Hello Maintainers,
>From last few days, we were trying to perform the chroma operation using Image
>Magick (IM) Package. For this operation, we need to pass two pixels one high
>and another low (RGB value of high pixel will be always greater than or equal
>to low pixel) and the concerned function should make all the pixel transparent
>that lie between the given range. As fuzz factor is defined for all three
>channels (which makes us difficult to pass different ranges for different
>channels ), we were not able to find any function (including transparent API)
>that can help us out.
Thus we wrote our own functions (on the lines of transparent API). I am
attaching the patch containing our function (for version 6.4.3-6), and wants to
request to the maintainers that if they found this function useful/suitable
please include it in the later releases of IM.
Thanks and Regards,
Manish Aggarwal
[EMAIL PROTECTED]
diff -aur ImageMagick-6.4.3/magick/paint.c ImageMagick-6.4.3_mod/magick/paint.c
--- ImageMagick-6.4.3/magick/paint.c 2008-08-22 21:45:13.000000000 +0530
+++ ImageMagick-6.4.3_mod/magick/paint.c 2008-11-14 17:24:40.000000000
+0530
@@ -823,3 +823,132 @@
image_view=DestroyCacheViewThreadSet(image_view);
return(status);
}
+
+/*
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% %
+% %
+% %
+% T r a n s p a r e n t P a i n t I m a g e C h r o m a %
+% %
+% %
+% %
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% TransparentPaintImageChroma() changes the opacity value associated with any
+% pixel that matches color to the value defined by opacity.
+%
+% As there is one fuzz value for the all the channels, the
TransparentPaintImage()
+% API is not suitable for the operations like chroma, where the tolerance for
+% similarity of two color component (RGB) can be different, Thus we defined
this
+% functon which takes two target pixel (one high and one low) and all the
+% pixels of an image which are lying between these two pixels are made
transparent.
+%
+% The format of the TransparentPaintImage method is:
+%
+% MagickBooleanType TransparentPaintImage(Image *image,
+% const MagickPixelPacket *target,const Quantum opacity,
+% const MagickBooleanType invert)
+%
+% A description of each parameter follows:
+%
+% o image: the image.
+%
+% o targetHigh: the high target color.
+%
+% o targetLow: the low target color.
+%
+% o opacity: the replacement opacity value.
+%
+% o invert: paint any pixel that does not match the target color.
+%
+*/
+MagickExport MagickBooleanType TransparentPaintImageChroma(Image *image,
+ const MagickPixelPacket *targetLow, const MagickPixelPacket *targetHigh,
const Quantum opacity,
+ const MagickBooleanType invert)
+{
+#define TransparentPaintImageTag "Transparent/Image"
+
+ long
+ progress,
+ y;
+
+ MagickBooleanType
+ status;
+
+ ViewInfo
+ **image_view;
+
+ assert(image != (Image *) NULL);
+ assert(image->signature == MagickSignature);
+ assert(targetHigh != (MagickPixelPacket *) NULL);
+ assert(targetLow != (MagickPixelPacket *) NULL);
+ if (image->debug != MagickFalse)
+ (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
+ if (SetImageStorageClass(image,DirectClass) == MagickFalse)
+ return(MagickFalse);
+ if (image->matte == MagickFalse)
+ (void) SetImageAlphaChannel(image,ResetAlphaChannel);
+ /*
+ Make image color transparent.
+ */
+ status=MagickTrue;
+ progress=0;
+ image_view=AcquireCacheViewThreadSet(image);
+ #pragma omp parallel for
+ for (y=0; y < (long) image->rows; y++)
+ {
+ MagickPixelPacket
+ pixel;
+
+ register IndexPacket
+ *indexes;
+
+ register long
+ id,
+ x;
+
+ register PixelPacket
+ *q;
+
+ if (status == MagickFalse)
+ continue;
+ id=GetCacheViewThreadId();
+ q=GetCacheViewPixels(image_view[id],0,y,image->columns,1);
+ if (q == (PixelPacket *) NULL)
+ {
+ status=MagickFalse;
+ continue;
+ }
+ indexes=GetCacheViewIndexes(image_view[id]);
+ GetMagickPixelPacket(image,&pixel);
+ for (x=0; x < (long) image->columns; x++)
+ {
+ SetMagickPixelPacket(image,q,indexes+x,&pixel);
+ //if (IsMagickColorSimilar(&pixel,target) != invert)
+ if( ( pixel.red >= targetLow->red && pixel.red <= targetHigh->red
&&
+ pixel.green >= targetLow->green && pixel.green <=
targetHigh->green &&
+ pixel.blue >= targetLow->blue && pixel.blue <= targetHigh->blue
) != invert )
+ q->opacity=opacity;
+ q++;
+ }
+ if (SyncCacheView(image_view[id]) == MagickFalse)
+ status=MagickFalse;
+ if (image->progress_monitor != (MagickProgressMonitor) NULL)
+ {
+ MagickBooleanType
+ proceed;
+
+ #pragma omp critical
+ proceed=SetImageProgress(image,TransparentPaintImageTag,progress++,
+ image->rows);
+ if (proceed == MagickFalse)
+ status=MagickFalse;
+ }
+ }
+ image_view=DestroyCacheViewThreadSet(image_view);
+ return(status);
+}
+
+
+
diff -aur ImageMagick-6.4.3/magick/paint.h ImageMagick-6.4.3_mod/magick/paint.h
--- ImageMagick-6.4.3/magick/paint.h 2008-01-08 08:40:03.000000000 +0530
+++ ImageMagick-6.4.3_mod/magick/paint.h 2008-11-14 17:47:34.000000000
+0530
@@ -38,6 +38,10 @@
TransparentPaintImage(Image *,const MagickPixelPacket *,
const Quantum,const MagickBooleanType);
+extern MagickExport MagickBooleanType TransparentPaintImageChroma(Image *image,
+ const MagickPixelPacket *targetLow, const MagickPixelPacket *targetHigh,
const Quantum opacity,
+ const MagickBooleanType invert);
+
#if defined(__cplusplus) || defined(c_plusplus)
}
#endif
diff -aur ImageMagick-6.4.3/Magick++/lib/Image.cpp
ImageMagick-6.4.3_mod/Magick++/lib/Image.cpp
--- ImageMagick-6.4.3/Magick++/lib/Image.cpp 2008-07-28 19:06:47.000000000
+0530
+++ ImageMagick-6.4.3_mod/Magick++/lib/Image.cpp 2008-11-14
17:34:18.000000000 +0530
@@ -1861,6 +1861,28 @@
throwImageException();
}
+// Add matte image to image, setting pixels matching color to transparent
+void Magick::Image::transparentChroma ( const Color &colorLow_, const Color
&colorHigh_)
+{
+ if ( !colorLow_.isValid() || !colorHigh_.isValid() )
+ {
+ throwExceptionExplicit( OptionError,
+ "Color argument is invalid" );
+ }
+
+ std::string colorLow = colorLow_;
+ std::string colorHigh = colorHigh_;
+
+ MagickPixelPacket targetLow;
+ MagickPixelPacket targetHigh;
+ (void)
QueryMagickColor(std::string(colorLow_).c_str(),&targetLow,&image()->exception);
+ (void)
QueryMagickColor(std::string(colorHigh_).c_str(),&targetHigh,&image()->exception);
+ modifyImage();
+ TransparentPaintImageChroma ( image(), &targetLow, &targetHigh,
TransparentOpacity, MagickFalse );
+ throwImageException();
+}
+
+
// Trim edges that are the background color from the image
void Magick::Image::trim ( void )
{
diff -aur ImageMagick-6.4.3/Magick++/lib/Magick++/Image.h
ImageMagick-6.4.3_mod/Magick++/lib/Magick++/Image.h
--- ImageMagick-6.4.3/Magick++/lib/Magick++/Image.h 2008-07-28
19:06:47.000000000 +0530
+++ ImageMagick-6.4.3_mod/Magick++/lib/Magick++/Image.h 2008-11-14
16:54:43.000000000 +0530
@@ -603,6 +603,10 @@
// transparent
void transparent ( const Color &color_ );
+ // Add matte image to image, for all the pixels that lies in between
+ // the given two color
+ void transparentChroma ( const Color &colorLow_, const Color &colorHigh_);
+
// Trim edges that are the background color from the image
void trim ( void );
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