fix: complex composition calculation not correct

package.json

@@ -1,6 +1,6 @@
 {
   "name": "fontkit-rs",
-  "version": "0.0.11-beta.3",
+  "version": "0.0.11-beta.5",
   "description": "Toolkit used to load, match, measure, and render texts",
   "main": "index.js",
   "directories": {

src/metrics.rs

@@ -288,14 +288,12 @@ impl TextMetrics {
         if self.units == 0 {
             return 0.0;
         }
-        let factor = font_size / self.units as f32;
         let positions = self.positions.read().unwrap();
         positions.iter().take(index).fold(0.0, |current, p| {
-            current
-                + p.kerning as f32 * factor
-                + p.metrics.advanced_x as f32 * factor
-                + letter_spacing
-        })
+            current + p.kerning as f32 + p.metrics.advanced_x as f32
+        }) * font_size
+            / self.units as f32
+            + letter_spacing * (index as f32)
     }
 
     pub fn width_trim_start(&self, font_size: f32, letter_spacing: f32) -> f32 {

src/metrics/compose.rs

@@ -184,7 +184,7 @@ where
             }
             is_first_line = false;
             let line_width = line.width();
-            if width - (line_width + current_line_width) >= -0.01 {
+            if width - (line_width + current_line_width) >= -0.1 {
                 // Current line fits, push all of its spans into current line
                 current_line_width += line_width;
                 current_line.spans.append(&mut line.spans);
@@ -195,7 +195,7 @@ where
                 // Go through spans to get the first not-fitting span
                 let index = line.spans.iter().position(|span| {
                     let span_width = span.width();
-                    if span_width + current_line_width <= width {
+                    if span_width + current_line_width - width <= 0.1 {
                         current_line_width += span_width;
                         false
                     } else {
@@ -231,7 +231,6 @@ where
                     span.letter_spacing,
                     width - current_line_width,
                 );
-
                 if new_metrics.count() != 0 {
                     failed_with_no_acception = false;
                 }
@@ -255,17 +254,23 @@ where
                 // Add new_span to next line
                 let mut new_line = Line {
                     hard_break: false,
-                    spans: vec![new_span],
+                    spans: vec![],
                 };
-                // Check for swallowed leading space
-                if new_line.spans[0].metrics.value().starts_with(" ") {
-                    new_line.spans[0].swallow_leading_space = true;
+                if new_span.metrics.count() != 0 {
+                    new_line.spans.push(new_span);
                 }
                 for span in line.spans.into_iter().skip(1) {
                     new_line.spans.push(span);
                 }
-                lines.push_front(new_line);
                 current_line_width = 0.0;
+                if new_line.spans.is_empty() {
+                    continue;
+                }
+                // Check for swallowed leading space
+                if new_line.spans[0].metrics.value().starts_with(" ") {
+                    new_line.spans[0].swallow_leading_space = true;
+                }
+                lines.push_front(new_line);
             }
         }
         if !current_line.spans.is_empty() {
@@ -460,7 +465,7 @@ impl TextMetrics {
         // Textwrap cannot find a good break point, we directly drop chars
         loop {
             let span_width = self.width_until(font_size, letter_spacing, naive_break_index);
-            if span_width <= width || naive_break_index == 0 {
+            if span_width - width <= 0.1 || naive_break_index == 0 {
                 break;
             }
             naive_break_index -= 1;
@@ -563,14 +568,10 @@ impl TextMetrics {
         drop(positions);
         // Split here, create a new span
         let mut new_metrics = self.clone();
-        if real_index == 0 {
-            new_metrics.positions = Arc::new(RwLock::new(vec![]));
-        } else {
-            new_metrics.positions = {
-                let mut p = self.positions.write().unwrap();
-                Arc::new(RwLock::new(p.split_off(real_index)))
-            };
-        }
+        new_metrics.positions = {
+            let mut p = self.positions.write().unwrap();
+            Arc::new(RwLock::new(p.split_off(real_index)))
+        };
         new_metrics
     }
 }

tests/basic.rs

@@ -54,7 +54,8 @@ pub fn test_search_font() -> Result<(), Error> {
 pub fn test_text_wrap() -> Result<(), Error> {
     let fontkit = FontKit::new();
     fontkit.search_fonts_from_path("examples/AlimamaFangYuanTiVF.ttf")?;
-    let key = fontkit.font_keys().next().unwrap();
+    let mut key = FontKey::default();
+    key.family = "AlimamaFangYuanTiVF-Medium-Round".into();
     let mut area = Area::<(), TextMetrics>::new();
     let metrics = fontkit
         .measure(&key, " 傲冬黑色真皮皮衣 穿着舒适显瘦")
@@ -69,6 +70,37 @@ pub fn test_text_wrap() -> Result<(), Error> {
     });
     area.unwrap_text();
     area.wrap_text(576.0)?;
-    assert_eq!(area.width(), 549.12);
+    assert_eq!(area.width(), 553.608);
+    Ok(())
+}
+
+#[test]
+pub fn test_complex_text_wrap() -> Result<(), Error> {
+    let fontkit = FontKit::new();
+    fontkit.search_fonts_from_path("examples/AlimamaFangYuanTiVF.ttf")?;
+    let mut key = FontKey::default();
+    key.family = "AlimamaFangYuanTiVF-Medium-Round".into();
+    let mut area = Area::<(), TextMetrics>::new();
+    let metrics = fontkit.measure(&key, "商家").unwrap();
+    let mut span = Span::default();
+    span.font_key = key.clone();
+    span.size = 32.0;
+    span.metrics = metrics;
+    let metrics = fontkit.measure(&key, "热卖12345678").unwrap();
+    let mut span_1 = Span::default();
+    span_1.font_key = key.clone();
+    span_1.size = 32.0;
+    span_1.metrics = metrics;
+    area.lines.push(Line {
+        spans: vec![span],
+        hard_break: true,
+    });
+    area.lines.push(Line {
+        spans: vec![span_1],
+        hard_break: true,
+    });
+    area.unwrap_text();
+    area.wrap_text(64.4)?;
+    assert_eq!(area.value_string(), "商家\n热卖\n1234\n567\n8");
     Ok(())
 }