While graphics_rotate, graphics_resize, and graphics_composite events already exist, they don't have the ability to *override* the standard process.
This makes it a bit tricky when you want to replace the standard procedure with another (e.g. use jpegtran to perform lossless jpg rotation).
Solution:
- make a temp filename.
- tell the events to use it as the output file.
- if an event makes something, use it and skip the standard process.
- resize: ensured that resize is skipped *only* if the metadata is valid or the options are well-defined and would upscale. Then, if resize is skipped, check to see if it still needs to be converted. Previous conditions would allow a small PNG to get copied to a JPG, and would allow a corrupted JPG to be copied to the output.
- rotate: add checks for empty file or empty options.
- use get_file_metadata instead of direct getimagesize call.
- add unit tests for rotate and resize, including some for corrupted input files and missing options.
* moves the composite method back into core
* requires that the operation be fully qualified i.e. gallery_graphics::resize
* caches the graphics rules on each request