From 085ab36680f7d9ce8030f34f91b5d0aabb71bf7c Mon Sep 17 00:00:00 2001
From: calixteman <calixte.denizet@gmail.com>
Date: Mon, 16 Mar 2026 23:19:21 +0100
Subject: [PATCH] Don't throw when a mesh shading is degenerated

The problem of throwing an error is that it removes an operation
from drawing list which can cause a rendering issue.
---
 src/core/pattern.js              |   9 +--------
 src/display/pattern_helper.js    |  24 ++++++++++++++----------
 test/pdfs/.gitignore             |   1 +
 test/pdfs/mesh_shading_empty.pdf | Bin 0 -> 1407 bytes
 test/test_manifest.json          |   7 +++++++
 5 files changed, 23 insertions(+), 18 deletions(-)
 create mode 100644 test/pdfs/mesh_shading_empty.pdf

diff --git a/src/core/pattern.js b/src/core/pattern.js
index 6059fdfcf..62f67618a 100644
--- a/src/core/pattern.js
+++ b/src/core/pattern.js
@@ -968,20 +968,13 @@ class MeshShading extends BaseShading {
   }
 
   getIR() {
-    const { bounds } = this;
-    // Ensure that the shading has non-zero width and height, to prevent errors
-    // in `pattern_helper.js` (fixes issue17848.pdf).
-    if (bounds[2] - bounds[0] === 0 || bounds[3] - bounds[1] === 0) {
-      throw new FormatError(`Invalid MeshShading bounds: [${bounds}].`);
-    }
-
     return [
       "Mesh",
       this.shadingType,
       this.coords,
       this.colors,
       this.figures,
-      bounds,
+      this.bounds,
       this.bbox,
       this.background,
     ];
diff --git a/src/display/pattern_helper.js b/src/display/pattern_helper.js
index 5a8da30a5..f66050d1b 100644
--- a/src/display/pattern_helper.js
+++ b/src/display/pattern_helper.js
@@ -462,16 +462,20 @@ class MeshShadingPattern extends BaseShadingPattern {
     const boundsWidth = Math.ceil(this._bounds[2]) - offsetX;
     const boundsHeight = Math.ceil(this._bounds[3]) - offsetY;
 
-    const width = Math.min(
-      Math.ceil(Math.abs(boundsWidth * combinedScale[0] * EXPECTED_SCALE)),
-      MAX_PATTERN_SIZE
-    );
-    const height = Math.min(
-      Math.ceil(Math.abs(boundsHeight * combinedScale[1] * EXPECTED_SCALE)),
-      MAX_PATTERN_SIZE
-    );
-    const scaleX = boundsWidth / width;
-    const scaleY = boundsHeight / height;
+    // Ensure that the shading has non-zero width and height, to prevent errors
+    // in `pattern_helper.js` (fixes issue17848.pdf).
+    const width =
+      Math.min(
+        Math.ceil(Math.abs(boundsWidth * combinedScale[0] * EXPECTED_SCALE)),
+        MAX_PATTERN_SIZE
+      ) || 1;
+    const height =
+      Math.min(
+        Math.ceil(Math.abs(boundsHeight * combinedScale[1] * EXPECTED_SCALE)),
+        MAX_PATTERN_SIZE
+      ) || 1;
+    const scaleX = boundsWidth ? boundsWidth / width : 1;
+    const scaleY = boundsHeight ? boundsHeight / height : 1;
 
     const context = {
       coords: this._coords,
diff --git a/test/pdfs/.gitignore b/test/pdfs/.gitignore
index 8e4b0a508..bcbcdd68a 100644
--- a/test/pdfs/.gitignore
+++ b/test/pdfs/.gitignore
@@ -884,3 +884,4 @@
 !form_two_pages.pdf
 !outlines_se.pdf
 !radial_gradients.pdf
+!mesh_shading_empty.pdf
diff --git a/test/pdfs/mesh_shading_empty.pdf b/test/pdfs/mesh_shading_empty.pdf
new file mode 100644
index 0000000000000000000000000000000000000000..1bc16ce7e58a061f2f590426ff19f86b3bec6f8c
GIT binary patch
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literal 0
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diff --git a/test/test_manifest.json b/test/test_manifest.json
index 96245b451..7dac82e9b 100644
--- a/test/test_manifest.json
+++ b/test/test_manifest.json
@@ -13998,5 +13998,12 @@
     "md5": "80e8bed66b83928698f008c33de47edd",
     "rounds": 1,
     "type": "eq"
+  },
+  {
+    "id": "mesh_shading_empty",
+    "file": "pdfs/mesh_shading_empty.pdf",
+    "md5": "5a1bf9cb73010d84b47d91bb66bae27d",
+    "rounds": 1,
+    "type": "eq"
   }
 ]