I wish I heard about locate() a few days ago as it would have greatly
simplified this troubleshooting process... Thanks for the tip!
The final step was indeed to subclass measureSpotSizes. It's a shame so
much was copy-pasted from the base method, but at least it works:
class CustScatter(pg.ScatterPlotItem):
def pointsAt(self, pos: QtCore.QPointF):
"""
The default implementation only checks a square around each spot.
However, this is not
precise enough for my needs. It also triggers when clicking *inside*
the spot boundary,
which I don't want.
"""
pts = []
for spot in self.points(): # type: pg.SpotItem
symb = QtGui.QPainterPath(spot.symbol())
symb.translate(spot.pos())
stroker = QtGui.QPainterPathStroker()
mousePath = stroker.createStroke(symb)
# Only trigger when clicking a boundary, not the inside of the shape
if mousePath.contains(pos):
pts.append(spot)
return pts[::-1]
def measureSpotSizes(self, dataSet):
for rec in dataSet:
## keep track of the maximum spot size and pixel size
symbol, size, pen, brush = self.getSpotOpts(rec)
br = symbol.boundingRect()
size = max(br.width(), br.height())*2
width = 0
pxWidth = 0
if self.opts['pxMode']:
pxWidth = size + pen.widthF()
else:
width = size
if pen.isCosmetic():
pxWidth += pen.widthF()
else:
width += pen.widthF()
self._maxSpotWidth = max(self._maxSpotWidth, width)
self._maxSpotPxWidth = max(self._maxSpotPxWidth, pxWidth)
self.bounds = [None, None]Enter code here...
On Sunday, June 7, 2020 at 11:04:29 PM UTC-4, Patrick wrote:
>
> Hi,
>
> As a guess, I'm thinking that your CustScatter is still only assuming the
> scatter plot points are just points with width the size of the pen width
> (see measureSpotSizes in ScatterPlotItem). You may need to override that
> method to calculate the shape sizes.
>
> Also, in the past I stumbled across the locate method of ViewBox
> <https://pyqtgraph.readthedocs.io/en/latest/graphicsItems/viewbox.html#pyqtgraph.ViewBox.locate>
>
> which has helped diagnosing problems like this, maybe it's useful to try
> here too.
>
> Patrick
>
> On Monday, 8 June 2020 12:06:30 UTC+9:30, Nathan Jessurun wrote:
>>
>> Attempt number 3: I almost have it doing what I want! I looked at what
>> PlotCurveItem does to make the curveClicked signal, and saw I had to make a
>> stroke path.
>>
>> The *last* piece of the puzzle is how to inform the graphics handler
>> that my spot size extends a bit beyond the natural bounding rect. Does
>> anyone know of a way to make this happen? I.e. the programming logic works,
>> but the check for self.itemsNearEvent() in the graphics scene fails for
>> a click near the top-right shape.
>> import pyqtgraph as pg
>> from pyqtgraph.Qt import QtWidgets, QtCore, QtGui
>> import numpy as np
>>
>> class CustScatter(pg.ScatterPlotItem):
>> def pointsAt(self, pos: QtCore.QPointF):
>> # if isinstance(pos, QtCore.QPointF):
>> # halfSz = 0.25
>> # pos = QtCore.QRectF(pos.x()-halfSz, pos.y()-halfSz, 2*halfSz,
>> 2*halfSz)
>> pts = []
>> for spot in self.points(): # type: pg.SpotItem
>> symb = QtGui.QPainterPath(spot.symbol())
>> symb.translate(spot.pos())
>> stroker = QtGui.QPainterPathStroker()
>> mousePath = stroker.createStroke(symb)
>> if mousePath.contains(pos):
>> pts.append(spot)
>> return pts[::-1]
>>
>> tri = np.array([[0,2.3,0,1,4,5,0], [0,4,4,8,8,3,0]]).T
>> tris = []
>> xyLocs = []
>> datas = []
>> for ii in np.arange(0, 16, 5):
>> curTri = tri + ii
>> tris.append(curTri)
>> xyLocs.append(curTri.min(0))
>> datas.append(ii)
>>
>> def ptsClicked(item, pts):
>> print(f'ID {pts[0].data()} Clicked!')
>>
>> def makeSymbol(verts: np.ndarray):
>> outSymbol = QtGui.QPainterPath()
>> symPath = pg.arrayToQPath(*verts.T)
>> outSymbol.addPath(symPath)
>> # From pyqtgraph.examples for plotting text
>> br = outSymbol.boundingRect()
>> tr = QtGui.QTransform()
>> tr.translate(-br.x(), -br.y())
>> outSymbol = tr.map(outSymbol)
>> return outSymbol
>>
>> app = pg.mkQApp()
>> pg.setConfigOption('background', 'w')
>>
>> symbs = []
>> for xyLoc, tri in zip(xyLocs, tris):
>> symbs.append(makeSymbol(tri))
>>
>> xyLocs = np.vstack(xyLocs)
>> tri2 = pg.PlotDataItem()
>> scat = CustScatter(*xyLocs.T, symbol=symbs, data=datas, connect='finite',
>> pxMode=False, brush=None, pen=pg.mkPen(width=5), size=
>> 1)
>> scat.sigClicked.connect(ptsClicked)
>> # Now each 'point' is one of the triangles, hopefully
>>
>> w = pg.PlotWindow()
>> w.plotItem.addItem(scat)
>> plt: pg.PlotItem = w.plotItem
>> plt.showGrid(True, True, 1)
>> w.show()
>> app.exec()
>>
>>
>>
>>
>> On Saturday, June 6, 2020 at 9:44:36 PM UTC-4, Nathan Jessurun wrote:
>>>
>>> Hi there,
>>>
>>> My overall goal is to have several clickable regions overlaid on an
>>> image, and if the plot boundary of any region is clicked I get a signal
>>> with the ID of that region. Something like this:
>>> I tried making each boundary a separate plot data item, but I have 1000s
>>> of bounds that update frequently so it lagged a ton. So, I just used
>>> connect='finite' within the same plot item to make it much faster.
>>>
>>> However, now I can't give a separate ID to each boundary. I have to make
>>> the vertices stand out, and connect to sigclicked(...pts) instead:
>>>
>>> This works, but I'd love to be able to click anywhere on one of the line
>>> segments for the same effect. Is there any way to make this happen?
>>>
>>> Relevant code is just a PlotDataItem on a plot widget.
>>>
>>> Thanks!
>>>
>>
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