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Merge pull request #5485 from CodingFabian/save-pr-5479

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fixed multi precinct handling in jpx
This commit is contained in:
Yury Delendik 2014-11-13 09:10:41 -06:00
commit de9838018e
1 changed files with 33 additions and 15 deletions
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src/core/jpx.js
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@ -480,6 +480,23 @@ var JpxImage = (function JpxImageClosure() {
// Section B.6 Division resolution to precincts
var precinctWidth = 1 << dimensions.PPx;
var precinctHeight = 1 << dimensions.PPy;
// Jasper introduces codeblock groups for mapping each subband codeblocks
// to precincts. Precinct partition divides a resolution according to width
// and height parameters. The subband that belongs to the resolution level
// has a different size than the level, unless it is the zero resolution.
// From Jasper documentation: jpeg2000.pdf, section K: Tier-2 coding:
// The precinct partitioning for a particular subband is derived from a
// partitioning of its parent LL band (i.e., the LL band at the next higher
// resolution level)... The LL band associated with each resolution level is
// divided into precincts... Each of the resulting precinct regions is then
// mapped into its child subbands (if any) at the next lower resolution
// level. This is accomplished by using the coordinate transformation
// (u, v) = (ceil(x/2), ceil(y/2)) where (x, y) and (u, v) are the
// coordinates of a point in the LL band and child subband, respectively.
var isZeroRes = resolution.resLevel === 0;
var precinctWidthInSubband = 1 << (dimensions.PPx + (isZeroRes ? 0 : -1));
var precinctHeightInSubband = 1 << (dimensions.PPy + (isZeroRes ? 0 : -1));
var numprecinctswide = (resolution.trx1 > resolution.trx0 ?
Math.ceil(resolution.trx1 / precinctWidth) -
Math.floor(resolution.trx0 / precinctWidth) : 0);
@ -487,18 +504,15 @@ var JpxImage = (function JpxImageClosure() {
Math.ceil(resolution.try1 / precinctHeight) -
Math.floor(resolution.try0 / precinctHeight) : 0);
var numprecincts = numprecinctswide * numprecinctshigh;
var precinctXOffset = Math.floor(resolution.trx0 / precinctWidth) *
precinctWidth;
var precinctYOffset = Math.floor(resolution.try0 / precinctHeight) *
precinctHeight;
resolution.precinctParameters = {
precinctXOffset: precinctXOffset,
precinctYOffset: precinctYOffset,
precinctWidth: precinctWidth,
precinctHeight: precinctHeight,
numprecinctswide: numprecinctswide,
numprecinctshigh: numprecinctshigh,
numprecincts: numprecincts
numprecincts: numprecincts,
precinctWidthInSubband: precinctWidthInSubband,
precinctHeightInSubband: precinctHeightInSubband
};
}
function buildCodeblocks(context, subband, dimensions) {
@ -525,18 +539,21 @@ var JpxImage = (function JpxImageClosure() {
tbx1: codeblockWidth * (i + 1),
tby1: codeblockHeight * (j + 1)
};
// calculate precinct number
var pi = Math.floor((codeblock.tbx0 -
precinctParameters.precinctXOffset) /
precinctParameters.precinctWidth);
var pj = Math.floor((codeblock.tby0 -
precinctParameters.precinctYOffset) /
precinctParameters.precinctHeight);
precinctNumber = pj + pi * precinctParameters.numprecinctswide;
codeblock.tbx0_ = Math.max(subband.tbx0, codeblock.tbx0);
codeblock.tby0_ = Math.max(subband.tby0, codeblock.tby0);
codeblock.tbx1_ = Math.min(subband.tbx1, codeblock.tbx1);
codeblock.tby1_ = Math.min(subband.tby1, codeblock.tby1);
// Calculate precinct number for this codeblock, codeblock position
// should be relative to its subband, use actual dimension and position
// See comment about codeblock group width and height
var pi = Math.floor((codeblock.tbx0_ - subband.tbx0) /
precinctParameters.precinctWidthInSubband);
var pj = Math.floor((codeblock.tby0_ - subband.tby0) /
precinctParameters.precinctHeightInSubband);
precinctNumber = pi + (pj * precinctParameters.numprecinctswide);
codeblock.precinctNumber = precinctNumber;
codeblock.subbandType = subband.type;
codeblock.Lblock = 3;
@ -701,6 +718,7 @@ var JpxImage = (function JpxImageClosure() {
resolution.try0 = Math.ceil(component.tcy0 / scale);
resolution.trx1 = Math.ceil(component.tcx1 / scale);
resolution.try1 = Math.ceil(component.tcy1 / scale);
resolution.resLevel = r;
buildPrecincts(context, resolution, blocksDimensions);
resolutions.push(resolution);