One of the features of ROX-Filer is the ability to provide thumbnail images for of certain files. These are small images based on the content of the file and used to replace the default type icon for that file in ROX-Filer windows. You can see this effect by viewing a directory containing JPEG files and turning on thumbnail mode (Display => Show Thumbnails, normally bound to ctrl-T). ROX-Filer shows "thumbs" in the titlebar when thumbnail mode is on.
By itself ROX-Filer can generate thumbnails for the most common image file types
* JPEG
* PNG
* GIF
* SVG (normally)
* and a few others
However it does not support all image types, nor does it generate thumbnails for other types of file such as video or font files. To do so would increase the size of the program and slow it down. Also the file types that the user would want thumbnailing would vary from user to user.
The solution is to allow ROX-Filer to call external programs which are capable of generating thumbnails for certain types. The user can then enable or disable whichever types they wish to thumbnail.
Available thumbnail helpers include:
* VideoThumbnail: many types of video files
* MagickThumbnail: image types not handled internally
The helper applications are normally implemented as Library Directories.
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