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An empty Canvas isn't much. All it shows is the title.
CanvasObject is used as an intelligent container for other robotic simulation objects. In itself, it does nothing.
CanvasObject.tcl can be used anywhere a group of managable objects will be instanciated. A prime example of this is an array of LEDs.
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An empty Canvas isn't much. All it shows is the title. |
There are several proc[eedures] in CanvasObject.tcl. We are interested in three of them.
proc Canvas_new { {CanvasObject} {NameOfCanv} {canvcolor}
{textcolor} {title} } \
{
# CanvasObject = Unique name for the canvas object.
# NameOfCanv = Graphical name of object.
# canvcolor = Color of the background.
# textcolor = Color of the title.
# title = Text that shows in the canvas.
The parameters CanvasName and NameOnCanv are constants.
proc Canvas_IncludeObject { {CanvasObject} {objecthandler} {objectname} } \
{
# CanvasObject = Name for this canvas object.
# objecthandler = Method for updating $objectname.
# objectname = name of object to update.
Once you have created a CanvasObject using Canvas_new, you can hand it objects to manage. That is done with Canvas_IncludeObject. Objecthandler is a statement that will update the object. Usually it is little more than "ThisThing_update MyObject".
# Update all objects that have been registered for CanvasObject.
proc Canvas_UpdateAll { {CanvasObject} } \
{
# CanvasObject = Name for this canvas object.
When Canvas_UpdateAll is called, it calls each of the objecthandlers for the objects it has been asked to manage.
First we declare a CanvasObject using Canvas_new.
set canvasname [Canvas_new led .oper_interf.left \
{#7f6f7f} {#000000} {Led Monitor}]
We can now declare one or more objects to be managed by it.
set labelname [Canvas_IncludeObject led Led_Update green0But]
Led_new green0But $labelname {$::LED_byte1 & 0x01} 7 3 "#00ff00" "#006000"
pack $labelname -side top
The object to managed is green0But. It's objecthandler is Led_Update.
Canvas_UpdateAll led
When Canvas_UpdateAll is called for this canvas object (here named led), it will call each objecthandler for each object. In this example there is only one object. So a single call is made:
Led_Update green0But
None.