fix bar cursors when moving through double-width cells

Don't render two copies of the cursor in the same cell,
and compute different graphics for double wide cells.

refs: #1548

wezterm-gui/src/customglyph.rs

@@ -3674,11 +3674,14 @@ impl<T: Texture2d> GlyphCache<T> {
         &mut self,
         shape: Option<CursorShape>,
         metrics: &RenderMetrics,
+        width: u8,
     ) -> anyhow::Result<Sprite<T>> {
-        if let Some(sprite) = self.cursor_glyphs.get(&shape) {
+        if let Some(sprite) = self.cursor_glyphs.get(&(shape, width)) {
             return Ok(sprite.clone());
         }
 
+        let metrics = metrics.scale_cell_width(width);
+
         let mut buffer = Image::new(
             metrics.cell_size.width as usize,
             metrics.cell_size.height as usize,
@@ -3740,7 +3743,7 @@ impl<T: Texture2d> GlyphCache<T> {
         }
 
         let sprite = self.atlas.allocate(&buffer)?;
-        self.cursor_glyphs.insert(shape, sprite.clone());
+        self.cursor_glyphs.insert((shape, width), sprite.clone());
         Ok(sprite)
     }
 

wezterm-gui/src/glyphcache.rs

@@ -254,7 +254,7 @@ pub struct GlyphCache<T: Texture2d> {
     frame_cache: HashMap<[u8; 32], Sprite<T>>,
     line_glyphs: HashMap<LineKey, Sprite<T>>,
     pub block_glyphs: HashMap<SizedBlockKey, Sprite<T>>,
-    pub cursor_glyphs: HashMap<Option<CursorShape>, Sprite<T>>,
+    pub cursor_glyphs: HashMap<(Option<CursorShape>, u8), Sprite<T>>,
     pub color: HashMap<(RgbColor, NotNan<f32>), Sprite<T>>,
 }
 

wezterm-gui/src/termwindow/render.rs

@@ -1970,28 +1970,21 @@ impl super::TermWindow {
 
                     let pixel_width = glyph.x_advance.get() as f32;
 
-                    // We'd like to render the cursor with the cell width
-                    // so that double-wide cells look more reasonable.
-                    // If we have a cursor shape, compute the intended cursor
-                    // width.  We only use that if we're the first cell that
-                    // comprises this glyph; if for some reason the cursor position
-                    // is in the middle of a glyph we just use a single cell.
-                    let cursor_width = cursor_shape
-                        .map(|_| {
-                            if glyph_idx == 0 {
-                                info.pos.num_cells
-                            } else {
-                                1
-                            }
-                        })
-                        .unwrap_or(1) as f32;
-
                     // Note: in use_pixel_positioning mode, we draw backgrounds
                     // for glyph_idx == 0 based on the whole glyph advance, rather than
                     // for each of the cells.
 
                     if cursor_shape.is_some() {
-                        if !params.use_pixel_positioning || glyph_idx == 0 {
+                        if glyph_idx == 0 {
+                            // We'd like to render the cursor with the cell width
+                            // so that double-wide cells look more reasonable.
+                            // If we have a cursor shape, compute the intended cursor
+                            // width.  We only use that if we're the first cell that
+                            // comprises this glyph; if for some reason the cursor position
+                            // is in the middle of a glyph we just use a single cell.
+                            let cursor_width =
+                                cursor_shape.map(|_| info.pos.num_cells).unwrap_or(1);
+
                             let mut quad = layers[0].allocate()?;
                             quad.set_position(
                                 pos_x,
@@ -2000,7 +1993,7 @@ impl super::TermWindow {
                                     + if params.use_pixel_positioning {
                                         pixel_width
                                     } else {
-                                        cursor_width * cell_width
+                                        cursor_width as f32 * cell_width
                                     },
                                 pos_y + cell_height,
                             );
@@ -2011,7 +2004,11 @@ impl super::TermWindow {
                                 gl_state
                                     .glyph_cache
                                     .borrow_mut()
-                                    .cursor_sprite(cursor_shape, &params.render_metrics)?
+                                    .cursor_sprite(
+                                        cursor_shape,
+                                        &params.render_metrics,
+                                        cursor_width,
+                                    )?
                                     .texture_coords(),
                             );
 
@@ -2274,7 +2271,7 @@ impl super::TermWindow {
                             gl_state
                                 .glyph_cache
                                 .borrow_mut()
-                                .cursor_sprite(cursor_shape, &params.render_metrics)?
+                                .cursor_sprite(cursor_shape, &params.render_metrics, 1)?
                                 .texture_coords(),
                         );
                         quad.set_fg_color(cursor_border_color);

wezterm-gui/src/utilsprites.rs

@@ -61,6 +61,12 @@ impl RenderMetrics {
         }
     }
 
+    pub fn scale_cell_width(&self, scale: u8) -> Self {
+        let mut scaled = self.clone();
+        scaled.cell_size.width *= scale as isize;
+        scaled
+    }
+
     pub fn new(fonts: &Rc<FontConfiguration>) -> anyhow::Result<Self> {
         let metrics = fonts
             .default_font_metrics()