Add theme customizer.

src/Terminal.zig

@@ -942,7 +942,7 @@ fn render(self: *Terminal, cr: *cairo.Context, _: c_int, _: c_int) !void {
     // Background. The pane frame around us clips to its own rounded corners,
     // so this just fills.
     const default_bg: theme.Rgb = if (term.colors.background.get()) |c|
-        .from(c)
+        .fromVt(c)
     else
         theme.bg();
     {
@@ -952,7 +952,7 @@ fn render(self: *Terminal, cr: *cairo.Context, _: c_int, _: c_int) !void {
     }
 
     const default_fg: theme.Rgb = if (term.colors.foreground.get()) |c|
-        .from(c)
+        .fromVt(c)
     else
         theme.fg();
 
@@ -1133,7 +1133,7 @@ fn drawCursor(
     const x = pad + @as(f64, @floatFromInt(cursor.x)) * self.cell_w;
     const y = pad + @as(f64, @floatFromInt(cursor.y)) * self.cell_h;
 
-    const color: theme.Rgb = if (term.colors.cursor.get()) |c| .from(c) else theme.cursor();
+    const color: theme.Rgb = if (term.colors.cursor.get()) |c| .fromVt(c) else theme.cursor();
     const r, const g, const b = color.cairoRgb();
     cr.setSourceRgb(r, g, b);
 
@@ -1191,7 +1191,7 @@ fn appearance(
     switch (cell.content_tag) {
         .bg_color_palette => return .{
             .fg = default_fg,
-            .bg = .from(palette[cell.content.color_palette.data]),
+            .bg = .fromVt(palette[cell.content.color_palette.data]),
             .bold = false,
             .italic = false,
             .underline = false,
@@ -1216,12 +1216,12 @@ fn appearance(
     var fg: theme.Rgb = switch (style.fg_color) {
         .none => default_fg,
         .palette => |i| brightIfBold(palette, i, style.flags.bold),
-        .rgb => |c| .from(c),
+        .rgb => |c| .fromVt(c),
     };
     var bg: ?theme.Rgb = switch (style.bg_color) {
         .none => null,
-        .palette => |i| .from(palette[i]),
-        .rgb => |c| .from(c),
+        .palette => |i| .fromVt(palette[i]),
+        .rgb => |c| .fromVt(c),
     };
 
     if (style.flags.inverse) {
@@ -1247,5 +1247,5 @@ fn appearance(
 /// with the matching bright color.
 fn brightIfBold(palette: *const [256]vt.color.RGB, index: u8, bold: bool) theme.Rgb {
     const effective = if (bold and index < 8) index + 8 else index;
-    return .from(palette[effective]);
+    return .fromVt(palette[effective]);
 }