config: add cursor-opacity

src/config/Config.zig

@@ -174,6 +174,13 @@ palette: Palette = .{},
 /// The color of the cursor. If this is not set, a default will be chosen.
 @"cursor-color": ?Color = null,
 
+/// The opacity level (opposite of transparency) of the cursor.
+/// A value of 1 is fully opaque and a value of 0 is fully transparent.
+/// A value less than 0 or greater than 1 will be clamped to the nearest
+/// valid value. Note that a sufficiently small value such as 0.3 may be
+/// effectively invisible and may make it difficult to find the cursor.
+@"cursor-opacity": f64 = 1.0,
+
 /// The style of the cursor. This sets the default style. A running
 /// programn can still request an explicit cursor style using escape
 /// sequences (such as CSI q). Shell configurations will often request

src/renderer/Metal.zig

@@ -104,6 +104,7 @@ pub const DerivedConfig = struct {
     font_features: std.ArrayList([]const u8),
     font_styles: font.Group.StyleStatus,
     cursor_color: ?terminal.color.RGB,
+    cursor_opacity: f64,
     cursor_text: ?terminal.color.RGB,
     background: terminal.color.RGB,
     background_opacity: f64,
@@ -144,6 +145,8 @@ pub const DerivedConfig = struct {
             else
                 null,
 
+            .cursor_opacity = @max(0, @min(1, config.@"cursor-opacity")),
+
             .background = config.background.toTerminalRGB(),
             .foreground = config.foreground.toTerminalRGB(),
 
@@ -1419,6 +1422,10 @@ fn addCursor(
     };
 
     const color = self.config.cursor_color orelse self.config.foreground;
+    const alpha: u8 = alpha: {
+        const alpha = 255 * self.config.cursor_opacity;
+        break :alpha @intFromFloat(@ceil(alpha));
+    };
 
     const sprite: font.Sprite = switch (cursor_style) {
         .block => .cursor_rect,
@@ -1444,7 +1451,7 @@ fn addCursor(
             @as(f32, @floatFromInt(screen.cursor.y)),
         },
         .cell_width = if (cell.attrs.wide) 2 else 1,
-        .color = .{ color.r, color.g, color.b, 0xFF },
+        .color = .{ color.r, color.g, color.b, alpha },
         .glyph_pos = .{ glyph.atlas_x, glyph.atlas_y },
         .glyph_size = .{ glyph.width, glyph.height },
         .glyph_offset = .{ glyph.offset_x, glyph.offset_y },

src/renderer/OpenGL.zig

@@ -219,6 +219,7 @@ pub const DerivedConfig = struct {
     font_styles: font.Group.StyleStatus,
     cursor_color: ?terminal.color.RGB,
     cursor_text: ?terminal.color.RGB,
+    cursor_opacity: f64,
     background: terminal.color.RGB,
     background_opacity: f64,
     foreground: terminal.color.RGB,
@@ -258,6 +259,8 @@ pub const DerivedConfig = struct {
             else
                 null,
 
+            .cursor_opacity = @max(0, @min(1, config.@"cursor-opacity")),
+
             .background = config.background.toTerminalRGB(),
             .foreground = config.foreground.toTerminalRGB(),
 
@@ -870,6 +873,10 @@ fn addCursor(
     };
 
     const color = self.config.cursor_color orelse self.config.foreground;
+    const alpha: u8 = alpha: {
+        const alpha = 255 * self.config.cursor_opacity;
+        break :alpha @intFromFloat(@ceil(alpha));
+    };
 
     const sprite: font.Sprite = switch (cursor_style) {
         .block => .cursor_rect,
@@ -896,7 +903,7 @@ fn addCursor(
         .fg_r = color.r,
         .fg_g = color.g,
         .fg_b = color.b,
-        .fg_a = 255,
+        .fg_a = alpha,
         .bg_r = 0,
         .bg_g = 0,
         .bg_b = 0,