Hi all,
I'm trying to write some code that will allow me to paint on an image in
different colors and I'm very confused about how to go about it. ImageItem
does implement a small drawing example but as I want to extend the
functionality further the ImageItem-draw example script has been of little
help.
Basically I need access to mouse click and mouse drag events on an
imageItem. I thought that grabbing the scene and connecting
sigMouseClicked would give me access to that, but I have no idea how to
interpret either the evt.pos() or evt.scenePos() points it returns. I have
an ImageItem inside a PlotItem so I have axes for the image, and the points
returned do not correspond at all to where I am clicking.
I've additionally tried to make a new class inheriting ImageItem, but
overwriting the mouseClick and mouseDrag events don't seem to work.
I'm overall very confused about where the mousedrag and mouseclick events
for things like dragging and scaling the scene are even handled? It
doesn't seem to be in pg.GraphicsItem/etc. This is important because I
want to be able to paint on an image and drag it still (maybe by
shift-dragging instead of just dragging, which would draw to the screen)?
Any advice or insight anyone could give me on this would be greatly
appreciated.
Example code:
def paintOn(evt):
global img
pos = evt.pos()
if evt.button() == QtCore.Qt.LeftButton:
x, y = (int(pos.x()), int(pos.y()))
print(pos)
print(evt.scenePos())
w, h, _ = img.image.shape
#x = x - h
#y = y-h
imcopy = img.image.copy()
imcopy[y-10:y+10, x-10:x+10, :] = [255, 255, 255]
img.setImage(imcopy, autoLevels=False)
# Interpret image data as row-major instead of row-major
pg.setConfigOptions(imageAxisOrder='row-major')
app = pg.mkQApp() #alias for QtGui.QApplication([])
## Create window with ImageView widget
win = pg.GraphicsLayoutWidget()
win.setWindowTitle('Watershed')
win.show()
## Add a PlotItem
p1 = win.addPlot()
# an ImageItem then goes in the viewbox to display an image
img = pg.ImageItem()
p1.addItem(img)
## Initially display the first frame
img.setImage(np.zeros((100, 100, 3)))
## make the image the correct orientation
## only have to do this once
img.getViewBox().invertY(True)
#get the scene of the imag
sc = img.scene()
sc.sigMouseClicked.connect(paintOn)
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