添加图像层失败 (GD) PHP

Question

我刚刚在我的 Apache 上安装了 GD 库，看起来我下面的脚本不起作用。 我正在尝试将图层“play.png”添加到 youtube 视频缩略图（http://img.youtube.com/vi/VIDEOID/default.jpg）

我已经尝试了许多不同的 videoID，但图像没有不加载。有一条消息表明该图形无法打开，因为它包含错误。

打开文件

我正在使用 postimage.php?v=7yV_JtFnIwo http://img.youtube .com/vi/7yV_JtFnIwo/default.jpg 也可以正确打开...

有谁知道问题出在哪里？

提前致谢！

<?php

  // The header line informs the server of what to send the output
  // as. In this case, the server will see the output as a .png
  // image and send it as such

  header ("Content-type: image/png"); 


  // Defining the background image. Optionally, a .jpg image could 
  // could be used using imagecreatefromjpeg, but I personally 
  // prefer working with png

  $background = imagecreatefromjpeg("http://img.youtube.com/vi/".$_GET['v']."/default.jpg"); 


  // Defining the overlay image to be added or combined.

  $insert = imagecreatefrompng("play.png"); 


  // Select the first pixel of the overlay image (at 0,0) and use
  // it's color to define the transparent color

  imagecolortransparent($insert,imagecolorat($insert,0,0));


  // Get overlay image width and hight for later use

  $insert_x = imagesx($insert); 
  $insert_y = imagesy($insert); 


  // Combine the images into a single output image. Some people
  // prefer to use the imagecopy() function, but more often than 
  // not, it sometimes does not work. (could be a bug)

  imagecopymerge($background,$insert,0,0,0,0,$insert_x,$insert_y,100); 


  // Output the results as a png image, to be sent to viewer's
  // browser. The results can be displayed within an HTML document
  // as an image tag or background image for the document, tables,
  // or anywhere an image URL may be acceptable.

  imagepng($background,"",100); 

?>

Answer 1

不要使用 ?> 关闭（避免空格或新闻行）脚本，并使用 NULL 代替 ""。

imagepng($background, NULL); 

然后，在 imagepng 中，质量参数介于 0 和 9 之间，如 http:// it.php.net/manual/en/function.imagepng.php。