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Lorthiz

TGA corner pixels have Red and Blue channels swapped after export

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TLDR: When exporting to TGA(Targa) format UpperRight and LowerRight corners have their Red and Blue channels swapped.

 

Steps to reproduce:

1) Create any document.

2) Place in UpperRight or LowerRight corner object with color that has different Red and Blue channels. eg. R:125 G:00 B:00

3) Export image as TGA(Targa)

4) Load exported TGA image to AffinityDesigner.

 

Actual result:

One pixel in both right corners has Red and Blue components swapped. If we saved this color in one of corners: (R:125 G:00 B:00) the loaded pixel in that corner will be: (R:00 G:00 B:125)

Expected result: components are not swapped during export. Especialy useful if you are writing TGA loaders/converters and you are expecting that data you are loading is correct...

 

Additional info:

I have not experienced any problems with Green or Alpha chanel so it seems to be affecting only Red and Blue.'

Export size seems to not have affect it's always one pixel from both corners.

It's not loading problem. After checking TGA files with Hex editors and checking values stored inside the incorrect values are saved during export.

 

Files to reproduce and screenshots are attatched:

2 .afdesign files with sources that can be used to export check source files.

3 Exported TGA images where inproper behaviour can be spotted

3 Screenshots from symetric gradient presenting incorrect data after export.

4x4.tga

TGABug.afdesign

4x4GreenEdition.tga

TGAGradientBug.afdesign

TGAGradientBugBig.tga

LeftBottomCorner.png

RightTopCorner.png

RightBottomCorner.png

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Hi Lorthiz,

Thanks for letting us know. I've reproduced this here and I believe there is a fault in both saving and loading the TGA. For example opening a TGA saved in Photoshop will display 1 inverted pixel as well! I will get it passed on to development.

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