Legacy ImageMagick Discussions Archive

Hi, tried to find info regarding if some functions need Image *, to be in a specific format...

this code don't change the image returned into mod_image

if ((mod_image = UnsharpMaskImage(resize_image, (const double)radius,(const double)sigma,(const double)amount,(const double)threshold,&exception)) == (Image *)NULL)
{
MagickError(exception.severity, exception.reason, exception.description);
DestroyImage(resize_image);
DestroyMagick();
return;
}
resize_image = mod_image;

but if i do writeImage to a .tif file, and then read image and then do the same UnsharpMaskImage
then the UnsharpMaskImage really do something to the image returned...

it seams a little bit strange to

1: read in JPEG
2: save it as TIF
3: read in TIF
4: do UnsharpMaskImage
5: save as JPEG

instead of

1: read in JPEG
2: do UnsharpMaskImage
3: save as JPEG

ps, i get the wanted result, but i really like to know why...