Extend and improve FcPattern bindings

The fontconfig `FcPattern` type is wrapped as `fc::Pattern` and
`fc::Pattern` ref. All methods for accessing data on the pattern now
return an `Iterator`. This API turns out to be much more ergonomic than
providing an integer index. We also override the default `nth`
implementation of `Iterator` on these accessors to allow random
(incremental only) access.

For instance, accessing `family` attributes from a pattern:

    let families = pattern.family();
    let second = pattern.nth(1);

Or printing available styles

    for style in pattern.style() {
        println!("style={}", style);
    }

1 files changed, 4 insertions, 4 deletions

diff --git a/font/src/ft/mod.rs b/font/src/ft/mod.rs
index 89ca6047..7a75d11f 100644
--- a/font/src/ft/mod.rs
+++ b/font/src/ft/mod.rs
@@ -19,7 +19,7 @@ use std::cmp::min;
 use freetype::{self, Library, Face};
 
 
-mod fc;
+pub mod fc;
 
 use super::{FontDesc, RasterizedGlyph, Metrics, Size, FontKey, GlyphKey, Weight, Slant, Style};
 
@@ -142,7 +142,7 @@ impl FreeTypeRasterizer {
         let font = fc::font_match(fc::Config::get_current(), &mut pattern)
             .ok_or_else(|| Error::MissingFont(desc.to_owned()))?;
 
-        if let (Some(path), Some(index)) = (font.file(0), font.index(0)) {
+        if let (Some(path), Some(index)) = (font.file(0), font.index().nth(0)) {
             return Ok(self.library.new_face(path, index)?);
         }
 
@@ -160,7 +160,7 @@ impl FreeTypeRasterizer {
 
         let font = fc::font_match(fc::Config::get_current(), &mut pattern)
             .ok_or_else(|| Error::MissingFont(desc.to_owned()))?;
-        if let (Some(path), Some(index)) = (font.file(0), font.index(0)) {
+        if let (Some(path), Some(index)) = (font.file(0), font.index().nth(0)) {
             println!("got font path={:?}", path);
             Ok(self.library.new_face(path, index)?)
         }
@@ -293,7 +293,7 @@ impl FreeTypeRasterizer {
         let config = fc::Config::get_current();
         match fc::font_match(config, &mut pattern) {
             Some(font) => {
-                if let (Some(path), Some(index)) = (font.file(0), font.index(0)) {
+                if let (Some(path), Some(index)) = (font.file(0), font.index().nth(0)) {
                     match self.keys.get(&path) {
                         // We've previously loaded this font, so don't
                         // load it again.