Add RulerROI

pyqtgraph/graphicsItems/ROI.py

@@ -2197,3 +2197,31 @@ class CrosshairROI(ROI):
         p.drawLine(Point(-radius, 0), Point(radius, 0))
         
         
+class RulerROI(LineSegmentROI):
+    def paint(self, p, *args):
+        LineSegmentROI.paint(self, p, *args)
+        h1 = self.handles[0]['item'].pos()
+        h2 = self.handles[1]['item'].pos()
+        p1 = p.transform().map(h1)
+        p2 = p.transform().map(h2)
+
+        vec = Point(h2) - Point(h1)
+        length = vec.length()
+        angle = vec.angle(Point(1, 0))
+
+        pvec = p2 - p1
+        pvecT = Point(pvec.y(), -pvec.x())
+        pos = 0.5 * (p1 + p2) + pvecT * 40 / pvecT.length()
+
+        p.resetTransform()
+
+        txt = fn.siFormat(length, suffix='m') + '\n%0.1f deg' % angle
+        p.drawText(QtCore.QRectF(pos.x()-50, pos.y()-50, 100, 100), QtCore.Qt.AlignCenter | QtCore.Qt.AlignVCenter, txt)
+
+    def boundingRect(self):
+        r = LineSegmentROI.boundingRect(self)
+        pxl = self.pixelLength(Point([1, 0]))
+        if pxl is None:
+            return r
+        pxw = 50 * pxl
+        return r.adjusted(-50, -50, 50, 50)