Create colormap widget for reversing colormaps

glue_qt/utils/colors.py

@@ -11,7 +11,7 @@
 
 __all__ = ['mpl_to_qt_color', 'qt_to_mpl_color', 'cmap2pixmap',
            'tint_pixmap', 'QColorBox', 'ColorProperty', 'connect_color',
-           'QColormapCombo']
+           'QColormapCombo', 'connect_colormap_widget', 'QColormapWidget']
 
 
 def mpl_to_qt_color(color, alpha=None):
@@ -219,6 +219,106 @@ def resizeEvent(self, *args, **kwargs):
         self._update_icons()
 
 
+class QColormapWidget(QtWidgets.QWidget):
+
+    changed = QtCore.Signal()
+
+    def __init__(self, *args, **kwargs):
+        super(QColormapWidget, self).__init__(*args, **kwargs)
+        layout = QtWidgets.QHBoxLayout()
+        self.cmap_combo = QColormapCombo()
+        self.cmap_combo.setMinimumWidth(100)
+        self.cmap_button = QtWidgets.QPushButton(text="⇄")
+        self.cmap_button.setCheckable(True)
+        self.cmap_button.setMaximumWidth(25)
+        layout.addWidget(self.cmap_combo, stretch=1)
+        layout.addWidget(self.cmap_button)
+        layout.setSpacing(3)
+        self.setLayout(layout)
+
+        self.cmap_button.toggled.connect(self._update_from_widget)
+        self.cmap_combo.currentIndexChanged.connect(self._update_from_widget)
+
+    def value(self):
+        wrapper = self.itemData(self.cmap_combo.currentIndex(), reverse=self.cmap_button.isChecked())
+        return wrapper.data if wrapper is not None else None
+
+    def isChecked(self):
+        return self.cmap_button.isChecked()
+
+    def _update_from_widget(self, value):
+        self.changed.emit()
+
+    def set(self, index, reverse):
+        with QtCore.QSignalBlocker(self.cmap_combo), QtCore.QSignalBlocker(self.cmap_button):
+            self.cmap_combo.setCurrentIndex(index)
+            self.cmap_button.setChecked(reverse)
+        reversible = callable(getattr(self.value(), 'reversed', None))
+        self.cmap_button.setEnabled(reversible)
+        self.changed.emit()
+
+    def count(self):
+        return self.cmap_combo.count()
+
+    def refresh_options(self):
+        self.cmap_combo.refresh_options()
+
+    def itemData(self, index, reverse=False):
+        wrapper = self.cmap_combo.itemData(index)
+        if wrapper is None:
+            return None
+        data = wrapper.data
+        if reverse:
+            data = data.reversed()
+        return UserDataWrapper(data=data)
+
+
+def _find_cmap_combo_data(widget, value):
+    """
+    Returns the index in a combo box where the colormap or its reverse equals the value
+
+    Raises a ValueError if data is not found
+    """
+    # Here we check that the result is True, because some classes may overload
+    # == and return other kinds of objects whether true or false.
+    for idx in range(widget.count()):
+        if (item_data := widget.itemData(idx)) is not None:
+            if isinstance(item_data, UserDataWrapper):
+                data = item_data.data
+            else:
+                data = item_data
+            if data is value or (data == value) is True:
+                return idx, False
+            if callable(getattr(data, 'reversed', None)):
+                data = data.reversed()
+                if data is value or (data == value) is True:
+                    return idx, True
+    return -1, False
+    raise ValueError("%s not found in combo box" % (value,))
+
+
+def connect_colormap_widget(client, prop, widget):
+
+    def update_widget(item):
+        try:
+            idx, reverse = _find_cmap_combo_data(widget, item)
+        except ValueError:
+            if item is None:
+                idx, reverse = -1, False
+            else:
+                raise
+        widget.set(idx, reverse)
+
+    def update_prop():
+        setattr(client, prop, widget.value())
+
+    add_callback(client, prop, update_widget)
+    widget.changed.connect(nonpartial(update_prop))
+    update_widget(getattr(client, prop))
+
+
+HANDLERS['cmap'] = connect_colormap_widget
+
 if __name__ == "__main__":
 
     from glue_qt.utils import get_qapp

glue_qt/utils/tests/test_colors.py

@@ -1,9 +1,10 @@
 from unittest.mock import MagicMock
 
 from echo import CallbackProperty
+from glue.config import colormaps
 from qtpy import QtGui
 
-from ..colors import qt_to_mpl_color, QColorBox, connect_color, QColormapCombo
+from ..colors import qt_to_mpl_color, QColorBox, connect_color, QColormapCombo, connect_colormap_widget, QColormapWidget
 
 
 def test_colors():
@@ -52,3 +53,41 @@ class FakeClass(object):
 def test_colormap_combo():
 
     combo = QColormapCombo()
+
+
+def test_colormap_widget():
+
+    widget = QColormapWidget()
+
+
+def test_colormap_widget_value():
+
+    class FakeClass(object):
+        cmap = CallbackProperty()
+
+    c = FakeClass()
+    widget = QColormapWidget()
+
+    connect_colormap_widget(c, 'cmap', widget)
+
+    cmap0 = colormaps.members[0][1]
+
+    widget.set(0, True)
+    assert c.cmap == cmap0.reversed()
+
+    cmap1 = colormaps.members[1][1]
+    widget.set(1, True)
+    assert c.cmap == cmap1.reversed()
+
+    widget.set(1, False)
+    assert c.cmap == cmap1
+
+    c.cmap = cmap0
+    assert widget.cmap_combo.currentIndex() == 0
+    assert not widget.cmap_button.isChecked()
+    assert widget.value() == cmap0
+
+    c.cmap = cmap1.reversed()
+    assert widget.cmap_combo.currentIndex() == 1
+    assert widget.cmap_button.isChecked()
+    assert widget.value() == cmap1.reversed()

glue_qt/viewers/image/layer_style_editor.py

@@ -30,7 +30,7 @@ def __init__(self, layer, parent=None):
     def _update_color_mode(self, color_mode):
         if color_mode == 'Colormaps':
             self.ui.color_color.hide()
-            self.ui.combodata_cmap.show()
+            self.ui.cmap_cmap.show()
         else:
             self.ui.color_color.show()
-            self.ui.combodata_cmap.hide()
+            self.ui.cmap_cmap.hide()

glue_qt/viewers/image/layer_style_editor.ui

@@ -7,7 +7,7 @@
     <x>0</x>
     <y>0</y>
     <width>292</width>
-    <height>197</height>
+    <height>204</height>
    </rect>
   </property>
   <property name="windowTitle">
@@ -43,7 +43,6 @@
     <widget class="QLabel" name="label_3">
      <property name="font">
       <font>
-       <weight>75</weight>
        <bold>true</bold>
       </font>
      </property>
@@ -59,7 +58,6 @@
     <widget class="QLabel" name="label_2">
      <property name="font">
       <font>
-       <weight>75</weight>
        <bold>true</bold>
       </font>
      </property>
@@ -92,20 +90,7 @@
      <item>
       <layout class="QVBoxLayout" name="verticalLayout">
        <item>
-        <widget class="QColormapCombo" name="combodata_cmap">
-         <property name="minimumSize">
-          <size>
-           <width>80</width>
-           <height>0</height>
-          </size>
-         </property>
-         <property name="sizeAdjustPolicy">
-          <enum>QComboBox::AdjustToMinimumContentsLengthWithIcon</enum>
-         </property>
-         <property name="frame">
-          <bool>false</bool>
-         </property>
-        </widget>
+        <widget class="QColormapWidget" name="cmap_cmap" native="true"/>
        </item>
        <item>
         <widget class="QColorBox" name="color_color">
@@ -249,7 +234,6 @@
     <widget class="QLabel" name="label_5">
      <property name="font">
       <font>
-       <weight>75</weight>
        <bold>true</bold>
       </font>
      </property>
@@ -265,7 +249,6 @@
     <widget class="QLabel" name="label">
      <property name="font">
       <font>
-       <weight>75</weight>
        <bold>true</bold>
       </font>
      </property>
@@ -299,9 +282,10 @@
    <header>glue_qt.utils.colors</header>
   </customwidget>
   <customwidget>
-   <class>QColormapCombo</class>
-   <extends>QComboBox</extends>
+   <class>QColormapWidget</class>
+   <extends>QWidget</extends>
    <header>glue_qt.utils.colors</header>
+   <container>1</container>
   </customwidget>
  </customwidgets>
  <resources/>

glue_qt/viewers/scatter/layer_style_editor.py

@@ -216,7 +216,7 @@ def _update_cmap_mode(self, cmap_mode=None):
             self.ui.valuetext_cmap_vmin.hide()
             self.ui.valuetext_cmap_vmax.hide()
             self.ui.button_flip_cmap.hide()
-            self.ui.combodata_cmap.hide()
+            self.ui.cmap_cmap.hide()
             self.ui.label_colormap.hide()
             self.ui.color_color.show()
         else:
@@ -226,7 +226,7 @@ def _update_cmap_mode(self, cmap_mode=None):
             self.ui.valuetext_cmap_vmin.show()
             self.ui.valuetext_cmap_vmax.show()
             self.ui.button_flip_cmap.show()
-            self.ui.combodata_cmap.show()
+            self.ui.cmap_cmap.show()
             self.ui.label_colormap.show()
             self.ui.color_color.hide()
 
@@ -242,9 +242,9 @@ def _update_cmaps(self, *args):
             if getattr(actual_component, 'preferred_cmap', False):
                 cmap = actual_component.preferred_cmap
                 name = actual_component.cmap_name
-                self.ui.combodata_cmap.refresh_options(colormaps=[(name, cmap)])
+                self.ui.cmap_cmap.refresh_options(colormaps=[(name, cmap)])
             else:
-                self.ui.combodata_cmap.refresh_options()
+                self.ui.cmap_cmap.refresh_options()
 
 
 class ScatterRegionLayerStyleEditor(QtWidgets.QWidget):