Дополнительный буфер для отрисовки broken line

src/render/cpu/broken.zig

@@ -9,15 +9,30 @@ const Object = Document.Object;
 const default_stroke: Color.PMA = .{ .r = 0, .g = 0, .b = 0, .a = 255 };
 const default_thickness: f32 = 2.0;
 
-/// Ломаная по точкам, обводка stroke_rgba.
-pub fn draw(ctx: *DrawContext, obj: *const Object) void {
+/// Ломаная по точкам, обводка stroke_rgba
+pub fn draw(
+    ctx: *DrawContext,
+    obj: *const Object,
+    allocator: std.mem.Allocator,
+) !void {
     const p_prop = obj.getProperty(.points) orelse return;
     const pts = p_prop.points.items;
     if (pts.len < 2) return;
     const stroke = if (obj.getProperty(.stroke_rgba)) |s| pipeline.rgbaToPma(s.stroke_rgba) else default_stroke;
     const thickness = if (obj.getProperty(.thickness)) |t| t.thickness else default_thickness;
+
+    const buffer = try allocator.alloc(Color.PMA, ctx.buf_width * ctx.buf_height);
+    @memset(buffer, .{ .r = 0, .g = 0, .b = 0, .a = 0 });
+    defer allocator.free(buffer);
+
+    var copy_ctx = ctx.*;
+    copy_ctx.pixels = buffer;
+    copy_ctx.replace_mode = true;
+
     var i: usize = 0;
     while (i + 1 < pts.len) : (i += 1) {
-        line.drawLine(ctx, pts[i].x, pts[i].y, pts[i + 1].x, pts[i + 1].y, stroke, thickness);
+        line.drawLine(&copy_ctx, pts[i].x, pts[i].y, pts[i + 1].x, pts[i + 1].y, stroke, thickness);
     }
+
+    ctx.compositeDrawerContext(&copy_ctx, copy_ctx.transform.opacity);
 }