1 files changed, 42 insertions, 1 deletions
diff --git a/Userland/Applications/PixelPaint/Selection.cpp b/Userland/Applications/PixelPaint/Selection.cpp
index db93e751f0..6e645e9ddb 100644
--- a/Userland/Applications/PixelPaint/Selection.cpp
+++ b/Userland/Applications/PixelPaint/Selection.cpp
@@ -10,9 +10,50 @@
 
 namespace PixelPaint {
 
+constexpr int marching_ant_length = 4;
+
 void Selection::paint(Gfx::Painter& painter, ImageEditor const& editor)
 {
-    painter.draw_rect(editor.image_rect_to_editor_rect(m_rect).to_type<int>(), Color::Magenta);
+    draw_marching_ants(painter, editor.image_rect_to_editor_rect(m_rect).to_type<int>());
+}
+
+Selection::Selection(ImageEditor& editor)
+    : m_editor(editor)
+{
+    m_marching_ants_timer = Core::Timer::create_repeating(80, [this] {
+        ++m_marching_ants_offset;
+        m_marching_ants_offset %= marching_ant_length;
+        if (!is_empty())
+            m_editor.update();
+    });
+    m_marching_ants_timer->start();
+}
+
+void Selection::draw_marching_ants(Gfx::Painter& painter, Gfx::IntRect const& rect) const
+{
+    int offset = m_marching_ants_offset;
+
+    auto draw_pixel = [&](int x, int y) {
+        if ((offset % marching_ant_length) != 0)
+            painter.set_pixel(x, y, Color::Black);
+        offset++;
+    };
+
+    // Top line
+    for (int x = rect.left(); x <= rect.right(); ++x)
+        draw_pixel(x, rect.top());
+
+    // Right line
+    for (int y = rect.top() + 1; y <= rect.bottom(); ++y)
+        draw_pixel(rect.right(), y);
+
+    // Bottom line
+    for (int x = rect.right() - 1; x >= rect.left(); --x)
+        draw_pixel(x, rect.bottom());
+
+    // Left line
+    for (int y = rect.bottom() - 1; y > rect.top(); --y)
+        draw_pixel(rect.left(), y);
 }
 
 }