Should be easy to find, right? All you want is a function that resizes an image to constraints (doesn't care if it should scale up or down), with possibility to select if you want to keep it proportional, and possibility to use either width or height as the constraint. Also, you want it to preserve transparency damn it! Surprisingly, I was unable to find a good function that does all that, so I decided to attempt writing it. This should do it.
Note: Original announcement and comments for the function are available at mediumexposure.com/techblog/smart-image-resizing-while-preserving-transparency-php-and-gd-library
* If you pass width as 0 (zero) -- this function will disregard width, and use height as constraint. Same vice versa. * If you set "proportional" to false - the function will simply stretch (or shrink) the image to its full constraints. * If one of the dimensions is set to zero, and proportional set to "false" - then the image will be forced to stretch or shrink the other dimension, and disregard the zeroed dimension (leave it the same). * If proportional is set to true - the image will resize to constraints proportionally, once again, with possibility to have either width or height set to zero. * The function can use either linux "rm" command, or php @unlink. Most probably you don't need to ever use that flag, but on some setups - @unlink won't work due to user access restrictions. * The function will simply replace the file that you give it, with the resized file. * The function supports gif, png, and jpeg, and preserves the transparency of gif and png images. * Tested on GD version 2.0.28 only.
Essentially, everything happens just as logically expected. Please, if you see anything wrong, and you know ways to enhance, or optimize it, let me know.
There is a new parameter “output” which can be set to either
* "file" - overwrite the given file (default) * "browser" - output image through http - with correct mime type * "return" - return GD Library Image object * or any filename of choice - save changed version to output path
There is another new parameter “delete_original”. Speaks for itself.
Copyright © 2008 Maxim Chernyak
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