Phpob_start () implements the variable program for storing images

After processing images with the phpGD library, you can only use imagejpeg () this is often not required for output or writing to a file. for example, to store images in a database, you need to write the images into variables and save them. use ob_start () to enable cache ob_get_contents ()

After processing images with the php GD library, you can only use imagejpeg () this is often not required for output or writing to a file. for example, to store images in a database, you need to write the images into variables and save them. use ob_start () to enable cache ob_get_contents () get the cache to write the image to the variable

The instance code is as follows:

2. $ ImgPath = "Image address ";
3. // Obtain image information $ imgPath can be a remote address
4. List ($ srcWidth, $ srcHeight, $ type) = getimagesize ($ imgPath );
5. ...
6. Switch ($ type ){
7. Case 1: $ imgCreate = 'imagecreatefromgif'; break;
8. Case 2: $ imgCreate = 'imagecreatefromjpeg '; break;
9. Case 3: $ imgCreate = 'imagecreatefrompng '; break;
10. Default: return false;
11. }
12. $ Orig = $ imgCreate ($ imgPath );
13. ...
14. // Enable cache
15. Ob_start ();
16. // Generate an image
17. Switch ($ type)
18. {
19. Case 1: imagegif ($ orig); break;
20. Case 2: imagejpeg ($ orig); break; // best quality
21. Case 3: imagepng ($ orig); break; // no compression
22. Default: echo ''; break;
23. }
24. // Save the image to a variable
25. $ ImageCode = ob_get_contents ();
26. Ob_end_clean ();

If you do not want to save the image as a variable, it will be a waste of resources. this is also a fun test.