fix: take visual bounds into consideration when text is centered

1 files changed, 55 insertions, 5 deletions

diff --git a/src/text.rs b/src/text.rs
index bef9ed4..204587b 100644
--- a/src/text.rs
+++ b/src/text.rs
@@ -178,6 +178,7 @@ pub struct State {
     dragging: Option<Dragging>,
     last_click: Option<mouse::Click>,
     keyboard_modifiers: keyboard::Modifiers,
+    visual_lines_bounds: Vec<core::Rectangle>,
 }
 
 /// The type of dragging selection.
@@ -204,10 +205,31 @@ impl State {
         };
         let bounded_y = point.y.max(bounds.y).min(bounds.y + bounds.height);
         let bounded_point = Point::new(bounded_x, bounded_y);
-        let relative_point =
+        let mut relative_point =
             bounded_point - core::Vector::new(bounds.x, bounds.y);
 
         let buffer = self.paragraph.buffer();
+        let line_height = buffer.metrics().line_height;
+        let visual_line = (relative_point.y / line_height).floor() as usize;
+        let visual_line_start_offset = self
+            .visual_lines_bounds
+            .get(visual_line)
+            .map(|r| r.x)
+            .unwrap_or_default();
+        let visual_line_end = self
+            .visual_lines_bounds
+            .get(visual_line)
+            .map(|r| r.x + r.width)
+            .unwrap_or_default();
+
+        if relative_point.x < visual_line_start_offset {
+            relative_point.x = visual_line_start_offset;
+        }
+
+        if relative_point.x > visual_line_end {
+            relative_point.x = visual_line_end;
+        }
+
         let cursor = buffer.hit(relative_point.x, relative_point.y)?;
         let value = buffer.lines[cursor.line].text();
 
@@ -269,17 +291,39 @@ impl State {
         if self.content != text.content {
             text.content.clone_into(&mut self.content);
             self.paragraph = Paragraph::with_text(text);
+            self.update_visual_bounds();
             return;
         }
 
         match self.paragraph.compare(text.with_content(())) {
             text::Difference::None => {}
-            text::Difference::Bounds => self.paragraph.resize(text.bounds),
+            text::Difference::Bounds => {
+                self.paragraph.resize(text.bounds);
+                self.update_visual_bounds();
+            }
             text::Difference::Shape => {
                 self.paragraph = Paragraph::with_text(text);
+                self.update_visual_bounds();
             }
         }
     }
+
+    fn update_visual_bounds(&mut self) {
+        let buffer = self.paragraph.buffer();
+        let line_height = buffer.metrics().line_height;
+        self.visual_lines_bounds = buffer
+            .lines
+            .iter()
+            .flat_map(|line| highlight_line(line, 0, line.text().len()))
+            .enumerate()
+            .map(|(visual_line, (x, width))| core::Rectangle {
+                x,
+                width,
+                y: visual_line as f32 * line_height - buffer.scroll().vertical,
+                height: line_height,
+            })
+            .collect();
+    }
 }
 
 impl<Message, Theme, Renderer> Widget<Message, Theme, Renderer>
@@ -788,10 +832,16 @@ fn highlight_line(
 
         let range = start.max(from)..end.min(to);
 
+        let x_offset = visual_line
+            .glyphs
+            .first()
+            .map(|glyph| glyph.x)
+            .unwrap_or_default();
+
         if range.is_empty() {
-            (0.0, 0.0)
+            (x_offset, 0.0)
         } else if range.start == start && range.end == end {
-            (0.0, visual_line.w)
+            (x_offset, visual_line.w)
         } else {
             let first_glyph = visual_line
                 .glyphs
@@ -809,7 +859,7 @@ fn highlight_line(
                 .map(|glyph| glyph.w)
                 .sum();
 
-            (x, width)
+            (x_offset + x, width)
         }
     })
 }