Always update transform when setting angle of a TextItem (#970)

* Always update transform when setting angle of a TextItem

* Add test to check TextItem.setAngle

* Relax test a bit but still check that setAngle has an effect

* Add docstring to setAngle

* Remove unneeded numpy testing function imports

pyqtgraph/graphicsItems/TextItem.py

@@ -110,9 +110,16 @@ class TextItem(GraphicsObject):
         self.updateTextPos()
         
     def setAngle(self, angle):
+        """
+        Set the angle of the text in degrees.
+
+        This sets the rotation angle of the text as a whole, measured
+        counter-clockwise from the x axis of the parent. Note that this rotation
+        angle does not depend on horizontal/vertical scaling of the parent.
+        """
         self.angle = angle
-        self.updateTransform()
-        
+        self.updateTransform(force=True)
+
     def setAnchor(self, anchor):
         self.anchor = Point(anchor)
         self.updateTextPos()
@@ -169,7 +176,7 @@ class TextItem(GraphicsObject):
             p.setRenderHint(p.Antialiasing, True)
             p.drawPolygon(self.textItem.mapToParent(self.textItem.boundingRect()))
         
-    def updateTransform(self):
+    def updateTransform(self, force=False):
         # update transform such that this item has the correct orientation
         # and scaling relative to the scene, but inherits its position from its
         # parent.
@@ -181,7 +188,7 @@ class TextItem(GraphicsObject):
         else:
             pt = p.sceneTransform()
         
-        if pt == self._lastTransform:
+        if not force and pt == self._lastTransform:
             return
 
         t = pt.inverted()[0]

pyqtgraph/graphicsItems/tests/test_TextItem.py

@@ -0,0 +1,23 @@
+import pytest
+import pyqtgraph as pg
+
+app = pg.mkQApp()
+
+
+def test_TextItem_setAngle():
+    plt = pg.plot()
+    plt.setXRange(-10, 10)
+    plt.setYRange(-20, 20)
+    item = pg.TextItem(text="test")
+    plt.addItem(item)
+
+    t1 = item.transform()
+
+    item.setAngle(30)
+    app.processEvents()
+
+    t2 = item.transform()
+
+    assert t1 != t2
+    assert not t1.isRotating()
+    assert t2.isRotating()