From 7923eb7edb411425e3aa7eeaa2160b31219f930c Mon Sep 17 00:00:00 2001
From: Nicholas Nethercote <nnethercote@mozilla.com>
Date: Thu, 12 Jun 2014 17:37:41 -0700
Subject: [PATCH] Fix mishandling of incomplete, inverted masks.
---
src/core/evaluator.js | 4 ++--
src/core/image.js | 35 ++++++++++++++++++++++++++---------
test/pdfs/issue4926.pdf.link | 1 +
test/test_manifest.json | 7 +++++++
4 files changed, 36 insertions(+), 11 deletions(-)
create mode 100644 test/pdfs/issue4926.pdf.link
diff --git a/src/core/evaluator.js b/src/core/evaluator.js
index 7ce1e3999..e353280cd 100644
--- a/src/core/evaluator.js
+++ b/src/core/evaluator.js
@@ -199,11 +199,11 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
var bitStrideLength = (width + 7) >> 3;
var imgArray = image.getBytes(bitStrideLength * height);
var decode = dict.get('Decode', 'D');
- var canTransfer = image instanceof DecodeStream;
var inverseDecode = (!!decode && decode[0] > 0);
imgData = PDFImage.createMask(imgArray, width, height,
- canTransfer, inverseDecode);
+ image instanceof DecodeStream,
+ inverseDecode);
imgData.cached = true;
args = [imgData];
operatorList.addOp(OPS.paintImageMaskXObject, args);
diff --git a/src/core/image.js b/src/core/image.js
index a66081f01..e14e204da 100644
--- a/src/core/image.js
+++ b/src/core/image.js
@@ -248,23 +248,40 @@ var PDFImage = (function PDFImageClosure() {
};
PDFImage.createMask =
- function PDFImage_createMask(imgArray, width, height, canTransfer,
- inverseDecode) {
- // If imgArray came from a DecodeStream, we're safe to transfer it.
- // Otherwise, copy it.
+ function PDFImage_createMask(imgArray, width, height,
+ imageIsFromDecodeStream, inverseDecode) {
+
+ // |imgArray| might not contain full data for every pixel of the mask, so
+ // we need to distinguish between |computedLength| and |actualLength|.
+ // In particular, if inverseDecode is true, then the array we return must
+ // have a length of |computedLength|.
+
+ var computedLength = ((width + 7) >> 3) * height;
var actualLength = imgArray.byteLength;
- var data;
- if (canTransfer) {
+ var haveFullData = computedLength == actualLength;
+ var data, i;
+
+ if (imageIsFromDecodeStream && (!inverseDecode || haveFullData)) {
+ // imgArray came from a DecodeStream and its data is in an appropriate
+ // form, so we can just transfer it.
data = imgArray;
- } else {
+ } else if (!inverseDecode) {
data = new Uint8Array(actualLength);
data.set(imgArray);
+ } else {
+ data = new Uint8Array(computedLength);
+ data.set(imgArray);
+ for (i = actualLength; i < computedLength; i++) {
+ data[i] = 0xff;
+ }
}
- // Invert if necessary. It's safe to modify the array -- whether it's the
+
+ // If necessary, invert the original mask data (but not any extra we might
+ // have added above). It's safe to modify the array -- whether it's the
// original or a copy, we're about to transfer it anyway, so nothing else
// in this thread can be relying on its contents.
if (inverseDecode) {
- for (var i = 0; i < actualLength; i++) {
+ for (i = 0; i < actualLength; i++) {
data[i] = ~data[i];
}
}
diff --git a/test/pdfs/issue4926.pdf.link b/test/pdfs/issue4926.pdf.link
new file mode 100644
index 000000000..405474b75
--- /dev/null
+++ b/test/pdfs/issue4926.pdf.link
@@ -0,0 +1 @@
+http://www.conservation.ca.gov/cgs/information/publications/cgs_notes/note_17/documents/note_17.pdf
diff --git a/test/test_manifest.json b/test/test_manifest.json
index 9bfb11a5f..143935840 100644
--- a/test/test_manifest.json
+++ b/test/test_manifest.json
@@ -1655,5 +1655,12 @@
"firstPage": 9,
"lastPage": 9,
"type": "eq"
+ },
+ { "id": "issue4926",
+ "file": "pdfs/issue4926.pdf",
+ "md5": "ed881c8ea2f9bc4be94ecb7f2b2c149b",
+ "rounds": 1,
+ "link": true,
+ "type": "eq"
}
]