Replace a hack with a proper implementation

Author: afishhh

crates/epaint/src/text/fonts.rs

@@ -730,7 +730,7 @@ impl GalleyCache {
     fn layout_multiline(&mut self, fonts: &mut FontsImpl, job: LayoutJob) -> Galley {
         let pixels_per_point = fonts.pixels_per_point;
         let round_to_pixel =
-            move |point: emath::Pos2| (point * pixels_per_point).round() / pixels_per_point;
+            move |point: f32| (point * pixels_per_point).round() / pixels_per_point;
 
         let mut current_section = 0;
         let mut current = 0;
@@ -816,7 +816,8 @@ impl GalleyCache {
             }
 
             merged_galley.rows.extend(rows.map(|placed_row| {
-                let new_pos = round_to_pixel(placed_row.pos + current_offset);
+                let mut new_pos = placed_row.pos + current_offset;
+                new_pos.y = round_to_pixel(new_pos.y);
                 merged_galley.mesh_bounds = merged_galley
                     .mesh_bounds
                     .union(placed_row.visuals.mesh_bounds.translate(new_pos.to_vec2()));

crates/epaint/src/text/text_layout.rs

@@ -1,4 +1,3 @@
-use std::ops::RangeInclusive;
 use std::sync::Arc;
 
 use emath::{pos2, vec2, Align, NumExt, Pos2, Rect, Vec2};
@@ -190,11 +189,6 @@ fn layout_section(
     }
 }
 
-/// We ignore y at this stage
-fn rect_from_x_range(x_range: RangeInclusive<f32>) -> Rect {
-    Rect::from_x_y_ranges(x_range, 0.0..=0.0)
-}
-
 // Ignores the Y coordinate.
 fn rows_from_paragraphs(
     paragraphs: Vec<Paragraph>,
@@ -222,23 +216,21 @@ fn rows_from_paragraphs(
                     size: vec2(0.0, paragraph.empty_paragraph_height),
                     ends_with_newline: !is_last_paragraph,
                 }),
-                pos: pos2(paragraph.cursor_x, 0.0),
+                pos: pos2(0.0, 0.0),
             });
         } else {
             let paragraph_max_x = paragraph.glyphs.last().unwrap().max_x();
             if paragraph_max_x <= job.effective_wrap_width() {
                 // Early-out optimization: the whole paragraph fits on one row.
-                let paragraph_min_x = paragraph.glyphs[0].pos.x;
-                let rect = rect_from_x_range(paragraph_min_x..=paragraph_max_x);
                 rows.push(PlacedRow {
                     row: Arc::new(Row {
                         section_index_at_start: paragraph.section_index_at_start,
                         glyphs: paragraph.glyphs,
                         visuals: Default::default(),
-                        size: rect.size(),
+                        size: vec2(paragraph_max_x, 0.0),
                         ends_with_newline: !is_last_paragraph,
                     }),
-                    pos: rect.min,
+                    pos: pos2(0.0, f32::NAN),
                 });
             } else {
                 line_break(&paragraph, job, &mut rows, elided);
@@ -283,16 +275,15 @@ fn line_break(
             {
                 // Allow the first row to be completely empty, because we know there will be more space on the next row:
                 // TODO(emilk): this records the height of this first row as zero, though that is probably fine since first_row_indentation usually comes with a first_row_min_height.
-                let rect = rect_from_x_range(first_row_indentation..=first_row_indentation);
                 out_rows.push(PlacedRow {
                     row: Arc::new(Row {
                         section_index_at_start: paragraph.section_index_at_start,
                         glyphs: vec![],
                         visuals: Default::default(),
-                        size: rect.size(),
+                        size: vec2(0.0, 0.0),
                         ends_with_newline: false,
                     }),
-                    pos: rect.min,
+                    pos: pos2(0.0, f32::NAN),
                 });
                 row_start_x += first_row_indentation;
                 first_row_indentation = 0.0;
@@ -308,19 +299,17 @@ fn line_break(
                     .collect();
 
                 let section_index_at_start = glyphs[0].section_index;
-                let paragraph_min_x = glyphs[0].pos.x;
                 let paragraph_max_x = glyphs.last().unwrap().max_x();
 
-                let rect = rect_from_x_range(paragraph_min_x..=paragraph_max_x);
                 out_rows.push(PlacedRow {
                     row: Arc::new(Row {
                         section_index_at_start,
                         glyphs,
                         visuals: Default::default(),
-                        size: rect.size(),
+                        size: vec2(paragraph_max_x, 0.0),
                         ends_with_newline: false,
                     }),
-                    pos: rect.min,
+                    pos: pos2(0.0, f32::NAN),
                 });
 
                 // Start a new row:
@@ -354,16 +343,15 @@ fn line_break(
             let paragraph_min_x = glyphs[0].pos.x;
             let paragraph_max_x = glyphs.last().unwrap().max_x();
 
-            let rect = rect_from_x_range(paragraph_min_x..=paragraph_max_x);
             out_rows.push(PlacedRow {
                 row: Arc::new(Row {
                     section_index_at_start,
                     glyphs,
                     visuals: Default::default(),
-                    size: rect.size(),
+                    size: vec2(paragraph_max_x - paragraph_min_x, 0.0),
                     ends_with_newline: false,
                 }),
-                pos: rect.min,
+                pos: pos2(paragraph_min_x, 0.0),
             });
         }
     }
@@ -609,8 +597,7 @@ fn halign_and_justify_row(
         }
     }
 
-    // Note we ignore the leading/trailing whitespace here!
-    pos.x = target_min_x;
+    // Note we **don't** ignore the leading/trailing whitespace here!
     row.size.x = target_max_x - target_min_x;
 }
 
@@ -647,10 +634,6 @@ fn galley_from_rows(
                 // When mixing different `FontImpl` (e.g. latin and emojis),
                 // we always center the difference:
                 + 0.5 * (glyph.font_height - glyph.font_impl_height);
-
-            // FIXME(afishhh): HACK! change the proper code above instead!!
-            //                 this should probably not be merged like this!
-            glyph.pos.x -= placed_row.pos.x;
         }
 
         placed_row.pos.y = cursor_y;