diff --git a/draw/src/stacked.rs b/draw/src/stacked.rs
index b94d41a..ae3fe34 100644
--- a/draw/src/stacked.rs
+++ b/draw/src/stacked.rs
@@ -79,8 +79,8 @@ fn draw_scaled_graph(image: &mut RgbImage, graph: &StackedSeries) {
             let color = colors[series_idx];
             let height_px = (graph.config.height_px as f32) * sample * scale;
             if height_px > 1f32 {
-                let rect = Rect::at(x_offset as i32, (y_offset - height_px) as i32)
-                    .of_size(graph.config.width_px_per_sample, height_px as u32);
+                let rect = Rect::at(x_offset as i32, (y_offset - height_px).ceil() as i32)
+                    .of_size(graph.config.width_px_per_sample, height_px.ceil() as u32);
                 draw_filled_rect_mut(image, rect, color);
                 y_offset -= height_px;
             }