servo: Introduce text run and glyph classes

Source-Repo: https://github.com/servo/servo
Source-Revision: 0f5eb549ab5c32dc118112311618938e55629b68

servo/src/servo/layout/base.rs

@@ -8,13 +8,14 @@ import gfx::geom::{size, rect, point, au, zero_size_au};
 import /*layout::*/block::block_layout_methods;
 import /*layout::*/inline::inline_layout_methods;
 import /*layout::*/style::style::*;
+import /*layout::*/text::{text_box, text_layout_methods};
 import util::tree;
 
 enum box_kind {
     bk_block,
     bk_inline,
     bk_intrinsic(@geom::size<au>),
-    bk_text(str)
+    bk_text(@text_box)
 }
 
 enum box = {
@@ -84,7 +85,7 @@ impl layout_methods for @box {
             bk_block { self.reflow_block(available_width) }
             bk_inline { self.reflow_inline(available_width) }
             bk_intrinsic(size) { self.reflow_intrinsic(*size) }
-            bk_text(s) { self.reflow_text(s) }
+            bk_text(subbox) { self.reflow_text(available_width, subbox) }
         }
     }
 
@@ -95,14 +96,6 @@ impl layout_methods for @box {
         #debug["reflow_intrinsic size=%?", self.bounds];
     }
 
-    #[doc="The reflow routine for text frames."]
-    fn reflow_text(text: str) {
-        self.bounds.size = {
-            mut width: au(text.len() as int * 60 * 10),
-            mut height: au(60 * 14)
-        };
-    }
-
     #[doc="Dumps the box tree, for debugging."]
     fn dump() {
         self.dump_indent(0u);

servo/src/servo/layout/box_builder.rs

@@ -7,6 +7,7 @@ import /*layout::*/base::{bk_block, bk_inline, bk_intrinsic, bk_text, box};
 import /*layout::*/base::{box_kind, btree, node_methods, ntree, rd_tree_ops};
 import /*layout::*/base::wr_tree_ops;
 import /*layout::*/style::style::{di_block, di_inline, style_methods};
+import /*layout::*/text::text_box;
 import util::tree;
 
 export box_builder_methods;
@@ -118,9 +119,9 @@ impl box_builder_priv for node {
     "]
     fn determine_box_kind() -> box_kind {
         alt self.rd({ |n| n.kind }) {
-            nk_img(size) { bk_intrinsic(@size) }
-            nk_div       { bk_block            }
-            nk_text(s)   { bk_text(s)          }
+            nk_img(size) { bk_intrinsic(@size)   }
+            nk_div       { bk_block              }
+            nk_text(s)   { bk_text(@text_box(s)) }
         }
     }
 }

servo/src/servo/layout/text.rs

@@ -0,0 +1,41 @@
+#[doc="Text layout."]
+
+import gfx::geom::au;
+import /*layout::*/base::*; // FIXME: Can't get around import *; resolve bug.
+import servo_text::text_run::text_run;
+
+class text_box {
+    let text: str;
+    let mut run: option<text_run>;
+
+    new(text: str) {
+        self.text = text;
+        self.run = none;
+    }
+}
+
+#[doc="The main reflow routine for text layout."]
+impl text_layout_methods for @box {
+    fn reflow_text(_available_width: au, subbox: @text_box) {
+        alt self.kind {
+            bk_text(*) { /* ok */ }
+            _ { fail "expected text box in reflow_text!" }
+        };
+
+        let run = text_run(subbox.text);
+        subbox.run = some(run);
+        run.shape();
+
+        self.bounds.size = {
+            mut width:
+                alt vec::last_opt(run.glyphs.get()) {
+                    some(glyph) {
+                        au(*glyph.pos.offset.x + *glyph.pos.advance.x)
+                    }
+                    none { au(0) }
+                },
+            mut height: au(60 * 14)
+        };
+    }
+}
+

servo/src/servo/servo.rc

@@ -43,6 +43,7 @@ mod layout {
     mod display_list;
     mod inline;
     mod layout;
+    mod text;
 }
 
 mod parser {
@@ -55,6 +56,11 @@ mod platform {
     mod osmain;
 }
 
+mod text {
+    mod glyph;
+    mod text_run;
+}
+
 mod util {
     mod tree;
 }
@@ -66,3 +72,6 @@ mod content {
 
 mod opts;
 mod engine;
+
+import servo_text = text;
+

servo/src/servo/text/glyph.rs

@@ -0,0 +1,30 @@
+import gfx::geom::{au, point, px_to_au};
+
+#[doc="The position of a glyph on the screen."]
+class glyph_pos {
+    let advance: point<au>;
+    let offset: point<au>;
+
+    new(hb_pos: harfbuzz::hb_glyph_position_t) {
+        self.advance = {
+            mut x: px_to_au(hb_pos.x_advance as int),
+            mut y: px_to_au(hb_pos.y_advance as int)
+        };
+        self.offset = {
+            mut x: px_to_au(hb_pos.x_offset as int),
+            mut y: px_to_au(hb_pos.y_offset as int)
+        };
+    }
+}
+
+#[doc="A single glyph."]
+class glyph {
+    let codepoint: uint;
+    let pos: glyph_pos;
+
+    new(codepoint: uint, pos: glyph_pos) {
+        self.codepoint = codepoint;
+        self.pos = pos;
+    }
+}
+

servo/src/servo/text/text_run.rs

@@ -0,0 +1,40 @@
+import libc::{c_void};
+import libc::types::common::c99::int32_t;
+import text::glyph::{glyph, glyph_pos};
+
+#[doc="A single, unbroken line of text."]
+class text_run {
+    let text: str;
+    let mut glyphs: option<[glyph]>;
+
+    new(text: str) {
+        self.text = text;
+        self.glyphs = none;
+    }
+
+    #[doc="
+        Shapes text. This determines the location of each glyph and determines
+        line break positions.
+    "]
+    fn shape() {
+        let mut glyphs = [];
+        let mut cur_x = 0u;
+        for self.text.each_char {
+            |ch|
+            // TODO: Use HarfBuzz!
+            let hb_pos = {
+                x_advance: 10 as int32_t,
+                y_advance: 0 as int32_t,
+                x_offset: cur_x as int32_t,
+                y_offset: 0 as int32_t,
+                var: 0
+            };
+
+            vec::push(glyphs, glyph(ch as uint, glyph_pos(hb_pos)));
+            cur_x += 10u;
+        };
+
+        self.glyphs = some(/* move */ glyphs);
+    }
+}
+