note 104554 added to function.imagecolortransparent

Pay attention, that some GIF images may not include a transparent color. A good example of forced transparency in resized GIF image was given by markglibres at yahoo dot com 29-Mar-2009 02:48. But sometimes the transparent color in GIF images can be not set. The problem is, that the color you force to be transparent can be used in the original GIF as opaque and you will loose that color in resized image. The solution is not to use some default transparent color and to leave the resized image without transparent color (the same as original GIF). I used (nearly) the following code to make resized GIF images trnsparent only when the transparency is needed: <?php /* ... */ $img = ImageCreateFromGIF($f); /* create image from existing GIF: original image file name $f you may take from where you need */ $transparent_index = ImageColorTransparent($img); /* gives the index of current transparent color or -1 */ if($transparent_index!=(-1)) $transparent_color = ImageColorsForIndex($img,$transparent_index); /* ... */ $img_resized = ImageCreateTrueColor( $nw, $nh ); /* (the new width $nw and height $nh must be defined before) */ if(!empty($transparent_color)) /* simple check to find wether transparent color was set or not */ { $transparent_new = ImageColorAllocate( $img_resized, $transparent_color['red'], $transparent_color['green'], $transparent_color['blue'] ); $transparent_new_index = ImageColorTransparent( $img_resized, $transparent_new ); ImageFill( $img_resized, 0,0, $transparent_new_index ); /* don't forget to fill the new image with the transparent color */ } list($w,$h) = GetImageSize($f); /* defines the original width $w and height $h */ if( ImageCopyResized( $img_resized, $img, 0,0, 0,0, $nw,$nh, $w,$h ) ) /* resized copying and replacing the original image */ { ImageDestroy($img); $img = $img_resized; } /* ... */ header('Content-Type: image/gif'); ImageGIF($img); ImageDestroy($img); ?> P.S. If there some errors, I hope you could understood the idea. ---- Server IP: 89.251.21.32 Probable Submitter: 91.124.217.223 ---- Manual Page -- http://www.php.net/manual/en/function.imagecolortransparent.php Edit -- https://master.php.net/note/edit/104554 Del: integrated -- https://master.php.net/note/delete/104554/integrated Del: useless -- https://master.php.net/note/delete/104554/useless Del: bad code -- https://master.php.net/note/delete/104554/bad+code Del: spam -- https://master.php.net/note/delete/104554/spam Del: non-english -- https://master.php.net/note/delete/104554/non-english Del: in docs -- https://master.php.net/note/delete/104554/in+docs Del: other reasons-- https://master.php.net/note/delete/104554 Reject -- https://master.php.net/note/reject/104554 Search -- https://master.php.net/manage/user-notes.php