owradviz: fix label overlap

* rotate variable labels
* shorten labels to 20 characters
* add tooltip for labels
* limit number of selected variables

Author: robertcv

Orange/widgets/utils/plot/owplotgui.py

@@ -58,13 +58,20 @@ class VariableSelectionModel(VariableListModel):
     SortRole = next(OrangeUserRole)
     selection_changed = pyqtSignal()
 
-    def __init__(self, selected_vars):
+    def __init__(self, selected_vars, max_vars=None):
         super().__init__(enable_dnd=True)
         self.selected_vars = selected_vars
+        self.max_vars = max_vars
 
     def is_selected(self, index):
         return self[index.row()] in self.selected_vars
 
+    def is_full(self):
+        if self.max_vars is None:
+            return False
+        else:
+            return len(self.selected_vars) >= self.max_vars
+
     def data(self, index, role):
         if role == self.IsSelected:
             return self.is_selected(index)
@@ -84,7 +91,7 @@ def toggle_item(self, index):
         var = self[index.row()]
         if var in self.selected_vars:
             self.selected_vars.remove(var)
-        else:
+        elif not self.is_full():
             self.selected_vars.append(var)
         self.selection_changed.emit()
 
@@ -131,17 +138,19 @@ def paint(self, painter, option, index):
         rect = QRect(option.rect)
 
         is_selected = index.data(VariableSelectionModel.IsSelected)
+        full_selection = index.model().sourceModel().is_full()
         if option.state & QStyle.State_MouseOver:
-            txt = [" Add ", " Remove "][is_selected]
-            txtw = painter.fontMetrics().width(txt)
-            painter.save()
-            painter.setPen(Qt.NoPen)
-            painter.setBrush(QColor("#ccc"))
-            brect = QRect(rect.x() + rect.width() - 8 - txtw, rect.y(),
-                          txtw, rect.height())
-            painter.drawRoundedRect(brect, 4, 4)
-            painter.restore()
-            painter.drawText(brect, Qt.AlignCenter, txt)
+            if not full_selection or (full_selection and is_selected):
+                txt = [" Add ", " Remove "][is_selected]
+                txtw = painter.fontMetrics().width(txt)
+                painter.save()
+                painter.setPen(Qt.NoPen)
+                painter.setBrush(QColor("#ccc"))
+                brect = QRect(rect.x() + rect.width() - 8 - txtw, rect.y(),
+                              txtw, rect.height())
+                painter.drawRoundedRect(brect, 4, 4)
+                painter.restore()
+                painter.drawText(brect, Qt.AlignCenter, txt)
 
         painter.save()
         double_pen = painter.pen()

Orange/widgets/visualize/owradviz.py

@@ -209,13 +209,14 @@ class OWRadvizGraph(OWGraphWithAnchors):
     def __init__(self, scatter_widget, parent):
         super().__init__(scatter_widget, parent)
         self.anchors_scatter_item = None
+        self.padding = 0.025
 
     def clear(self):
         super().clear()
         self.anchors_scatter_item = None
 
     def set_view_box_range(self):
-        self.view_box.setRange(QRectF(-1.2, -1.05, 2.4, 2.1), padding=0.025)
+        self.view_box.setRange(QRectF(-1, -1, 2, 2), padding=self.padding)
 
     def closest_draggable_item(self, pos):
         points, _ = self.master.get_anchors()
@@ -231,18 +232,36 @@ def update_anchors(self):
         points, labels = self.master.get_anchors()
         if points is None:
             return
-        if self.anchor_items is None:
-            self.anchor_items = []
-            for point, label in zip(points, labels):
-                anchor = TextItem()
-                anchor.setText(label)
-                anchor.setColor(QColor(0, 0, 0))
-                anchor.setPos(*point)
-                self.plot_widget.addItem(anchor)
-                self.anchor_items.append(anchor)
-        else:
-            for anchor, point in zip(self.anchor_items, points):
-                anchor.setPos(*point)
+        if self.anchor_items is not None:
+            for anchor in self.anchor_items:
+                self.plot_widget.removeItem(anchor)
+
+        self.anchor_items = []
+        label_len = []
+        for point, label in zip(points, labels):
+            anchor = TextItem()
+            anchor.textItem.setToolTip(f"<b>{label}</b>")
+            if len(label) > 20:
+                label = label[:17] + "..."
+            anchor.setText(label)
+            label_len.append(len(label))
+            anchor.setColor(QColor(0, 0, 0))
+
+            x, y = point
+            angle = np.rad2deg(np.arctan2(y, x))
+            anchor.setPos(x * 1.025, y * 1.025)
+
+            if abs(angle) < 90:
+                anchor.setAngle(angle)
+                anchor.setAnchor((0, 0.5))
+            else:
+                anchor.setAngle(angle + 180)
+                anchor.setAnchor((1, 0.5))
+
+            self.plot_widget.addItem(anchor)
+            self.anchor_items.append(anchor)
+
+        self.padding = max(label_len) * 0.02
         self._update_anchors_scatter_item(points)
 
     def _update_anchors_scatter_item(self, points):
@@ -284,9 +303,11 @@ class Warning(OWAnchorProjectionWidget.Warning):
         invalid_embedding = widget.Msg("No projection for selected features")
         removed_vars = widget.Msg("Categorical variables with more than"
                                   " two values are not shown.")
+        max_vars_selected = widget.Msg("Maximum number of selected variables reached.")
 
     def _add_controls(self):
-        self.model_selected = VariableSelectionModel(self.selected_vars)
+        self.model_selected = VariableSelectionModel(self.selected_vars,
+                                                     max_vars=20)
         variables_selection(self.controlArea, self, self.model_selected)
         self.model_selected.selection_changed.connect(
             self.__model_selected_changed)
@@ -318,6 +339,10 @@ def vizrank_set_attrs(self, *attrs):
         self.model_selected.selection_changed.emit()
 
     def __model_selected_changed(self):
+        if self.model_selected.is_full():
+            self.Warning.max_vars_selected()
+        else:
+            self.Warning.max_vars_selected.clear()
         self.init_projection()
         self.setup_plot()
         self.commit()