Fix a bug when image width is odd in sycc422_to_rgb

Fix a bug when image width is odd in sycc422_to_rgb

BUG=418881
R=tsepez@chromium.org

Committed: https://pdfium.googlesource.com/pdfium/+/6cf012af4954807255ce7cdb5b92a20f74d34e6d

[Bo Xu, 2014-10-10 20:24:53]

bo_xu@foxitsoftware.com changed reviewers:
+ jun_fang@foxitsoftware.com, tsepez@chromium.org

[Bo Xu, 2014-10-10 20:24:54]

Hi Tom, please review this change. 

They suggested this patch. Some other sycc** functions may also need to be
changed. I will merge them here after I confirmed with openjpeg group.

[Tom Sepez, 2014-10-10 20:55:23]

lgtm

[Tom Sepez, 2014-10-10 21:03:41]

Or some such ...

https://codereview.chromium.org/648823002/diff/1/core/src/fxcodec/codec/fx_co...
File core/src/fxcodec/codec/fx_codec_jpx_opj.cpp (right):

https://codereview.chromium.org/648823002/diff/1/core/src/fxcodec/codec/fx_co...
core/src/fxcodec/codec/fx_codec_jpx_opj.cpp:184: if (j < maxw) {
nit: alternatively, you could run though this loop incrementing by one (and I've
collapsed this for readability, no need in real code);

  for(j = 0; j < maxw; ++j) {
    sycc_to_rgb(offset, upb, *y, *cb, *cr, r, g, b);
    ++y, ++r, g++, b++;
    if (j % 2)
       ++cr, ++cb;
  }

[Tom Sepez, 2014-10-10 21:05:45]

for (j = 0; j < maxw; ++j, ++y, ++r, ++g, ++b) {
  sycc_to_rgb(offset, upb, *y, *cb, *cr, r, g, b);
  if (j % 2) {
     ++cr;
     ++cb;
  }
}

[jun_fang, 2014-10-10 21:06:08]

https://codereview.chromium.org/648823002/diff/1/core/src/fxcodec/codec/fx_co...
File core/src/fxcodec/codec/fx_codec_jpx_opj.cpp (right):

https://codereview.chromium.org/648823002/diff/1/core/src/fxcodec/codec/fx_co...
core/src/fxcodec/codec/fx_codec_jpx_opj.cpp:170: for(j = 0; j < (maxw &
~(OPJ_UINT32)1); j += 2) {
shall keep & ~(OPJ_UINT32)1 here.

[jun_fang, 2014-10-10 21:34:34]

On 2014/10/10 21:06:08, jun_fang wrote:
>
https://codereview.chromium.org/648823002/diff/1/core/src/fxcodec/codec/fx_co...
> File core/src/fxcodec/codec/fx_codec_jpx_opj.cpp (right):
> 
>
https://codereview.chromium.org/648823002/diff/1/core/src/fxcodec/codec/fx_co...
> core/src/fxcodec/codec/fx_codec_jpx_opj.cpp:170: for(j = 0; j < (maxw &
> ~(OPJ_UINT32)1); j += 2) {
> shall keep & ~(OPJ_UINT32)1 here.

Or follow Tom's solution. It will cause more loops than expected after removing
"& ~(OPJ_UINT32)1" when maxw is odd.

[Bo Xu, 2014-10-10 21:56:37]

On 2014/10/10 21:05:45, Tom Sepez wrote:
> for (j = 0; j < maxw; ++j, ++y, ++r, ++g, ++b) {
>   sycc_to_rgb(offset, upb, *y, *cb, *cr, r, g, b);
>   if (j % 2) {
>      ++cr;
>      ++cb;
>   }
> }

This is a much cleaner way :) I will upstream this to openjpeg as well.

[Bo Xu, 2014-10-10 22:57:45]

Committed patchset #2 (id:120001) manually as
6cf012af4954807255ce7cdb5b92a20f74d34e6d (presubmit successful).