Brontekst bekijken van Webdesign:PHP:How to Resize Image Dynamically in PHP

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{{sys:blockfloat|top=Mthumb is a PHP tool for resizing images on the fly. It is a better and securer version of TimThumb.
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Here are the major changes:
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- Removed the WebShots features entirely<br>
- Removed the PHP Memory settings entirely<br>
- Disabled all remote/external sites by default<br>
- Removed option to allow all remote sites<br>
- Changed cache folder to use system cache by default<br>
- Increased default caching time and time between cleans<br>
- Increased default allowed file size and dimensions<br>
- Enabled PNG compression by default<br>
- Enabled PNG transparency by default<br>
- Removed error output that revealed script versions and error images<br>
- Tilde support in URLs (for user home directories was added)<br>
- Code cleanup and PHP docblock comments<br>
- Added check to ensure class was defined before calling start method<br>
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Download from {{#tag:easyview|https://github.com/mindsharelabs/mthumb|type=iframe|thumbnail=Github|direct=true}}
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{{sys:head|size=24|text=mThumb Parameters}}
<html>
<table>
<tbody>
<tr>
<th></th>
<th>stands for</th>
<th>values</th>
<th>What it does</th>
</tr>
<tr>
<td>src</td>
<td>source</td>
<td>url to image</td>
<td>Tells mThumb which image to resize › <a href="http://www.binarymoon.co.uk/2010/08/timthumb/">mThumb basic properties tutorial</a></td>
</tr>
<tr>
<td>w</td>
<td>width</td>
<td>the width to resize to</td>
<td>Remove the width to scale proportionally (will then need the height) › <a href="http://www.binarymoon.co.uk/2010/08/timthumb/">mThumb width tutorial</a></td>
</tr>
<tr>
<td>h</td>
<td>height</td>
<td>the height to resize to</td>
<td>Remove the height to scale proportionally (will then need the width) › <a href="http://www.binarymoon.co.uk/2010/08/timthumb/">mThumb height tutorial</a></td>
</tr>
<tr>
<td>q</td>
<td>quality</td>
<td>0 – 100</td>
<td>Compression quality. The higher the number the nicer the image will look. I wouldn’t recommend going any higher than about 95 else the image will get too large › <a href="http://www.binarymoon.co.uk/2010/08/timthumb/">mThumb image quality tutorial</a></td>
</tr>
<tr>
<td>a</td>
<td>alignment</td>
<td>c, t, l, r, b, tl, tr, bl, br</td>
<td>Crop alignment. c = center, t = top, b = bottom, r = right, l = left. The positions can be joined to create diagonal positions › <a href="http://www.binarymoon.co.uk/2010/08/timthumb-part-4-moving-crop-location/">mThumb crop position tutorial</a></td>
</tr>
<tr>
<td>zc</td>
<td>zoom / crop</td>
<td>0, 1, 2, 3</td>
<td>Change the cropping and scaling settings › <a href="http://www.binarymoon.co.uk/2011/03/timthumb-proportional-scaling-security-improvements/">mThumb crop scaling tutorial</a></td>
</tr>
<tr>
<td>f</td>
<td>filters</td>
<td>too many to mention</td>
<td>Let’s you apply image filters to change the resized picture. For instance you can change brightness/ contrast or even blur the image › <a href="http://www.binarymoon.co.uk/2010/08/timthumb-image-filters/">mThumb image filter tutorial</a></td>
</tr>
<tr>
<td>s</td>
<td>sharpen</td>
<td></td>
<td>Apply a sharpen filter to the image, makes scaled down images look a little crisper › <a href="http://www.binarymoon.co.uk/2010/08/timthumb-image-filters/">tutorial</a></td>
</tr>
<tr>
<td>cc</td>
<td>canvas colour</td>
<td>hexadecimal colour value (#ffffff)</td>
<td>Change background colour. Most used when changing the zoom and crop settings, which in turn can add borders to the image.</td>
</tr>
<tr>
<td>ct</td>
<td>canvas transparency</td>
<td>true (1)</td>
<td>Use transparency and ignore background colour</td>
</tr>
</tbody>
</table></html>
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You can override certain built in settings in mThumb. by creating a config file called mthumb-config.php and would contain a series of define statements that change default settings. 

There are a whole bunch of settings that are not controlled by the normal query string parameters.

<html><table>
<tbody>
<tr>
<th>constant</th>
<th>values</th>
<th>What it does</th>
</tr>
<tr>
<td>DEBUG_ON</td>
<td>true/ false</td>
<td>Turn on debug logging to the standard PHP error log</td>
</tr>
<tr>
<td>DEBUG_LEVEL</td>
<td>1, 2, 3</td>
<td>Debug level 1 is less noisy and level 3 is the most noisy</td>
</tr>
<tr>
<td>ALLOW_EXTERNAL</td>
<td>true/ false</td>
<td>Allow images from external sites to be resized. Restricted to the images defined in the <em>$allowed_sites</em> array.</td>
</tr>
<tr>
<td>FILE_CACHE_ENABLED</td>
<td>true/ false</td>
<td>Should we cache the files on disk to speed up your website? (hint: the answer is yes, unless you’re testing/ developing things! :))</td>
</tr>
<tr>
<td>FILE_CACHE_TIME_BETWEEN_CLEANS</td>
<td>86400 (milliseconds)</td>
<td>mThumb automatically cleans up the cached files. This defines the amount of time between the different the cache cleaning.</td>
</tr>
<tr>
<td>FILE_CACHE_MAX_FILE_AGE</td>
<td>86400 (milliseconds)</td>
<td>How old should a file be before it’s cleaned?</td>
</tr>
<tr>
<td>FILE_CACHE_SUFFIX</td>
<td>.txt</td>
<td>What to put at the end of all files in the cache directory so we can identify them easily</td>
</tr>
<tr>
<td>FILE_CACHE_PREFIX</td>
<td>mthumb</td>
<td>What to put at the start of the cache files so we can identify them easily</td>
</tr>
<tr>
<td>FILE_CACHE_DIRECTORY</td>
<td>.<code>system temporary directory</code></td>
<td>the name of the image cache directory. Left blank it will use the system temporary directory (which is better for security, but is not supported by all web hosts)</td>
</tr>
<tr>
<td>MAX_FILE_SIZE</td>
<td>10485760</td>
<td>10 Megs is 10485760. This is the max internal or external file size that we’ll process</td>
</tr>
<tr>
<td>CURL_TIMEOUT</td>
<td>20</td>
<td>Timeout duration for Curl. This only applies if you have Curl installed and aren’t using PHP’s default URL fetching mechanism.</td>
</tr>
<tr>
<td>WAIT_BETWEEN_FETCH_ERRORS</td>
<td>20</td>
<td>Time to wait between errors fetching remote file.</td>
</tr>
<tr>
<td>BROWSER_CACHE_MAX_AGE</td>
<td>864000</td>
<td>Browser cache duration (to prevent images from being reloaded more than once – the higher the number the better).</td>
</tr>
<tr>
<td>BROWSER_CACHE_DISABLE</td>
<td>true/ false</td>
<td>Use for testing if you want to disable browser caching.</td>
</tr>
<tr>
<td>MAX_WIDTH</td>
<td>3600</td>
<td>Put a sensible limit of the width of the resized image (so that crazy large images can’t be created)</td>
</tr>
<tr>
<td>MAX_HEIGHT</td>
<td>3600</td>
<td>Put a sensible limit of the height of the resized image (so that crazy large images can’t be created)</td>
</tr>
<tr>
<td>PNG_IS_TRANSPARENT</td>
<td>TRUE</td>
<td>Define if a png image should have a transparent background color. Use False value if you want to display a custom coloured canvas_colour</td>
</tr>
</tbody>
</table></html>
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