VisualBuilder: Work on selecting a widget and moving it around.

Applications/VisualBuilder/.gitignore

@@ -1,3 +1,3 @@
 *.o
 *.d
-InterfaceEditor
+VisualBuilder

Applications/VisualBuilder/VBForm.cpp

@@ -1,4 +1,5 @@
 #include "VBForm.h"
+#include "VBWidget.h"
 #include <LibGUI/GPainter.h>
 
 VBForm::VBForm(const String& name, GWidget* parent)
@@ -6,6 +7,14 @@ VBForm::VBForm(const String& name, GWidget* parent)
 {
     set_fill_with_background_color(true);
     set_background_color(Color::LightGray);
+
+    auto box1 = VBWidget::create(*this);
+    box1->set_rect({ 10, 10, 61, 41 });
+    m_widgets.append(move(box1));
+
+    auto box2 = VBWidget::create(*this);
+    box2->set_rect({ 100, 100, 161, 141 });
+    m_widgets.append(move(box2));
 }
 
 VBForm::~VBForm()
@@ -22,4 +31,61 @@ void VBForm::paint_event(GPaintEvent& event)
             painter.set_pixel({ x, y }, Color::Black);
         }
     }
+
+    for (auto& widget : m_widgets) {
+        widget->paint(painter);
+    }
+}
+
+bool VBForm::is_selected(const VBWidget& widget) const
+{
+    return &widget == m_selected_widget.ptr();
+}
+
+VBWidget* VBForm::widget_at(const Point& position)
+{
+    for (int i = m_widgets.size() - 1; i >= 0; --i) {
+        auto& widget = *m_widgets[i];
+        if (widget.rect().contains(position))
+            return &widget;
+    }
+    return nullptr;
+}
+
+void VBForm::mousedown_event(GMouseEvent& event)
+{
+    auto* widget = widget_at(event.position());
+    if (!widget) {
+        if (m_selected_widget) {
+            m_selected_widget = nullptr;
+            update();
+        }
+        return;
+    }
+    if (event.button() == GMouseButton::Left) {
+        m_selected_widget = widget->make_weak_ptr();
+        m_transform_event_origin = event.position();
+        m_transform_widget_origin_rect = widget->rect();
+        update();
+    }
+}
+
+void VBForm::mousemove_event(GMouseEvent& event)
+{
+    if (event.buttons() & GMouseButton::Left && m_selected_widget) {
+        auto delta = event.position() - m_transform_event_origin;
+        auto new_rect = m_transform_widget_origin_rect.translated(delta);
+        new_rect.set_x(new_rect.x() - (new_rect.x() % m_grid_size));
+        new_rect.set_y(new_rect.y() - (new_rect.y() % m_grid_size));
+        m_selected_widget->set_rect(new_rect);
+        update();
+    }
+}
+
+void VBForm::mouseup_event(GMouseEvent& event)
+{
+    if (event.button() == GMouseButton::Left) {
+        m_transform_event_origin = { };
+        m_transform_widget_origin_rect = { };
+    }
 }

Applications/VisualBuilder/VBForm.h

@@ -9,12 +9,24 @@ public:
     explicit VBForm(const String& name, GWidget* parent = nullptr);
     virtual ~VBForm() override;
 
+    bool is_selected(const VBWidget&) const;
+    VBWidget* widget_at(const Point&);
+
+    void set_should_snap_to_grip(bool snap) { m_should_snap_to_grid = snap; }
+    bool should_snap_to_grid() const { return m_should_snap_to_grid; }
+
 protected:
     virtual void paint_event(GPaintEvent&) override;
+    virtual void mousedown_event(GMouseEvent&) override;
+    virtual void mousemove_event(GMouseEvent&) override;
+    virtual void mouseup_event(GMouseEvent&) override;
 
 private:
     String m_name;
     int m_grid_size { 5 };
-
-    Vector<VBWidget*> m_widgets;
+    bool m_should_snap_to_grid { true };
+    Vector<Retained<VBWidget>> m_widgets;
+    WeakPtr<VBWidget> m_selected_widget;
+    Point m_transform_event_origin;
+    Rect m_transform_widget_origin_rect;
 };

Applications/VisualBuilder/VBWidget.cpp

@@ -0,0 +1,55 @@
+#include "VBWidget.h"
+#include "VBForm.h"
+#include <LibGUI/GPainter.h>
+
+VBWidget::VBWidget(VBForm& form)
+    : m_form(form)
+{
+}
+
+VBWidget::~VBWidget()
+{
+}
+
+bool VBWidget::is_selected() const
+{
+    return m_form.is_selected(*this);
+}
+
+Rect VBWidget::grabber_rect(Direction direction) const
+{
+    int grabber_size = 5;
+    int half_grabber_size = grabber_size / 2;
+    switch (direction) {
+    case Direction::Left:
+        return { m_rect.x() - half_grabber_size, m_rect.center().y() - half_grabber_size, grabber_size, grabber_size };
+    case Direction::UpLeft:
+        return { m_rect.x() - half_grabber_size, m_rect.y() - half_grabber_size, grabber_size, grabber_size };
+    case Direction::Up:
+        return { m_rect.center().x() - half_grabber_size, m_rect.y() - half_grabber_size, grabber_size, grabber_size };
+    case Direction::UpRight:
+        return { m_rect.right() - half_grabber_size, m_rect.y() - half_grabber_size, grabber_size, grabber_size };
+    case Direction::Right:
+        return { m_rect.right() - half_grabber_size, m_rect.center().y() - half_grabber_size, grabber_size, grabber_size };
+    case Direction::DownLeft:
+        return { m_rect.x() - half_grabber_size, m_rect.bottom() - half_grabber_size, grabber_size, grabber_size };
+    case Direction::Down:
+        return { m_rect.center().x() - half_grabber_size, m_rect.bottom() - half_grabber_size, grabber_size, grabber_size };
+    case Direction::DownRight:
+        return { m_rect.right() - half_grabber_size, m_rect.bottom() - half_grabber_size, grabber_size, grabber_size };
+    default:
+        ASSERT_NOT_REACHED();
+    }
+}
+
+void VBWidget::paint(GPainter& painter)
+{
+    painter.fill_rect(m_rect, Color::White);
+    painter.draw_rect(m_rect, Color::Black);
+
+    if (is_selected()) {
+        for_each_direction([&] (Direction direction) {
+            painter.fill_rect(grabber_rect(direction), Color::Black);
+        });
+    }
+}

Applications/VisualBuilder/VBWidget.h

@@ -1,15 +1,44 @@
 #pragma once
 
 #include <SharedGraphics/Rect.h>
+#include <AK/Retainable.h>
+#include <AK/Retained.h>
+#include <AK/Weakable.h>
 
-class VBWidget {
+class GPainter;
+class VBForm;
+
+enum class Direction { None, Left, UpLeft, Up, UpRight, Right, DownRight, Down, DownLeft };
+template<typename Callback>
+inline void for_each_direction(Callback callback)
+{
+    callback(Direction::Left);
+    callback(Direction::UpLeft);
+    callback(Direction::Up);
+    callback(Direction::UpRight);
+    callback(Direction::Right);
+    callback(Direction::DownRight);
+    callback(Direction::Down);
+    callback(Direction::DownLeft);
+}
+
+class VBWidget : public Retainable<VBWidget>, public Weakable<VBWidget> {
 public:
-    VBWidget();
+    static Retained<VBWidget> create(VBForm& form) { return adopt(*new VBWidget(form)); }
     virtual ~VBWidget();
 
+    bool is_selected() const;
+
     Rect rect() const { return m_rect; }
     void set_rect(const Rect& rect) { m_rect = rect; }
 
+    Rect grabber_rect(Direction) const;
+
+    void paint(GPainter&);
+
 private:
+    VBWidget(VBForm&);
+
+    VBForm& m_form;
     Rect m_rect;
 };