diff --git a/src/Document.zig b/src/Document.zig
new file mode 100644
index 0000000..359deef
--- /dev/null
+++ b/src/Document.zig
@@ -0,0 +1 @@
+// Файл векторного документа
diff --git a/src/WindowContext.zig b/src/WindowContext.zig
new file mode 100644
index 0000000..df5a241
--- /dev/null
+++ b/src/WindowContext.zig
@@ -0,0 +1,76 @@
+const std = @import("std");
+const dvui = @import("dvui");
+const Color = dvui.Color;
+
+const WindowContext = @This();
+
+allocator: std.mem.Allocator,
+canvas_texture: ?dvui.Texture = null,
+canvas_width: u32 = 400,
+canvas_height: u32 = 300,
+
+pub fn init(allocator: std.mem.Allocator) WindowContext {
+    return .{
+        .allocator = allocator,
+    };
+}
+
+/// Заполнить canvas случайным цветом на CPU
+pub fn fillRandomColor(self: *WindowContext) !void {
+    var prng = std.Random.DefaultPrng.init(@intCast(std.time.microTimestamp()));
+    const random = prng.random();
+
+    // Выделить буфер пиксельных данных
+    const pixels = try self.allocator.alloc(Color.PMA, @as(usize, self.canvas_width) * self.canvas_height);
+    defer self.allocator.free(pixels);
+
+    // Заполнить случайными цветами
+    const r = random.int(u8);
+    const g = random.int(u8);
+    const b = random.int(u8);
+
+    var prev: dvui.Color.PMA = .{
+        .r = r,
+        .g = g,
+        .b = b,
+        .a = 255,
+    };
+    for (pixels) |*pixel| {
+        const r_delta = random.intRangeAtMost(i16, -1, 1);
+        const g_delta = random.intRangeAtMost(i16, -1, 1);
+        const b_delta = random.intRangeAtMost(i16, -1, 1);
+
+        const r_new: i16 = @as(i16, prev.r) + r_delta;
+        const g_new: i16 = @as(i16, prev.g) + g_delta;
+        const b_new: i16 = @as(i16, prev.b) + b_delta;
+
+        pixel.* = .{
+            .r = @intCast(std.math.clamp(r_new, 0, 255)),
+            .g = @intCast(std.math.clamp(g_new, 0, 255)),
+            .b = @intCast(std.math.clamp(b_new, 0, 255)),
+            .a = 255,
+        };
+        prev = pixel.*;
+    }
+
+    // Удалить старую текстуру
+    if (self.canvas_texture) |tex| {
+        dvui.Texture.destroyLater(tex);
+    }
+
+    // Создать новую текстуру из пиксельных данных
+    self.canvas_texture = try dvui.textureCreate(pixels, self.canvas_width, self.canvas_height, .linear);
+}
+
+/// Отобразить canvas в UI
+pub fn render(self: WindowContext, rect: dvui.Rect.Physical) !void {
+    if (self.canvas_texture) |texture| {
+        try dvui.renderTexture(texture, .{ .r = rect }, .{});
+    }
+}
+
+pub fn deinit(self: *WindowContext) void {
+    if (self.canvas_texture) |texture| {
+        dvui.Texture.destroyLater(texture);
+    }
+}
diff --git a/src/main.zig b/src/main.zig
index c3570e7..3339901 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -2,6 +2,8 @@ const std = @import("std");
 const builtin = @import("builtin");
 const dvui = @import("dvui");
 const SDLBackend = @import("sdl-backend");
+const Document = @import("Document.zig");
+const WindowContext = @import("WindowContext.zig");
 const sdl_c = SDLBackend.c;
 const Allocator = std.mem.Allocator;
 const Color = dvui.Color;
@@ -24,9 +26,11 @@ pub fn main() !void {
             .dark => dvui.Theme.builtin.adwaita_dark,
         },
     });
-
     defer win.deinit();
 
+    var ctx = WindowContext.init(allocator);
+    defer ctx.deinit();
+
     var interrupted = false;
 
     main_loop: while (true) {
@@ -44,7 +48,7 @@ pub fn main() !void {
         _ = SDLBackend.c.SDL_SetRenderDrawColor(backend.renderer, 0, 0, 0, 255);
         _ = SDLBackend.c.SDL_RenderClear(backend.renderer);
 
-        const keep_running = gui_frame();
+        const keep_running = gui_frame(&ctx);
         if (!keep_running) break :main_loop;
 
         // marks end of dvui frame, don't call dvui functions after this
@@ -64,7 +68,7 @@ pub fn main() !void {
     }
 }
 
-fn gui_frame() bool {
+fn gui_frame(ctx: *WindowContext) bool {
     for (dvui.events()) |*e| {
         if (e.evt == .window and e.evt.window.action == .close) return false;
         if (e.evt == .app and e.evt.app.action == .quit) return false;
@@ -83,7 +87,11 @@ fn gui_frame() bool {
         defer left_panel.deinit();
 
         dvui.label(@src(), "Tools", .{}, .{});
-        _ = dvui.button(@src(), "Button", .{}, .{});
+        if (dvui.button(@src(), "Fill Random Color", .{}, .{})) {
+            ctx.fillRandomColor() catch |err| {
+                std.debug.print("Error filling canvas: {}\n", .{err});
+            };
+        }
     }
 
     // Правая панель - занимает оставшееся пространство
@@ -95,20 +103,40 @@ fn gui_frame() bool {
         );
         defer back.deinit();
 
-        const fill_color = Color.white.opacity(0.5);
-        var right_panel = dvui.box(
-            @src(),
-            .{ .dir = .vertical },
-            .{
-                .expand = .both,
-                .background = true,
-                .corner_radius = dvui.Rect.all(10),
-                .color_fill = fill_color,
-            },
-        );
-        defer right_panel.deinit();
+        {
+            const fill_color = Color.white.opacity(0.5);
+            var right_panel = dvui.box(
+                @src(),
+                .{ .dir = .vertical },
+                .{
+                    .expand = .both,
+                    .background = true,
+                    .corner_radius = dvui.Rect.all(10),
+                    .color_fill = fill_color,
+                },
+            );
+            defer right_panel.deinit();
 
-        dvui.label(@src(), "Canvas", .{}, .{ .gravity_x = 0.5 });
+            const overlay = dvui.overlay(@src(), .{
+                .expand = .both,
+            });
+            defer overlay.deinit();
+
+            // Отобразить canvas внутри контейнера
+            if (ctx.canvas_texture) |texture| {
+                _ = dvui.image(@src(), .{
+                    .source = .{ .texture = texture },
+                }, .{
+                    .expand = .both,
+                    .min_size_content = .{
+                        .w = @floatFromInt(ctx.canvas_width),
+                        .h = @floatFromInt(ctx.canvas_height),
+                    },
+                });
+            }
+
+            dvui.label(@src(), "Canvas", .{}, .{ .gravity_x = 0.5, .gravity_y = 0.0 });
+        }
     }
 
     return true;
diff --git a/src/render/IRenderEngine.zig b/src/render/IRenderEngine.zig
new file mode 100644
index 0000000..2cf24d8
--- /dev/null
+++ b/src/render/IRenderEngine.zig
@@ -0,0 +1 @@
+// Интерфейс для рендеринга документа