png图片
function imageResizer($url, $width, $height) { $image = imagecreatefrompng($url); $width_orig = imagesx($image); $height_orig = imagesy($image); $ratio_orig = $width_orig/$height_orig; if ($width/$height > $ratio_orig) { $width = floor($height*$ratio_orig); } else { $height = floor($width/$ratio_orig); } $image_p = @imagecreate($width, $height)or die("Cannot Initialize new GD image stream"); $alpha = imagecolorallocatealpha($image_p, 0, 0, 0, 127); //为一幅图像分配颜色 + alpha //int imagecolorallocatealpha ( resource $image , int $red , int $green , int $blue , int $alpha ) //imagecolorallocatealpha() 的行为和 imagecolorallocate() 相同，但多了一个额外的透明度参数 alpha，其值从 0 到 127。0 表示完全不透明，127 表示完全透明。如果分配失败则返回 FALSE。 imagefill($image_p, 0, 0, $alpha); $aa=imagecopyresampled($image_p, $image, 0, 0, 0, 0, $width, $height, $width_orig, $height_orig); imagesavealpha($image_p, true); header('Content-type: image/png'); imagepng($image_p,"2.png");//输出到图片文件2.png } imageResizer("1.png", 100, 20);JPEG图片 function imageResizer($url, $width, $height) { list($width_orig, $height_orig) = getimagesize($url); $ratio_orig = $width_orig/$height_orig; if ($width/$height > $ratio_orig) { $width = $height*$ratio_orig; } else { $height = $width/$ratio_orig; } // 重新取样 $image_p = imagecreatetruecolor($width, $height); $image = imagecreatefromjpeg($url); imagecopyresampled($image_p, $image, 0, 0, 0, 0, $width, $height, $width_orig, $height_orig); // 输出 header('Content-type: image/jpeg'); imagejpeg($image_p, "2.jpg", 100); } imageResizer("1.jpg", 100, 200);
