Implement drag select for widgets

studio/feature/design.py

@@ -24,6 +24,7 @@
 from studio.parsers.loader import DesignBuilder, BaseStudioAdapter
 from studio.ui import geometry
 from studio.ui.widgets import DesignPad, CoordinateIndicator
+from studio.ui.highlight import RegionHighlighter
 from studio.context import BaseContext
 from studio import __version__
 
@@ -132,6 +133,7 @@ def __init__(self, master, studio):
         self._shortcut_mgr = KeyMap(self._frame)
         self._set_shortcuts()
         self._last_click_pos = None
+        self._region_highlight = RegionHighlighter(self, self.style)
 
         self._empty = Label(
             self,
@@ -525,6 +527,23 @@ def layout_at(self, bounds):
 
         return candidate or self
 
+    def show_select_region(self, bounds):
+        bounds = geometry.resolve_bounds(bounds, self)
+        self._region_highlight.highlight_bounds(bounds)
+
+    def clear_select_region(self):
+        self._region_highlight.clear()
+
+    def select_in_region(self, widget, bounds):
+        if isinstance(widget, Container):
+            bounds = geometry.resolve_bounds(bounds, self)
+            to_select = []
+            for child in widget._children:
+                if geometry.compute_overlap(child.get_bounds(), bounds):
+                    to_select.append(child)
+            if to_select:
+                self.studio.selection.set(to_select)
+
     def _attach(self, obj):
         # bind events for context menu and object selection
         # all widget additions call this method so clear empty message

studio/lib/legacy.py

@@ -35,6 +35,7 @@ class Canvas(PseudoWidget, tk.Canvas):
     icon = "paint"
     impl = tk.Canvas
     allow_direct_move = False
+    allow_drag_select = False
 
     def __init__(self, master, id_):
         super().__init__(master)

studio/lib/pseudo.py

@@ -101,6 +101,7 @@ class PseudoWidget:
     impl = None
     is_toplevel = False
     allow_direct_move = True
+    allow_drag_select = False
     # special handlers (intercepts) for attributes that need additional processing
     # to interface with the studio easily
     _intercepts = {
@@ -145,6 +146,8 @@ def setup_widget(self):
         self.bind("<Motion>", self._on_drag, add='+')
 
         self._active = False
+        self._select_mode_active = False
+        self._select_bounds = None
         self.prev_stack_index = None
 
     def set_name(self, name):
@@ -173,23 +176,41 @@ def lift(self, above_this):
             super().lift(above_this)
 
     def _on_press(self, event):
+        if not self.allow_direct_move and not event.state & EventMask.SHIFT:
+            if not self.allow_drag_select:
+                return
+            self._select_mode_active = True
+            self._pos_fix = (event.x_root, event.y_root)
+            return
         if not self._handle:
             return
         self._pos_fix = (event.x_root, event.y_root)
         self.handle_active('all')
         self._active = True
 
     def _on_release(self, _):
+        if self._select_mode_active:
+            self.designer.clear_select_region()
+            self._select_mode_active = False
+            if self._select_bounds is not None:
+                self.designer.select_in_region(self, self._select_bounds)
+                self._select_bounds = None
+
         if not self._active:
             return
         self.handle_inactive('all')
         self._active = False
 
     def _on_drag(self, event):
+        if self._select_mode_active:
+            x1, y1 = self._pos_fix
+            x2, y2 = event.x_root, event.y_root
+            bounds = min(x1, x2), min(y1, y2), max(x1, x2), max(y1, y2)
+            self._select_bounds = bounds
+            self.designer.show_select_region(bounds)
+
         if not self._active or not event.state & EventMask.MOUSE_BUTTON_1:
             return
-        if not self.allow_direct_move and not event.state & EventMask.SHIFT:
-            return
         x, y = self._pos_fix
         self._pos_fix = (event.x_root, event.y_root)
         self.handle_resize('all', (event.x_root - x, event.y_root - y))
@@ -379,6 +400,7 @@ def __repr__(self):
 class Container(PseudoWidget):
     LAYOUTS = layouts.layouts
     allow_direct_move = False
+    allow_drag_select = True
 
     def setup_widget(self):
         self.parent = self.designer = self._get_designer()

studio/ui/highlight.py

@@ -41,6 +41,10 @@ def clear(self):
             element.place_forget()
 
 
+class RegionHighlighter(WidgetHighlighter):
+    OUTLINE = 1
+
+
 class EdgeIndicator(tk.Frame):
     """
     Generates a conspicuous line at the edges of a widget for various indication purposes