2 files changed, 6 insertions, 0 deletions
diff --git a/core/fpdfapi/render/cpdf_dibsource.cpp b/core/fpdfapi/render/cpdf_dibsource.cpp
index 8a752374b6..3c8d471767 100644
--- a/core/fpdfapi/render/cpdf_dibsource.cpp
+++ b/core/fpdfapi/render/cpdf_dibsource.cpp
@@ -708,6 +708,10 @@ RetainPtr<CPDF_DIBSource> CPDF_DIBSource::DetachMask() {
   return std::move(m_pMask);
 }
 
+bool CPDF_DIBSource::IsJBigImage() const {
+  return m_pStreamAcc->GetImageDecoder() == "JBIG2Decode";
+}
+
 CPDF_DIBSource::LoadState CPDF_DIBSource::StartLoadMaskDIB() {
   m_pMask = pdfium::MakeRetain<CPDF_DIBSource>();
   LoadState ret = m_pMask->StartLoadDIBSource(
diff --git a/core/fpdfapi/render/cpdf_dibsource.h b/core/fpdfapi/render/cpdf_dibsource.h
index a3e44c57e7..a29385f6ad 100644
--- a/core/fpdfapi/render/cpdf_dibsource.h
+++ b/core/fpdfapi/render/cpdf_dibsource.h
@@ -76,6 +76,8 @@ class CPDF_DIBSource : public CFX_DIBSource {
   LoadState ContinueLoadDIBSource(IFX_PauseIndicator* pPause);
   RetainPtr<CPDF_DIBSource> DetachMask();
 
+  bool IsJBigImage() const;
+
  private:
   CPDF_DIBSource();