Add PlotPlugin and cleanup code.

skimage/viewer/plugins/base.py

@@ -1,7 +1,31 @@
 from PyQt4 import QtGui
+
+import numpy as np
+import matplotlib as mpl
+import matplotlib.pyplot as plt
+from matplotlib.backends.backend_qt4agg import FigureCanvasQTAgg
 from skimage.io._plugins.q_color_mixer import IntelligentSlider
 
 
+class PlotCanvas(FigureCanvasQTAgg):
+    """Canvas for displaying images.
+
+    This canvas derives from Matplotlib, and has attributes `fig` and `ax`,
+    which point to Matplotlib figure and axes.
+    """
+    def __init__(self, parent, height, width, **kwargs):
+        print height, width
+        self.fig, self.ax = plt.subplots(figsize=(height, width), **kwargs)
+
+        FigureCanvasQTAgg.__init__(self, self.fig)
+        FigureCanvasQTAgg.setSizePolicy(self,
+                                        QtGui.QSizePolicy.Expanding,
+                                        QtGui.QSizePolicy.Expanding)
+        FigureCanvasQTAgg.updateGeometry(self)
+        # Note: `setParent` must be called after `FigureCanvasQTAgg.__init__`.
+        self.setParent(parent)
+
+
 class Plugin(QtGui.QDialog):
     """Base class for widgets that interact with the axes.
 
@@ -12,24 +36,22 @@ class Plugin(QtGui.QDialog):
     useblit : bool
         If True, use blitting to speed up animation. Only available on some
         backends. If None, set to True when using Agg backend, otherwise False.
-    figure : :class:`~matplotlib.figure.Figure`
-        If None, create a figure with a single axes.
-    no_toolbar : bool
-        If True, figure created by plugin has no toolbar. This has no effect
-        on figures passed into `Plugin`.
 
     Attributes
     ----------
-    viewer : ImageViewer
+    image_viewer : ImageViewer
         Window containing image used in measurement.
     image : array
         Image used in measurement/manipulation.
     overlay : array
         Image used in measurement/manipulation.
     """
-    def __init__(self, image_viewer, callback=None, height=100, width=400):
-        self._viewer = image_viewer
+    def __init__(self, image_viewer, callback=None, height=100, width=400,
+                 useblit=None):
+        self.image_viewer = image_viewer
         QtGui.QDialog.__init__(self, image_viewer)
+        self.image_viewer.plugins.append(self)
+
         self.setWindowTitle('Image Plugin')
         self.layout = QtGui.QGridLayout(self)
         self.resize(width, height)
@@ -40,8 +62,17 @@ class Plugin(QtGui.QDialog):
         self.arguments = [image_viewer.original_image]
         self.keyword_arguments= {}
 
-        self.overlay = self._viewer.overlay
-        self.image = self._viewer.image
+        self.overlay = self.image_viewer.overlay
+        self.image = self.image_viewer.image
+
+
+        if useblit is None:
+            useblit = True if mpl.backends.backend.endswith('Agg') else False
+        self.useblit = useblit
+        self.cids = []
+        self.artists = []
+
+        self.connect_event('draw_event', self.on_draw)
 
     def caller(self, *args):
         arguments = [self._get_value(a) for a in self.arguments]
@@ -69,3 +100,88 @@ class Plugin(QtGui.QDialog):
         self.layout.addWidget(slider, self.row, 0)
         self.row += 1
         return name.replace(' ', '_'), slider
+
+    def redraw(self):
+        self.canvas.draw_idle()
+
+    def closeEvent(self, event):
+        """Disconnect all artists and events from ImageViewer.
+
+        Note that events must be connected using `self.connect_event` and
+        artists must be appended to `self.artists`.
+        """
+        self.disconnect_image_events()
+        self.remove_artists()
+        self.image_viewer.plugins.remove(self)
+        self.image_viewer.redraw()
+        self.close()
+
+    def connect_event(self, event, callback):
+        """Connect callback with an event.
+
+        This should be used in lieu of `figure.canvas.mpl_connect` since this
+        function stores call back ids for later clean up.
+        """
+        cid = self.image_viewer.connect_event(event, callback)
+        self.cids.append(cid)
+
+    def disconnect_image_events(self):
+        """Disconnect all events created by this widget."""
+        for c in self.cids:
+            self.image_viewer.disconnect_event(c)
+
+    def remove_artists(self):
+        """Disconnect artists that are connected to the *image plot*."""
+        for a in self.artists:
+            self.image_viewer.remove_artist(a)
+
+
+class PlotPlugin(Plugin):
+    """Plugin for ImageViewer that contains a plot Canvas.
+
+    Parameters
+    ----------
+    image_viewer : ImageViewer instance.
+        Window containing image used in measurement/manipulation.
+    figure : :class:`~matplotlib.figure.Figure`
+        If None, create a figure with a single axes.
+    useblit : bool
+        If True, use blitting to speed up animation. Only available on some
+        backends. If None, set to True when using Agg backend, otherwise False.
+
+    Attributes
+    ----------
+    image_viewer : ImageViewer
+        Window containing image used in measurement.
+    image : array
+        Image used in measurement/manipulation.
+    overlay : array
+        Image used in measurement/manipulation.
+    """
+    def __init__(self, image_viewer, useblit=None, **kwargs):
+        Plugin.__init__(self, image_viewer, **kwargs)
+        # Add plot for displaying intensity profile.
+        self.add_plot()
+        self.connect_event('draw_event', self.on_draw)
+
+    def on_draw(self, event):
+        """Save image background when blitting.
+
+        The saved image is used to "clear" the figure before redrawing artists.
+        """
+        if self.useblit:
+            bbox = self.image_viewer.ax.bbox
+            self.img_background = self.image_viewer.canvas.copy_from_bbox(bbox)
+
+    def add_plot(self, height=4, width=4):
+        self.canvas = PlotCanvas(self, height, width)
+        self.fig = self.canvas.fig
+        #TODO: Converted color is slightly different than Qt background.
+        qpalette = QtGui.QPalette()
+        qcolor = qpalette.color(QtGui.QPalette.Window)
+        bgcolor = qcolor.toRgb().value()
+        if np.isscalar(bgcolor):
+            bgcolor = str(bgcolor / 255.)
+        self.fig.patch.set_facecolor(bgcolor)
+        self.ax = self.canvas.ax
+        self.layout.addWidget(self.canvas, self.row, 0)

skimage/viewer/plugins/canny.py

@@ -17,4 +17,4 @@ class CannyPlugin(Plugin):
 
     def callback(self, *args, **kwargs):
         image = canny(*args, **kwargs)
-        self._viewer.overlay = image
+        self.image_viewer.overlay = image

skimage/viewer/viewers/core.py

@@ -53,6 +53,17 @@ class ImageViewer(QtGui.QMainWindow):
         self.canvas = ImageCanvas(self.main_widget, image)
         self.fig = self.canvas.fig
         self.ax = self.canvas.ax
+        self.ax.autoscale(enable=False)
+        self.image_plot = self.ax.images[0]
+        self.plugins = []
+
+        # List of axes artists to check for removal.
+        self._axes_artists = [self.ax.artists,
+                              self.ax.collections,
+                              self.ax.images,
+                              self.ax.lines,
+                              self.ax.patches,
+                              self.ax.texts]
 
         self.layout = QtGui.QVBoxLayout(self.main_widget)
         self.layout.addWidget(self.canvas)
@@ -61,6 +72,8 @@ class ImageViewer(QtGui.QMainWindow):
         # self.statusBar().showMessage("coordinates")
         self.original_image = image
         self.image = image
+
+        self.overlay_plot = None
         self._overlay = None
 
     @property
@@ -80,10 +93,10 @@ class ImageViewer(QtGui.QMainWindow):
     @overlay.setter
     def overlay(self, image):
         self._overlay = image
-        if len(self.ax.images) == 1:
-            self.ax.imshow(image, cmap=self.overlay_cmap)
+        if self.overlay_plot is None:
+            self.overlay_plot = self.ax.imshow(image, cmap=self.overlay_cmap)
         else:
-            self.ax.images[1].set_array(image)
+            self.overlay_plot.set_array(image)
         self.canvas.draw_idle()
 
     def closeEvent(self, ce):
@@ -93,4 +106,32 @@ class ImageViewer(QtGui.QMainWindow):
         super(ImageViewer, self).show()
         sys.exit(qApp.exec_())
 
+    @property
+    def climits(self):
+        return self.image_plot.get_clim()
+
+    @climits.setter
+    def climits(self, limits):
+        cmin, cmax = limits
+        self.image_plot.set_clim(vmin=cmin, vmax=cmax)
+
+    def connect_event(self, event, callback):
+        cid = self.canvas.mpl_connect(event, callback)
+        return cid
+
+    def disconnect_event(self, callback_id):
+        self.canvas.mpl_disconnect(callback_id)
+
+    def add_artist(self, artist):
+        self.ax.add_artist(artist)
+
+    def remove_artist(self, artist):
+        """Disconnect all artists created by this widget."""
+        # There's probably a smarter way to do this.
+        for artist_list in self._axes_artists:
+            if artist in artist_list:
+                artist_list.remove(artist)
+
+    def redraw(self):
+        self.canvas.draw_idle()