Fix feMorphology kernel size and radius rounding

crates/resvg/src/filter/morphology.rs

@@ -13,19 +13,15 @@ use usvg::filter::MorphologyOperator;
 ///
 /// This method will allocate a copy of the `src` image as a back buffer.
 pub fn apply(operator: MorphologyOperator, rx: f32, ry: f32, src: ImageRefMut) {
-    // No point in making matrix larger than image.
-    let columns = std::cmp::min(rx.ceil() as u32 * 2, src.width);
-    let rows = std::cmp::min(ry.ceil() as u32 * 2, src.height);
-    let target_x = (columns as f32 / 2.0).floor() as u32;
-    let target_y = (rows as f32 / 2.0).floor() as u32;
-
-    let width_max = src.width as i32 - 1;
-    let height_max = src.height as i32 - 1;
+    let width_max = src.width - 1;
+    let height_max = src.height - 1;
+    let rx = (rx.round() as u32).min(width_max);
+    let ry = (ry.round() as u32).min(height_max);
 
     let mut buf = vec![RGBA8::default(); src.data.len()];
     let mut buf = ImageRefMut::new(src.width, src.height, &mut buf);
-    let mut x = 0;
-    let mut y = 0;
+    let mut x: u32 = 0;
+    let mut y: u32 = 0;
     for _ in src.data.iter() {
         let mut new_p = RGBA8::default();
         if operator == MorphologyOperator::Erode {
@@ -35,26 +31,22 @@ pub fn apply(operator: MorphologyOperator, rx: f32, ry: f32, src: ImageRefMut) {
             new_p.a = 255;
         }
 
-        for oy in 0..rows {
-            for ox in 0..columns {
-                let tx = x as i32 - target_x as i32 + ox as i32;
-                let ty = y as i32 - target_y as i32 + oy as i32;
-
-                if tx < 0 || tx > width_max || ty < 0 || ty > height_max {
-                    continue;
-                }
+        let x_range = x.saturating_sub(rx)..=(x + rx).min(width_max);
+        let y_range = y.saturating_sub(ry)..=(y + ry).min(height_max);
 
-                let p = src.pixel_at(tx as u32, ty as u32);
+        for ty in y_range {
+            for tx in x_range.clone() {
+                let p = src.pixel_at(tx, ty);
                 if operator == MorphologyOperator::Erode {
-                    new_p.r = std::cmp::min(p.r, new_p.r);
-                    new_p.g = std::cmp::min(p.g, new_p.g);
-                    new_p.b = std::cmp::min(p.b, new_p.b);
-                    new_p.a = std::cmp::min(p.a, new_p.a);
+                    new_p.r = p.r.min(new_p.r);
+                    new_p.g = p.g.min(new_p.g);
+                    new_p.b = p.b.min(new_p.b);
+                    new_p.a = p.a.min(new_p.a);
                 } else {
-                    new_p.r = std::cmp::max(p.r, new_p.r);
-                    new_p.g = std::cmp::max(p.g, new_p.g);
-                    new_p.b = std::cmp::max(p.b, new_p.b);
-                    new_p.a = std::cmp::max(p.a, new_p.a);
+                    new_p.r = p.r.max(new_p.r);
+                    new_p.g = p.g.max(new_p.g);
+                    new_p.b = p.b.max(new_p.b);
+                    new_p.a = p.a.max(new_p.a);
                 }
             }
         }

crates/resvg/tests/integration/render.rs

@@ -209,10 +209,13 @@ use crate::render;
 #[test] fn filters_feMerge_color_interpolation_filters_eq_linearRGB() { assert_eq!(render("tests/filters/feMerge/color-interpolation-filters=linearRGB"), 0); }
 #[test] fn filters_feMerge_color_interpolation_filters_eq_sRGB() { assert_eq!(render("tests/filters/feMerge/color-interpolation-filters=sRGB"), 0); }
 #[test] fn filters_feMerge_complex_transform() { assert_eq!(render("tests/filters/feMerge/complex-transform"), 0); }
+#[test] fn filters_feMorphology_centered_kernel() { assert_eq!(render("tests/filters/feMorphology/centered-kernel"), 0); }
 #[test] fn filters_feMorphology_empty_radius() { assert_eq!(render("tests/filters/feMorphology/empty-radius"), 0); }
+#[test] fn filters_feMorphology_fractional_radius() { assert_eq!(render("tests/filters/feMorphology/fractional-radius"), 0); }
 #[test] fn filters_feMorphology_negative_radius() { assert_eq!(render("tests/filters/feMorphology/negative-radius"), 0); }
 #[test] fn filters_feMorphology_no_radius() { assert_eq!(render("tests/filters/feMorphology/no-radius"), 0); }
 #[test] fn filters_feMorphology_operator_eq_dilate() { assert_eq!(render("tests/filters/feMorphology/operator=dilate"), 0); }
+#[test] fn filters_feMorphology_radius_larger_than_region() { assert_eq!(render("tests/filters/feMorphology/radius-larger-than-region"), 0); }
 #[test] fn filters_feMorphology_radius_with_too_many_values() { assert_eq!(render("tests/filters/feMorphology/radius-with-too-many-values"), 0); }
 #[test] fn filters_feMorphology_radius_eq_0_5_with_objectBoundingBox() { assert_eq!(render("tests/filters/feMorphology/radius=0.5-with-objectBoundingBox"), 0); }
 #[test] fn filters_feMorphology_radius_eq_0_5() { assert_eq!(render("tests/filters/feMorphology/radius=0.5"), 0); }