add rusttype rasterizer

src/font/hbwrap.rs

@@ -1,5 +1,5 @@
 //! Higher level harfbuzz bindings
-
+#![allow(dead_code)]
 #[cfg(any(target_os = "android", all(unix, not(target_os = "macos"))))]
 use freetype;
 

src/font/mod.rs

@@ -110,6 +110,7 @@ impl FontConfiguration {
     }
 }
 
+#[allow(dead_code)]
 pub fn shape_with_harfbuzz(
     font: &mut NamedFont,
     font_idx: system::FallbackIdx,

src/font/rtype.rs

@@ -2,20 +2,19 @@
 
 use super::hbwrap as harfbuzz;
 use config::{Config, TextStyle};
-use failure::{self, Error};
-use font::{
-    shape_with_harfbuzz, FallbackIdx, Font, FontMetrics, FontSystem, GlyphInfo, NamedFont,
-    RasterizedGlyph,
-};
+use failure::Error;
+use font::{FallbackIdx, Font, FontMetrics, FontSystem, GlyphInfo, NamedFont, RasterizedGlyph};
 use font_loader::system_fonts;
-use rusttype::{Font as RTFont, FontCollection, Scale};
-use std::cell::RefCell;
+use rusttype::{
+    point, Codepoint, Font as RTFont, FontCollection, PositionedGlyph, Rect, Scale, VMetrics,
+};
 
 struct NamedFontImpl<'a> {
-    collection: FontCollection<'a>,
+    _collection: FontCollection<'a>,
     font: RTFont<'a>,
-    hbfont: RefCell<harfbuzz::Font>,
     scale: Scale,
+    vmetrics: VMetrics,
+    cell_height: f64,
 }
 
 pub type FontSystemImpl = RustTypeFonts;
@@ -36,37 +35,75 @@ impl FontSystem for RustTypeFonts {
         let (data, idx) = system_fonts::get(&font_props)
             .ok_or_else(|| format_err!("no font matching {:?}", style))?;
         eprintln!("want idx {} in bytes of len {}", idx, data.len());
-        let hbfont = RefCell::new(harfbuzz::Font::new_from_slice(&data, idx as u32)?);
         let collection = FontCollection::from_bytes(data)?;
         let font = collection.font_at(idx as usize)?;
         eprintln!("made a font for {:?}", style);
         let scale = Scale::uniform(config.font_size as f32 * 96.0 / 72.0);
+        let vmetrics = font.v_metrics(scale);
+        eprintln!("vmetrics {:?}", vmetrics);
+        let cell_height = f64::from(vmetrics.ascent - vmetrics.descent + vmetrics.line_gap);
         Ok(Box::new(NamedFontImpl {
-            collection,
-            hbfont,
+            _collection: collection,
+            cell_height,
             font,
             scale,
+            vmetrics,
         }))
     }
 }
 
+fn bounds(g: &PositionedGlyph) -> Rect<i32> {
+    match g.pixel_bounding_box() {
+        Some(bounds) => bounds,
+        None => rusttype::Rect {
+            min: point(0, 0),
+            max: point(0, 0),
+        },
+    }
+}
+
 impl<'a> NamedFont for NamedFontImpl<'a> {
     fn get_fallback(&mut self, idx: FallbackIdx) -> Result<&Font, Error> {
         ensure!(idx == 0, "no fallback fonts available (idx={})", idx);
         Ok(self)
     }
     fn shape(&mut self, s: &str) -> Result<Vec<GlyphInfo>, Error> {
-        shape_with_harfbuzz(self, 0, s)
+        let mut shaped = Vec::new();
+
+        for (cluster, c) in s.chars().enumerate() {
+            let glyph = self.font.glyph(Codepoint(c as u32)).scaled(self.scale);
+            let hmetrics = glyph.h_metrics();
+            let glyph = glyph.positioned(point(0.0, 0.0));
+
+            if c != ' ' {
+                eprintln!("{} -> glyph {} {:?}", c, glyph.id().0, hmetrics);
+            }
+
+            shaped.push(GlyphInfo {
+                #[cfg(debug_assertions)]
+                text: s[cluster..cluster].to_string(),
+                cluster: cluster as u32,
+                num_cells: 1,
+                font_idx: 0,
+                glyph_pos: glyph.id().0,
+                x_advance: hmetrics.advance_width.into(),
+                x_offset: (-hmetrics.left_side_bearing).into(),
+                y_advance: 0.0,
+                y_offset: 0.0, //(-bounds.max.y).into(),
+                               // vmetrics.descent.into(),
+            })
+        }
+        Ok(shaped)
     }
 }
 
 impl<'a> Font for NamedFontImpl<'a> {
     fn harfbuzz_shape(
         &self,
-        buf: &mut harfbuzz::Buffer,
-        features: Option<&[harfbuzz::hb_feature_t]>,
+        _buf: &mut harfbuzz::Buffer,
+        _features: Option<&[harfbuzz::hb_feature_t]>,
     ) {
-        self.hbfont.borrow_mut().shape(buf, features)
+        unimplemented!();
     }
 
     fn has_color(&self) -> bool {
@@ -74,20 +111,49 @@ impl<'a> Font for NamedFontImpl<'a> {
     }
 
     fn metrics(&self) -> FontMetrics {
-        let vmetrics = self.font.v_metrics(self.scale);
         let hmetrics = self
             .font
-            .glyph(rusttype::Codepoint(33))
+            .glyph(Codepoint(33))
             .scaled(self.scale)
             .h_metrics();
         FontMetrics {
-            cell_height: f64::from(vmetrics.ascent - vmetrics.descent + vmetrics.line_gap),
+            cell_height: self.cell_height,
             cell_width: hmetrics.advance_width.into(),
-            descender: vmetrics.descent as i16,
+            descender: self.vmetrics.descent as i16,
         }
     }
 
     fn rasterize_glyph(&self, glyph_pos: u32) -> Result<RasterizedGlyph, Error> {
-        unimplemented!();
+        let g = self
+            .font
+            .glyph(rusttype::GlyphId(glyph_pos))
+            .scaled(self.scale)
+            .positioned(point(0.0, 0.0));
+        let bounds = bounds(&g);
+        let width = bounds.width() as usize;
+        let height = bounds.height() as usize;
+        let mut data = Vec::with_capacity(width * height * 4);
+        g.draw(|_x, _y, value| {
+            let v = (value * 255.0) as u8;
+            data.push(v); // alpha
+            data.push(v); // red
+            data.push(v); // green
+            data.push(v); // blue
+        });
+        eprintln!(
+            "rasterize_glyph {} {}x{} {} bounds {:?}",
+            glyph_pos, width, height, self.cell_height, bounds
+        );
+        // FIXME: there's something funky about either the bearing
+        // calculation here or the y_offset calculation in the
+        // shape function that causes the baseline to vary and
+        // the text look crazy.
+        Ok(RasterizedGlyph {
+            data,
+            height,
+            width,
+            bearing_x: bounds.min.x,
+            bearing_y: -bounds.min.y,
+        })
     }
 }

src/font/system.rs

@@ -40,6 +40,7 @@ pub struct GlyphInfo {
 }
 
 impl GlyphInfo {
+    #[allow(dead_code)]
     pub fn new(
         text: &str,
         font_idx: usize,