EXIF specs V3 added the UTF-8 data type. The MicroExif class now allows serializations to choose whether to support the V2 or V3 format. To maximize compatibility with old readers, even when V3 is set, the ASCII data type is used if possible.
The JXR plugin, based on TIFF V6 container, does not allow to use the V3 format (it does not recognize the UTF-8 data type) and therefore V2 has been forced. For all other plugins using MicroExif, it is now possible to save, e.g., descriptions in Japanese.
Please note that this patch is also a bugfix: when saving, version 3 was set but the strings were always saved as ASCII.
Improved metadata support via EXIF metadata. Since JXR is based on a TIFF container, EXIF data is read directly from the file so it always works (even with versions of libjxr that don't have the metadata reading API).
It also solves the following issues:
- Incorrect date format on saved JXR files (was saved in ISO format instead of `yyyy:MM:dd HH:mm:ss`).
- Incorrect date type setting in EXIF data: the `DateTime` tag should be updated on every save (verified by GIMP and Photoshop). Our `CreationDate` metadata is the equivalent of the EXIF `DateTimeOriginal` tag.
Closes#22
The goal of MR is to control the correct saving of metadata and resolution in plugins that support them.
- Modified the basic write test to verify that resolution and metadata are saved correctly.
- Verifies the correct functioning of MicroExif in plugins that use it to save metadata.
- EXR: fixed wrong vertical resolution (error found with this MR).
- Added EXR, JXR, JXL, PCX metadata test.
