Scroll 100%

stuff = image.loadsprite("stuff.png",16,16)
dofile("mapa.txt")

scroll={x=0,y=0,w=16,h=16}


function blit_map(x,y,w,h)
x,y,w,h = x or 0, y or 0, w or 16, h or 16
for a = math.max(1,-math.ceil(y/h)), math.min(#mapa,272/h-y/h+1) do
 for b = math.max(1,-math.ceil(x/w)), math.min(#mapa[a],480/w-x/w+1) do
    if tonumber(mapa[a][b]) > 0 then stuff:setframe(tonumber(mapa[a][b])) stuff:resize(w,h) stuff:blit(x+(b-1)*w,y+(a-1)*h) end
 end
 screen.print(5,5,screen.fps().."  "..x..":"..y.." -  "..w..":"..h)
end


end


while true do
controls.read()

blit_map(scroll.x,scroll.y,scroll.w,scroll.h)


if controls.triangle() then scroll.h = scroll.h -0.5 end
if controls.cross() then scroll.h = scroll.h +0.5 end
if controls.circle() then scroll.w = scroll.w +0.5 end
if controls.square() then scroll.w = scroll.w -0.5 end

if controls.start() then scroll={x=0,y=0,w=16,h=16} end

if controls.up() then scroll.y = scroll.y -2 end
if controls.down() then scroll.y = scroll.y +2 end
if controls.right() then scroll.x = scroll.x +2 end
if controls.left() then scroll.x = scroll.x -2 end


if controls.select() then a() end
screen.flip()
end