From b6012f1fc4bf10015db89817ff0c66bf5d833425 Mon Sep 17 00:00:00 2001
From: Roman Pytkov <mr.pytkov@gmail.com>
Date: Sun, 22 Feb 2026 22:25:49 +0300
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---
 src/Canvas.zig | 27 ++++++++++++++++++++++++++-
 src/main.zig   |  5 ++++-
 2 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/src/Canvas.zig b/src/Canvas.zig
index fbf88a4..9ec7692 100644
--- a/src/Canvas.zig
+++ b/src/Canvas.zig
@@ -18,8 +18,12 @@ scroll: dvui.ScrollInfo = .{
     .horizontal = .auto,
 },
 native_scaling: bool = true,
+/// Максимальная частота перерисовки при зуме. 0 = без ограничения.
+redraw_throttle_ms: u32 = 40,
 _visible_rect: ?ImageRect = null,
 _zoom: f32 = 1,
+_redraw_pending: bool = false,
+_last_redraw_time_ms: i64 = 0,
 
 pub fn init(allocator: std.mem.Allocator, document: *Document, engine: RenderEngine) Canvas {
     return .{
@@ -60,6 +64,7 @@ pub fn redrawExample(self: *Canvas) !void {
 
         self.texture = tex;
     }
+    self._last_redraw_time_ms = std.time.milliTimestamp();
 }
 
 // Ресетнуть example изображение в renderEngine
@@ -77,6 +82,26 @@ pub fn addZoom(self: *Canvas, value: f32) void {
     self._zoom = @max(self._zoom, 0.01);
 }
 
+/// Запросить перерисовку (выполнится с учётом redraw_throttle_ms при вызове processPendingRedraw).
+pub fn requestRedraw(self: *Canvas) void {
+    self._redraw_pending = true;
+}
+
+/// Выполнить отложенную перерисовку, если прошло не менее redraw_throttle_ms с прошлой отрисовки.
+pub fn processPendingRedraw(self: *Canvas) !void {
+    if (!self._redraw_pending) return;
+    if (self.redraw_throttle_ms == 0) {
+        self._redraw_pending = false;
+        try self.redrawExample();
+        return;
+    }
+    const now_ms = std.time.milliTimestamp();
+    const elapsed: i64 = if (self._last_redraw_time_ms == 0) self.redraw_throttle_ms else now_ms - self._last_redraw_time_ms;
+    if (elapsed < @as(i64, @intCast(self.redraw_throttle_ms))) return;
+    self._redraw_pending = false;
+    try self.redrawExample();
+}
+
 pub fn getScaledImageSize(self: Canvas) ImageRect {
     const doc = self.document;
     return .{
@@ -103,7 +128,7 @@ pub fn updateVisibleImageRect(self: *Canvas, viewport: dvui.Rect, scroll_offset:
         std.debug.print("Visible Image Rect: {{ x: {}, y: {}, w: {}, h: {} }}\n", .{ next.x, next.y, next.w, next.h });
     }
     if (changed or self.texture == null) {
-        try self.redrawExample();
+        requestRedraw(self);
     }
 }
 
diff --git a/src/main.zig b/src/main.zig
index a449eb1..eb264a0 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -189,6 +189,9 @@ fn gui_frame(ctx: *WindowContext) bool {
                                 canvas.updateVisibleImageRect(viewport_px, scroll_px) catch |err| {
                                     std.debug.print("updateVisibleImageRect error: {}\n", .{err});
                                 };
+                                canvas.processPendingRedraw() catch |err| {
+                                    std.debug.print("processPendingRedraw error: {}\n", .{err});
+                                };
 
                                 const content_w_px: u32 = img_size.x + img_size.w;
                                 const content_h_px: u32 = img_size.y + img_size.h;
@@ -237,7 +240,7 @@ fn gui_frame(ctx: *WindowContext) bool {
                                                     switch (action) {
                                                         .wheel_y => |y| {
                                                             canvas.addZoom(y / 1000);
-                                                            canvas.redrawExample() catch {};
+                                                            canvas.requestRedraw();
                                                         },
                                                         else => {},
                                                     }