LibWeb: Unify selection and cursor rects for painting

Instead of calculating the cursor rect separately, reuse
PaintableFragment::range_rect() and check for the selection state of
'None' where appropriate.

Author: gmta

Libraries/LibWeb/DOM/Range.cpp

@@ -1163,7 +1163,10 @@ GC::Ref<Geometry::DOMRectList> Range::get_client_rects()
     for (GC::Ptr<Node> node = start_node; node && node != end_node->next_in_pre_order(); node = node->next_in_pre_order()) {
         auto selection_state = Painting::Paintable::SelectionState::Full;
         if (node == start_node && node == end_node) {
-            selection_state = Painting::Paintable::SelectionState::StartAndEnd;
+            if (m_start_offset == m_end_offset)
+                selection_state = Painting::Paintable::SelectionState::None;
+            else
+                selection_state = Painting::Paintable::SelectionState::StartAndEnd;
         } else if (node == start_node) {
             selection_state = Painting::Paintable::SelectionState::Start;
         } else if (node == end_node) {
@@ -1186,17 +1189,12 @@ GC::Ref<Geometry::DOMRectList> Range::get_client_rects()
             // are identical), include scaled DOMRect object (for the part that is selected, not the whole line box).
             auto const& text = static_cast<DOM::Text const&>(*node);
             auto const* paintable = text.paintable();
-            if (paintable) {
-                auto const* containing_block = paintable->containing_block();
-                if (is<Painting::PaintableWithLines>(*containing_block)) {
-                    auto const& paintable_lines = static_cast<Painting::PaintableWithLines const&>(*containing_block);
-                    auto fragments = paintable_lines.fragments();
+            if (paintable && selection_state != Painting::Paintable::SelectionState::None) {
+                if (auto const* paintable_lines = as_if<Painting::PaintableWithLines>(paintable->containing_block())) {
+                    auto fragments = paintable_lines->fragments();
                     for (auto frag = fragments.begin(); frag != fragments.end(); frag++) {
                         auto rect = frag->range_rect(selection_state, start_offset(), end_offset());
-                        if (rect.is_empty())
-                            continue;
-                        rects.append(Geometry::DOMRect::create(realm(),
-                            Gfx::FloatRect(rect)));
+                        rects.append(Geometry::DOMRect::create(realm(), rect.to_type<float>()));
                     }
                 } else {
                     dbgln("FIXME: Failed to get client rects for node {}", node->debug_description());

Libraries/LibWeb/Painting/PaintableBox.cpp

@@ -742,22 +742,9 @@ void paint_cursor_if_needed(DisplayListRecordingContext& context, TextPaintable
     if (caret_color.alpha() == 0)
         return;
 
-    auto fragment_rect = fragment.absolute_rect();
-    auto text = fragment.text();
+    auto cursor_rect = fragment.range_rect(paintable.selection_state(), cursor_position->offset(), cursor_position->offset());
+    VERIFY(cursor_rect.width() == 1);
 
-    auto const& font = fragment.glyph_run() ? fragment.glyph_run()->font() : fragment.layout_node().first_available_font();
-    auto cursor_offset = font.width(text.substring_view(0, cursor_position->offset() - fragment.start_offset()));
-
-    auto font_metrics = font.pixel_metrics();
-
-    auto cursor_height = font_metrics.ascent + font_metrics.descent;
-
-    CSSPixelRect cursor_rect {
-        fragment_rect.x() + CSSPixels::nearest_value_for(cursor_offset),
-        fragment_rect.top() + fragment.baseline() - CSSPixels::nearest_value_for(font_metrics.ascent),
-        1,
-        CSSPixels::nearest_value_for(cursor_height)
-    };
     auto cursor_device_rect = context.rounded_device_rect(cursor_rect).to_type<int>();
 
     context.display_list_recorder().fill_rect(cursor_device_rect, caret_color);

Libraries/LibWeb/Painting/PaintableFragment.cpp

@@ -65,9 +65,6 @@ size_t PaintableFragment::index_in_node_for_point(CSSPixelPoint position) const
 
 CSSPixelRect PaintableFragment::range_rect(Paintable::SelectionState selection_state, size_t start_offset_in_code_units, size_t end_offset_in_code_units) const
 {
-    if (selection_state == Paintable::SelectionState::None)
-        return {};
-
     if (selection_state == Paintable::SelectionState::Full)
         return absolute_rect();
 
@@ -77,16 +74,13 @@ CSSPixelRect PaintableFragment::range_rect(Paintable::SelectionState selection_s
     auto const& font = glyph_run() ? glyph_run()->font() : layout_node().first_available_font();
     auto text = this->text();
 
-    if (selection_state == Paintable::SelectionState::StartAndEnd) {
+    if (first_is_one_of(selection_state, Paintable::SelectionState::StartAndEnd, Paintable::SelectionState::None)) {
         // we are in the start/end node (both the same)
         if (start_index > end_offset_in_code_units)
             return {};
         if (end_index < start_offset_in_code_units)
             return {};
 
-        if (start_offset_in_code_units == end_offset_in_code_units)
-            return {};
-
         auto selection_start_in_this_fragment = max(0, start_offset_in_code_units - m_start_offset);
         auto selection_end_in_this_fragment = min(m_length_in_code_units, end_offset_in_code_units - m_start_offset);
         auto pixel_distance_to_first_selected_character = CSSPixels::nearest_value_for(font.width(text.substring_view(0, selection_start_in_this_fragment)));
@@ -180,7 +174,11 @@ Gfx::Orientation PaintableFragment::orientation() const
 
 CSSPixelRect PaintableFragment::selection_rect() const
 {
-    if (auto focused_area = paintable().document().focused_area(); is<HTML::FormAssociatedTextControlElement>(focused_area.ptr())) {
+    auto const selection_state = paintable().selection_state();
+    if (selection_state == Paintable::SelectionState::None)
+        return {};
+
+    if (auto const* focused_area = as_if<HTML::FormAssociatedTextControlElement>(paintable().document().focused_area().ptr())) {
         HTML::FormAssociatedTextControlElement const* text_control_element = nullptr;
         if (auto const* input_element = as_if<HTML::HTMLInputElement>(*focused_area)) {
             text_control_element = input_element;
@@ -191,7 +189,7 @@ CSSPixelRect PaintableFragment::selection_rect() const
         }
         auto selection_start = text_control_element->selection_start();
         auto selection_end = text_control_element->selection_end();
-        return range_rect(paintable().selection_state(), selection_start, selection_end);
+        return range_rect(selection_state, selection_start, selection_end);
     }
 
     auto selection = paintable().document().get_selection();
@@ -201,7 +199,7 @@ CSSPixelRect PaintableFragment::selection_rect() const
     if (!range)
         return {};
 
-    return range_rect(paintable().selection_state(), range->start_offset(), range->end_offset());
+    return range_rect(selection_state, range->start_offset(), range->end_offset());
 }
 
 Utf16View PaintableFragment::text() const