No transparency

[AngReload]

Any GIFs having transparent pixels are decoded as full opaque.
For example: https://upload.wikimedia.org/wikipedia/commons/c/ce/Transparent.gif

#[test]
fn minimal_example() {
    let file = File::open("tests/Transparent.gif").unwrap();
    let mut decoder = gif::Decoder::new(file);

    decoder.set(gif::ColorOutput::Indexed);

    let mut reader = decoder.read_info().unwrap();

    let mut screen = gif_dispose::Screen::new_reader(&reader);
    while let Some(frame) = reader.read_next_frame().unwrap() {
        screen.blit_frame(&frame).unwrap();

        let mut t = "alpha == 255";
        for pixel in screen.pixels.as_ref() {
            if pixel.a != 255 {
                t = "transparent";
            }
        }
        println!("{}", t); // "alpha == 255"
    }
}

[kornelski]

Thanks for the report.

I've assumed that when a GIF has a background color set, it wants to have a background. This image does set background color to index 0.

[kornelski]

For this image I think fe9b8a3 solves it.

I've also found another issue, which I don't know how to solve: image-rs/image-gif#52

[AngReload]

Okay, this only works for the first frame. Looks like we have to wait a decision on the issue gif-crate.