Minor change to AP generation logic

Current behavior:
    Our CPVT_GenerateAP::Generate*AP() functions do not get called as
    long as the annotation dictionary has an "AP" entry.

Problem:
    We always need the "N" entry in AP dictionary to display an
    annotation. Even though the spec requires "AP" dictionary to have an
    "N" entry for normal mode appearance, in case of a malformed pdf
    with "AP" but without "N" in "AP", we won't be able to display the
    annotation at all.

Fix:
    Always check if "AP" has "N" entry to decide whether AP needs to be
    generated. If not, then we still need to generate AP, and add to the
    AP dictionary under the key "N".

Bug=pdfium:778
Change-Id: Icf0c6a681b3c8c22b0b67bf8d16ce6fefdc2c45b
Reviewed-on: https://pdfium-review.googlesource.com/6692
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Jane Liu <janeliulwq@google.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/fpdfsdk/fpdfannot_embeddertest.cpp b/fpdfsdk/fpdfannot_embeddertest.cpp
index 85f9b68240..b7dee88b78 100644
--- a/fpdfsdk/fpdfannot_embeddertest.cpp
+++ b/fpdfsdk/fpdfannot_embeddertest.cpp
@@ -13,6 +13,23 @@
 
 class FPDFAnnotEmbeddertest : public EmbedderTest, public TestSaver {};
 
+TEST_F(FPDFAnnotEmbeddertest, RenderAnnotWithOnlyRolloverAP) {
+  // Open a file with one annotation and load its first page.
+  ASSERT_TRUE(OpenDocument("annotation_highlight_rollover_ap.pdf"));
+  FPDF_PAGE page = FPDF_LoadPage(document(), 0);
+  ASSERT_TRUE(page);
+
+  // This annotation has a malformed appearance stream, which does not have its
+  // normal appearance defined, only its rollover appearance. In this case, its
+  // normal appearance should be generated, allowing the highlight annotation to
+  // still display.
+  FPDF_BITMAP bitmap = RenderPageWithFlags(page, FPDF_ANNOT);
+  CompareBitmap(bitmap, 612, 792, "dc98f06da047bd8aabfa99562d2cbd1e");
+  FPDFBitmap_Destroy(bitmap);
+
+  UnloadPage(page);
+}
+
 TEST_F(FPDFAnnotEmbeddertest, ExtractHighlightLongContent) {
   // Open a file with one annotation and load its first page.
   ASSERT_TRUE(OpenDocument("annotation_highlight_long_content.pdf"));