From ddcbbf771fb6e9acc9f470723bded5c6e2653c4f Mon Sep 17 00:00:00 2001
From: Mira Grudzinska <mira@lottiefiles.com>
Date: Thu, 13 Feb 2025 15:47:39 +0100
Subject: [PATCH] wg_engine: handle properly odd numbers of dashes/gaps

If the provided list has an odd number of values, then it
should be repeated to yield an even number of values.

@Issue: https://github.com/thorvg/thorvg/issues/3205
---
 src/renderer/wg_engine/tvgWgGeometry.h | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/src/renderer/wg_engine/tvgWgGeometry.h b/src/renderer/wg_engine/tvgWgGeometry.h
index 6de3bfc6..ce6156f4 100755
--- a/src/renderer/wg_engine/tvgWgGeometry.h
+++ b/src/renderer/wg_engine/tvgWgGeometry.h
@@ -309,10 +309,10 @@ struct WgVertexBufferInd
         }
         len_total -= dashOffset;
         // iterate by polyline points
+        auto gap = false;
         for (uint32_t i = 0; i < buff.vcount - 1; i++) {
             // append current polyline point
-            if (index_dash % 2 == 0)
-                dashed.append(buff.vbuff[i]);
+            if (!gap) dashed.append(buff.vbuff[i]);
             // move inside polyline segment
             while(len_total < buff.vdist[i+1]) {
                 // get current point
@@ -321,17 +321,18 @@ struct WgVertexBufferInd
                 index_dash = (index_dash + 1) % dashCnt;
                 len_total += dashPattern[index_dash];
                 // preceed stroke if dash
-                if (index_dash % 2 != 0) {
+                if (!gap) {
                     dashed.updateDistances();
                     appendStrokes(dashed, rstroke);
                     dashed.reset(tscale);
                 }
+                gap = !gap;
             }
             // update current subline length
             len_total -= buff.vdist[i+1];
         }
         // draw last subline
-        if (index_dash % 2 == 0) {
+        if (!gap) {
             dashed.append(buff.last());
             dashed.updateDistances();
             appendStrokes(dashed, rstroke);