render: separate text and item alignment

crates/obscura-render/src/dom.rs

@@ -341,6 +341,7 @@ pub fn layout_dom_with_images(
             font_size: Option<f32>,
             font_weight: Option<String>,
             font_family: Option<String>,
+            text_align: Option<taffy::AlignItems>,
             visibility_hidden: bool,
             opacity_product: f32,
             list_style: crate::ListStyle,
@@ -362,6 +363,7 @@ pub fn layout_dom_with_images(
                     font_size: None,
                     font_weight: None,
                     font_family: None,
+                    text_align: None,
                     visibility_hidden: false,
                     opacity_product: 1.0,
                     // CSS initial value of list-style-type.
@@ -466,6 +468,7 @@ pub fn layout_dom_with_images(
                 }
                 match &style.font_weight { Some(w) => inh.font_weight = Some(w.clone()), None => style.font_weight = inh.font_weight.clone() }
                 match &style.font_family { Some(f) => inh.font_family = Some(f.clone()), None => style.font_family = inh.font_family.clone() }
+                match style.text_align { Some(a) => inh.text_align = Some(a), None => style.text_align = inh.text_align }
                 inh.visibility_hidden = style.visibility_hidden.unwrap_or(inh.visibility_hidden);
                 inh.opacity_product *= style.opacity.unwrap_or(1.0);
                 style.effectively_invisible = inh.visibility_hidden || inh.opacity_product < 0.02;
@@ -2056,17 +2059,11 @@ fn build(
         taffy_style.flex_direction = taffy::FlexDirection::Row;
         taffy_style.flex_wrap = taffy::FlexWrap::Wrap;
 
-        // Before promotion, `align_items` was the horizontal-position stand-in
+        // The promoted container's main axis is horizontal, so text alignment
-        // for a column container (from `text-align` or `<center>`; see
+        // belongs on `justify_content`. Real `justify-content` from actual CSS
-        // `style::apply_value`'s "text-align" arm): correct there, since a
+        // wins if present.
-        // column's cross axis is horizontal. The promoted container's *main*
-        // axis is horizontal instead, so that same "where should content sit
-        // horizontally" intent now belongs on `justify_content`, not
-        // `align_items` — otherwise e.g. `text-align: right` shoves wrapped
-        // text to the bottom of its line (the new cross axis) rather than to
-        // the right. Real `justify-content` from actual CSS wins if present.
         if style.justify_content.is_none() {
-            taffy_style.justify_content = match style.align_items {
+            taffy_style.justify_content = match style.text_align {
                 Some(taffy::AlignItems::FLEX_END) => Some(taffy::JustifyContent::FLEX_END),
                 Some(taffy::AlignItems::CENTER) => Some(taffy::JustifyContent::CENTER),
                 _ => taffy_style.justify_content,
@@ -2349,11 +2346,11 @@ fn run_leaf_style() -> taffy::Style {
 
 /// Style for an anonymous inline-run wrapper: a full-width block-level box
 /// whose interior is the flex-wrap approximation of an inline formatting
-/// context. The parent's `text-align` stand-in (align_items) moves the run's
+/// context. The parent's `text-align` moves the run's line content via
-/// line content via justify-content, exactly as the old whole-container
+/// justify-content, exactly as the old whole-container
 /// promotion did, but scoped to the run so sibling blocks stay full width.
 fn run_wrapper_style(parent: &crate::LayoutStyle) -> taffy::Style {
-    let justify = match parent.align_items {
+    let justify = match parent.text_align {
         Some(taffy::AlignItems::FLEX_END) => Some(taffy::JustifyContent::FLEX_END),
         Some(taffy::AlignItems::CENTER) => Some(taffy::JustifyContent::CENTER),
         _ => None,

crates/obscura-render/src/inline.rs

@@ -246,7 +246,7 @@ impl TextEngine {
         let rich = spans.iter().map(|(t, a)| (t.as_str(), a.to_attrs()));
         buffer.set_rich_text(&mut self.font_system, rich, Attrs::new().family(Family::Name(FAMILY)), Shaping::Advanced);
 
-        let align = match base.align_items {
+        let align = match base.text_align {
             Some(taffy::AlignItems::CENTER) => Some(Align::Center),
             Some(taffy::AlignItems::FLEX_END) => Some(Align::End),
             _ => None,

crates/obscura-render/src/lib.rs

@@ -278,6 +278,10 @@ pub struct LayoutStyle {
     /// resolves it to a bundled face (Liberation Sans/Serif/Mono) the way
     /// Chromium picks a generic family on this host.
     pub font_family: Option<String>,
+    /// Inherited `text-align`, represented with the matching horizontal
+    /// alignment keywords. Kept separate from flex/grid `align-items`: using
+    /// one field for both made `text-align:left` shrink-wrap flex children.
+    pub text_align: Option<taffy::AlignItems>,
     pub align_items: Option<taffy::AlignItems>,
     pub flex_direction: Option<taffy::FlexDirection>,
     pub flex_wrap: Option<taffy::FlexWrap>,
@@ -644,16 +648,12 @@ pub(crate) fn to_taffy_style(style: &LayoutStyle) -> Style {
         BoxSizing::Inherit => taffy::BoxSizing::ContentBox,
     };
 
-    // A block box that wants non-default cross-axis alignment (from
+    // A block box with centered/right inline content needs a flex-column
-    // text-align: center/right, the only way our engine currently sets
+    // stand-in because taffy's native block algorithm has no line alignment.
-    // align_items on a block-level element) needs a flex column to have any
+    // `text_align` is separate from real flex/grid `align-items`, so a
-    // effect at all: taffy's native block algorithm (used for plain
+    // text-align declaration never changes how flex children are sized.
-    // Display::Block) has no align-items concept whatsoever, it only ever
-    // places block children at the start edge. Promote such boxes to a flex
-    // column, matching the same column-flex approximation already used for
-    // elements like <td> and <center>.
     let promote_for_alignment = style.display == Display::Block
-        && matches!(style.align_items, Some(taffy::AlignItems::CENTER) | Some(taffy::AlignItems::FLEX_END));
+        && matches!(style.text_align, Some(taffy::AlignItems::CENTER) | Some(taffy::AlignItems::FLEX_END));
 
     s.display = match style.display {
         Display::Block if promote_for_alignment => taffy::style::Display::Flex,
@@ -665,6 +665,7 @@ pub(crate) fn to_taffy_style(style: &LayoutStyle) -> Style {
     };
     if promote_for_alignment {
         s.flex_direction = taffy::FlexDirection::Column;
+        s.align_items = style.text_align;
     }
     if let Some(fd) = style.flex_direction {
         s.flex_direction = fd;
@@ -704,9 +705,14 @@ pub(crate) fn to_taffy_style(style: &LayoutStyle) -> Style {
             s.aspect_ratio = Some(ar);
         }
     }
+    if style.display != Display::Block {
         if let Some(ai) = style.align_items {
             s.align_items = Some(ai);
         }
+    } else if !promote_for_alignment {
+        // `align-items` has no effect on a block formatting context.
+        s.align_items = None;
+    }
     if let Some(jc) = style.justify_content {
         s.justify_content = Some(jc);
     }

crates/obscura-render/src/style.rs

@@ -394,15 +394,13 @@ fn apply_value(style: &mut LayoutStyle, name: &str, value: &str) {
                 style.font_family = Some(v);
             }
         }
-        // Our engine has no real inline formatting context, so text-align is
+        // Text alignment is inherited and applies to inline line boxes. It is
-        // approximated the same way as align-items: it positions a block's
+        // deliberately separate from flex/grid `align-items`, which positions
-        // (or column-flex's) children along the cross axis. See
+        // child boxes rather than text inside them.
-        // `to_taffy_style`'s block-to-flex-column promotion, which is what
-        // makes this actually take effect on plain block elements.
         "text-align" => match value {
-            "right" => style.align_items = Some(taffy::AlignItems::FLEX_END),
+            "right" | "end" => style.text_align = Some(taffy::AlignItems::FLEX_END),
-            "center" => style.align_items = Some(taffy::AlignItems::CENTER),
+            "center" => style.text_align = Some(taffy::AlignItems::CENTER),
-            "left" | "start" | "justify" => style.align_items = Some(taffy::AlignItems::FLEX_START),
+            "left" | "start" | "justify" => style.text_align = Some(taffy::AlignItems::FLEX_START),
             _ => {}
         },
         "align-items" => {