[Image-SIG] image.transform problem

[Fredrik Lundh]

"akonsu" <akonsu at gmail.com> wrote:

> Hello, is there a way to change the colour of the background that is
> output when performing an image transform?
>
> image = Image.new("L", w, h, 0xff)
> ...
> image = image.transform(image.size, Image.QUAD, (0, 0, 0, 2 * h, w -
> 1, h - 1, w - 1, 0))
>
> produces black area at the bottom (or wherever the destination image
> does not correspond to the source image)

in current PIL versions, you have to resort to brute force (which isn't
that bad, really):

    mask = Image.new("1", image.size, 1)

    image = image.transform(... params ...)
    mask = mask.transform(... same params ...)

    out = Image.new(image.mode, image.size, background_color)
    out.paste(image, mask)

(if you're not using NEAREST sampling, you can try using a "L" mask
instead, with the pixels set to 255)

</F>