Sakurai/pdf.js
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fix bugs with predictors, png predictor type 0 and 5 (ie noop and paeth)

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sbarman 2011-09-25 16:27:06 -07:00
parent 7751b83821
commit c4699a46da
1 changed files with 8 additions and 4 deletions
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12
pdf.js
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@ -714,7 +714,6 @@ var PredictorStream = (function() {
var columns = this.columns = params.get('Columns') || 1;
this.pixBytes = (colors * bits + 7) >> 3;
// add an extra pixByte to represent the pixel left of column 0
this.rowBytes = (columns * colors * bits + 7) >> 3;
DecodeStream.call(this);
@ -796,10 +795,12 @@ var PredictorStream = (function() {
var currentRow = buffer.subarray(bufferLength, bufferLength + rowBytes);
var prevRow = buffer.subarray(bufferLength - rowBytes, bufferLength);
if (prevRow.length == 0)
prevRow = currentRow;
prevRow = new Uint8Array(rowBytes);
switch (predictor) {
case 0:
for (var i = 0; i < rowBytes; ++i)
currentRow[i] = rawBytes[i];
break;
case 1:
for (var i = 0; i < pixBytes; ++i)
@ -822,8 +823,11 @@ var PredictorStream = (function() {
case 4:
// we need to save the up left pixels values. the simplest way
// is to create a new buffer
for (var i = 0; i < pixBytes; ++i)
currentRow[i] = rawBytes[i];
for (var i = 0; i < pixBytes; ++i) {
var up = prevRow[i];
var c = rawBytes[i];
currentRow[i] = up + c;
}
for (; i < rowBytes; ++i) {
var up = prevRow[i];
var upLeft = prevRow[i - pixBytes];