Question

I am using the matplotlib PatchCollection to hold a bunch of matplotlib.patches.Rectangles. But I want them to be invisible when first drawn (only turn visible when something else is clicked). This works fine when I was drawing the Rectangle’s straight to the canvas with add_artist, but I want to change this to using a PatchCollection. For some reason, when I create the PatchCollection and add it with add_collection, they are all visible.

self.plotFigure = Figure()
self.plotAxes = self.plotFigure.add_subplot(111)

self.selectionPatches = []
for node in self.nodeList:
    node.selectionRect = Rectangle((node.posX - node.radius*0.15 , node.posY - node.radius*0.15),
                                    node.radius*0.3,
                                    node.radius*0.3,
                                    linewidth = 0,
                                    facecolor = mpl.colors.ColorConverter.colors['k'],
                                    zorder = z,
                                    visible = False)
    self.selectionPatches.append(node.selectionRect)

self.p3 = PatchCollection(self.selectionPatches, match_original=True)
self.plotAxes.add_collection(self.p3)

If I iterate through self.selectionPatches and print out each Rectangle’s get_visible(), it returns false. But they are clearly visible when they get drawn. If anyone can help me see why this is happening, I would be very grateful.

Answer 1

When you create a PatchCollection it extracts a whole bunch of information from the objects you hand in (shape, location, styling(if you use match_original)), but does not keep the patch objects around for later reference (so it discards the per-patch visible). If you want all of the rectangles to be visible/invisible together you can do

self.p3 = PatchCollection(self.selectionPatches, 
                          match_original=True, 
                          visible=False)

other wise I think you will have to group them into the sets you want to appear together.

Look at the __init__ function of PatchCollection(here) and the rest of the cascade up through Collection and Artist.