Make FPDFBitmap_GetFormat() work for JBIG images.

BUG=pdfium:945

Change-Id: I2a880e747b6f5a2fabed4d34ce47b69ff589ce3f
Reviewed-on: https://pdfium-review.googlesource.com/27814
Commit-Queue: dsinclair <dsinclair@chromium.org>
Reviewed-by: dsinclair <dsinclair@chromium.org>

5 files changed, 19 insertions, 7 deletions

diff --git a/core/fpdfapi/page/cpdf_image.cpp b/core/fpdfapi/page/cpdf_image.cpp
index 8ce4185446..b74de62250 100644
--- a/core/fpdfapi/page/cpdf_image.cpp
+++ b/core/fpdfapi/page/cpdf_image.cpp
@@ -331,7 +331,13 @@ RetainPtr<CFX_DIBSource> CPDF_Image::LoadDIBSource() const {
   if (!source->Load(m_pDocument.Get(), m_pStream.Get()))
     return nullptr;
 
-  return source;
+  if (!source->IsJBigImage())
+    return source;
+
+  CPDF_DIBSource::LoadState ret = CPDF_DIBSource::LoadState::kContinue;
+  while (ret == CPDF_DIBSource::LoadState::kContinue)
+    ret = source->ContinueLoadDIBSource(nullptr);
+  return ret == CPDF_DIBSource::LoadState::kSuccess ? source : nullptr;
 }
 
 RetainPtr<CFX_DIBSource> CPDF_Image::DetachBitmap() {
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();
 
diff --git a/core/fxge/dib/cfx_dibsource.cpp b/core/fxge/dib/cfx_dibsource.cpp
index f96ca1e074..104b3caf96 100644
--- a/core/fxge/dib/cfx_dibsource.cpp
+++ b/core/fxge/dib/cfx_dibsource.cpp
@@ -1225,12 +1225,13 @@ bool CFX_DIBSource::ConvertBuffer(
     }
     case FXDIB_8bppRgb:
     case FXDIB_8bppRgba: {
-      if (bpp == 8 && !pSrcBitmap->GetPalette()) {
+      const bool bpp_1_or_8 = (bpp == 1 || bpp == 8);
+      if (bpp_1_or_8 && !pSrcBitmap->GetPalette()) {
         return ConvertBuffer(FXDIB_8bppMask, dest_buf, dest_pitch, width,
                              height, pSrcBitmap, src_left, src_top, p_pal);
       }
       p_pal->reset(FX_Alloc(uint32_t, 256));
-      if ((bpp == 1 || bpp == 8) && pSrcBitmap->GetPalette()) {
+      if (bpp_1_or_8 && pSrcBitmap->GetPalette()) {
         ConvertBuffer_Plt2PltRgb8(dest_buf, dest_pitch, width, height,
                                   pSrcBitmap, src_left, src_top, p_pal->get());
         return true;
diff --git a/fpdfsdk/fpdfedit_embeddertest.cpp b/fpdfsdk/fpdfedit_embeddertest.cpp
index 8754a665f7..3fc6cae8b4 100644
--- a/fpdfsdk/fpdfedit_embeddertest.cpp
+++ b/fpdfsdk/fpdfedit_embeddertest.cpp
@@ -1131,12 +1131,11 @@ TEST_F(FPDFEditEmbeddertest, ExtractJBigImageBitmap) {
   FPDF_PAGEOBJECT obj = FPDFPage_GetObject(page, 0);
   ASSERT_EQ(FPDF_PAGEOBJ_IMAGE, FPDFPageObj_GetType(obj));
   {
-    // TODO(bug_945): This should return a valid bitmap. This test should be
-    // able to successfully check |bitmap| using FPDFBitmap_GetFormat() and
-    // CompareBitmap().
     std::unique_ptr<void, FPDFBitmapDeleter> bitmap(
         FPDFImageObj_GetBitmap(obj));
-    ASSERT_FALSE(bitmap);
+    ASSERT_TRUE(bitmap);
+    EXPECT_EQ(FPDFBitmap_Gray, FPDFBitmap_GetFormat(bitmap.get()));
+    CompareBitmap(bitmap.get(), 1152, 720, "3f6a48e2b3e91b799bf34567f55cb4de");
   }
 
   UnloadPage(page);