imagepng（）和imagegif（）中的图像透明度

Question

I want to resize 2 types of images (png, gif) with transparent background...

1. But in png it works well in big size of the original image. eg. Original file dimension is 150x150

   change into 200x200 or exceeding the original size it works well. but in 100x100 it displays

2. Then the last GIF it doesn't work.

   Here my code for png

    $new_img = imagecreatetruecolor($max_w, $max_h);

    imagealphablending($new_img, false);
    imagesavealpha($new_img, true);

    $transparentindex = imagecolorallocatealpha($new_img, 255, 255, 255, 127);

    imagefill($new_img, 0, 0, $transparentindex);

    imagepng($new_img, $dir);

    Here my code for gif

    imagegif($new_img, $dir);

Answer 1

I know no PHP, but this seems to do the trick:

#!/usr/local/bin/php -f
<?php
    $neww=100;
    $newh=100;

    // Load original image and get its dimensions
    $img = imagecreatefrompng("badge.png");
    $w=imagesx($img);
    $h=imagesy($img);

    // Create output image, and fill with lots of transparency
    $out = imagecreatetruecolor($neww,$newh);
    imagealphablending($out,false);
    $transparentindex = imagecolorallocatealpha($out,0,0,0,127);
    imagefill($out,0,0,$transparentindex);
    imagesavealpha($out, true);

    // Copy original image, reized on top
    imagecopyresized($out,$img,0,0,0,0,$neww,$newh,$w,$h);
    imagepng($out,"out.png");
?>