3 files changed, 71 insertions, 10 deletions
diff --git a/third_party/agg23/0000-bug-466.patch b/third_party/agg23/0000-bug-466.patch
new file mode 100644
index 0000000000..3217b3838a
--- /dev/null
+++ b/third_party/agg23/0000-bug-466.patch
@@ -0,0 +1,45 @@
+diff --git a/third_party/agg23/agg_math_stroke.h b/third_party/agg23/agg_math_stroke.h
+index 6d7ba8a..2b06b1b 100644
+--- a/third_party/agg23/agg_math_stroke.h
++++ b/third_party/agg23/agg_math_stroke.h
+@@ -60,28 +60,30 @@ void stroke_calc_arc(VertexConsumer& out_vertices,
+     }
+     da = FXSYS_acos(width / (width + ((1.0f / 8) / approximation_scale))) * 2;
+     out_vertices.add(coord_type(x + dx1, y + dy1));
+-    if(!ccw) {
+-        if(a1 > a2) {
+-            a2 += 2 * FX_PI;
++    if (da > 0) {
++      if (!ccw) {
++        if (a1 > a2) {
++          a2 += 2 * FX_PI;
+         }
+         a2 -= da / 4;
+         a1 += da;
+-        while(a1 < a2) {
++        while (a1 < a2) {
+           out_vertices.add(coord_type(x + (width * FXSYS_cos(a1)),
+                                       y + (width * FXSYS_sin(a1))));
+-            a1 += da;
++          a1 += da;
+         }
+-    } else {
+-        if(a1 < a2) {
+-            a2 -= 2 * FX_PI;
++      } else {
++        if (a1 < a2) {
++          a2 -= 2 * FX_PI;
+         }
+         a2 += da / 4;
+         a1 -= da;
+-        while(a1 > a2) {
++        while (a1 > a2) {
+           out_vertices.add(coord_type(x + (width * FXSYS_cos(a1)),
+                                       y + (width * FXSYS_sin(a1))));
+-            a1 -= da;
++          a1 -= da;
+         }
++      }
+     }
+     out_vertices.add(coord_type(x + dx2, y + dy2));
+ }
diff --git a/third_party/agg23/README.pdfium b/third_party/agg23/README.pdfium
new file mode 100644
index 0000000000..54687934b6
--- /dev/null
+++ b/third_party/agg23/README.pdfium
@@ -0,0 +1,14 @@
+Name: Anti-Grain Geometry
+URL: https://sourceforge.net/projects/agg/
+Version: 2.3
+Security Critical: yes
+License: MIT
+
+Description:
+2D vector graphics library.
+
+Local Modifications:
+
+0000-bug-466.patch: Fixes an infinite loop in stroke_calc_arc().
+Various changes to use FX_ library functions.
+Possibly more?
diff --git a/third_party/agg23/agg_math_stroke.h b/third_party/agg23/agg_math_stroke.h
index 6d7ba8a96e..2b06b1bfda 100644
--- a/third_party/agg23/agg_math_stroke.h
+++ b/third_party/agg23/agg_math_stroke.h
@@ -60,28 +60,30 @@ void stroke_calc_arc(VertexConsumer& out_vertices,
     }
     da = FXSYS_acos(width / (width + ((1.0f / 8) / approximation_scale))) * 2;
     out_vertices.add(coord_type(x + dx1, y + dy1));
-    if(!ccw) {
-        if(a1 > a2) {
-            a2 += 2 * FX_PI;
+    if (da > 0) {
+      if (!ccw) {
+        if (a1 > a2) {
+          a2 += 2 * FX_PI;
         }
         a2 -= da / 4;
         a1 += da;
-        while(a1 < a2) {
+        while (a1 < a2) {
           out_vertices.add(coord_type(x + (width * FXSYS_cos(a1)),
                                       y + (width * FXSYS_sin(a1))));
-            a1 += da;
+          a1 += da;
         }
-    } else {
-        if(a1 < a2) {
-            a2 -= 2 * FX_PI;
+      } else {
+        if (a1 < a2) {
+          a2 -= 2 * FX_PI;
         }
         a2 += da / 4;
         a1 -= da;
-        while(a1 > a2) {
+        while (a1 > a2) {
           out_vertices.add(coord_type(x + (width * FXSYS_cos(a1)),
                                       y + (width * FXSYS_sin(a1))));
-            a1 -= da;
+          a1 -= da;
         }
+      }
     }
     out_vertices.add(coord_type(x + dx2, y + dy2));
 }