color: Do not enforce T(0)=0 and T(1)=1 constraints in approxmation

color: Do not enforce T(0)=0 and T(1)=1 constraints in approxmation

Enforcing these constraints can end up giving us an inaccurate
approximation, as some transfer functions overshoot T(1).

BUG=703966
Review-Url: https://codereview.chromium.org/2784673006
Cr-Commit-Position: refs/heads/master@{#461203}
Committed: https://chromium.googlesource.com/chromium/src/+/95f83c51ade772da4b9d9aa8b1a6c40ad696a897

[ccameron, 2017-03-29 22:33:51]

Description was changed from

==========
color: Do not enforce T(0)=0 and T(1)=1 constraints in approxmation

Enforcing these constraints can end up giving us an inaccurate
approximation, as some transfer functions overshoot T(1).

BUG=703966
==========

to

==========
color: Do not enforce T(0)=0 and T(1)=1 constraints in approxmation

Enforcing these constraints can end up giving us an inaccurate
approximation, as some transfer functions overshoot T(1).

BUG=703966
==========

[ccameron, 2017-03-29 22:33:51]

ccameron@chromium.org changed reviewers:
+ msarett@chromium.org

[ccameron, 2017-03-29 22:34:42]

This returns us to the old behavior.

I like the idea of enforcing continuity ... that should be do-able by doing a
search for fD, but might be expensive. I'll take a look at it.

[msarett1, 2017-03-30 22:55:52]

I don't really like this.  Though I guess it's "safe" as long as we clamp.

I like the idea of forcing some sort of sanity on the dst profiles that are
passed to us.  If someone gives us a dst profile of T(x) = 0, we'll draw
everything black.  Is that their fault or our fault?

Of course:
(1) You can argue either way.
(2) This CL leaves us in a better state than before.
(3) We're still iterating on this.

lgtm

[ccameron, 2017-03-30 23:48:53]

Thanks.

Yeah, I'm not 100% certain on how to handle this.

I think that the intention of this profile is that we clamp the higher values.

I looked into what the best approximation of this that satisfies the 0->0 and
1->1 constraints is, and it's really not good (even when we take out the
discontinuity). I'll write up a bit more about this.

[ccameron, 2017-03-30 23:49:03]

The CQ bit was checked by ccameron@chromium.org

[commit-bot: I haz the power, 2017-03-30 23:49:41]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-03-31 00:26:51]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-03-31 00:26:51]

Try jobs failed on following builders:
  linux_chromium_chromeos_ozone_rel_ng on master.tryserver.chromium.linux
(JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[ccameron, 2017-03-31 00:55:00]

The CQ bit was checked by ccameron@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-03-31 00:56:02]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-03-31 01:26:08]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-03-31 01:26:09]

Dry run: Try jobs failed on following builders:
  mac_chromium_rel_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

[ccameron, 2017-03-31 18:34:00]

The CQ bit was checked by ccameron@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-03-31 18:34:39]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-03-31 19:33:44]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-03-31 19:33:45]

Dry run: This issue passed the CQ dry run.

[ccameron, 2017-03-31 20:03:53]

The CQ bit was checked by ccameron@chromium.org

[ccameron, 2017-03-31 20:03:53]

The patchset sent to the CQ was uploaded after l-g-t-m from msarett@chromium.org
Link to the patchset: https://codereview.chromium.org/2784673006/#ps40001
(title: "Fix the right error bound")

[commit-bot: I haz the power, 2017-03-31 20:04:39]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-03-31 20:16:16]

CQ is committing da patch.

Bot data: {"patchset_id": 40001, "attempt_start_ts": 1490990633502160,
"parent_rev": "232fbc4bc87a4c35ea8ab60e1f7ff8e4e8e14de5", "commit_rev":
"95f83c51ade772da4b9d9aa8b1a6c40ad696a897"}

[commit-bot: I haz the power, 2017-03-31 20:17:03]

Description was changed from

==========
color: Do not enforce T(0)=0 and T(1)=1 constraints in approxmation

Enforcing these constraints can end up giving us an inaccurate
approximation, as some transfer functions overshoot T(1).

BUG=703966
==========

to

==========
color: Do not enforce T(0)=0 and T(1)=1 constraints in approxmation

Enforcing these constraints can end up giving us an inaccurate
approximation, as some transfer functions overshoot T(1).

BUG=703966

Review-Url: https://codereview.chromium.org/2784673006
Cr-Commit-Position: refs/heads/master@{#461203}
Committed:
https://chromium.googlesource.com/chromium/src/+/95f83c51ade772da4b9d9aa8b1a6...
==========

[commit-bot: I haz the power, 2017-03-31 20:17:04]

Committed patchset #3 (id:40001) as
https://chromium.googlesource.com/chromium/src/+/95f83c51ade772da4b9d9aa8b1a6...