From ba00675559f5df9d5d8fca655090ee92d542bc72 Mon Sep 17 00:00:00 2001
From: Hermet Park <hermet@lottiefiles.com>
Date: Mon, 24 Mar 2025 23:43:33 +0900
Subject: [PATCH] renderer: safety++

introduced a threshold for the minimum dash size
to prevent excessive fragmentation.

issue: https://github.com/thorvg/thorvg/issues/3332
---
 src/renderer/gl_engine/tvgGlTessellator.cpp | 4 ++--
 src/renderer/sw_engine/tvgSwShape.cpp       | 5 ++---
 src/renderer/tvgRender.h                    | 2 ++
 3 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/src/renderer/gl_engine/tvgGlTessellator.cpp b/src/renderer/gl_engine/tvgGlTessellator.cpp
index 8846918a..e2e159e1 100644
--- a/src/renderer/gl_engine/tvgGlTessellator.cpp
+++ b/src/renderer/gl_engine/tvgGlTessellator.cpp
@@ -2284,7 +2284,7 @@ void DashStroke::dashLineTo(const GlPoint &to)
     } else {
         detail::Line curr{mPtCur, to};
 
-        while (len - mCurrLen > 0.0001f) {
+        while (len - mCurrLen > DASH_PATTERN_THRESHOLD) {
             detail::Line right;
             if (mCurrLen > 0.0f) {
                 detail::Line left;
@@ -2347,7 +2347,7 @@ void DashStroke::dashCubicTo(const GlPoint &cnt1, const GlPoint &cnt2, const GlP
             this->cubicTo(cnt1, cnt2, end);
         }
     } else {
-        while (len - mCurrLen > 0.0001f) {
+        while (len - mCurrLen > DASH_PATTERN_THRESHOLD) {
             Bezier right;
             if (mCurrLen > 0.0f) {
                 Bezier left;
diff --git a/src/renderer/sw_engine/tvgSwShape.cpp b/src/renderer/sw_engine/tvgSwShape.cpp
index ce46b582..87c2da90 100644
--- a/src/renderer/sw_engine/tvgSwShape.cpp
+++ b/src/renderer/sw_engine/tvgSwShape.cpp
@@ -102,7 +102,6 @@ static void _dashLineTo(SwDashStroke& dash, const Point* to, const Matrix& trans
 {
     Line cur = {dash.ptCur, *to};
     auto len = cur.length();
-
     if (tvg::zero(len)) {
         _outlineMoveTo(*dash.outline, &dash.ptCur, transform);
     //draw the current line fully
@@ -117,7 +116,7 @@ static void _dashLineTo(SwDashStroke& dash, const Point* to, const Matrix& trans
         }
     //draw the current line partially
     } else {
-        while (len - dash.curLen > 0.0001f) {
+        while (len - dash.curLen > DASH_PATTERN_THRESHOLD) {
             Line left, right;
             if (dash.curLen > 0) {
                 len -= dash.curLen;
@@ -178,7 +177,7 @@ static void _dashCubicTo(SwDashStroke& dash, const Point* ctrl1, const Point* ct
         }
     //draw the current line partially
     } else {
-        while ((len - dash.curLen) > 0.0001f) {
+        while ((len - dash.curLen) > DASH_PATTERN_THRESHOLD) {
             Bezier left, right;
             if (dash.curLen > 0) {
                 len -= dash.curLen;
diff --git a/src/renderer/tvgRender.h b/src/renderer/tvgRender.h
index 7d432cac..ce4a1bc9 100644
--- a/src/renderer/tvgRender.h
+++ b/src/renderer/tvgRender.h
@@ -35,6 +35,8 @@ namespace tvg
 using RenderData = void*;
 using pixel_t = uint32_t;
 
+#define DASH_PATTERN_THRESHOLD 0.001f
+
 enum RenderUpdateFlag : uint8_t {None = 0, Path = 1, Color = 2, Gradient = 4, Stroke = 8, Transform = 16, Image = 32, GradientStroke = 64, Blend = 128, All = 255};
 enum CompositionFlag : uint8_t {Invalid = 0, Opacity = 1, Blending = 2, Masking = 4, PostProcessing = 8};  //Composition Purpose