LibWeb: Move mouse event and label logic from layout to painting tree

Input events have nothing to do with layout, so let's not send them to
layout nodes.

The job of Paintable starts to become clear. It represents a paintable
item that can be rendered into the viewport, which means it can also
be targeted by the mouse cursor.

1 files changed, 85 insertions, 2 deletions

diff --git a/Userland/Libraries/LibWeb/Painting/ButtonPaintable.cpp b/Userland/Libraries/LibWeb/Painting/ButtonPaintable.cpp
index 87c343ca83..dd406293bb 100644
--- a/Userland/Libraries/LibWeb/Painting/ButtonPaintable.cpp
+++ b/Userland/Libraries/LibWeb/Painting/ButtonPaintable.cpp
@@ -4,8 +4,11 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
+#include <LibGUI/Event.h>
+#include <LibWeb/HTML/BrowsingContext.h>
 #include <LibWeb/HTML/HTMLImageElement.h>
 #include <LibWeb/Layout/ButtonBox.h>
+#include <LibWeb/Layout/Label.h>
 #include <LibWeb/Painting/ButtonPaintable.h>
 
 namespace Web::Painting {
@@ -16,7 +19,7 @@ NonnullRefPtr<ButtonPaintable> ButtonPaintable::create(Layout::ButtonBox const&
 }
 
 ButtonPaintable::ButtonPaintable(Layout::ButtonBox const& layout_box)
-    : PaintableBox(layout_box)
+    : LabelablePaintable(layout_box)
 {
 }
 
@@ -25,6 +28,11 @@ Layout::ButtonBox const& ButtonPaintable::layout_box() const
     return static_cast<Layout::ButtonBox const&>(layout_node());
 }
 
+Layout::ButtonBox& ButtonPaintable::layout_box()
+{
+    return static_cast<Layout::ButtonBox&>(layout_node());
+}
+
 void ButtonPaintable::paint(PaintContext& context, PaintPhase phase) const
 {
     if (!is_visible())
@@ -34,10 +42,85 @@ void ButtonPaintable::paint(PaintContext& context, PaintPhase phase) const
 
     if (phase == PaintPhase::Foreground) {
         auto text_rect = enclosing_int_rect(absolute_rect());
-        if (layout_box().being_pressed())
+        if (m_being_pressed)
             text_rect.translate_by(1, 1);
         context.painter().draw_text(text_rect, layout_box().dom_node().value(), layout_box().font(), Gfx::TextAlignment::Center, computed_values().color());
     }
 }
 
+void ButtonPaintable::handle_mousedown(Badge<EventHandler>, const Gfx::IntPoint&, unsigned button, unsigned)
+{
+    if (button != GUI::MouseButton::Primary || !layout_box().dom_node().enabled())
+        return;
+
+    m_being_pressed = true;
+    set_needs_display();
+
+    m_tracking_mouse = true;
+    browsing_context().event_handler().set_mouse_event_tracking_layout_node(&layout_box());
+}
+
+void ButtonPaintable::handle_mouseup(Badge<EventHandler>, const Gfx::IntPoint& position, unsigned button, unsigned)
+{
+    if (!m_tracking_mouse || button != GUI::MouseButton::Primary || !layout_box().dom_node().enabled())
+        return;
+
+    // NOTE: Handling the click may run arbitrary JS, which could disappear this node.
+    NonnullRefPtr protected_this = *this;
+    NonnullRefPtr protected_browsing_context = browsing_context();
+
+    bool is_inside_node_or_label = enclosing_int_rect(absolute_rect()).contains(position);
+    if (!is_inside_node_or_label)
+        is_inside_node_or_label = Layout::Label::is_inside_associated_label(layout_box(), position);
+
+    if (is_inside_node_or_label)
+        const_cast<Layout::ButtonBox&>(layout_box()).dom_node().did_click_button({});
+
+    m_being_pressed = false;
+    m_tracking_mouse = false;
+
+    protected_browsing_context->event_handler().set_mouse_event_tracking_layout_node(nullptr);
+}
+
+void ButtonPaintable::handle_mousemove(Badge<EventHandler>, const Gfx::IntPoint& position, unsigned, unsigned)
+{
+    if (!m_tracking_mouse || !layout_box().dom_node().enabled())
+        return;
+
+    bool is_inside_node_or_label = enclosing_int_rect(absolute_rect()).contains(position);
+    if (!is_inside_node_or_label)
+        is_inside_node_or_label = Layout::Label::is_inside_associated_label(layout_box(), position);
+
+    if (m_being_pressed == is_inside_node_or_label)
+        return;
+
+    m_being_pressed = is_inside_node_or_label;
+    set_needs_display();
+}
+
+void ButtonPaintable::handle_associated_label_mousedown(Badge<Layout::Label>)
+{
+    m_being_pressed = true;
+    set_needs_display();
+}
+
+void ButtonPaintable::handle_associated_label_mouseup(Badge<Layout::Label>)
+{
+    // NOTE: Handling the click may run arbitrary JS, which could disappear this node.
+    NonnullRefPtr protected_this = *this;
+    NonnullRefPtr protected_browsing_context = browsing_context();
+
+    layout_box().dom_node().did_click_button({});
+    m_being_pressed = false;
+}
+
+void ButtonPaintable::handle_associated_label_mousemove(Badge<Layout::Label>, bool is_inside_node_or_label)
+{
+    if (m_being_pressed == is_inside_node_or_label)
+        return;
+
+    m_being_pressed = is_inside_node_or_label;
+    set_needs_display();
+}
+
 }