function META:Fill(callback)
    check(callback, "function")

    local img = self:GetPixelTable(true)
    local w = self:GetSize()
    local x, y = 0, 0

    for i = 0, self:GetPixelLength() do

        if x >= w then
            x = 0
            y = y + 1
        else
            x = x + 1
        end

        local r, g, b, a = callback(x, y, img[i].r, img[i].g, img[i].b, img[i].a)

        img[i].r = r*255 or img[i].r
        img[i].g = g*255 or img[i].g
        img[i].b = b*255 or img[i].b
        img[i].a = a*255 or img[i].a
    end

    self:SetPixelTable(img)
end