Add some primitive text line breaking

src/servo/layout/display_list_builder.rs

@@ -84,14 +84,20 @@ fn box_to_display_items(list: dl::DisplayList, box: @Box, origin: Point2D<au>) {
 
     match box.kind {
       TextBoxKind(subbox) => {
-        let run = copy subbox.run;
-        assert run.is_some();
+        let runs = &mut subbox.runs;
         list.push(~dl::SolidColor(bounds, 255u8, 255u8, 255u8));
-        let glyph_run = text_run_to_dl_glyph_run(run.get_ref());
-        list.push(~dl::Glyphs(bounds, glyph_run));
+
+        let mut bounds = bounds;
+        for uint::range(0, runs.len()) |i| {
+            bounds.size.height = runs[i].size().height;
+            let glyph_run = text_run_to_dl_glyph_run(&mut runs[i]);
+            list.push(~dl::Glyphs(bounds, glyph_run));
+            bounds.origin.y += bounds.size.height;
+        }
         return;
 
-        fn text_run_to_dl_glyph_run(text_run: &TextRun) -> dl::GlyphRun {
+        pure fn text_run_to_dl_glyph_run(text_run: &mut TextRun) ->
+                dl::GlyphRun {
             dl::GlyphRun {
                 glyphs: copy text_run.glyphs
             }

src/servo/layout/text.rs

@@ -1,20 +1,20 @@
 #[doc="Text layout."]
 
 use geom::size::Size2D;
-use gfx::geometry::au;
+use gfx::geometry::{au, px_to_au};
 use servo_text::text_run::TextRun;
 use servo_text::font_library::FontLibrary;
 use base::{Box, TextBoxKind};
 
 struct TextBox {
     text: ~str,
-    mut run: Option<TextRun>,
+    mut runs: ~[TextRun],
 }
 
 fn TextBox(text: ~str) -> TextBox {
     TextBox {
         text: text,
-        run: None,
+        runs: ~[],
     }
 }
 
@@ -33,9 +33,48 @@ impl @Box : TextLayout {
         // FIXME: The font library should not be initialized here
         let flib = FontLibrary();
         let font = flib.get_test_font();
-        let run = TextRun(font, subbox.text);
-        self.bounds.size = run.size();
-        subbox.run = Some(run);
+
+        // Do line breaking.
+        let mut current = TextRun(font, subbox.text);
+        let mut lines = dvec::DVec();
+        let mut width_left = px_to_au(800);
+        let mut max_width = au(0);
+
+        while current.size().width > width_left {
+            let min_width = current.min_break_width();
+
+            debug!("line %d, current width %d, width left %d, min width %d",
+                   lines.len() as int,
+                   *current.size().width as int,
+                   *width_left as int,
+                   *min_width as int);
+
+            if min_width > width_left {
+                // Too bad, we couldn't break. Overflow.
+                break;
+            }
+
+            let (prev_line, next_line) = current.split(font, width_left);
+            let prev_width = prev_line.size().width;
+            if max_width < prev_width {
+                max_width = prev_width;
+            }
+
+            lines.push(move prev_line);
+            current = next_line;
+        }
+
+        let remaining_width = current.size().width;
+        if max_width < remaining_width {
+            max_width = remaining_width;
+        }
+
+        let line_count = 1 + (lines.len() as i32);
+        let total_height = au(*current.size().height * line_count);
+        lines.push(move current);
+
+        self.bounds.size = Size2D(max_width, total_height);
+        subbox.runs = dvec::unwrap(lines);
     }
 }
 

src/servo/text/text_run.rs

@@ -17,8 +17,8 @@ struct TextRun {
 
 impl TextRun {
     /// The size of the entire TextRun
-    fn size() -> Size2D<au> { self.size_ }
-    fn min_break_width() -> au { self.min_break_width_ }
+    pure fn size() -> Size2D<au> { self.size_ }
+    pure fn min_break_width() -> au { self.min_break_width_ }
 
     /// Split a run of text in two
     // FIXME: Should be storing a reference to the Font inside