#84 Patch: use primary image for heic even when have multiple image

[Kevin Clauson]

This patch does not add multi-image support for HEIF, which is what the comment in the code is asking for. However, it does allow for these images to succeed using the primary image. I'm sure this has been considered. But thought I would just see if there was any appetite for allowing for these images to succeed. The primary image is the intended display image in multi-image HEIF files and the HEIF spec requires a primary image.
https://github.com/strukturag/libheif/blob/1a131f9be0e899004233b605cd3102251986d933/libheif/api/libheif/heif.cc#L620
So being able to convert these images to jpeg using the primary image would be great.

Thanks in advance for your consideration of this patch,
Kevin

[Kevin Clauson]

Here was my multi-image heic that I used for testing.

[Kevin Clauson]

I also tested it with this heic image which is an example of where the primary image is not the first image.

[Bob Friesenhahn]

Your very useful changes have been incorporated as Mercurial changeset 17675:9f09bb6ab080 and will be in the daily development snapshot. Many more changes will be necessary in order to read multi-frame HEIF formats.