PHP实现对png图像进行缩放的方法(支持透明背景)

= 0) { // Get the original image's transparent color's RGB values $trnprt_color = imagecolorsforindex($image,$trnprt_indx); // Allocate the same color in the new image resource $trnprt_indx = imagecolorallocate($image_resized,$trnprt_color['red'],$trnprt_color['green'],$trnprt_color['blue']); // Completely fill the background of the new image with allocated color. imagefill($image_resized,$trnprt_indx); // Set the background color for new image to transparent imagecolortransparent($image_resized,$trnprt_indx); } // Always make a transparent background color for PNGs that don't have one allocated already elseif ($info[2] == IMAGETYPE_PNG) { // Turn off transparency blending (temporarily) imagealphablending($image_resized,false); // Create a new transparent color for image $color = imagecolorallocatealpha($image_resized,127); // Completely fill the background of the new image with allocated color. imagefill($image_resized,$color); // Restore transparency blending imagesavealpha($image_resized,true); } } imagecopyresampled($image_resized,$image,$final_width,$final_height,$width_old,$height_old); if ( $delete_original ) { if ( $use_linux_commands ) exec('rm '.$file); else @unlink($file); } switch ( strtolower($output) ) { case 'browser': $mime = image_type_to_mime_type($info[2]); header("Content-type: $mime"); $output = NULL; break; case 'file': $output = $file; break; case 'return': return $image_resized; break; default: break; } switch ($info[2] ) { case IMAGETYPE_GIF: imagegif($image_resized,$output); break; case IMAGETYPE_JPEG: imagejpeg($image_resized,$output); break; case IMAGETYPE_PNG: imagepng($image_resized,$output); break; default: return false; } return true; }