#38226 [Opn->Asn]: Patch for Bug 30863

ID: 38226 Updated by: tony2001@php.net Reported By: seth at pricepages dot org -Status: Open +Status: Assigned Bug Type: GD related Operating System: Mac 10.4 PHP Version: 5.1.4 -Assigned To: +Assigned To: pajoye Previous Comments: ------------------------------------------------------------------------ [2006-07-26 17:03:24] seth at pricepages dot org Description: ------------ This small patch fixes the bug outlined in 30863 (http://bugs.php.net/bug.php?id=30863 ). The problem is a one pixel shift of the transparency. A one pixel border on one side remains the default color. Caution: this fix strikes me as *too* simple. I'm worried that I'm breaking something that I'm not noticing. Original code (gd.c line ~1331): /* If the pixel is transparent, we assign it the palette index that * will later be added at the end of the palette as the transparent * index. */ if ((oim->transparent >= 0) && (oim->transparent == * (inptr - 1))) { *outptr++ = nim->colorsTotal; inptr++; continue; } Fixed code ("inptr - 1" changed): /* If the pixel is transparent, we assign it the palette index that * will later be added at the end of the palette as the transparent * index. */ if ((oim->transparent >= 0) && (oim->transparent == (*inptr))) { *outptr++ = nim->colorsTotal; inptr++; continue; } In other news: GD's quantization << pngquant Maybe someday I'll port the code. Interest? Reproduce code: --------------- <?php $img = imagecreatetruecolor(100,100); //Start with a transparent canvas $trans = imagecolorresolve($img, 255,255,255); //Specifying a color as transparent (& below) causes the pixel shift imagecolortransparent($img, $trans); imagefilledrectangle($img, 0,0, 100,100, $trans); //Make a solid grey box $grey = imagecolorresolve($img, 128,128,128); imagefilledrectangle($img, 0,50, 100,100, $grey); //Draw a black line $black = imagecolorresolve($img, 0,0,0); imageline($img, 50,0, 50,100, $black); //Converting to palette (& above) causes a pixel shift imagetruecolortopalette($img, false, 256); imagepng($img, 'test.png'); ?> ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=38226&edit=1