кнопка для переключения сэмпла

src/main.zig

@@ -92,10 +92,18 @@ fn gui_frame(ctx: *WindowContext) bool {
             canvas.exampleReset() catch |err| {
                 std.debug.print("Error filling canvas: {}\n", .{err});
             };
-            ctx.canvas.pos = .{ .x = 400, .y = 400 };
+            canvas.pos = .{ .x = 400, .y = 400 };
             //ctx.canvas.setZoom(dvui.windowNaturalScale());
         }
         if (dvui.checkbox(@src(), &canvas.native_scaling, "Scaling", .{})) {}
+        if (dvui.button(@src(), if (ctx.cpu_render.type == .Gradient) "Gradient" else "Squares", .{}, .{})) {
+            if (ctx.cpu_render.type == .Gradient) {
+                ctx.cpu_render.type = .Squares;
+            } else {
+                ctx.cpu_render.type = .Gradient;
+            }
+            canvas.redrawExample() catch {};
+        }
     }
     left_panel.deinit();