contrast,const double midpoint,
- ExceptionInfo *exception)
-{
-#define SigmoidalContrastImageTag "SigmoidalContrast/Image"
- CacheView
- *image_view;
+/*
+ ImageMagick 6 has a version of this function which uses LUTs.
+*/
- MagickBooleanType
- status;
+/*
+ Sigmoidal function Sigmoidal with inflexion point moved to b and "slope
+ constant" set to a.
- MagickOffsetType
- progress;
+ The first version, based on the hyperbolic tangent tanh, when combined with
+ the scaling step, is an exact arithmetic clone of the the sigmoid function
+ based on the logistic curve. The equivalence is based on the identity
- ssize_t
- y;
+ 1/(1+exp(-t)) = (1+tanh(t/2))/2
- /*
- Side effect: clamps values unless contrast<MagickEpsilon, in which
- case nothing is done.
- */
- if (contrast<MagickEpsilon)
- return(MagickTrue);
+ (http://de.wikipedia.org/wiki/Sigmoidfunktion) and the fact that the
+ scaled sigmoidal derivation is invariant under affine transformations of
+ the ordinate.
- /*
- Sigmoidal function with inflexion point moved to b and "slope
- constant" set to a.
- The first version, based on the hyperbolic tangent tanh, when
- combined with the scaling step, is an exact arithmetic clone of the
- the sigmoid function based on the logistic curve. The equivalence is
- based on the identity
- 1/(1+exp(-t)) = (1+tanh(t/2))/2
- (http://de.wikipedia.org/wiki/Sigmoidfunktion) and the fact that the
- scaled sigmoidal derivation is invariant under affine transformations
- of the ordinate.
- The tanh version is almost certainly more accurate and cheaper.
- The 0.5 factor in its argument is to clone the legacy ImageMagick
- behavior. The reason for making the define depend on atanh even
- though it only uses tanh has to do with the construction of the
- inverse of the scaled sigmoidal.
- */
+ The tanh version is almost certainly more accurate and cheaper. The 0.5
+ factor in the argument is to clone the legacy ImageMagick behavior. The
+ reason for making the define depend on atanh even though it only uses tanh
+ has to do with the construction of the inverse of the scaled sigmoidal.
+*/
#if defined(MAGICKCORE_HAVE_ATANH)
#define Sigmoidal(a,b,x) ( tanh((0.5*(a))*((x)-(b))) )
#else
#define Sigmoidal(a,b,x) ( 1.0/(1.0+exp((a)*((b)-(x)))) )
#endif
- /*
- Scaled sigmoidal formula:
+/*
+ Scaled sigmoidal function:
+
( Sigmoidal(a,b,x) - Sigmoidal(a,b,0) ) /
( Sigmoidal(a,b,1) - Sigmoidal(a,b,0) )
- See http://osdir.com/ml/video.image-magick.devel/2005-04/msg00006.html
- and http://www.cs.dartmouth.edu/farid/downloads/tutorials/fip.pdf.
- The limit of ScaledSigmoidal as a->0 is the identity, but a=0 gives a
- division by zero. This is fixed above by exiting immediately when
- contrast is small, leaving the image (or colormap) unmodified. This
- appears to be safe because the series expansion of the logistic
- sigmoidal function around x=b is 1/2-a*(b-x)/4+... so that the key
- denominator s(1)-s(0) is about a/4 (a/2 with tanh).
- */
+
+ See http://osdir.com/ml/video.image-magick.devel/2005-04/msg00006.html and
+ http://www.cs.dartmouth.edu/farid/downloads/tutorials/fip.pdf. The limit
+ of ScaledSigmoidal as a->0 is the identity, but a=0 gives a division by
+ zero. This is fixed below by exiting immediately when contrast is small,
+ leaving the image (or colormap) unmodified. This appears to be safe because
+ the series expansion of the logistic sigmoidal function around x=b is
+
+ 1/2-a*(b-x)/4+...
+
+ so that the key denominator s(1)-s(0) is about a/4 (a/2 with tanh).
+*/
#define ScaledSigmoidal(a,b,x) ( \
(Sigmoidal((a),(b),(x))-Sigmoidal((a),(b),0.0)) / \
(Sigmoidal((a),(b),1.0)-Sigmoidal((a),(b),0.0)) )
- /*
- Inverse of ScaledSigmoidal, used for +sigmoidal-contrast. In HDRI,
- the argument of the hyperbolic tangent or the logistic sigmoidal
- may be outside of the interval (-1,1), hence the branching.
- InverseScaledSigmoidal is not a two-side inverse of
- ScaledSigmoidal: It is only a right inverse. This is unavoidable.
- */
+/*
+ Inverse of ScaledSigmoidal, used for +sigmoidal-contrast. Because b
+ may be 0 or 1, the argument of the hyperbolic tangent (resp. logistic
+ sigmoidal) may be outside of the interval (-1,1) (resp. (0,1)), even
+ when creating a LUT from in gamut values, hence the branching. In
+ addition, HDRI may have out of gamut values.
+ InverseScaledSigmoidal is not a two-sided inverse of ScaledSigmoidal:
+ It is only a right inverse. This is unavoidable.
+*/
+static inline double InverseScaledSigmoidal(const double a,const double b,
+ const double x)
+{
+ const double sig0=Sigmoidal(a,b,0.0);
+ const double sig1=Sigmoidal(a,b,1.0);
+ const double argument=(sig1-sig0)*x+sig0;
+ const double clamped=
+ (
#if defined(MAGICKCORE_HAVE_ATANH)
-#define InverseScaledSigmoidal(a,b,x) ({ \
- const double _argument = \
- (Sigmoidal((a),(b),1.0)-Sigmoidal((a),(b),0.0)) * (x) + \
- Sigmoidal((a),(b),0.0); \
- const double _clamped_argument = \
- ( _argument < -1+MagickEpsilon ? -1+MagickEpsilon : \
- ( _argument > 1-MagickEpsilon ? 1-MagickEpsilon : _argument ) ); \
- (b) + (2.0/(a)) * atanh(_clamped_argument); })
+ argument < -1+MagickEpsilon
+ ?
+ -1+MagickEpsilon
+ :
+ ( argument > 1-MagickEpsilon ? 1-MagickEpsilon : argument )
+ );
+ return(b+(2.0/a)*atanh(clamped));
#else
-#define InverseScaledSigmoidal(a,b,x) ({ \
- const double _argument = \
- (Sigmoidal((a),(b),1.0)-Sigmoidal((a),(b),0.0)) * (x) + \
- Sigmoidal((a),(b),0.0); \
- const double _clamped_argument = \
- ( _argument < MagickEpsilon ? MagickEpsilon : \
- ( _argument > 1-MagickEpsilon ? 1-MagickEpsilon : _argument ) ); \
- (b) + (-1.0/(a)) * log(1.0/_clamped_argument+-1.0); })
+ argument < MagickEpsilon
+ ?
+ MagickEpsilon
+ :
+ ( argument > 1-MagickEpsilon ? 1-MagickEpsilon : argument )
+ );
+ return(b-log(1.0/clamped-1.0)/a);
#endif
- /*
- Convenience macros.
- */
+}
+
+MagickExport MagickBooleanType SigmoidalContrastImage(Image *image,
+ const MagickBooleanType sharpen,const double contrast,const double midpoint,
+ ExceptionInfo *exception)
+{
+#define SigmoidalContrastImageTag "SigmoidalContrast/Image"
#define ScaledSig(x) ( ClampToQuantum(QuantumRange* \
- ScaledSigmoidal(contrast,QuantumScale*midpoint,QuantumScale*(x))) )
+ ScaledSigmoidal(contrast,QuantumScale*midpoint,QuantumScale*(x))) )
#define InverseScaledSig(x) ( ClampToQuantum(QuantumRange* \
- InverseScaledSigmoidal(contrast,QuantumScale*midpoint,QuantumScale*(x))) )
+ InverseScaledSigmoidal(contrast,QuantumScale*midpoint,QuantumScale*(x))) )
+
+ CacheView
+ *image_view;
+ MagickBooleanType
+ status;
+
+ MagickOffsetType
+ progress;
+
+ ssize_t
+ y;
+
+ /*
+ Convenience macros.
+ */
assert(image != (Image *) NULL);
assert(image->signature == MagickSignature);
if (image->debug != MagickFalse)
(void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
+ /*
+ Side effect: may clamp values unless contrast<MagickEpsilon, in which
+ case nothing is done.
+ */
+ if (contrast < MagickEpsilon)
+ return(MagickTrue);
/*
Sigmoidal-contrast enhance colormap.
*/
if (image->storage_class == PseudoClass)
{
register ssize_t
- i;
+ i;
if (sharpen != MagickFalse)
- {
- for (i=0; i < (ssize_t) image->colors; i++)
- {
- if ((GetPixelRedTraits(image) & UpdatePixelTrait) != 0)
- image->colormap[i].red=ScaledSig(image->colormap[i].red);
- if ((GetPixelGreenTraits(image) & UpdatePixelTrait) != 0)
- image->colormap[i].green=ScaledSig(image->colormap[i].green);
- if ((GetPixelBlueTraits(image) & UpdatePixelTrait) != 0)
- image->colormap[i].blue=ScaledSig(image->colormap[i].blue);
- if ((GetPixelAlphaTraits(image) & UpdatePixelTrait) != 0)
- image->colormap[i].alpha=ScaledSig(image->colormap[i].alpha);
- }
- }
+ for (i=0; i < (ssize_t) image->colors; i++)
+ {
+ if ((GetPixelRedTraits(image) & UpdatePixelTrait) != 0)
+ image->colormap[i].red=ScaledSig(image->colormap[i].red);
+ if ((GetPixelGreenTraits(image) & UpdatePixelTrait) != 0)
+ image->colormap[i].green=ScaledSig(image->colormap[i].green);
+ if ((GetPixelBlueTraits(image) & UpdatePixelTrait) != 0)
+ image->colormap[i].blue=ScaledSig(image->colormap[i].blue);
+ if ((GetPixelAlphaTraits(image) & UpdatePixelTrait) != 0)
+ image->colormap[i].alpha=ScaledSig(image->colormap[i].alpha);
+ }
else
- {
- for (i=0; i < (ssize_t) image->colors; i++)
- {
- if ((GetPixelRedTraits(image) & UpdatePixelTrait) != 0)
- image->colormap[i].red=
- InverseScaledSig(image->colormap[i].red);
- if ((GetPixelGreenTraits(image) & UpdatePixelTrait) != 0)
- image->colormap[i].green=
- InverseScaledSig(image->colormap[i].green);
- if ((GetPixelBlueTraits(image) & UpdatePixelTrait) != 0)
- image->colormap[i].blue=
- InverseScaledSig(image->colormap[i].blue);
- if ((GetPixelAlphaTraits(image) & UpdatePixelTrait) != 0)
- image->colormap[i].alpha=
- InverseScaledSig(image->colormap[i].alpha);
- }
- }
+ for (i=0; i < (ssize_t) image->colors; i++)
+ {
+ if ((GetPixelRedTraits(image) & UpdatePixelTrait) != 0)
+ image->colormap[i].red=InverseScaledSig(image->colormap[i].red);
+ if ((GetPixelGreenTraits(image) & UpdatePixelTrait) != 0)
+ image->colormap[i].green=InverseScaledSig(image->colormap[i].green);
+ if ((GetPixelBlueTraits(image) & UpdatePixelTrait) != 0)
+ image->colormap[i].blue=InverseScaledSig(image->colormap[i].blue);
+ if ((GetPixelAlphaTraits(image) & UpdatePixelTrait) != 0)
+ image->colormap[i].alpha=InverseScaledSig(image->colormap[i].alpha);
+ }
}
/*
Sigmoidal-contrast enhance image.
for (x=0; x < (ssize_t) image->columns; x++)
{
register ssize_t
- i;
+ i;
if (GetPixelMask(image,q) != 0)
{
traits=GetPixelChannelTraits(image,channel);
if ((traits & UpdatePixelTrait) == 0)
continue;
- if (sharpen != MagickFalse)
- q[i]=ScaledSig(q[i]);
- else
- q[i]=InverseScaledSig(q[i]);
+ if (sharpen != MagickFalse)
+ q[i]=ScaledSig(q[i]);
+ else
+ q[i]=InverseScaledSig(q[i]);
}
q+=GetPixelChannels(image);
}
projects / imagemagick / blobdiff