Hello everyone,
I'm writing an application which displays a series of parallel graphs,
all packed in one window.
There is a main graph drawn by a gtk.DrawingArea inheriting class.
There are several other graphs, each of them, inheriting the main graph
class, overriding the
data feed and draw methods.
I created a graphic cursor which tracks the mouse movement when it is on
any of the graphs.
What I want to achieve is a situation where the cursor is updated to the
same position in all
the graphs (all cursors follow the mouse position, no matter where the
mouse is hovering).
My idea was to connect with the mouse movement event and emit a signal
which will update
the cursor movement.
Eventually - it works, but only in the graph in which the mouse is in.
It does not propagate to
the other graphs.
Here are the relevant parts of the code:
class priceGraph(gtk.DrawingArea):
# Define a new signal - 'data_cursor_moved'
__gsignals__ = {'data_cursor_moved' :(gobject.SIGNAL_ACTION,
gobject.TYPE_NONE,
(gobject.TYPE_PYOBJECT,))
}
def __init__(self, caller, graphtype = "FULL"):
gtk.DrawingArea.__init__(self)
self.connect("expose_event", self.expose)
self.add_events(gtk.gdk.POINTER_MOTION_MASK|
gtk.gdk.POINTER_MOTION_HINT_MASK)
self.connect("motion_notify_event", self.detectMove)
self.connect("data_cursor_moved", self.handleMove)
<<<rest of init stuff and other methods...>>>
def detectMove(self, widget, event):
self.emit("data_cursor_moved", event)
def handleMove(self, widget, event):
""" Redraw the cursor in the event location """
context = self.window.cairo_create()
widget.queue_draw_area(*self.cursorRect)
context.set_source_rgba(1,0.2,0.3,0.5)
context.set_dash([2,3,2],2)
context.set_line_width(1)
context.move_to(event.x, self.mapY(self.Ymin))
context.line_to(event.x, self.mapY(self.Ymax))
context.stroke()
self.cursorRect =
(int(event.x-2),int(self.mapY(self.Ymax)),4,int(self.mapY(self.Ymin)))
return False
<<< Rest of class methods... lots of stuff...>>>
gobject.type_register(priceGraph)
class stochastics(priceGraph):
"""Class inheriting main graph, overriding loadData and draw
methods"""
<<<.....class stuff>>>
gobject.type_register(stochastics)
Same goes for 4 other similar inheriting classes.
My initial understanding was, that the signal catching of the
"data_cursor_moved" signal
should be inherited by all classes, hence the signal will be caught by
all of them.
This doesn't happen - where am I wrong here?
In the pygtk FAQ 3.11 I read:
"A single signal emission will only call handlers attached to the object
it was emitted on. The propagation of events up the heirachy is acheived
by emitting the signal a number of times."
So isn't an inheriting class instance considered the same object?
I could not properly understand the second sentence about emitting the
signal a number of times.
Is this what should be done? Can anyone give me an example code for
this?
How would you suggest I do that?
Thanks very much in advance,
Ben.
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