extractor.lua

local sprite      = app.activeSprite;
local data_layer  = get_layer(sprite, "Data")
local cel   = data_layer.cels[1]
local image = cel.image
local red_pixel = app.pixelColor.rgba(255, 0, 0)
local origin = nil

print("sprite.width " .. sprite.width)
print("sprite.height " .. sprite.height)
print("image.width " .. image.width)
print("image.height " .. image.height)
print("Looking for " .. red_pixel)

for y = 0, sprite.height - 1 do
    for x = 0, sprite.width - 1 do
        pixel = image:getPixel(x, y)
        print(y .. " " .. x .. " " .. pixel)
        if pixel == red_pixel then
            origin = { x = x, y = y }
        end
    end
end