Windows
One window
A sketch that never opens a window gets one of 800 by 600. window opens one of your choice, with its settings as words:
window size 400 300 title "garden" resizable falsebackground navycircle at 200 150 radius 60 fill gold
Other settings are at (where on the screen), bordered, topmost, fullscreen, alpha (how solid the whole window is), smallest and largest (size limits), ratio, cursor none, and more; the window page lists them all. width and height are the size of the window the code runs in.
Changing a window that is open
A window is read as a record of its settings, and changed with set and the same words:
w = window size 400 300on key "1" [ set w size 400 300 ]on key "2" [ set w size 640 480 ]on key "t" [ set w topmost (not w.topmost) ]draw w [ background 240 circle at (w.width / 2) (w.height / 2) radius 40]Some settings are only a request on some systems: a window manager may decide where a window goes, for example.
Several windows
Each window gets its own draw block, named after the window:
palette = window size 200 200 title "palette"canvas = window size 400 300 title "canvas"draw palette [ background tomato ]draw canvas [ background 240 circle at mouse radius 20]on can name a window too: on canvas key "space" [ ... ] runs only for keys pressed in that window.
Sending values between windows
send puts a value in another window’s post, and on window receive name takes it, a frame later:
control = window size 200 150 title "control"canvas = window size 400 300 title "canvas"spot = { 200, 150 }on control mouse down [ send canvas { at: mouse * 2 } ]on canvas receive message [ spot = message.at ]draw canvas [ background 30 circle at spot radius 20 fill gold]A message is copied on the way, so the two windows never share a list or record.