Mid-way through overhaul. Proposed code path looks like:

    setRange -> updateViewRange -> matrix dirty
                            -> sigRangeChanged

    ... -> prepareForPaint -> updateAutoRange, updateMatrix if dirty

pyqtgraph/graphicsItems/GraphicsObject.py

@@ -12,6 +12,7 @@ class GraphicsObject(GraphicsItem, QtGui.QGraphicsObject):
     """
     _qtBaseClass = QtGui.QGraphicsObject
     def __init__(self, *args):
+        self.__inform_view_on_changes = True
         QtGui.QGraphicsObject.__init__(self, *args)
         self.setFlag(self.ItemSendsGeometryChanges)
         GraphicsItem.__init__(self)
@@ -20,7 +21,7 @@ class GraphicsObject(GraphicsItem, QtGui.QGraphicsObject):
         ret = QtGui.QGraphicsObject.itemChange(self, change, value)
         if change in [self.ItemParentHasChanged, self.ItemSceneHasChanged]:
             self.parentChanged()
-        if change in [self.ItemPositionHasChanged, self.ItemTransformHasChanged]:
+        if self.__inform_view_on_changes and change in [self.ItemPositionHasChanged, self.ItemTransformHasChanged]:
             self.informViewBoundsChanged()
             
         ## workaround for pyqt bug:

pyqtgraph/graphicsItems/tests/ViewBox.py

@@ -15,41 +15,58 @@ ViewBox test cases:
 
 import pyqtgraph as pg
 app = pg.mkQApp()
-win = pg.GraphicsWindow()
-vb = win.addViewBox(name="image view")
-vb.setAspectLocked()
-p1 = win.addPlot(name="plot 1")
-p2 = win.addPlot(name="plot 2", row=1, col=0)
-win.ci.layout.setRowFixedHeight(1, 150)
-win.ci.layout.setColumnFixedWidth(1, 150)
 
-def viewsMatch():
-    r0 = pg.np.array(vb.viewRange())
-    r1 = pg.np.array(p1.vb.viewRange()[1])
-    r2 = pg.np.array(p2.vb.viewRange()[1])
-    match = (abs(r0[1]-r1) <= (abs(r1) * 0.001)).all() and (abs(r0[0]-r2) <= (abs(r2) * 0.001)).all()
-    return match
-
-p1.setYLink(vb)
-p2.setXLink(vb)
-print "link views match:", viewsMatch()
-win.show()
-print "show views match:", viewsMatch()
 imgData = pg.np.zeros((10, 10))
-imgData[0] = 1
-imgData[-1] = 1
-imgData[:,0] = 1
-imgData[:,-1] = 1
-img = pg.ImageItem(imgData)
-vb.addItem(img)
-p1.plot(x=imgData.sum(axis=0), y=range(10))
-p2.plot(x=range(10), y=imgData.sum(axis=1))
-print "add items views match:", viewsMatch()
-#p1.setAspectLocked()
-#grid = pg.GridItem()
-#vb.addItem(grid)
+imgData[0] = 3
+imgData[-1] = 3
+imgData[:,0] = 3
+imgData[:,-1] = 3
+
+def testLinkWithAspectLock():
+    global win, vb
+    win = pg.GraphicsWindow()
+    vb = win.addViewBox(name="image view")
+    vb.setAspectLocked()
+    vb.enableAutoRange(x=False, y=False)
+    p1 = win.addPlot(name="plot 1")
+    p2 = win.addPlot(name="plot 2", row=1, col=0)
+    win.ci.layout.setRowFixedHeight(1, 150)
+    win.ci.layout.setColumnFixedWidth(1, 150)
+
+    def viewsMatch():
+        r0 = pg.np.array(vb.viewRange())
+        r1 = pg.np.array(p1.vb.viewRange()[1])
+        r2 = pg.np.array(p2.vb.viewRange()[1])
+        match = (abs(r0[1]-r1) <= (abs(r1) * 0.001)).all() and (abs(r0[0]-r2) <= (abs(r2) * 0.001)).all()
+        return match
 
+    p1.setYLink(vb)
+    p2.setXLink(vb)
+    print "link views match:", viewsMatch()
+    win.show()
+    print "show views match:", viewsMatch()
+    img = pg.ImageItem(imgData)
+    vb.addItem(img)
+    vb.autoRange()
+    p1.plot(x=imgData.sum(axis=0), y=range(10))
+    p2.plot(x=range(10), y=imgData.sum(axis=1))
+    print "add items views match:", viewsMatch()
+    #p1.setAspectLocked()
+    #grid = pg.GridItem()
+    #vb.addItem(grid)
+    pg.QtGui.QApplication.processEvents()
+    pg.QtGui.QApplication.processEvents()
+    #win.resize(801, 600)
 
+def testAspectLock():
+    global win, vb
+    win = pg.GraphicsWindow()
+    vb = win.addViewBox(name="image view")
+    vb.setAspectLocked()
+    img = pg.ImageItem(imgData)
+    vb.addItem(img)
+    
+    
 #app.processEvents()
 #print "init views match:", viewsMatch()
 #p2.setYRange(-300, 300)
@@ -72,3 +89,7 @@ print "add items views match:", viewsMatch()
 #win.resize(600, 100)
 #app.processEvents()
 #print vb.viewRange()
+
+
+if __name__ == '__main__':
+    testLinkWithAspectLock()