ENH: Add SaveButtons widget.

skimage/viewer/plugins/base.py

@@ -137,6 +137,7 @@ class Plugin(QtGui.QDialog):
             widget.callback = self.filter_image
         elif widget.ptype == 'plugin':
             widget.callback = self.update_plugin
+        widget.plugin = self
         self.layout.addWidget(widget, self.row, 0)
         self.row += 1
 

skimage/viewer/widgets/__init__.py

@@ -1 +1,2 @@
 from core import *
+from history import *

skimage/viewer/widgets/core.py

@@ -19,17 +19,22 @@ from PyQt4.QtCore import Qt
 from PyQt4 import QtGui
 from PyQt4 import QtCore
 
+from ..utils import RequiredAttr
+
 
 __all__ = ['BaseWidget', 'Slider', 'ComboBox']
 
 
 class BaseWidget(QtGui.QWidget):
 
+    plugin = RequiredAttr("Widget is not attached to a Plugin.")
+
     def __init__(self, name, ptype, callback):
         super(BaseWidget, self).__init__()
         self.name = name
         self.ptype = ptype
         self.callback = callback
+        self.plugin = None
 
     @property
     def val(self):

skimage/viewer/widgets/history.py

@@ -0,0 +1,66 @@
+import os
+from textwrap import dedent
+
+from PyQt4 import QtGui
+
+from skimage import io
+from .core import BaseWidget
+
+
+__all__ = ['SaveButtons']
+
+
+class SaveButtons(BaseWidget):
+
+    def __init__(self, default_format='png'):
+        name = 'Save to:'
+        ptype = None
+        callback = None
+        super(SaveButtons, self).__init__(name, ptype, callback)
+
+        self.default_format = default_format
+
+        self.name_label = QtGui.QLabel()
+        self.name_label.setText(name)
+
+        self.save_file = QtGui.QPushButton('File')
+        self.save_file.clicked.connect(self.save_to_file)
+        self.save_stack = QtGui.QPushButton('Stack')
+        self.save_stack.clicked.connect(self.save_to_stack)
+
+        self.layout = QtGui.QHBoxLayout(self)
+        self.layout.addWidget(self.name_label)
+        self.layout.addWidget(self.save_stack)
+        self.layout.addWidget(self.save_file)
+
+    def save_to_stack(self):
+        image = self.plugin.image_viewer.image.copy()
+        io.push(image)
+
+        msg = dedent('''\
+            The image has been pushed to the io stack.
+            Use io.pop() to retrieve the most recently pushed image.
+            NOTE: The io stack only works in interactive sessions.''')
+        notify(msg)
+
+    def save_to_file(self):
+        filename = str(QtGui.QFileDialog.getSaveFileName())
+        if len(filename) == 0:
+            return
+        #TODO: io plugins should assign default image formats
+        basename, ext = os.path.splitext(filename)
+        if not ext:
+            filename = '%s.%s' % (filename, self.default_format)
+        io.imsave(filename, self.plugin.image_viewer.image)
+
+
+def notify(msg):
+    msglabel = QtGui.QLabel(msg)
+    dialog = QtGui.QDialog()
+    ok = QtGui.QPushButton('OK', dialog)
+    ok.clicked.connect(dialog.accept)
+    ok.setDefault(True)
+    dialog.layout = QtGui.QGridLayout(dialog)
+    dialog.layout.addWidget(msglabel, 0, 0, 1, 3)
+    dialog.layout.addWidget(ok, 1, 1)
+    dialog.exec_()

viewer_examples/plugins/median_filter.py

@@ -0,0 +1,18 @@
+from skimage import data
+from skimage.filter import median_filter
+
+from skimage.viewer import ImageViewer
+from skimage.viewer.widgets import Slider
+from skimage.viewer.widgets.history import SaveButtons
+from skimage.viewer.plugins.overlayplugin import Plugin
+
+
+image = data.coins()
+viewer = ImageViewer(image)
+
+plugin = Plugin(image_filter=median_filter)
+plugin += Slider('radius', 2, 10, value_type='int', update_on='release')
+plugin += SaveButtons()
+
+viewer += plugin
+viewer.show()