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Merge pull request #840 from OE-FET/patch-3

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Clipping: don't assume that x-values have uniform spacing
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Ogi Moore 2019-06-26 22:29:31 -07:00 committed by GitHub
commit 7f327329f4
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2 changed files with 39 additions and 4 deletions
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21
pyqtgraph/graphicsItems/PlotDataItem.py
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@ -542,13 +542,26 @@ class PlotDataItem(GraphicsObject):
if self.opts['clipToView']:
view = self.getViewBox()
if view is None or not view.autoRangeEnabled()[0]:
# this option presumes that x-values have uniform spacing
# this option presumes that x-values are in increasing order
range = self.viewRect()
if range is not None and len(x) > 1:
# clip to visible region extended by downsampling value, assuming
# uniform spacing of x-values, has O(1) performance
dx = float(x[-1]-x[0]) / (len(x)-1)
# clip to visible region extended by downsampling value
x0 = np.clip(int((range.left()-x[0])/dx)-1*ds , 0, len(x)-1)
x1 = np.clip(int((range.right()-x[0])/dx)+2*ds , 0, len(x)-1)
x0 = np.clip(int((range.left()-x[0])/dx) - 1*ds, 0, len(x)-1)
x1 = np.clip(int((range.right()-x[0])/dx) + 2*ds, 0, len(x)-1)
# if data has been clipped too strongly (in case of non-uniform
# spacing of x-values), refine the clipping region as required
# worst case performance: O(log(n))
# best case performance: O(1)
if x[x0] > range.left():
x0 = np.searchsorted(x, range.left()) - 1*ds
x0 = np.clip(x0, a_min=0, a_max=len(x))
if x[x1] < range.right():
x1 = np.searchsorted(x, range.right()) + 2*ds
x1 = np.clip(x1, a_min=0, a_max=len(x))
x = x[x0:x1]
y = y[x0:x1]

22
pyqtgraph/graphicsItems/tests/test_PlotDataItem.py
View File

@ -64,3 +64,25 @@ def test_clear_in_step_mode():
c = pg.PlotDataItem([1,4,2,3], [5,7,6], stepMode=True)
w.addItem(c)
c.clear()
def test_clipping():
y = np.random.normal(size=150)
x = np.exp2(np.linspace(5, 10, 150)) # non-uniform spacing
w = pg.PlotWidget(autoRange=True, downsample=5)
c = pg.PlotDataItem(x, y)
w.addItem(c)
w.show()
c.setClipToView(True)
w.setXRange(200, 600)
for x_min in range(100, 2**10 - 100, 100):
w.setXRange(x_min, x_min + 100)
xDisp, _ = c.getData()
vr = c.viewRect()
assert xDisp[0] <= vr.left()
assert xDisp[-1] >= vr.right()