diff --git a/crates/resvg/src/filter/iir_blur.rs b/crates/resvg/src/filter/iir_blur.rs
index e49608b2..5af7009b 100644
--- a/crates/resvg/src/filter/iir_blur.rs
+++ b/crates/resvg/src/filter/iir_blur.rs
@@ -65,7 +65,7 @@ pub fn apply(sigma_x: f64, sigma_y: f64, src: ImageRefMut) {
     gaussian_channel(data, &d, 3, buf);
 }
 
-fn gaussian_channel(data: &mut [u8], d: &BlurData, channel: usize, buf: &mut Vec<f64>) {
+fn gaussian_channel(data: &mut [u8], d: &BlurData, channel: usize, buf: &mut [f64]) {
     for i in 0..data.len() / 4 {
         buf[i] = data[i * 4 + channel] as f64 / 255.0;
     }
@@ -77,7 +77,7 @@ fn gaussian_channel(data: &mut [u8], d: &BlurData, channel: usize, buf: &mut Vec
     }
 }
 
-fn gaussianiir2d(d: &BlurData, buf: &mut Vec<f64>) {
+fn gaussianiir2d(d: &BlurData, buf: &mut [f64]) {
     // Filter horizontally along each row.
     let (lambda_x, dnu_x) = if d.sigma_x > 0.0 {
         let (lambda, dnu) = gen_coefficients(d.sigma_x, d.steps);