diff --git a/src/Canvas.zig b/src/Canvas.zig
index 21b9aba..bec812c 100644
--- a/src/Canvas.zig
+++ b/src/Canvas.zig
@@ -35,6 +35,7 @@ redraw_throttle_ms: u32 = 50,
 frame_index: u64 = 0,
 
 _zoom: f32 = 1,
+_rendering_quality: f32 = 100.0,
 _last_redraw_time_ms: i64 = 0, // Метка последней перерисовки чтобы ограничить частоту
 _visible_rect: ?Rect_i = null,
 _redraw_pending: bool = false,
@@ -59,9 +60,9 @@ pub fn deinit(self: *Canvas) void {
 fn redraw(self: *Canvas) !void {
     const full = self.getZoomedImageSize();
 
-    const vis: Rect_i = self._visible_rect orelse Rect_i{ .x = 0, .y = 0, .w = 0, .h = 0 };
+    const vis_full: Rect_i = self._visible_rect orelse Rect_i{ .x = 0, .y = 0, .w = 0, .h = 0 };
 
-    if (vis.w == 0 or vis.h == 0) {
+    if (vis_full.w == 0 or vis_full.h == 0) {
         if (self.texture) |tex| {
             dvui.Texture.destroyLater(tex);
             self.texture = null;
@@ -69,11 +70,42 @@ fn redraw(self: *Canvas) !void {
         return;
     }
 
-    const canvas_size: Size_i = .{ .w = full.w, .h = full.h };
+    // Качество рендеринга задаётся в процентах площади (1–100),
+    // при этом фактически уменьшаем ширину/высоту холста на корень из этой доли.
+    const quality_percent: f32 = self.getRenderingQuality();
+    const quality_area: f32 = quality_percent / 100.0;
+    const quality_side: f32 = std.math.sqrt(quality_area);
+    const scale: f32 = std.math.clamp(quality_side, 0.01, 1.0);
+
+    const canvas_size: Size_i = .{
+        .w = @max(@as(u32, 1), @as(u32, @intFromFloat(@as(f32, @floatFromInt(full.w)) * scale))),
+        .h = @max(@as(u32, 1), @as(u32, @intFromFloat(@as(f32, @floatFromInt(full.h)) * scale))),
+    };
+
+    var vis_scaled = Rect_i{
+        .x = @as(u32, @intFromFloat(@as(f32, @floatFromInt(vis_full.x)) * scale)),
+        .y = @as(u32, @intFromFloat(@as(f32, @floatFromInt(vis_full.y)) * scale)),
+        .w = @max(@as(u32, 1), @as(u32, @intFromFloat(@as(f32, @floatFromInt(vis_full.w)) * scale))),
+        .h = @max(@as(u32, 1), @as(u32, @intFromFloat(@as(f32, @floatFromInt(vis_full.h)) * scale))),
+    };
+
+    if (vis_scaled.x >= canvas_size.w or vis_scaled.y >= canvas_size.h) {
+        if (self.texture) |tex| {
+            dvui.Texture.destroyLater(tex);
+            self.texture = null;
+        }
+        return;
+    }
+
+    const max_vis_w: u32 = canvas_size.w - vis_scaled.x;
+    const max_vis_h: u32 = canvas_size.h - vis_scaled.y;
+    if (vis_scaled.w > max_vis_w) vis_scaled.w = max_vis_w;
+    if (vis_scaled.h > max_vis_h) vis_scaled.h = max_vis_h;
+
     const new_texture = if (self.draw_document)
-        self.render_engine.render(self.document, canvas_size, vis) catch null
+        self.render_engine.render(self.document, canvas_size, vis_scaled) catch null
     else
-        self.render_engine.example(canvas_size, vis) catch null;
+        self.render_engine.example(canvas_size, vis_scaled) catch null;
 
     if (new_texture) |tex| {
         if (self.texture) |old_tex| {
@@ -114,6 +146,15 @@ pub fn getZoom(self: Canvas) f32 {
     return self._zoom;
 }
 
+pub fn setRenderingQuality(self: *Canvas, value: f32) void {
+    self._rendering_quality = std.math.clamp(value, 1.0, 100.0);
+    self.requestRedraw();
+}
+
+pub fn getRenderingQuality(self: Canvas) f32 {
+    return self._rendering_quality;
+}
+
 pub fn requestRedraw(self: *Canvas) void {
     self._redraw_pending = true;
 }
diff --git a/src/ui/left_panel.zig b/src/ui/left_panel.zig
index eb93771..f4f2b1f 100644
--- a/src/ui/left_panel.zig
+++ b/src/ui/left_panel.zig
@@ -176,6 +176,18 @@ pub fn leftPanel(ctx: *WindowContext) void {
                     canvas.requestRedraw();
                 }
                 if (dvui.checkbox(@src(), &canvas.show_render_stats, "Show stats", .{})) {}
+                {
+                    dvui.label(@src(), "Rendering quality", .{}, .{});
+                    var quality = canvas.getRenderingQuality();
+                    if (dvui.sliderEntry(
+                        @src(),
+                        "{d:0.0}%",
+                        .{ .value = &quality, .min = 1.0, .max = 100.0, .interval = 1.0 },
+                        .{ .expand = .horizontal },
+                    )) {
+                        canvas.setRenderingQuality(quality);
+                    }
+                }
                 if (!canvas.draw_document) {
                     if (dvui.button(@src(), if (doc.cpu_render.type == .Gradient) "Gradient" else "Squares", .{}, .{})) {
                         if (doc.cpu_render.type == .Gradient) {