+++ /dev/null
-//////////////////////////////////////////////////////////////
-/// phpThumb() by James Heinrich <info@silisoftware.com> //
-// available at http://phpthumb.sourceforge.net ///
-//////////////////////////////////////////////////////////////
-/// //
-// Frequently Asked Questions (FAQ) about phpThumb() //
-// ///
-//////////////////////////////////////////////////////////////
-
-
-Q: My question isn't answered here and I can't find any
- forums, how do I get support?
-A: Please email me directly at info@silisoftware.com with
- any questions, suggestions, donations, etc.
-
-
-Q: I think I found a bug, what's the first thing I should do?
-A: Please make sure you're using the latest version. There's
- a good chance I may have already fixed the bug, so please
- make sure you can reproduce it with the latest version
- before reporting the bug.
-
-
-Q: phpThumb doesn't work as expected, and it may be a server
- configuration issue -- how do I check?
-A: Please run /demo/demo.check.php to find out how your server
- matches up with the recommended configuration and for
- suggestions on what to change for improved performance.
-
-
-Q: What is the GPL? Can I use this for commercial sites?
-A: See the GPL FAQ: http://www.gnu.org/licenses/gpl-faq.html
- In general, if you just want to call phpThumb.php in the
- standard <img src="phpThumb.php?src=pic.jpg&w=100"> manner
- then there is no problem, you're free to do this no matter
- if you site is commercial or not, or what license your code
- is released under.
- If you're calling phpThumb() as an object then you will
- probably run into license issues, so consult the above FAQ
- and the GPL itself.
- No matter if you use phpThumb() commercially or not, no
- payment is required. However, donations are always welcome
- and can be made at http://phpthumb.sourceforge.net
-
-
-Q: Some images generate thumbnails, but some fail (the original
- non-resized image is output instead).
-A: Your PHP installation does not have a high enough memory_limit
- and ImageMagick is not installed on the server. The PHP memory
- required is 5 times the number of pixels in the image.
- For example:\r
- 640x480x5 = 1.5MB\r
- 1600x1200x5 = 9.2MB\r
- You can adjust the PHP memory limit in php.ini (if you have
- permission on your server to do so), or (better yet) install
- ImageMagick on the server and that will bypass the memory limit
- issue. If you can't do either of the above, you can resize the
- images manually (with your favourite image editor) to a size
- that your memory_limit setting can handle, and/or you can
- re-save the images with an image editor that can embed an EXIF
- thumbnail (Photoshop for example) which phpThumb can use as an
- image source (lower image quality, but perhaps better than
- nothing).\r
-
-
-Q: I'm getting is this error message:\r
- Failed: RenderToFile(<filename>) failed because\r
- !is_resource($this->gdimg_output)\r
-A: You missed the call to GenerateThumbnail() before
- RenderToFile() or OutputThumbnail.
- See /demo/phpThumb.demo.object.php for an example.
-
-
-Q: I'm trying to save a phpThumb-generated image in Internet
- Explorer and it saves in BMP format, why?
-A: This is not phpThumb's fault, it is an IE issue:
- http://support.microsoft.com/default.aspx?scid=kb;en-us;810978\r
- http://support.microsoft.com/default.aspx?scid=kb;en-us;260650\r
-
-
-Q: PNG images with transparent areas show up with gray background
- in the areas that are supposed to be transparent.
-A: Internet Explorer has had a broken PNG alpha-channel display
- implementation for a decade, so it may never get fixed. Other
- major browsers generally handle alpha-transparent PNGs fine.
- See http://www.silisoftware.com/png_transparency/
- For an alpha-channel PNG display in IE hack, see this page:
- http://www.koivi.com/ie-png-transparency/
-
-
-Q: I'm getting "<filename> does not exist" when I know the
- file does exist
-A: Check that these two values are present and properly
- configured in phpThumb.config.php (introduced in v1.6.0):
- $PHPTHUMB_CONFIG['allow_src_above_docroot'] (default=false)
- $PHPTHUMB_CONFIG['allow_src_above_phpthumb'] (default=true)
- If your images are outside DOCUMENT_ROOT then you will have
- to configure 'allow_src_above_docroot' to true.
- Make sure whatever user the webserver is running as has read
- permission to the file/directory you're reading from\r
-
-
-Q: Should I use phpThumb.php, or use phpThumb() as an object?
-A: phpThumb.php is easier to use (less coding) for basic uses.
- phpThumb.php handles all caching; your own object will need
- to have its own caching code. If you just want to display a
- thumbnailed version of an existing image, use phpThumb.php
- If you want to render one (or more) thumbnails to static
- files (during upload, for example), that's an appropriate
- use for the object mode. Also, phpThumb.config.php is only
- used by phpThumb.php, so if you instantiate your own object
- you need to manually set all configuration options because
- phpThumb.config.php has NO effect. So, to repeat:
- **always use phpThumb.php unless you NEED to have an object**
-
-
-Q: The first time I go to a page which contains thumbnails I
- don't actually see the thumbnail, I just get a browser image
- placeholder (or no image). As soon as I hit refresh, all the
- thumbnail images pop into place really fast.
-A: You can try and see if it works better with\r
- $PHPTHUMB_CONFIG['cache_force_passthru'] = false;\r
- but typically the default setting works better.
- This is something of an unresolved issue on some servers,
- where for whatever reason I haven't (yet?) been able to
- figure out a setting that always works the first time. If the
- above config setting doesn't help, you might be stuck with
- having to manually or automagically pre-cache thumbnails as
- they're created. Please email info@silisoftware.com if you
- have a better solution...
-
-
-Q: Are there any front-end GUI interfaces to phpThumb()?
-A: See /demo/readme.demo.txt
-
-
-Q: Are there / have there been any security issues in phpThumb?
-A: http://secunia.com/product/5199/
-
-
-Q: Why can't Flash work with images output from phpThumb()?
-A: Flash doesn't like progressive JPEG. Set:
- $PHPTHUMB_CONFIG['output_interlace'] = false;
-
-
-Q: Image quality is not very good - why?
-A: If you're using GD v1.x, no way around it. Upgrade to GD v2.x
-
-
-Q: Image quality is very bad, very pixelated -- why?
-A: You may be trying to resize images larger than the available
- PHP memory, so phpThumb is simply extracting and using the
- EXIF thumbnail as the image source, which is usually about
- 160x120 (so if you resize it to 640x480 it will look very bad).
- To calculate the required size for memory_limit in php.ini,
- calculate the number of pixels in the image and multiply by 5:
- For example, 1600x1200 = 1600 * 1200 * 5 = 9600000 = 10M
- Easy solution: install ImageMagick
-
-
-Q: Can I save the generated thumbnail to a file?
-A: Yes, there are several ways to do so; the best way is to call
- phpThumb as an object and call RenderToFile() to save the
- thumbnail to whatever filename you want.
- See /demo/phpThumb.demo.object.php for an example.
- The other way is to use the 'file' parameter (see
- /docs/phpthumb.readme.txt) but this parameter is deprecated
- and may not exist in future versions of phpThumb().\r
-
-
-Q: "Off-server thumbnailing is not allowed" -- how do I enable it?
-A: By default, phpThumb() only makes thumbnails for the same
- domain that it is running on. To allow it to make thumbnails
- for a limited number of other domains, add them
- (in phpThumb.config.php) like this:
- $PHPTHUMB_CONFIG['nohotlink_valid_domains'] = array(
- @$_SERVER['HTTP_HOST'], 'example.com', 'www.example.com',
- 'subdomain.example.net', 'example.org');
- To disable off-server thumbnail blocking, just set:
- $PHPTHUMB_CONFIG['nohotlink_enabled'] = false;
-
-
-Q: Is it possible to set the parameters (like w/h/fltr[]) in
- the config, so that they can't be changed over the URL?\r
-A: Take a look at $PHPTHUMB_DEFAULTS at the bottom of
- phpThumb.config.php You'll want to set
- $PHPTHUMB_DEFAULTS_GETSTRINGOVERRIDE = false\r
- possibly also
- $PHPTHUMB_DEFAULTS_DISABLEGETPARAMS = true\r
- You may also want to investigate
- $PHPTHUMB_CONFIG['high_security_enabled'] = true
- (see the example at the bottom of phpThumb.config.php
- for how to call images in HighSecurity mode)
-
-
-Q: Is there a way to use phpThumb() object to create thumbnails
- without the parameters in the URL showing the location of
- the image etc?\r
-A: There is a demo in /demo/phpThumb.demo.object.php. You could
- modify this into your own file, but there still remains the
- problem of passing parameters to the file, whether it's
- phpThumb.php or your own instantiation of a phpThumb() object.
- I would suggest is putting as many of the common parameters
- into phpThumb.config.php as possible under $PHPTHUMB_DEFAULTS,
- so you then don't have to pass them for each image. If you
- don't want people modifying the parameters, turn on
- $PHPTHUMB_CONFIG['high_security_enabled'] and set a password
- (you'll need to generate the <img> tags with phpThumbURL()
- provided at the bottom of phpThumb.config.php). If you don't
- want people accessing your source images at all, you can
- place them outside DOCUMENT_ROOT on your server (as long as
- phpThumb/PHP has read access to the directory). The other
- option is to put your source images in a MySQL database
- and set $PHPTHUMB_CONFIG['mysql_query'] and related
- parameters in phpThumb.config.php to pull your source images
- from the database. That way it's impossible to retrieve the
- images except through phpThumb.php, and if high_security is
- enabled, then nobody can modify the parameters to view
- anything except what you want to show. So, yes, it's possible
- to use your own object, but it's probably better to use
- phpThumb.php if possible -- one notable issue is that
- phpThumb.php handles all the caching, so you're on your own
- to deal with that if you create your own object.
-
-
-Q: How do I write the output thumbnail back to a database instead
- of outputting to the browser or a file?
-A: See /demo/phpThumb.demo.object.php Basically you need to call
- $this->GenerateThumbnail() then $this->RenderOutput() and then
- the output raw image data is found in $this->outputImageData
-
-
-Q: phpThumb runs slowly, as if the images aren't cached, when I use HTTP source
- images (not on my server). How can I make it go faster?
-A: $PHPTHUMB_CONFIG['cache_source_filemtime_ignore_remote'] = true;
- // if true, remote source images will not be checked for modification date and
- // cached image will be used if available, even if source image is changed or removed\r
-
-
-Q: What does the "cache_default_only_suffix" configuration option do?
-A: Cache files are normally created with big ugly names like
- "phpThumb_cache_www.example.com_src1a482c2c760463795ff18faf073b389f_par3e099041c2f4a73041a7f5d7e7fc481a_dat1119952152.jpeg"
- but if cache_default_only_suffix is enabled, cache filenames are simplified to
- "pic_thumb.jpg" (for example). The problem is that only one version of that
- thumbnail is possible, and you can never call it again with a different size,
- or different filters, etc. Generally you don't want that enabled, but it's
- there because some people asked for it.
-
-
-Q: Why is the visual size of rotated images smaller than the unrotated images?
-A: phpThumb fits the rotated image into the 'w' and 'h' dimensions.
- Try not specifying a 'w' parameter: phpThumb.php?src=file.png&ra=15\r
- That should leave the image the apparent same size as the unrotated image
- (in actual fact the canvas size is enlarged to fit the rotated image in it).\r
-
-
-Q: How can I purge cached files when I delete the source image?
-A: You can either let phpThumb's built-in cache purging features (see phpThumb.config.php)
- take effect, or you can manually walk through your source images to delete and find
- the matching cache files and delete them:
- if ($dh = opendir($sourcedir)) {
- while ($file = readddir($dh)) {
- if ($file == $WhatIwantToDelete) {
- $md5 = md5_file($sourcedir.'/'.$file);
- unlink($phpthumb_cache_dir.'/phpThumb_cache_www.example.com_src'.$md5.'*.*');
- }
- }
- closedir($dh);
- }
-
-
-Q: What is the proper name for this script/program/library?
-A: The official name is "phpThumb()" but it may be written
- as simply "phpThumb" in short form (or where parentheses
- are not permitted), or "phpthumb" in case-insensitive
- environments. The following is a non-exhaustive sample of
- unacceptable forms: PHPthumb; phpThumbs; phpthump;
- phpthumbnailer; phpThumbnail; PHP Thumb; Phpthumb; etc.
-
-
projects / atutor.git / blobdiff