What's the spec of apple compliant bmp format? On Tue, Oct 4, 2022, 9:00 AM Ian Clark <[email protected]> wrote:
> Following recent security updates to macOS and iPadOS, they now refuse to > display bitmaps generated by addon graphics/bmp, or any bitmaps shipped > with j904. For example: /Applications/j904/addons/graphics/bmp/toucan.bmp > > However, if I copy this BMP file to my iCloud Drive, I can display it okay > on a pre-Monterey macOS. This applies to all BMPs in the latest addons > folder (I count 11 such files). > > Other image formats: .jpg, .png are not affected (not fully tested). > > BUT macOS and iPadOS do still display bitmaps. I've verified this by > generating one of the sample BMP files published in > https://en.wikipedia.org/wiki/BMP_file_format > I'm happy to post my code, but it's only noise at this stage. The point is: > Apple has not withdrawn support for BMP, but tightened its checks for > compliance with the spec. > > This has broken viewmat in j901-for-iOS. > > It would be good to fix addon: graphics/bmp to generate Apple-compliant > BMPs, and replace the bad BMPs in all addons shipped with j904. That would > allow users to fix viewmat in j901-for-iOS without having to wait for the > bug release. But I cannot find the bug in graphics/bmp. > > In an earlier thread, I promised to take the matter up with Apple. I did, > but their reply is overdue. > > I am aware that viewmat in jqt now uses PNG not BMP. I confirm that the > latest version of graphics/viewmat generates correct PNGs which display > okay on iPadOS, using the Files app. But j901-for-iOS needs Swift > code-changes and a full re-install from App Store before it can correctly > handle the resulting ~temp/viewmat.png which will replace ~temp/vmat.bmp . > Simple in principle but messy in practice. I haven't worked out how best to > do it. > > Ian Clark > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
