Add Font.shape_text(), and instantiate/reuse Shaper instance off of Font lazily. Shaper now takes a font, text, and glyph storage.

src/servo/text/font.rs

@@ -11,9 +11,10 @@ use gfx::render_context::RenderContext;
 use geom::point::Point2D;
 use geom::rect::Rect;
 use geom::size::Size2D;
-use glyph::GlyphIndex;
+use glyph::{GlyphStore, GlyphIndex};
 use native_font::NativeFont;
 use servo_util::range::Range;
+use shaper::Shaper;
 use text::text_run::TextRun;
 
 // Used to abstract over the shaper's choice of fixed int representation.
@@ -83,6 +84,7 @@ struct Font {
     priv fontbuf: @~[u8],
     priv native_font: NativeFont,
     priv mut azure_font: Option<AzScaledFontRef>,
+    priv mut shaper: Option<@Shaper>,
     style: FontStyle,
     metrics: FontMetrics,
 
@@ -102,11 +104,25 @@ impl Font {
             fontbuf : fontbuf,
             native_font : move native_font,
             azure_font: None,
+            shaper: None,
             style: move style,
             metrics: move metrics,
         }
     }
 
+    priv fn get_shaper(&self) -> @Shaper {
+        // fast path: already created a shaper
+        match self.shaper {
+            Some(shaper) => { return shaper; },
+            None => {}
+        }
+
+        // XXX(Issue #163): wrong! use typedef (as commented out)
+        let shaper = @harfbuzz::shaper::HarfbuzzShaper::new();
+        self.shaper = Some(shaper);
+        shaper
+    }
+
     priv fn get_azure_font() -> AzScaledFontRef {
         use libc::{c_int, c_double};
         use azure::{
@@ -207,6 +223,7 @@ impl Font {
 pub trait FontMethods {
     fn draw_text_into_context(rctx: &RenderContext, run: &TextRun, range: Range, baseline_origin: Point2D<Au>);
     fn measure_text(&TextRun, Range) -> RunMetrics;
+    fn shape_text(&self, &str) -> GlyphStore;
 
     fn buf(&self) -> @~[u8];
     // these are used to get glyphs and advances in the case that the
@@ -301,6 +318,13 @@ pub impl Font : FontMethods {
         return metrics;
     }
 
+    fn shape_text(&self, text: &str) -> GlyphStore {
+        let store = GlyphStore(text.len());
+        let shaper = self.get_shaper();
+        shaper.shape_text(text, self, &store);
+        return move store;
+    }
+
     fn buf(&self) -> @~[u8] {
         self.fontbuf
     }

src/servo/text/harfbuzz/shaper.rs

@@ -11,7 +11,6 @@ use libc::types::common::c99::int32_t;
 use libc::{c_uint, c_int, c_void, c_char};
 use ptr::{null, to_unsafe_ptr, offset};
 use std::arc;
-use text_run::TextRun;
 use util::*;
 
 use harfbuzz::{HB_MEMORY_MODE_READONLY,
@@ -59,13 +58,13 @@ pub impl HarfbuzzShaper {
     Calculate the layout metrics associated with a some given text
     when rendered in a specific font.
     */
-    pub fn shape_textrun(run: &TextRun) {
+    pub fn shape_text(text: &str, font: &Font, glyphs: &GlyphStore) {
-        debug!("shaping text '%s'", run.text);
+        debug!("shaping text '%s'", text);
 
         // TODO(Issue #94): harfbuzz fonts and faces should be cached on the 
         // Shaper object, which is owned by the Font instance.
         // TODO(Issue #92): font tables should be stored in Font object and cached per-task
-        let face_blob: *hb_blob_t = vec::as_imm_buf(*(run.font).fontbuf, |buf: *u8, len: uint| {
+        let face_blob: *hb_blob_t = vec::as_imm_buf(*(font).fontbuf, |buf: *u8, len: uint| {
             hb_blob_create(buf as *c_char,
                            len as c_uint,
                            HB_MEMORY_MODE_READONLY,
@@ -77,7 +76,7 @@ pub impl HarfbuzzShaper {
         let hb_font: *hb_font_t = hb_font_create(hb_face);
 
         // Set points-per-em. if zero, performs no hinting in that direction.
-        let pt_size = run.font.style.pt_size;
+        let pt_size = font.style.pt_size;
         hb_font_set_ppem(hb_font, pt_size as c_uint, pt_size as c_uint);
         // Set scaling. Note that this takes 16.16 fixed point.
         hb_font_set_scale(hb_font, float_to_fixed_hb(pt_size) as c_int, float_to_fixed_hb(pt_size) as c_int);
@@ -87,7 +86,7 @@ pub impl HarfbuzzShaper {
         hb_font_funcs_set_glyph_h_advance_func(funcs, glyph_h_advance_func, null(), null());
 
         unsafe {
-            let font_data: *c_void = core::ptr::addr_of(run.font) as *c_void;
+            let font_data: *c_void = core::ptr::addr_of(font) as *c_void;
             hb_font_set_funcs(hb_font, funcs, font_data, null());
         };
 
@@ -95,12 +94,12 @@ pub impl HarfbuzzShaper {
         hb_buffer_set_direction(hb_buffer, HB_DIRECTION_LTR);
 
         // Using as_buf because it never does a copy - we don't need the trailing null
-        str::as_buf(run.text, |ctext: *u8, _l: uint| {
+        str::as_buf(text, |ctext: *u8, _l: uint| {
             hb_buffer_add_utf8(hb_buffer, 
                                ctext as *c_char,
-                               run.text.len() as c_int,
+                               text.len() as c_int,
                                0 as c_uint,
-                               run.text.len() as c_int);
+                               text.len() as c_int);
         });
 
         hb_shape(hb_font, hb_buffer, null(), 0 as c_uint);
@@ -131,7 +130,7 @@ pub impl HarfbuzzShaper {
                    i, codepoint, advance, offset);
 
             let data = GlyphData(codepoint, advance, offset, false, false, false);
-            run.glyphs.add_glyph_for_index(i, &data);
+            glyphs.add_glyph_for_index(i, &data);
         } /* unsafe */ }
 
         hb_buffer_destroy(hb_buffer);

src/servo/text/text_run.rs

@@ -42,17 +42,12 @@ impl TextRun {
     static fn new(font: @Font, text: ~str) -> TextRun {
         use shaper::Shaper;
 
-        let glyph_store = GlyphStore(text.len());
+        let glyph_store = font.shape_text(text);
         let run = TextRun {
             text: move text,
             font: font,
             glyphs: move glyph_store,
         };
-
-        // XXX(Issue #163): wrong! use typedef (as commented out)
-        let shaper = harfbuzz::shaper::HarfbuzzShaper::new();
-        // let shaper = Shaper::new();
-        shaper.shape_textrun(&run);
         return move run;
     }