examples: add font-info example

examples/font-info.rs

@@ -0,0 +1,178 @@
+// font-kit/examples/font-info.rs
+//
+// A simple example that loads a system font and prints detailed information
+// about it: metadata, CSS properties, font metrics, and a glyph inspection.
+
+use font_kit::family_name::FamilyName;
+use font_kit::hinting::HintingOptions;
+use font_kit::outline::OutlineSink;
+use font_kit::properties::{Properties, Style, Weight};
+use font_kit::source::SystemSource;
+use pathfinder_geometry::line_segment::LineSegment2F;
+use pathfinder_geometry::transform2d::Transform2F;
+use pathfinder_geometry::vector::Vector2F;
+
+// ---------------------------------------------------------------------------
+// A simple OutlineSink that counts the path commands in a glyph outline.
+// ---------------------------------------------------------------------------
+struct OutlineCounter {
+    moves: u32,
+    lines: u32,
+    quads: u32,
+    cubics: u32,
+}
+
+impl OutlineCounter {
+    fn new() -> Self {
+        OutlineCounter { moves: 0, lines: 0, quads: 0, cubics: 0 }
+    }
+
+    fn total(&self) -> u32 {
+        self.moves + self.lines + self.quads + self.cubics
+    }
+}
+
+impl OutlineSink for OutlineCounter {
+    fn move_to(&mut self, _to: Vector2F) {
+        self.moves += 1;
+    }
+    fn line_to(&mut self, _to: Vector2F) {
+        self.lines += 1;
+    }
+    fn quadratic_curve_to(&mut self, _ctrl: Vector2F, _to: Vector2F) {
+        self.quads += 1;
+    }
+    fn cubic_curve_to(&mut self, _ctrl: LineSegment2F, _to: Vector2F) {
+        self.cubics += 1;
+    }
+    fn close(&mut self) {}
+}
+
+// ---------------------------------------------------------------------------
+
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let source = SystemSource::new();
+
+    // -----------------------------------------------------------------------
+    // 1. Select the best-matching sans-serif font (normal weight + style).
+    // -----------------------------------------------------------------------
+    let properties = Properties::new();
+    let handle = source.select_best_match(&[FamilyName::SansSerif], &properties)?;
+    let font = handle.load()?;
+
+    println!("=== Font Metadata ===");
+    println!("  Full name      : {}", font.full_name());
+    println!("  Family name    : {}", font.family_name());
+    println!(
+        "  PostScript name: {}",
+        font.postscript_name().unwrap_or_else(|| "(none)".into())
+    );
+    println!("  Monospace      : {}", font.is_monospace());
+    println!("  Glyph count    : {}", font.glyph_count());
+
+    // -----------------------------------------------------------------------
+    // 2. CSS-style properties.
+    // -----------------------------------------------------------------------
+    let props = font.properties();
+    println!("\n=== CSS Properties ===");
+    println!("  Style          : {:?}", props.style);
+    println!("  Weight         : {:.0}", props.weight.0);
+    println!("  Stretch        : {:.3}", props.stretch.0);
+
+    // -----------------------------------------------------------------------
+    // 3. Font-level metrics (from the OS/2 / head tables).
+    // -----------------------------------------------------------------------
+    let metrics = font.metrics();
+    println!("\n=== Font Metrics (in font units, 1 em = {} units) ===", metrics.units_per_em);
+    println!("  Ascent             : {:.2}", metrics.ascent);
+    println!("  Descent            : {:.2}", metrics.descent);
+    println!("  Line gap           : {:.2}", metrics.line_gap);
+    println!("  Cap height         : {:.2}", metrics.cap_height);
+    println!("  x-height           : {:.2}", metrics.x_height);
+    println!("  Underline position : {:.2}", metrics.underline_position);
+    println!("  Underline thickness: {:.2}", metrics.underline_thickness);
+    let bb = metrics.bounding_box;
+    println!(
+        "  Bounding box       : ({:.0}, {:.0}) – ({:.0}, {:.0})",
+        bb.origin_x(),
+        bb.origin_y(),
+        bb.max_x(),
+        bb.max_y(),
+    );
+
+    // -----------------------------------------------------------------------
+    // 4. Inspect a few individual glyphs.
+    // -----------------------------------------------------------------------
+    let sample = ['A', 'g', '@', '€'];
+    println!("\n=== Glyph Inspection ===");
+    println!("  {:<6} {:<8} {:<14} {:<14} {:<30}", "Char", "Glyph ID", "Advance (fu)", "Origin (fu)", "Outline commands");
+    println!("  {}", "-".repeat(78));
+
+    for &ch in &sample {
+        match font.glyph_for_char(ch) {
+            None => println!("  '{}'  — no glyph in this font", ch),
+            Some(glyph_id) => {
+                let advance = font.advance(glyph_id).unwrap_or(Vector2F::zero());
+                let origin  = font.origin(glyph_id).unwrap_or(Vector2F::zero());
+
+                let mut sink = OutlineCounter::new();
+                let _ = font.outline(glyph_id, HintingOptions::None, &mut sink);
+
+                println!(
+                    "  {:<6} {:<8} ({:>6.1},{:>5.1})   ({:>5.1},{:>5.1})   \
+                     {} moves, {} lines, {} quads, {} cubics ({} total)",
+                    format!("'{}'", ch),
+                    glyph_id,
+                    advance.x(), advance.y(),
+                    origin.x(),  origin.y(),
+                    sink.moves, sink.lines, sink.quads, sink.cubics, sink.total(),
+                );
+            }
+        }
+    }
+
+    // -----------------------------------------------------------------------
+    // 5. Demonstrate CSS font-matching: request bold italic.
+    // -----------------------------------------------------------------------
+    println!("\n=== CSS Match: Bold Italic Sans-Serif ===");
+    let mut bold_italic = Properties::new();
+    bold_italic.style(Style::Italic).weight(Weight::BOLD);
+
+    match source.select_best_match(&[FamilyName::SansSerif], &bold_italic) {
+        Ok(h) => {
+            let f = h.load()?;
+            println!("  Matched          : {}", f.full_name());
+            println!("  PostScript name  : {}", f.postscript_name().unwrap_or_else(|| "(none)".into()));
+            println!("  Weight           : {:.0}", f.properties().weight.0);
+            println!("  Style            : {:?}", f.properties().style);
+        }
+        Err(e) => println!("  No match found: {:?}", e),
+    }
+
+    // -----------------------------------------------------------------------
+    // 6. Raster bounds for the letter 'H' at 24 pt.
+    // -----------------------------------------------------------------------
+    println!("\n=== Raster Bounds: 'H' at 24pt ===");
+    if let Some(glyph_id) = font.glyph_for_char('H') {
+        use font_kit::canvas::RasterizationOptions;
+        let bounds = font.raster_bounds(
+            glyph_id,
+            24.0,
+            Transform2F::default(),
+            HintingOptions::None,
+            RasterizationOptions::GrayscaleAa,
+        )?;
+        println!(
+            "  Origin : ({}, {})",
+            bounds.origin().x(),
+            bounds.origin().y(),
+        );
+        println!(
+            "  Size   : {}w × {}h pixels",
+            bounds.size().x(),
+            bounds.size().y(),
+        );
+    }
+
+    Ok(())
+}