[librsvg] (#395): Morphology needs positive radii even after the transformation

[Federico Mena Quintero <federico src gnome org>]

commit f464913a429c885ff90af1e0d7c3abf897050b37
Author: Federico Mena Quintero <federico gnome org>
Date:   Sat Dec 29 12:32:08 2018 -0600

    (#395): Morphology needs positive radii even after the transformation
    
    This is the same pattern as in gaussian_blur.rs; the paffine
    transformation can leave us with negative radii, so take their
    absolute value after the transformation.
    
    Fixes https://gitlab.gnome.org/GNOME/librsvg/issues/395

 rsvg_internals/src/filters/morphology.rs           |  4 ++++
 .../395-feMorphology-negative-scaling.svg          | 28 ++++++++++++++++++++++
 2 files changed, 32 insertions(+)
---
diff --git a/rsvg_internals/src/filters/morphology.rs b/rsvg_internals/src/filters/morphology.rs
index 7723cff7..61338593 100644
--- a/rsvg_internals/src/filters/morphology.rs
+++ b/rsvg_internals/src/filters/morphology.rs
@@ -96,6 +96,10 @@ impl Filter for Morphology {
         let (rx, ry) = self.radius.get();
         let (rx, ry) = ctx.paffine().transform_distance(rx, ry);
 
+        // The radii can become negative here due to the transform.
+        let rx = rx.abs();
+        let ry = ry.abs();
+
         let operator = self.operator.get();
 
         let mut output_surface = ImageSurface::create(
diff --git a/tests/fixtures/render-crash/395-feMorphology-negative-scaling.svg 
b/tests/fixtures/render-crash/395-feMorphology-negative-scaling.svg
new file mode 100644
index 00000000..168e3b01
--- /dev/null
+++ b/tests/fixtures/render-crash/395-feMorphology-negative-scaling.svg
@@ -0,0 +1,28 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg width="53px" height="53px" viewBox="0 0 53 53" version="1.1" xmlns="http://www.w3.org/2000/svg"; 
xmlns:xlink="http://www.w3.org/1999/xlink";>
+    <!-- Generator: Sketch 47 (45396) - http://www.bohemiancoding.com/sketch -->
+    <title>next_normal</title>
+    <desc>Created with Sketch.</desc>
+    <defs>
+        <rect id="path-1" x="9" y="4" width="35" height="35" rx="4"></rect>
+        <filter x="-44.3%" y="-30.0%" width="188.6%" height="188.6%" filterUnits="objectBoundingBox" 
id="filter-2">
+            <feMorphology radius="1" operator="dilate" in="SourceAlpha" 
result="shadowSpreadOuter1"></feMorphology>
+            <feOffset dx="0" dy="5" in="shadowSpreadOuter1" result="shadowOffsetOuter1"></feOffset>
+            <feGaussianBlur stdDeviation="4" in="shadowOffsetOuter1" 
result="shadowBlurOuter1"></feGaussianBlur>
+            <feComposite in="shadowBlurOuter1" in2="SourceAlpha" operator="out" 
result="shadowBlurOuter1"></feComposite>
+            <feColorMatrix values="0 0 0 0 0   0 0 0 0 0   0 0 0 0 0  0 0 0 0.2 0" type="matrix" 
in="shadowBlurOuter1"></feColorMatrix>
+        </filter>
+    </defs>
+    <g id="Page-1" stroke="none" stroke-width="1" fill="none" fill-rule="evenodd">
+        <g id="图标" transform="translate(-146.000000, -142.000000)">
+            <g id="Group-Copy-7" transform="translate(172.500000, 168.500000) scale(-1, 1) 
translate(-172.500000, -168.500000) translate(146.000000, 142.000000)">
+                <g id="Rectangle-2">
+                    <use fill="black" fill-opacity="1" filter="url(#filter-2)" xlink:href="#path-1"></use>
+                    <use fill-opacity="0.4" fill="#000000" fill-rule="evenodd" xlink:href="#path-1"></use>
+                    <rect stroke-opacity="0.2" stroke="#FFFFFF" stroke-width="1" x="8.5" y="3.5" width="36" 
height="36" rx="4"></rect>
+                </g>
+                <path d="M22.4742121,14.0008305 C22.2710317,14.0118483 22.0947892,14.1448834 
22.0285097,14.3372651 C21.9622303,14.5296468 22.0191331,14.7430052 22.1724121,14.8768305 
L29.2593121,21.2546305 L22.1724121,27.6326305 C22.0359184,27.7510215 21.9739085,27.9338375 
22.0102072,28.1108385 C22.0465059,28.2878395 22.1754668,28.4314919 22.3475416,28.4866027 
C22.5196164,28.5417136 22.7080378,28.4997101 22.8404121,28.3767305 L30.3404121,21.6267305 
C30.4460251,21.5318878 30.5063531,21.3966286 30.5063531,21.2546805 C30.5063531,21.1127325 
30.4460251,20.9774733 30.3404121,20.8826305 L22.8404121,14.1326305 C22.7411687,14.0410113 
22.6090829,13.9934359 22.4742121,14.0007305 L22.4742121,14.0008305 Z" id="polyline34476" fill="#FFFFFF" 
opacity="0.699999988" transform="translate(26.253177, 21.255221) scale(-1, 1) translate(-26.253177, 
-21.255221) "></path>
+            </g>
+        </g>
+    </g>
+</svg>
\ No newline at end of file