eyefalo.blogg.se - Exif data viewer reddit

The first page is the camera information and the second page is the thumbnail. Here are some answers for your questions:ġ) The EXIF data is laid out like a TIFF file with 2 pages. Or is there a way to guarantee that the size of the newly rotated thumbnail will be smaller or equal to previous thumbnail size to replace with?.So, is there a standard way to iterate through all tags and sub-directories, to recognize which EXIF tags contain offsets, and to update them if needed? Or the only way is to read a maximum of tags and rewrite only that are known? If not, then each tags containing an offset that points to a location beyond the thumbnail to replace should be updated.Is there any guarantee in the EXIF standards that the thumbnails are always written in the late EXIF data, just before the primary image?.

What are the supported formats for thumbnails? (I found JPEG and TIFF, are there other?).

Can the EXIF data contains more than 1 thumbnail, and if yes, what is the maximum thumbnail count that an image can contain?.

For this reason I need to write in the EXIF data, to replace the existing thumbnail.īut this raises some questions, that I've some trouble answering, namely: But I also need to rotate the thumbnail contained in the EXIF data, if any, to keep the image coherent. I already wrote the code to rotate and save the primary JPEG image, and it works well. I want to rotate and write the photo data itself, not just rewrite the orientation tag. However, I would add a new option to rotate photos. In this context, I wrote a small class to be able to read and use some EXIF data, as e.g.