HackStudio: Start implementing basic widget selection in CursorTool

You can now select widgets by clicking on them with the CursorTool,
and toggle the selection state of a widget by Ctrl+clicking it.

DevTools/HackStudio/CursorTool.cpp

@@ -1,10 +1,21 @@
 #include "CursorTool.h"
+#include "FormEditorWidget.h"
+#include "FormWidget.h"
 #include <AK/LogStream.h>
 
 void CursorTool::on_mousedown(GMouseEvent& event)
 {
- (void)event;
  dbg() << "CursorTool::on_mousedown";
+ auto& form_widget = m_editor.form_widget();
+ auto result = form_widget.hit_test(event.position(), GWidget::ShouldRespectGreediness::No);
+ if (result.widget && result.widget != &form_widget) {
+ if (event.modifiers() & Mod_Ctrl)
+ m_editor.selection().toggle(*result.widget);
+ else
+ m_editor.selection().set(*result.widget);
+ // FIXME: Do we need to update any part of the FormEditorWidget outside the FormWidget?
+ form_widget.update();
+ }
 }
 
 void CursorTool::on_mouseup(GMouseEvent& event)

DevTools/HackStudio/FormEditorWidget.h

@@ -18,12 +18,61 @@ class FormEditorWidget final : public GScrollableWidget {
 
  void set_tool(NonnullOwnPtr<Tool>);
 
+ class WidgetSelection {
+ public:
+ bool is_empty() const
+ {
+ return m_widgets.is_empty();
+ }
+
+ bool contains(GWidget& widget) const
+ {
+ return m_widgets.contains(&widget);
+ }
+
+ void toggle(GWidget& widget)
+ {
+ if (contains(widget))
+ remove(widget);
+ else
+ add(widget);
+ }
+
+ void set(GWidget& widget)
+ {
+ clear();
+ add(widget);
+ }
+
+ void remove(GWidget& widget)
+ {
+ ASSERT(m_widgets.contains(&widget));
+ m_widgets.remove(&widget);
+ }
+
+ void add(GWidget& widget)
+ {
+ m_widgets.set(&widget);
+ }
+
+ void clear()
+ {
+ m_widgets.clear();
+ }
+
+ WidgetSelection() {}
+ private:
+ HashTable<GWidget*> m_widgets;
+ };
+
+ WidgetSelection& selection() { return m_selection; }
+
 private:
  virtual void paint_event(GPaintEvent&) override;
 
  explicit FormEditorWidget(GWidget* parent);
 
  RefPtr<FormWidget> m_form_widget;
-
  NonnullOwnPtr<Tool> m_tool;
+ WidgetSelection m_selection;
 };

DevTools/HackStudio/FormWidget.cpp

@@ -39,6 +39,21 @@ void FormWidget::paint_event(GPaintEvent& event)
  }
 }
 
+void FormWidget::second_paint_event(GPaintEvent& event)
+{
+ if (editor().selection().is_empty())
+ return;
+
+ GPainter painter(*this);
+ painter.add_clip_rect(event.rect());
+ for_each_child_widget([&](auto& child) {
+ if (editor().selection().contains(child)) {
+ painter.draw_rect(child.relative_rect(), Color::Blue);
+ }
+ return IterationDecision::Continue;
+ });
+}
+
 void FormWidget::mousedown_event(GMouseEvent& event)
 {
  editor().tool().on_mousedown(event);

DevTools/HackStudio/FormWidget.h

@@ -14,6 +14,7 @@ class FormWidget final : public GWidget {
 
 private:
  virtual void paint_event(GPaintEvent&) override;
+ virtual void second_paint_event(GPaintEvent&) override;
  virtual void mousedown_event(GMouseEvent&) override;
  virtual void mouseup_event(GMouseEvent&) override;
  virtual void mousemove_event(GMouseEvent&) override;