Hi Olivier,

There is nothing scaling inside!
The command

I_CANVAS 0 , 0 , 200 , 200

creates a canvas of 200 x 200 pixels (on the dialog)
Then for example a command:
id=1000
I_POLY 5 , id ,
0 , 0 ,
100 , 0 ,
100 , 100 ,
0 , 100 ,
0 , 0

->creates a box on this canvas. (Dimensions are also in pixels!)
Result -> see test.png

The only thing you have to keep in mind:
On the dialog, the Y-Direction is downwards ! That means the origin (0,0) of the dialog
(and also of the canvas) is the upper left corner!

You can zoom into the drawing on the canvas with the mouse wheel, and reset
to entire with double click of middle mouse button inside the canvas.

If you click to an item, the you get the id as GLOB_BUTTON_ID, and can
react to this inside the parameter script with:

if GLOB_UI_BUTTON_ID=1000 THEN
... !do something
ENDIF

Regards Jörg