Merge pull request #1876 from ixjlyons/fix-lineroi-coords

Fix LineROI handle positions

pyqtgraph/graphicsItems/ROI.py

@@ -1676,8 +1676,8 @@ class LineROI(ROI):
         pos2 = Point(pos2)
         d = pos2-pos1
         l = d.length()
-        ra = Point(1, 0).angle(d, units="radians")
-        c = Point(-width/2. * sin(ra), -width/2. * cos(ra))
+        ra = d.angle(Point(1, 0), units="radians")
+        c = Point(width/2. * sin(ra), -width/2. * cos(ra))
         pos1 = pos1 + c
         
         ROI.__init__(self, pos1, size=Point(l, width), angle=degrees(ra), **args)

tests/graphicsItems/test_ROI.py

@@ -6,6 +6,7 @@ import platform
 from pyqtgraph.Qt import QtCore, QtGui, QtTest
 from tests.image_testing import assertImageApproved
 from tests.ui_testing import mouseMove, mouseDrag, mouseClick, resizeWindow
+import math
 
 app = pg.mkQApp()
 pg.setConfigOption("mouseRateLimit", 0)
@@ -251,4 +252,22 @@ def test_PolyLineROI():
         assert len(r.getState()['points']) == 3
     
     plt.hide()
-    
+
+
+@pytest.mark.parametrize("p1,p2", [
+    ((1, 1), (2, 5)),
+    ((0.1, 0.1), (-1, 5)),
+    ((3, -1), (5, -6)),
+    ((-2, 1), (-4, -8)),
+])
+def test_LineROI_coords(p1, p2):
+    pw = pg.plot()
+
+    lineroi = pg.LineROI(p1, p2, width=0.5, pen="r")
+    pw.addItem(lineroi)
+
+    # first two handles are the scale-rotate handles positioned by pos1, pos2
+    for expected, (name, scenepos) in zip([p1, p2], lineroi.getSceneHandlePositions()):
+        got = lineroi.mapSceneToParent(scenepos)
+        assert math.isclose(got.x(), expected[0])
+        assert math.isclose(got.y(), expected[1])