Fix blank page issue caused by too strict correction on bpc
For bit per component (bpc), PDF spec mentions that a RunLengthDecode or DCTDecode filter shall always deliver 8-bit samples. However, some PDF files don't follow this rule. We can find that filter is RunLengthDecode but bpc is 1 in the provided test file. In this case, pdfium will correct bpc to 8 but the actual bpc is 1. It causes a failure because the data is much more than the expected. To handle this case, pdfium doesn't correct bpc to 8 when the original bpc is 1.
BUG=512557
R=tsepez@chromium.org
Review URL: https://codereview.chromium.org/1328213002 .
diff --git a/core/src/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp b/core/src/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp
index 0362ff2..9497943 100644
--- a/core/src/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp
+++ b/core/src/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp
@@ -957,8 +957,11 @@
m_bpc = 1;
m_nComponents = 1;
}
- if (filter == FX_BSTRC("RunLengthDecode") ||
- filter == FX_BSTRC("DCTDecode")) {
+ if (filter == FX_BSTRC("RunLengthDecode")) {
+ if (m_bpc != 1) {
+ m_bpc = 8;
+ }
+ } else if (filter == FX_BSTRC("DCTDecode")) {
m_bpc = 8;
}
} else if (pFilter->GetType() == PDFOBJ_ARRAY) {
diff --git a/testing/resources/pixel/bug_512557.in b/testing/resources/pixel/bug_512557.in
new file mode 100644
index 0000000..5f35334
--- /dev/null
+++ b/testing/resources/pixel/bug_512557.in
Binary files differ
diff --git a/testing/resources/pixel/bug_512557_expected.pdf.0.png b/testing/resources/pixel/bug_512557_expected.pdf.0.png
new file mode 100644
index 0000000..66c73ae
--- /dev/null
+++ b/testing/resources/pixel/bug_512557_expected.pdf.0.png
Binary files differ
