LibWeb: Basic support for CSS `text-indent: <length-percentage>`

Note that this simple form of text-indent only affects the first line
of formatted content in each block.

Percentages are resolved against the width of the block.

4 files changed, 14 insertions, 0 deletions

diff --git a/Userland/Libraries/LibWeb/CSS/ComputedValues.h b/Userland/Libraries/LibWeb/CSS/ComputedValues.h
index 1098a2264b..9b126ce330 100644
--- a/Userland/Libraries/LibWeb/CSS/ComputedValues.h
+++ b/Userland/Libraries/LibWeb/CSS/ComputedValues.h
@@ -39,6 +39,7 @@ public:
     static CSS::Length text_decoration_thickness() { return Length::make_auto(); }
     static CSS::TextDecorationStyle text_decoration_style() { return CSS::TextDecorationStyle::Solid; }
     static CSS::TextTransform text_transform() { return CSS::TextTransform::None; }
+    static CSS::LengthPercentage text_indent() { return CSS::Length::make_px(0); }
     static CSS::Display display() { return CSS::Display { CSS::Display::Outside::Inline, CSS::Display::Inside::Flow }; }
     static Color color() { return Color::Black; }
     static Color stop_color() { return Color::Black; }
@@ -211,6 +212,7 @@ public:
     Optional<int> const& z_index() const { return m_noninherited.z_index; }
     CSS::TextAlign text_align() const { return m_inherited.text_align; }
     CSS::TextJustify text_justify() const { return m_inherited.text_justify; }
+    CSS::LengthPercentage const& text_indent() const { return m_inherited.text_indent; }
     Vector<CSS::TextDecorationLine> const& text_decoration_line() const { return m_noninherited.text_decoration_line; }
     CSS::LengthPercentage const& text_decoration_thickness() const { return m_noninherited.text_decoration_thickness; }
     CSS::TextDecorationStyle text_decoration_style() const { return m_noninherited.text_decoration_style; }
@@ -310,6 +312,7 @@ protected:
         CSS::TextAlign text_align { InitialValues::text_align() };
         CSS::TextJustify text_justify { InitialValues::text_justify() };
         CSS::TextTransform text_transform { InitialValues::text_transform() };
+        CSS::LengthPercentage text_indent { InitialValues::text_indent() };
         CSS::WhiteSpace white_space { InitialValues::white_space() };
         CSS::ListStyleType list_style_type { InitialValues::list_style_type() };
         CSS::Visibility visibility { InitialValues::visibility() };
@@ -413,6 +416,7 @@ public:
     void set_text_decoration_color(Color value) { m_noninherited.text_decoration_color = value; }
     void set_text_transform(CSS::TextTransform value) { m_inherited.text_transform = value; }
     void set_text_shadow(Vector<ShadowData>&& value) { m_noninherited.text_shadow = move(value); }
+    void set_text_indent(CSS::LengthPercentage value) { m_inherited.text_indent = move(value); }
     void set_position(CSS::Position position) { m_noninherited.position = position; }
     void set_white_space(CSS::WhiteSpace value) { m_inherited.white_space = value; }
     void set_width(CSS::Size const& width) { m_noninherited.width = width; }
diff --git a/Userland/Libraries/LibWeb/Layout/LineBuilder.cpp b/Userland/Libraries/LibWeb/Layout/LineBuilder.cpp
index 9be5355c45..0967203225 100644
--- a/Userland/Libraries/LibWeb/Layout/LineBuilder.cpp
+++ b/Userland/Libraries/LibWeb/Layout/LineBuilder.cpp
@@ -15,6 +15,7 @@ LineBuilder::LineBuilder(InlineFormattingContext& context, LayoutState& layout_s
     , m_layout_state(layout_state)
     , m_containing_block_state(layout_state.get_mutable(context.containing_block()))
 {
+    m_text_indent = m_context.containing_block().computed_values().text_indent().to_px(m_context.containing_block(), m_containing_block_state.content_width());
     begin_new_line(false);
 }
 
@@ -66,6 +67,11 @@ void LineBuilder::begin_new_line(bool increment_y, bool is_first_break_in_sequen
     recalculate_available_space();
     m_max_height_on_current_line = 0;
     m_last_line_needs_update = true;
+
+    // FIXME: Support text-indent with "each-line".
+    if (m_containing_block_state.line_boxes.size() <= 1) {
+        ensure_last_line_box().m_width += m_text_indent;
+    }
 }
 
 LineBox& LineBuilder::ensure_last_line_box()
diff --git a/Userland/Libraries/LibWeb/Layout/LineBuilder.h b/Userland/Libraries/LibWeb/Layout/LineBuilder.h
index 5d07a86c3e..35964764d9 100644
--- a/Userland/Libraries/LibWeb/Layout/LineBuilder.h
+++ b/Userland/Libraries/LibWeb/Layout/LineBuilder.h
@@ -57,6 +57,7 @@ private:
     CSSPixels m_available_width_for_current_line { 0 };
     CSSPixels m_current_y { 0 };
     CSSPixels m_max_height_on_current_line { 0 };
+    CSSPixels m_text_indent { 0 };
 
     bool m_last_line_needs_update { false };
 };
diff --git a/Userland/Libraries/LibWeb/Layout/Node.cpp b/Userland/Libraries/LibWeb/Layout/Node.cpp
index 7b4c21d771..3f494ba0de 100644
--- a/Userland/Libraries/LibWeb/Layout/Node.cpp
+++ b/Userland/Libraries/LibWeb/Layout/Node.cpp
@@ -507,6 +507,9 @@ void NodeWithStyle::apply_style(const CSS::StyleProperties& computed_style)
     if (text_align.has_value())
         computed_values.set_text_justify(text_justify.value());
 
+    if (auto text_indent = computed_style.length_percentage(CSS::PropertyID::TextIndent); text_indent.has_value())
+        computed_values.set_text_indent(text_indent.release_value());
+
     auto white_space = computed_style.white_space();
     if (white_space.has_value())
         computed_values.set_white_space(white_space.value());