Fix dash increment

Dashing wasn't incrementing index for dash and could get stuck if 0 length dash was provided. This will leave an empty path if it finds an impossible dashing condition. Diffs= b06e05dc1 Fix dash increment (#8038) Co-authored-by: Luigi Rosso <[email protected]>
rive-app · Sep 3, 2024 · dc59953 · dc59953
1 parent 33a51d0
commit dc59953
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Showing 3 changed files with 57 additions and 13 deletions.
diff --git a/.rive_head b/.rive_head
@@ -1 +1 @@
-5c312867e32d4a347e5483dca9798b1dd3dd30d1
+b06e05dc18248d218807e00779d35c94bdfb8efe
diff --git a/src/shapes/paint/dash_path.cpp b/src/shapes/paint/dash_path.cpp
@@ -5,7 +5,7 @@ using namespace rive;
 
 Dash::Dash() : m_value(0.0f), m_percentage(false) {}
 Dash::Dash(float value, bool percentage) : m_value(value), m_percentage(percentage) {}
-float Dash::value() const { return m_value; }
+float Dash::value() const { return m_value < 0.0 ? 0.0f : m_value; }
 bool Dash::percentage() const { return m_percentage; }
 
 void PathDasher::invalidateSourcePath()
@@ -36,21 +36,36 @@ RenderPath* PathDasher::dash(const RawPath& source,
         }
     }
 
-    int dashIndex = 0;
-    for (const rcp<ContourMeasure>& contour : m_contours)
+    // Make sure dashes have some length.
+    bool hasValidDash = false;
+    for (auto dash : dashes)
     {
-        float distance = offset.percentage() ? offset.value() * contour->length() : offset.value();
-        bool draw = true;
-        while (distance < contour->length())
+        if (dash.value() > 0.0f)
         {
-            const Dash& dash = dashes[dashIndex];
-            float dashLength = dash.percentage() ? dash.value() * contour->length() : dash.value();
-            if (draw)
+            hasValidDash = true;
+            break;
+        }
+    }
+    if (hasValidDash)
+    {
+        int dashIndex = 0;
+        for (const rcp<ContourMeasure>& contour : m_contours)
+        {
+            float distance =
+                offset.percentage() ? offset.value() * contour->length() : offset.value();
+            bool draw = true;
+            while (distance < contour->length())
             {
-                contour->getSegment(distance, distance + dashLength, &m_rawPath, true);
+                const Dash& dash = dashes[dashIndex++ % dashes.size()];
+                float dashLength =
+                    dash.percentage() ? dash.value() * contour->length() : dash.value();
+                if (draw)
+                {
+                    contour->getSegment(distance, distance + dashLength, &m_rawPath, true);
+                }
+                distance += dashLength;
+                draw = !draw;
             }
-            distance += dashLength;
-            draw = !draw;
         }
     }
 

diff --git a/test/dash_test.cpp b/test/dash_test.cpp
@@ -0,0 +1,29 @@
+#include "rive/shapes/paint/dash_path.hpp"
+#include "utils/no_op_factory.hpp"
+#include <catch.hpp>
+#include <cstdio>
+
+class _TestDasher : public rive::PathDasher
+{
+
+public:
+    rive::RenderPath* dash(const rive::RawPath& source,
+                           rive::Dash offset,
+                           rive::Span<rive::Dash> dashes)
+    {
+        rive::NoOpFactory noOpFactory;
+        return rive::PathDasher::dash(source, &noOpFactory, offset, dashes);
+    }
+};
+
+TEST_CASE("0 length dashes don't cause a crash", "[dashing]")
+{
+    rive::RawPath rawPath;
+    rawPath.addRect({1, 1, 5, 6});
+
+    _TestDasher dasher;
+    std::vector dashes = {rive::Dash(0.0f, false), rive::Dash(0.0f, false)};
+
+    rive::Dash offset(0.0f, false);
+    dasher.dash(rawPath, offset, dashes);
+}