DataView Image channel (#683)

* Add support for images to value types.

* Add image support to Qt dataview.

* Add images to column example.

* Update to give IImageResource to dataview, rather than toolkit object.

* Add images for example, plus license file.

* Prohibit None image values.

examples/data_view/column_example.py

@@ -14,9 +14,9 @@
 from functools import partial
 from random import choice, randint
 
-from traits.api import HasStrictTraits, Instance, Int, Str, List
+from traits.api import Dict, HasStrictTraits, Instance, Int, Str, List
 
-from pyface.api import ApplicationWindow, GUI
+from pyface.api import ApplicationWindow, GUI, Image, ImageResource
 from pyface.data_view.i_data_view_widget import IDataViewWidget
 from pyface.data_view.data_view_widget import DataViewWidget
 from pyface.data_view.value_types.api import IntValue, TextValue, no_value
@@ -25,6 +25,11 @@
     AbstractRowInfo, ColumnDataModel, HasTraitsRowInfo
 )
 
+flags = {
+    'UK': ImageResource('gb.png'),
+    'USA': ImageResource('us.png'),
+}
+
 
 class Address(HasStrictTraits):
 
@@ -44,6 +49,17 @@ class Person(HasStrictTraits):
     address = Instance(Address)
 
 
+class CountryValue(TextValue):
+
+    flags = Dict(Str, Image, update_value_type=True)
+
+    def get_image(self, model, row, column):
+        value = model.get_value(row, column)
+        if value in self.flags:
+            return self.flags[value]
+        return None
+
+
 row_info = HasTraitsRowInfo(
     title='People',
     value='name',
@@ -72,7 +88,9 @@ class Person(HasStrictTraits):
                 HasTraitsRowInfo(
                     title="Country",
                     value="address.country",
-                    value_type=TextValue(),
+                    value_type=CountryValue(
+                        flags=flags,
+                    ),
                 ),
             ],
         ),

examples/data_view/images/image_LICENSE.txt

@@ -0,0 +1,15 @@
+The icons are mostly derived work from other icons. As such they are
+licensed accordingly to the original license:
+
+Project            License         File
+------------------ --------------- -----------------------------------------
+FamFamFam Flags    Public Domain   http://www.famfamfam.com/lab/icons/flags/
+
+Unless stated in this file, icons are the work of Enthought, and are
+released under a 3 clause BSD license.
+
+Files and orginal authors:
+----------------------------------------------------------------------------
+examples/data_view/images:
+      gb.png | FamFamFam Flags
+      us.png | FamFamFam Flags

pyface/data_view/abstract_value_type.py

@@ -182,11 +182,11 @@ def set_text(self, model, row, column, text):
         """
         raise DataViewSetError("Cannot set value.")
 
-    def has_tooltip(self, model, row, column):
-        """ Whether or not the value has a tooltip.
+    def has_image(self, model, row, column):
+        """ Whether or not the value has an image associated with it.
 
-        The default implementation returns True if ``get_tooltip``
-        returns a non-empty value.
+        The default implementation returns True if ``get_image``
+        returns a non-None value.
 
         Parameters
         ----------
@@ -199,15 +199,15 @@ def has_tooltip(self, model, row, column):
 
         Returns
         -------
-        has_tooltip : bool
-            Whether or not the value has a textual representation.
+        has_image : bool
+            Whether or not the value has an image associated with it.
         """
-        return self.get_tooltip(model, row, column) != ""
+        return False
 
-    def get_tooltip(self, model, row, column):
-        """ The tooltip for the underlying value.
+    def get_image(self, model, row, column):
+        """ An image associated with the underlying value.
 
-        The default implementation returns an empty string.
+        The default implementation returns None.
 
         Parameters
         ----------
@@ -220,6 +220,27 @@ def get_tooltip(self, model, row, column):
 
         Returns
         -------
+        image : IImageResource
+            The image associated with the underlying value.
+        """
+        from pyface.image_resource import ImageResource
+        return ImageResource("image_not_found")
+
+    def has_tooltip(self, model, row, column):
+        """ Whether or not the value has a tooltip.
+
+        The default implementation returns True if ``get_tooltip``
+        returns a non-empty value.
+        has_tooltip : bool
+            Whether or not the value has a textual representation.
+        """
+        return self.get_tooltip(model, row, column) != ""
+
+    def get_tooltip(self, model, row, column):
+        """ The tooltip for the underlying value.
+
+        The default implementation returns an empty string.
+
         tooltip : str
             The textual representation of the underlying value.
         """

pyface/data_view/tests/test_abstract_value_type.py

@@ -74,6 +74,16 @@ def test_set_text(self):
         with self.assertRaises(DataViewSetError):
             value_type.set_text(self.model, [0], [0], "2.0")
 
+    def test_has_image(self):
+        value_type = ValueType()
+        result = value_type.has_image(self.model, [0], [0])
+        self.assertFalse(result)
+
+    def test_get_image(self):
+        value_type = ValueType()
+        result = value_type.get_image(self.model, [0], [0])
+        self.assertEqual(result.name, "image_not_found")
+
     def test_parameter_update(self):
         value_type = ValueType()
         with self.assertTraitChanges(value_type, 'updated', count=1):

pyface/data_view/value_types/constant_value.py

@@ -11,6 +11,7 @@
 from traits.api import Str
 
 from pyface.data_view.abstract_value_type import AbstractValueType
+from pyface.ui_traits import Image
 
 
 class ConstantValue(AbstractValueType):
@@ -24,6 +25,9 @@ class ConstantValue(AbstractValueType):
     #: The text value to display.
     text = Str(update_value_type=True)
 
+    #: The image value to display.
+    image = Image(update_value_type=True)
+
     #: The tooltip value to display.
     tooltip = Str(update_value_type=True)
 
@@ -33,5 +37,13 @@ def has_editor_value(self, model, row, column):
     def get_text(self, model, row, column):
         return self.text
 
+    def has_image(self, model, row, column):
+        return self.image is not None
+
+    def get_image(self, model, row, column):
+        if self.image is not None:
+            return self.image
+        return super().get_image(model, row, column)
+
     def get_tooltip(self, model, row, column):
         return self.tooltip

pyface/data_view/value_types/no_value.py

@@ -20,6 +20,9 @@ def has_editor_value(self, model, row, column):
     def has_text(self, model, row, column):
         return False
 
+    def has_image(self, model, row, column):
+        return False
+
     def has_tooltip(self, model, row, column):
         return False
 

pyface/data_view/value_types/tests/test_constant_value.py

@@ -14,6 +14,7 @@
 from traits.testing.unittest_tools import UnittestTools
 
 from pyface.data_view.value_types.constant_value import ConstantValue
+from pyface.image_resource import ImageResource
 
 
 class TestConstantValue(UnittestTools, TestCase):
@@ -51,6 +52,34 @@ def test_text_changed(self):
             value_type.text = 'something'
         self.assertEqual(value_type.text, 'something')
 
+    def test_has_image(self):
+        value_type = ConstantValue()
+        self.assertFalse(value_type.has_image(self.model, [0], [0]))
+
+    def test_has_image_true(self):
+        value_type = ConstantValue(image="question")
+        self.assertTrue(value_type.has_image(self.model, [0], [0]))
+
+    def test_get_image(self):
+        image = ImageResource("question")
+        value_type = ConstantValue(image=image)
+        self.assertEqual(
+            value_type.get_image(self.model, [0], [0]),
+            image
+        )
+
+    def test_get_image_none(self):
+        value_type = ConstantValue()
+        image = value_type.get_image(self.model, [0], [0])
+        self.assertEqual(image.name, "image_not_found")
+
+    def test_image_changed(self):
+        value_type = ConstantValue()
+        image = ImageResource("question")
+        with self.assertTraitChanges(value_type, 'updated'):
+            value_type.image = image
+        self.assertEqual(value_type.image, image)
+
     def test_has_tooltip(self):
         value_type = ConstantValue()
         self.assertFalse(value_type.has_tooltip(self.model, [0], [0]))

pyface/data_view/value_types/tests/test_no_value.py

@@ -27,6 +27,10 @@ def test_has_text(self):
         value_type = NoValue()
         self.assertFalse(value_type.has_text(self.model, [0], [0]))
 
+    def test_has_image(self):
+        value_type = NoValue()
+        self.assertFalse(value_type.has_image(self.model, [0], [0]))
+
     def test_has_tooltip(self):
         value_type = NoValue()
         self.assertFalse(value_type.has_tooltip(self.model, [0], [0]))

pyface/ui/qt4/data_view/data_view_item_model.py

@@ -10,6 +10,7 @@
 
 import logging
 
+from pyface.i_image_resource import IImageResource
 from pyface.qt import is_qt5
 from pyface.qt.QtCore import QAbstractItemModel, QModelIndex, Qt
 from pyface.data_view.index_manager import Root
@@ -148,6 +149,11 @@ def data(self, index, role=Qt.DisplayRole):
         elif role == Qt.EditRole:
             if value_type.has_editor_value(self.model, row, column):
                 return value_type.get_editor_value(self.model, row, column)
+        elif role == Qt.DecorationRole:
+            if value_type.has_image(self.model, row, column):
+                image = value_type.get_image(self.model, row, column)
+                if isinstance(image, IImageResource):
+                    return image.create_image()
         elif role == Qt.ToolTipRole:
             if value_type.has_tooltip(self.model, row, column):
                 return value_type.get_tooltip(self.model, row, column)