-- Apply a kind of AA filter on picture
-- Get the picture size
w, h = getpicturesize();
-- Here is the filtering matrix
matrix = {
{ 0, -1, 0 },
{ -1, 5, -1 },
{ 0, -1, 0 }};
-- Loop trough all the pixels
-- To make this script simpler we don't handle the picture borders
-- (the matrix would get pixels outside the picture space)
-- for var = start_value, end_value, step do ...
for y = 1, h - 2, 1 do
for x = 1, w - 2, 1 do
filtered =
matrix[1][1] * getbackuppixel(x - 1, y - 1) +
matrix[1][2] * getbackuppixel(x , y - 1) +
matrix[1][3] * getbackuppixel(x + 1, y - 1) +
matrix[2][1] * getbackuppixel(x - 1, y ) +
matrix[2][2] * getbackuppixel(x , y ) +
matrix[2][3] * getbackuppixel(x + 1, y ) +
matrix[3][1] * getbackuppixel(x - 1, y + 1) +
matrix[3][2] * getbackuppixel(x , y + 1) +
matrix[3][3] * getbackuppixel(x + 1, y + 1);
putpicturepixel(x,y,filtered);
end
end