renderer/metal: re-enable preedit rendering

src/font/SharedGrid.zig

@@ -199,7 +199,38 @@ pub const Render = struct {
     presentation: Presentation,
 };
 
-/// Render a glyph. This automatically determines the correct texture
+/// Render a codepoint. This uses the first font index that has the codepoint
+/// and matches the presentation requested. If the codepoint cannot be found
+/// in any font, an null render is returned.
+pub fn renderCodepoint(
+    self: *SharedGrid,
+    alloc: Allocator,
+    cp: u32,
+    style: Style,
+    p: ?Presentation,
+    opts: RenderOptions,
+) !?Render {
+    // Note: we could optimize the below to use way less locking, but
+    // at the time of writing this codepath is only called for preedit
+    // text which is relatively rare and almost non-existent in multiple
+    // surfaces at the same time.
+
+    // Get the font that has the codepoint
+    const index = try self.getIndex(alloc, cp, style, p) orelse return null;
+
+    // Get the glyph for the font
+    const glyph_index = glyph_index: {
+        self.lock.lockShared();
+        defer self.lock.unlockShared();
+        const face = try self.resolver.collection.getFace(index);
+        break :glyph_index face.glyphIndex(cp) orelse return null;
+    };
+
+    // Render
+    return try self.renderGlyph(alloc, index, glyph_index, opts);
+}
+
+/// Render a glyph index. This automatically determines the correct texture
 /// atlas to use and caches the result.
 pub fn renderGlyph(
     self: *SharedGrid,

src/renderer/Metal.zig

@@ -2033,39 +2033,25 @@ fn addPreeditCell(
     x: usize,
     y: usize,
 ) !void {
-    if (true) @panic("TODO"); // TODO(fontmem)
-
     // Preedit is rendered inverted
     const bg = self.foreground_color;
     const fg = self.background_color;
 
-    // Get the font for this codepoint.
-    const font_index = if (self.font_group.indexForCodepoint(
+    // Render the glyph for our preedit text
+    const render_ = self.font_grid.renderCodepoint(
         self.alloc,
         @intCast(cp.codepoint),
         .regular,
         .text,
-    )) |index| index orelse return else |_| return;
-
-    // Get the font face so we can get the glyph
-    const face = self.font_group.group.faceFromIndex(font_index) catch |err| {
-        log.warn("error getting face for font_index={} err={}", .{ font_index, err });
-        return;
-    };
-
-    // Use the face to now get the glyph index
-    const glyph_index = face.glyphIndex(@intCast(cp.codepoint)) orelse return;
-
-    // Render the glyph for our preedit text
-    const glyph = self.font_group.renderGlyph(
-        self.alloc,
-        font_index,
-        glyph_index,
         .{ .grid_metrics = self.grid_metrics },
     ) catch |err| {
         log.warn("error rendering preedit glyph err={}", .{err});
         return;
     };
+    const render = render_ orelse {
+        log.warn("failed to find font for preedit codepoint={X}", .{cp.codepoint});
+        return;
+    };
 
     // Add our opaque background cell
     self.cells_bg.appendAssumeCapacity(.{
@@ -2083,9 +2069,9 @@ fn addPreeditCell(
         .cell_width = if (cp.wide) 2 else 1,
         .color = .{ fg.r, fg.g, fg.b, 255 },
         .bg_color = .{ bg.r, bg.g, bg.b, 255 },
-        .glyph_pos = .{ glyph.atlas_x, glyph.atlas_y },
-        .glyph_size = .{ glyph.width, glyph.height },
-        .glyph_offset = .{ glyph.offset_x, glyph.offset_y },
+        .glyph_pos = .{ render.glyph.atlas_x, render.glyph.atlas_y },
+        .glyph_size = .{ render.glyph.width, render.glyph.height },
+        .glyph_offset = .{ render.glyph.offset_x, render.glyph.offset_y },
     });
 }