PHP solution to shrink png images without losing transparent color_PHP tutorial

Mainly use two methods of the gd library:

Copy code The code is as follows:

imagecolorallocatealpha //Assign colors + alpha

imagesavealpha //Set to save complete alpha channel information when saving png images

Code example:

Copy code The code is as follows:

//Get the source image gd image identifier
$srcImg = imagecreatefrompng(' ./src.png');
$srcWidth = imagesx($srcImg);
$srcHeight = imagesy($srcImg);

//Create a new image
$newWidth = round($srcWidth / 2);
$newHeight = round($srcHeight / 2);
$newImg = imagecreatetruecolor($newWidth, $newHeight) ;
//Assign color + alpha, fill the color onto the new image
$alpha = imagecolorallocatealpha($newImg, 0, 0, 0, 127);
imagefill($newImg, 0, 0, $alpha);

//Copy the source image to the new image, and set it to save the complete alpha channel information when saving the PNG image
imagecopyresampled($newImg, $srcImg, 0, 0, 0, 0, $newWidth, $ newHeight, $srcWidth, $srcHeight);
imagesavealpha($newImg, true);
imagepng($newImg, './dst.png');

http://www.bkjia.com/PHPjc/621653.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/621653.htmlTechArticleMainly use two methods of the gd library: Copy the code The code is as follows: imagecolorallocatealpha //Assign color + alpha imagesavealpha / /Set to save full alpha when saving png images...