Is image format for GTR/GTS 3/4 not Truevision_TGA (.tga) in fact?

[Lilonu]

Hi everybody (first post of mine here),

after playing and fiddling with watchface making on code level, I almost bricked my GTS-4 with inadvertingly feeding it an image in the wrong format (see here). With the (true) png images I used, the watchfaces did not install and so I examined the example images(.png) on the binary level and discovered that they in fact are Truevision_TGA images, non-compressed, indexed (or paletted), 255 color, origin left top.

With wrongly using a non-indexed, compressed (RLE) left bottom version I send, as mentioned, my watch into a boot loop, which I escaped only with luck later.

Before I make another test with a (I assume) correct tga: Anybody been there before?

[asoo]

I used to pack the dials using normal png, but didn't find any looping. The watch only shows the wrong color or not show image on screen (on GTR 3) , and you can delete it out normally
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If you want to manipulate png used in ZeppOS, I recommend checking out this tool.

viewtopic.php?p=14958#p14958

Hopefully it will be of benefit.

[Lilonu]

Thank you!

A I create my images in Gimp I'd like to skip that step: Gimp can export indexed, non-compressed, left-top tga files - but I'm a little afraid of (almost) bricking the gts-4 again. So if anybody has tried that already, I'd like to be reassured - or warned

[Lilonu]

I had a closer (sourcecode) look at another tool by the same author, SashaCX75, ImageToGTR3 of what asoo mentioned:

If you want to manipulate png used in ZeppOS, I recommend checking out this tool.
viewtopic.php?p=14958#p14958

Actually, the files are Truevision_TGA files, but with a few twist (e.g. the width always a multiple of 16 and rgba mirrored to abgr).

[SashaCX75]

Probably better to look at a newer version. But the general principles are the same. The format is based on TGA, but there are some differences (depending on the watch model).
https://github.com/SashaCX75/ImageToGTR3_v2