LibVT: Don't commit to opening a hyperlink until mouseup

It felt too rushed to open links when simply mousedown'ing on them.
Improve this by implementing basic "click" semantics instead.

This patch also introduces the ability to prevent link opening if you
want to force selection instead. Hold shift and we will not open links.

Libraries/LibVT/TerminalWidget.cpp

@@ -388,12 +388,28 @@ void TerminalWidget::paint_event(GUI::PaintEvent& event)
                     painter.clear_rect(cell_rect, color_from_rgb(should_reverse_fill_for_cursor_or_selection ? attribute.foreground_color : attribute.background_color).with_alpha(m_opacity));
                 }
 
-                bool should_paint_underline = attribute.flags & VT::Attribute::Underline
-                    || (!m_hovered_href.is_empty() && m_hovered_href_id == attribute.href_id);
-
-                bool should_paint_dotted_underline = !attribute.href.is_empty() && m_hovered_href_id != attribute.href_id;
+                enum class UnderlineStyle {
+                    None,
+                    Dotted,
+                    Solid,
+                };
+
+                auto underline_style = UnderlineStyle::None;
+
+                if (attribute.flags & VT::Attribute::Underline) {
+                    // Content has specified underline
+                    underline_style = UnderlineStyle::Solid;
+                } else if (!attribute.href.is_empty()) {
+                    // We're hovering a hyperlink
+                    if (m_hovered_href_id == attribute.href_id)
+                        underline_style = UnderlineStyle::Solid;
+                    else
+                        underline_style = UnderlineStyle::Dotted;
+                }
 
-                if (should_paint_dotted_underline) {
+                if (underline_style == UnderlineStyle::Solid) {
+                    painter.draw_line(cell_rect.bottom_left(), cell_rect.bottom_right(), color_from_rgb(should_reverse_fill_for_cursor_or_selection ? attribute.background_color : attribute.foreground_color));
+                } else if (underline_style == UnderlineStyle::Dotted) {
                     auto color = color_from_rgb(should_reverse_fill_for_cursor_or_selection ? attribute.background_color : attribute.foreground_color).darkened(0.6f);
                     int x1 = cell_rect.bottom_left().x();
                     int x2 = cell_rect.bottom_right().x();
@@ -402,8 +418,6 @@ void TerminalWidget::paint_event(GUI::PaintEvent& event)
                         if ((x % 3) == 0)
                             painter.set_pixel({ x, y }, color);
                     }
-                } else if (should_paint_underline) {
-                    painter.draw_line(cell_rect.bottom_left(), cell_rect.bottom_right(), color_from_rgb(should_reverse_fill_for_cursor_or_selection ? attribute.background_color : attribute.foreground_color));
                 }
             }
 
@@ -616,15 +630,28 @@ void TerminalWidget::copy()
         GUI::Clipboard::the().set_data(selected_text());
 }
 
-void TerminalWidget::mousedown_event(GUI::MouseEvent& event)
+void TerminalWidget::mouseup_event(GUI::MouseEvent& event)
 {
     if (event.button() == GUI::MouseButton::Left) {
         auto attribute = m_terminal.attribute_at(buffer_position_at(event.position()));
-        if (!attribute.href.is_empty()) {
+        if (!m_active_href_id.is_null() && attribute.href_id == m_active_href_id) {
             dbg() << "Open hyperlinked URL: _" << attribute.href << "_";
             Desktop::Launcher::open(attribute.href);
+        }
+        m_active_href_id = {};
+    }
+    return;
+}
+
+void TerminalWidget::mousedown_event(GUI::MouseEvent& event)
+{
+    if (event.button() == GUI::MouseButton::Left) {
+        auto attribute = m_terminal.attribute_at(buffer_position_at(event.position()));
+        if (!(event.modifiers() & Mod_Shift) && !attribute.href.is_empty()) {
+            m_active_href_id = attribute.href_id;
             return;
         }
+        m_active_href_id = {};
 
         if (m_triple_click_timer.is_valid() && m_triple_click_timer.elapsed() < 250) {
             int start_column = 0;
@@ -651,9 +678,15 @@ void TerminalWidget::mousemove_event(GUI::MouseEvent& event)
     auto position = buffer_position_at(event.position());
 
     auto attribute = m_terminal.attribute_at(position);
+
     if (attribute.href_id != m_hovered_href_id) {
-        m_hovered_href_id = attribute.href_id;
-        m_hovered_href = attribute.href;
+        if (m_active_href_id.is_null() || m_active_href_id == attribute.href_id) {
+            m_hovered_href_id = attribute.href_id;
+            m_hovered_href = attribute.href;
+        } else {
+            m_hovered_href_id = {};
+            m_hovered_href = {};
+        }
         if (!m_hovered_href.is_empty())
             window()->set_override_cursor(GUI::StandardCursor::Hand);
         else
@@ -664,6 +697,9 @@ void TerminalWidget::mousemove_event(GUI::MouseEvent& event)
     if (!(event.buttons() & GUI::MouseButton::Left))
         return;
 
+    if (!m_active_href_id.is_null())
+        return;
+
     auto old_selection_end = m_selection_end;
     m_selection_end = position;
     if (old_selection_end != m_selection_end)

Libraries/LibVT/TerminalWidget.h

@@ -94,6 +94,7 @@ private:
     virtual void keydown_event(GUI::KeyEvent&) override;
     virtual void keyup_event(GUI::KeyEvent&) override;
     virtual void mousedown_event(GUI::MouseEvent&) override;
+    virtual void mouseup_event(GUI::MouseEvent&) override;
     virtual void mousemove_event(GUI::MouseEvent&) override;
     virtual void mousewheel_event(GUI::MouseEvent&) override;
     virtual void doubleclick_event(GUI::MouseEvent&) override;
@@ -133,6 +134,8 @@ private:
     String m_hovered_href;
     String m_hovered_href_id;
 
+    String m_active_href_id;
+
     // Snapshot of m_hovered_href when opening a context menu for a hyperlink.
     String m_context_menu_href;