Transparency / alpha channel

This tool is really cool! The UX is a lot better than TiledGGD (that tool uses hotkeys and / or nested menus). However, one thing that TiledGGD has that this program does not is transparency / an alpha channel. I understand that this tool is probably for viewing images that don't have transparency, and that I'm meant to use something else to extract the actual image data, but it would be cool if transparency was added.

[bbbradsmith]

If you are using a BPP low enough to support a palette, you can click on palette 0 or 255 or whatever the transparent one should be and set it to some contrasting colour (e.g. 255,0,255 magenta), or the same as the background colour.

If you're looking at RGB32 specifically, or otherwise want a blend of transparency, I can't think of any simple intuitive option for this. Currently you can redirect the bits to another channel if you want to visualize it with a colour, I suppose. So, what kind of display/UI would you propose for this? We could perhaps implement blending with the chosen background, or would you want some sort of checkerboard 2-tone background option? It might be a little confusing what you're looking at, depending if it was ARGB or RGBA or different endian...

Another question is whether this is wanted for BPP low enough to support a palette? I don't think there are standard winforms colour controls that support an alpha, so at that point we'd need some customized colour picker UI too?

So... theoretically it could support this but I'm not sure what direction would be useful. I guess the most pertinent question is what are you using it for that would benefit from this? Like, for the original purpose of data format discovery I think transparency would just add confusion about what we're looking at. However, if the purpose is to look at a known format, that isn't an issue.

Well, I am trying to extract sprites from a video game. I don't know the exact format of the images, but with TiledGGD I was able to get the sprites to look correct (though I'm not sure if they are actually correct) by selecting the correct offset for the palette in the sprite and setting it up so that each color was 4 bytes and in RGBA order. I couldn't find any option to do that here, and right clicking on a pixel at the end doesn't give me the right colors for the palette.

I guess what I'm trying to extract from doesn't use a standard format. It's a mobile game for Android. I don't really know much about binary files, so I just adjusted numbers until the sprites looked okay. So transparency isn't represented by a single color in the palette, but it's on every color in the palette. All colors except one are fully opaque, but I'm not sure how to tell Binxel to skip every fourth byte when making the color palette from the image.

[bbbradsmith]

If you set BPP to 24 and then turn off "auto" for the Pixel size and set it to 4 bytes instead of 3, you can get RGBA with the A ignored. Alternatively, do the same and advance 1 byte forward in the position to get ARGB with the A ignored.

Maybe it would be worth adding 2 presets to cover those two cases, since they're both common.

Though, yes this has the problem that the A channel is ignored... very likely the transparent pixels will be indistinguishable from black. To solve that, I think we'd need something like described in my first reply, though I'm open to other ideas if you can think of something simpler.

Unfortunately I don't think setting BPP to 24 works for my image. I set it to 8 in order to get the image to be the right size, so setting it to 24 just makes the image too small, it seems. And the image is mostly black as well. However, it does look like the colors at the end of the image are sort of correct... I mean that they are wrong, but they match what colors I get when I set the palette to ABGR order instead of RGBA order in TiledGDD. I tried playing around with other settings but I couldn't get the palette to match.

It's fine if you don't feel the need to add support for an alpha channel into your project 👍 I doubt the files I'm looking at are in any kind of standard format, so it wouldn't be much use to add support for one type of file from one game.