Fix resolution reporting for odd-sized images with a clap box

[dreifachstein]

A 15x15 sample image:
15x15.heic.zip

[farindk]

Thanks for the example file. I'm currently having a look at the problem.
Did you notice that the ispe box of the input also contains a wrong size (16x16):

| | | Box: ispe -----
| | | size: 20   (header size: 12)
| | | version: 0
| | | flags: 0
| | | image width: 16
| | | image height: 16
| | | 
| | | Box: clap -----
| | | size: 40   (header size: 8)
| | | clean_aperture: 15/1 x 15/1
| | | offset: -32768/65536 ; -32768/65536

How was this file generated?

[farindk]

i've corrected this with a simpler patch. Please see above.
No idea why it was done so complicated in the original source...

[dreifachstein]

Thanks for the example file. I'm currently having a look at the problem. Did you notice that the ispe box of the input also contains a wrong size (16x16):

| | | Box: ispe -----
| | | size: 20   (header size: 12)
| | | version: 0
| | | flags: 0
| | | image width: 16
| | | image height: 16
| | | 
| | | Box: clap -----
| | | size: 40   (header size: 8)
| | | clean_aperture: 15/1 x 15/1
| | | offset: -32768/65536 ; -32768/65536

How was this file generated?

The file was generated by the mac os image preview tool and the image size in ispe matches the decoder output.