Difference between revisions of "Code snippets"

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(Observing mouse events in the 3D viewer via Python)
(Observing mouse events in the 3D viewer via Python)
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The following event types are supported
 
The following event types are supported
SoEvent -- all kind of events
+
* SoEvent -- all kind of events
SoButtonEvent -- all mouse and button events
+
* SoButtonEvent -- all mouse and button events
SoLocation2Event -- all 2D movement events (normally mouse movements)
+
* SoLocation2Event -- all 2D movement events (normally mouse movements)
SoMotion3Event -- all 3D movement events (normally spaceball)
+
* SoMotion3Event -- all 3D movement events (normally spaceball)
SoKeyboradEvent -- all keyboard down and up events
+
* SoKeyboradEvent -- all keyboard down and up events
SoMouseButtonEvent -- all mouse button down and up events
+
* SoMouseButtonEvent -- all mouse button down and up events
SoSpaceballButtonEvent -- all spaceball button down and up events
+
* SoSpaceballButtonEvent -- all spaceball button down and up events
  
 
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Revision as of 11:07, 5 October 2007

This page contains examples, pieces, chunks of FreeCAD python code collected from users experiences and discussions on the forums. Read and use it as a start for your own scripts...


A typical InitGui.py file

Every module must contain, besides your main module file, an InitGui.py file, responsible for inserting the module in the main Gui. This is an example of a simple one.

class ScriptWorkbench ( Workbench ): 
	def Activate(self): 
		try: 
			import Scripts # assuming Scripts.py is your module
			if Gui.HasWorkbench('Scripts') == False:
				w = Gui.CreateWorkbench('Scripts') 
				list = ["Script_Cmd"] # That list must contain command names, that can be defined in Scripts.py
				w.AppendToolbar("My Scripts",list) 
		except: 
			raise 
	def GetClassName(self): 
		return "Gui::PythonWorkbench" 


Gui.AddWorkbenchHandler("Scripts",ScriptWorkbench())

A typical module file

This is an example of a main module file, containing everything your module does. It is the Scripts.py file invoked by the previous example. You can have all your custom commands here.

import FreeCAD, FreeCADGui 

class ScriptCmd: 
	def Activated(self): 
		# Here your write what your ScriptCmd does...
		FreeCAD.PrintMessage("Hello, World!\n")
	def GetResources(self): 
		return {'Pixmap' : 'path_to_an_icon/myicon.png', 'MenuText': 'Short text', 'ToolTip': 'More detailed text'} 


FreeCADGui.AddCommand('Script_Cmd', ScriptCmd())

Import a new filetype

Making an importer for a new filetype in FreeCAD is easy. FreeCAD doesn't consider that you import data in an opened document, but rather that you simply can directly open the new filetype. So what you need to do is to add the new file extension to FreeCAD's list of known extensions, and write the code that will read the file and create the FreeCAD objects you want:

This line must be added to the InitGui.py file to add the new file extension to the list:

# Assumes Import_Ext.py is the file that has the code for opening and reading .ext files
FreeCAD.EndingAdd("Your new File Type (*.ext)","Import_Ext") 

Then in the Import_Ext.py file:

def open(filename): 
	doc=App.newDocument()
	# here you do all what is needed with filename, read, classify data, create corresponding FreeCAD objects
	doc.recompute()

Adding a line

A line simply has 2 points.

import Part,PartGui 
doc=App.activeDocument() 
# add a line element to the document and set its points 
l=doc.addObject("Part::Line","Line") 
l.b=(0.0,0.0,0.0) 
l.e=(1.0,1.0,1.0)
doc.recompute()

Adding a polygon

A polygon is simply a set of connected line segments (a polyline in AutoCAD). It doesn't need to be closed.

import Part,PartGui 
doc=App.activeDocument()
n=list() 
# create a 3D vector, set its coordinates and add it to the list 
v=App.Vector() 
v.set(0,0,0) 
n.append(v) 
v=App.Vector() 
v.set(10,0,0) 
n.append(v) 
#... repeat for all nodes 
# Create a polygon object and set its nodes 
p=doc.addObject("Part::Polygon","Polygon") 
p.Nodes=n 
doc.recompute()

Adding an object to a group

doc=App.activeDocument() 
grp=doc.addObject("App::DocumentObjectGroup", "Group") 
l=grp.addObject("Part::Line", "Line") 
l.b=(0,0,0) 
l.e=(0,0,5) 
doc.recompute()

Adding a Mesh

import Mesh
doc=App.activeDocument()
# create a new empty mesh
m = Mesh.mesh()
# build up box out of 12 facets
m.addFacet(0.0,0.0,0.0, 0.0,0.0,1.0, 0.0,1.0,1.0)
m.addFacet(0.0,0.0,0.0, 0.0,1.0,1.0, 0.0,1.0,0.0)
m.addFacet(0.0,0.0,0.0, 1.0,0.0,0.0, 1.0,0.0,1.0)
m.addFacet(0.0,0.0,0.0, 1.0,0.0,1.0, 0.0,0.0,1.0)
m.addFacet(0.0,0.0,0.0, 0.0,1.0,0.0, 1.0,1.0,0.0)
m.addFacet(0.0,0.0,0.0, 1.0,1.0,0.0, 1.0,0.0,0.0)
m.addFacet(0.0,1.0,0.0, 0.0,1.0,1.0, 1.0,1.0,1.0)
m.addFacet(0.0,1.0,0.0, 1.0,1.0,1.0, 1.0,1.0,0.0)
m.addFacet(0.0,1.0,1.0, 0.0,0.0,1.0, 1.0,0.0,1.0)
m.addFacet(0.0,1.0,1.0, 1.0,0.0,1.0, 1.0,1.0,1.0)
m.addFacet(1.0,1.0,0.0, 1.0,1.0,1.0, 1.0,0.0,1.0)
m.addFacet(1.0,1.0,0.0, 1.0,0.0,1.0, 1.0,0.0,0.0)
# scale to a edge langth of 100
m.scale(100.0)
# add the mesh to the active document
me=doc.addObject("Mesh::Feature","Cube")
me.Mesh=m
doc.recompute()

Adding an arc or a circle

import Part
doc = App.activeDocument()
c = Part.circle() # create a circle object with undefined radius 
c.setRadius(10)  
f = doc.addObject("Part::Circle", "Circle") # create a document with a circle feature 
f.Circ = c # Assign the circle object to the Circ property 
doc.recompute()

Accessing and changing representation of an object

Each object in a FreeCAD document has an associated view representation object that stores all the parameters that define how the object appear, like color, linewidth, etc...

gad=Gui.activeDocument()   # access the active document containing all 
                           # view representations of the features in the
                           # corresponding App document 

v=gad.getObject("Cube")    # access the view representation to the Mesh feature 'Cube' 
v.ShapeColor               # prints the color to the console 
v.ShapeColor=(1.0,1.0,1.0) # sets the shape color to white

Observing mouse events in the 3D viewer via Python

The Inventor framework allows to add one or more callback nodes to the scenegraph of the viewer. By default in FreeCAD one callback node is installed per viewer which allows to add global or static C++ functions. In the appropriate Python binding some methods are provided to make use of this technique from within Python code.

App.newDocument()
v=Gui.activeDocument().activeView()

#This class logs any mouse button events. As the registered callback function fires twice for 'down' and
#'up' events we need a boolean flag to handle this.
class ViewObserver:
	down=True
	def logPosition(self, x, y):
		if (self.down):
			FreeCAD.PrintMessage("Clicked on position: ("+str(x)+", "+str(y)+")\n")
		self.down = not self.down


o = ViewObserver()
c = v.addEventCallback("SoMouseButtonEvent",o.logPosition)

Now, pick somewhere on the area in the 3D viewer and observe the messages in the output window. To finish the observation just call

v.removeEventCallback("SoMouseButtonEvent",c)

The following event types are supported

  • SoEvent -- all kind of events
  • SoButtonEvent -- all mouse and button events
  • SoLocation2Event -- all 2D movement events (normally mouse movements)
  • SoMotion3Event -- all 3D movement events (normally spaceball)
  • SoKeyboradEvent -- all keyboard down and up events
  • SoMouseButtonEvent -- all mouse button down and up events
  • SoSpaceballButtonEvent -- all spaceball button down and up events