Merge pull request #21383 from calixteman/ko_inner_bd

Add knockout_inner_backdrop ref test

Author: timvandermeij

test/pdfs/.gitignore

@@ -17,6 +17,7 @@
 !issue18408_reduced.pdf
 !bug1907000_reduced.pdf
 !knockout_blend_multiply.pdf
+!knockout_inner_backdrop.pdf
 !knockout_isolated_overlap.pdf
 !knockout_nested.pdf
 !knockout_nested_group_alpha.pdf

test/pdfs/knockout_inner_backdrop.pdf

@@ -6832,6 +6832,14 @@
     "type": "eq",
     "about": "Non-isolated knockout group with a Multiply blend mode element on a yellow backdrop; the element must blend against the backdrop, not against a transparent temp canvas."
   },
+  {
+    "id": "knockout_inner_backdrop",
+    "file": "pdfs/knockout_inner_backdrop.pdf",
+    "md5": "4b3b77319b9b2c6e6f1836c121f488c7",
+    "rounds": 1,
+    "type": "eq",
+    "about": "Non-isolated, non-knockout subgroup that needs isolation (Multiply blend mode in its content) nested inside a knockout group; the subgroup's elements must blend against its own initial backdrop while its transparent areas leave the parent untouched."
+  },
   {
     "id": "issue6010_1",
     "file": "pdfs/issue6010_1.pdf",