Bugfixes and example for view linking

examples/__main__.py

@@ -19,6 +19,7 @@ examples = OrderedDict([
         ('Scatter Plot', 'ScatterPlot.py'),
         ('Text Item', 'text.py'),
         ('ViewBox', 'ViewBox.py'),
+        ('Linked Views', 'linkedViews.py'),
         ('Arrow', 'Arrow.py'),
     ])),
     ('Widgets', OrderedDict([

examples/linkedViews.py

@@ -0,0 +1,48 @@
+# -*- coding: utf-8 -*-
+
+## This example demonstrates the ability to link the axes of views together
+## Views can be linked manually using the context menu, but only if they are given names.
+
+
+import initExample ## Add path to library (just for examples; you do not need this)
+
+
+from pyqtgraph.Qt import QtGui, QtCore
+import numpy as np
+import pyqtgraph as pg
+
+#QtGui.QApplication.setGraphicsSystem('raster')
+app = QtGui.QApplication([])
+#mw = QtGui.QMainWindow()
+#mw.resize(800,800)
+
+x = np.linspace(-50, 50, 1000)
+y = np.sin(x) / x
+
+win = pg.GraphicsWindow(title="View Linking Examples")
+win.resize(800,600)
+
+win.addLabel("Views linked at runtime:", colspan=2)
+win.nextRow()
+
+p1 = win.addPlot(x=x, y=y, name="Plot1", title="Plot1")
+p2 = win.addPlot(x=x, y=y, name="Plot2", title="Plot2 - Y linked with Plot1")
+p2.setLabel('bottom', "Label to test offset")
+p2.setYLink(p1)
+
+win.nextRow()
+
+p3 = win.addPlot(x=x, y=y, name="Plot3", title="Plot3 - X linked with Plot1")
+p4 = win.addPlot(x=x, y=y, name="Plot4", title="Plot4 - X and Y linked with Plot1")
+p3.setLabel('left', "Label to test offset")
+QtGui.QApplication.processEvents()
+p3.setXLink(p1)
+p4.setXLink(p1)
+p4.setYLink(p1)
+
+
+## Start Qt event loop unless running in interactive mode or using pyside.
+import sys
+if (sys.flags.interactive != 1) or not hasattr(QtCore, 'PYQT_VERSION'):
+    app.exec_()
+

graphicsItems/GraphicsLayout.py

@@ -33,7 +33,6 @@ class GraphicsLayout(GraphicsWidget):
         return self.currentCol-colspan
         
     def addPlot(self, row=None, col=None, rowspan=1, colspan=1, **kargs):
-        from PlotItem import PlotItem
         plot = PlotItem(**kargs)
         self.addItem(plot, row, col, rowspan, colspan)
         return plot
@@ -43,6 +42,11 @@ class GraphicsLayout(GraphicsWidget):
         self.addItem(vb, row, col, rowspan, colspan)
         return vb
         
+    def addLabel(self, text, row=None, col=None, rowspan=1, colspan=1, **kargs):
+        text = LabelItem(text, **kargs)
+        self.addItem(text, row, col, rowspan, colspan)
+        return text
+        
 
     def addItem(self, item, row=None, col=None, rowspan=1, colspan=1):
         if row is None:
@@ -95,3 +99,4 @@ class GraphicsLayout(GraphicsWidget):
 ## Must be imported at the end to avoid cyclic-dependency hell:
 from ViewBox import ViewBox
 from PlotItem import PlotItem
+from LabelItem import LabelItem

graphicsItems/LabelItem.py

@@ -10,12 +10,11 @@ class LabelItem(GraphicsWidget):
     GraphicsWidget displaying text.
     Used mainly as axis labels, titles, etc.
     
-    Note: To display text inside a scaled view (ViewBox, PlotWidget, etc) use QGraphicsTextItem
+    Note: To display text inside a scaled view (ViewBox, PlotWidget, etc) use TextItem
-          with the flag ItemIgnoresTransformations set.
     """
     
     
-    def __init__(self, text, parent=None, **args):
+    def __init__(self, text, parent=None, angle=0, **args):
         GraphicsWidget.__init__(self, parent)
         self.item = QtGui.QGraphicsTextItem(self)
         self.opts = args
@@ -26,6 +25,7 @@ class LabelItem(GraphicsWidget):
                 self.opts['color'] = fn.colorStr(args['color'])[:6]
         self.sizeHint = {}
         self.setText(text)
+        self.setAngle(angle)
         
             
     def setAttr(self, attr, value):

graphicsItems/ViewBox/ViewBox.py

@@ -480,11 +480,13 @@ class ViewBox(GraphicsWidget):
         self.linksBlocked = b  ## prevents recursive plot-change propagation
 
     def linkedXChanged(self):
+        ## called when x range of linked view has changed
         view = self.state['linkedViews'][0]
         self.linkedViewChanged(view, ViewBox.XAxis)
 
     def linkedYChanged(self):
-        view = self.state['linkedViews'][0]
+        ## called when y range of linked view has changed
+        view = self.state['linkedViews'][1]
         self.linkedViewChanged(view, ViewBox.YAxis)
         
 
@@ -502,15 +504,27 @@ class ViewBox(GraphicsWidget):
         view.blockLink(True)
         try:
             if axis == ViewBox.XAxis:
-                upp = float(vr.width()) / vg.width()
+                overlap = min(sg.right(), vg.right()) - max(sg.left(), vg.left())
-                x1 = vr.left() + (sg.x()-vg.x()) * upp
+                if overlap < min(vg.width()/3, sg.width()/3):  ## if less than 1/3 of views overlap, 
-                x2 = x1 + sg.width() * upp
+                                                               ## then just replicate the view
+                    x1 = vr.left()
+                    x2 = vr.right()
+                else:  ## views overlap; line them up
+                    upp = float(vr.width()) / vg.width()
+                    x1 = vr.left() + (sg.x()-vg.x()) * upp
+                    x2 = x1 + sg.width() * upp
                 self.enableAutoRange(ViewBox.XAxis, False)
                 self.setXRange(x1, x2, padding=0)
             else:
-                upp = float(vr.height()) / vg.height()
+                overlap = min(sg.bottom(), vg.bottom()) - max(sg.top(), vg.top())
-                x1 = vr.bottom() + (sg.y()-vg.y()) * upp
+                if overlap < min(vg.height()/3, sg.height()/3):  ## if less than 1/3 of views overlap, 
-                x2 = x1 + sg.height() * upp
+                                                               ## then just replicate the view
+                    x1 = vr.top()
+                    x2 = vr.bottom()
+                else:  ## views overlap; line them up
+                    upp = float(vr.height()) / vg.height()
+                    x1 = vr.top() + (sg.y()-vg.y()) * upp
+                    x2 = x1 + sg.height() * upp
                 self.enableAutoRange(ViewBox.YAxis, False)
                 self.setYRange(x1, x2, padding=0)
         finally:

widgets/GraphicsLayoutWidget.py

@@ -7,6 +7,6 @@ class GraphicsLayoutWidget(GraphicsView):
     def __init__(self, parent=None, **kargs):
         GraphicsView.__init__(self, parent)
         self.ci = GraphicsLayout(**kargs)
-        for n in ['nextRow', 'nextCol', 'addPlot', 'addViewBox', 'addItem', 'getItem']:
+        for n in ['nextRow', 'nextCol', 'addPlot', 'addViewBox', 'addItem', 'getItem', 'addLabel']:
             setattr(self, n, getattr(self.ci, n))
         self.setCentralItem(self.ci)