Added TextItem and example

examples/__main__.py

@@ -17,6 +17,7 @@ examples = OrderedDict([
         ('Region-of-Interest', 'ROItypes.py'),
         ('GraphicsLayout', 'GraphicsLayout.py'),
         ('Scatter Plot', 'ScatterPlot.py'),
+        ('Text Item', 'text.py'),
         ('ViewBox', 'ViewBox.py'),
         ('Arrow', 'Arrow.py'),
     ])),

examples/text.py

@@ -9,15 +9,44 @@ from pyqtgraph.Qt import QtCore, QtGui
 import numpy as np
 
 
-x = np.linspace(-100, 100, 1000)
+x = np.linspace(-20, 20, 1000)
 y = np.sin(x) / x
-plot = pg.plot(x, y)
+plot = pg.plot()   ## create an empty plot widget
+plot.setYRange(-1, 2)
+curve = plot.plot(x,y)  ## add a single curve
 
-## Create text object, use HTML tags to specify color (default is black; won't be visible)
-text = pg.TextItem(html='<div style="text-align: center"><span style="color: #FFF;">This is the</span><br><span style="color: #FF0;">PEAK</span></div>')
+## Create text object, use HTML tags to specify color/size
+text = pg.TextItem(html='<div style="text-align: center"><span style="color: #FFF;">This is the</span><br><span style="color: #FF0; font-size: 16pt;">PEAK</span></div>', anchor=(-0.3,1.3), border='w', fill=(0, 0, 255, 100))
 plot.addItem(text)
 text.setPos(0, y.max())
 
+## Draw an arrowhead next to the text box
+arrow = pg.ArrowItem(pos=(0, y.max()), angle=-45)
+plot.addItem(arrow)
+
+
+## Set up an animated arrow and text that track the curve
+curvePoint = pg.CurvePoint(curve)
+plot.addItem(curvePoint)
+text2 = pg.TextItem("test", anchor=(0.5, -1.0))
+text2.setParentItem(curvePoint)
+arrow2 = pg.ArrowItem(angle=90)
+arrow2.setParentItem(curvePoint)
+
+## update position every 10ms
+index = 0
+def update():
+    global curvePoint, index
+    index = (index + 1) % len(x)
+    curvePoint.setPos(float(index)/(len(x)-1))
+    #text2.viewRangeChanged()
+    text2.setText('[%0.1f, %0.1f]' % (x[index], y[index]))
+    
+timer = QtCore.QTimer()
+timer.timeout.connect(update)
+timer.start(10)
+
+
 
 ## Start Qt event loop unless running in interactive mode or using pyside.
 import sys

graphicsItems/CurvePoint.py

@@ -14,12 +14,15 @@ class CurvePoint(GraphicsObject):
     Note: This class does not display anything; see CurveArrow for an applied example
     """
     
-    def __init__(self, curve, index=0, pos=None):
+    def __init__(self, curve, index=0, pos=None, rotate=True):
         """Position can be set either as an index referring to the sample number or
-        the position 0.0 - 1.0"""
+        the position 0.0 - 1.0
+        If *rotate* is True, then the item rotates to match the tangent of the curve.
+        """
         
         GraphicsObject.__init__(self)
         #QObjectWorkaround.__init__(self)
+        self._rotate = rotate
         self.curve = weakref.ref(curve)
         self.setParentItem(curve)
         self.setProperty('position', 0.0)
@@ -76,6 +79,7 @@ class CurvePoint(GraphicsObject):
         p2 = self.parentItem().mapToScene(QtCore.QPointF(x[i2], y[i2]))
         ang = np.arctan2(p2.y()-p1.y(), p2.x()-p1.x()) ## returns radians
         self.resetTransform()
+        if self._rotate:
             self.rotate(180+ ang * 180 / np.pi) ## takes degrees
         QtGui.QGraphicsItem.setPos(self, *newPos)
         return True

graphicsItems/TextItem.py

@@ -0,0 +1,120 @@
+from pyqtgraph.Qt import QtCore, QtGui
+import pyqtgraph as pg
+from UIGraphicsItem import *
+
+class TextItem(UIGraphicsItem):
+    """
+    GraphicsItem displaying unscaled text (the text will always appear normal even inside a scaled ViewBox). 
+    """
+    def __init__(self, text='', color=(200,200,200), html=None, anchor=(0,0), border=None, fill=None):
+        """
+        Arguments:
+        *text*   The text to display 
+        *color*  The color of the text (any format accepted by pg.mkColor)
+        *html*   If specified, this overrides both *text* and *color*
+        *anchor* A QPointF or (x,y) sequence indicating what region of the text box will 
+                 be anchored to the item's position. A value of (0,0) sets the upper-left corner
+                 of the text box to be at the position specified by setPos(), while a value of (1,1)
+                 sets the lower-right corner.
+        *border* A pen to use when drawing the border
+        *fill*   A brush to use when filling within the border
+        """
+        UIGraphicsItem.__init__(self)
+        self.textItem = QtGui.QGraphicsTextItem()
+        self.lastTransform = None
+        self._bounds = QtCore.QRectF()
+        if html is None:
+            self.setText(text, color)
+        else:
+            self.setHtml(html)
+        self.anchor = pg.Point(anchor)
+        self.fill = pg.mkBrush(fill)
+        self.border = pg.mkPen(border)
+        #self.setFlag(self.ItemIgnoresTransformations)  ## This is required to keep the text unscaled inside the viewport
+
+    def setText(self, text, color=(200,200,200)):
+        color = pg.mkColor(color)
+        self.textItem.setDefaultTextColor(color)
+        self.textItem.setPlainText(text)
+        #html = '<span style="color: #%s; text-align: center;">%s</span>' % (color, text)
+        #self.setHtml(html)
+        
+    def updateAnchor(self):
+        pass
+        #self.resetTransform()
+        #self.translate(0, 20)
+        
+    def setPlainText(self, *args):
+        self.textItem.setPlainText(*args)
+        self.updateText()
+        
+    def setHtml(self, *args):
+        self.textItem.setHtml(*args)
+        self.updateText()
+        
+    def setTextWidth(self, *args):
+        self.textItem.setTextWidth(*args)
+        self.updateText()
+        
+    def setFont(self, *args):
+        self.textItem.setFont(*args)
+        self.updateText()
+        
+    def updateText(self):
+        self.viewRangeChanged()
+
+    #def getImage(self):
+        #if self.img is None:
+            #br = self.textItem.boundingRect()
+            #img = QtGui.QImage(int(br.width()), int(br.height()), QtGui.QImage.Format_ARGB32)
+            #p = QtGui.QPainter(img)
+            #self.textItem.paint(p, QtGui.QStyleOptionGraphicsItem(), None)
+            #p.end()
+            #self.img = img
+        #return self.img
+        
+    def textBoundingRect(self):
+        ## return the bounds of the text box in device coordinates
+        pos = self.mapToDevice(QtCore.QPointF(0,0))
+        if pos is None:
+            return None
+        tbr = self.textItem.boundingRect()
+        return QtCore.QRectF(pos.x() - tbr.width()*self.anchor.x(), pos.y() - tbr.height()*self.anchor.y(), tbr.width(), tbr.height())
+
+
+    def viewRangeChanged(self):
+        br = self.textBoundingRect()
+        if br is None:
+            return
+        self.prepareGeometryChange()
+        self._bounds = self.deviceTransform().inverted()[0].mapRect(br)
+        #print self._bounds
+
+    def boundingRect(self):
+        return self._bounds
+        
+    def paint(self, p, *args):
+        tr = p.transform()
+        if self.lastTransform is not None:
+            if tr != self.lastTransform:
+                self.viewRangeChanged()
+        self.lastTransform = tr
+        
+        
+        tbr = self.textBoundingRect()
+        
+        #p.setPen(pg.mkPen('r'))
+        #p.drawRect(self.boundingRect())
+        
+        p.setPen(self.border)
+        p.setBrush(self.fill)
+        
+        
+        #p.fillRect(tbr)
+        p.resetTransform()
+        p.drawRect(tbr)
+        
+        
+        p.translate(tbr.left(), tbr.top())
+        self.textItem.paint(p, QtGui.QStyleOptionGraphicsItem(), None)
+