代码如下:
502_1@imagecolorallocatealpha //分配颜色 + alpha
imagesavealpha //设置在保存 png 图像时保存完整的 alpha 通道信息@H_502_1@
代码示例：
代码如下:
502_1@//获取源图gd图像标识符@H_502_1@$srcImg = imagecreatefrompng('./src.png');@H_502_1@$srcWidth = imagesx($srcImg);@H_502_1@$srcHeight = imagesy($srcImg);
//创建新图@H_502_1@$newWidth = round($srcWidth / 2);@H_502_1@$newHeight = round($srcHeight / 2);@H_502_1@$newImg = imagecreatetruecolor($newWidth,$newHeight);@H_502_1@//分配颜色 + alpha，将颜色填充到新图上@H_502_1@$alpha = imagecolorallocatealpha($newImg,127);@H_502_1@imagefill($newImg,$alpha);
//将源图拷贝到新图上，并设置在保存 PNG 图像时保存完整的 alpha 通道信息@H_502_1@imagecopyresampled($newImg,$srcImg,$newWidth,$newHeight,$srcWidth,$srcHeight);@H_502_1@imagesavealpha($newImg,true);@H_502_1@imagepng($newImg,'./dst.png');@H_502_1@
