Force tiles in SampleApp to integer boundaries.

Force tiles in SampleApp to integer boundaries.

The current behavior is to create tiles from the rounded ideal tile size,
tell the tile that it's upper left pixel is at the ideal location, and
then draw those tiles at the ideal locations. As a result, the tiles are
be out of phase with each other internally and then actually drawn at
the rounded pixel location instead of the ideal location.

The new behavior is to always round up to get the tile size, make the
tile translation an integer offset, and then draw at the exact pixel.

This also modifies SampleApp to use the numeric keypad to provide an
extra manual 1/32 pixel translation for fine grained movement.

BUG=skia:5020
Committed: https://skia.googlesource.com/skia/+/ce56026db55d8585c2f920a6107a25b40fd5160a

[bungeman-skia, 2016-03-03 21:06:59]

Description was changed from

==========
Force tiles in SampleApp to integer boundaries.

The current behavior is to create tiles from the rounded ideal tile size,
tell the tile that it's upper left pixel is at the ideal location, and
then draw those tiles at the ideal locations. As a result, the tiles are
be out of phase with each other internally and then actually drawn at
the rounded pixel location instead of the ideal location.

The new behavior is to always round up to get the tile size, make the
tile translation an integer offset, and then draw at the exact pixel.

BUG=skia:5020
==========

to

==========
Force tiles in SampleApp to integer boundaries.

The current behavior is to create tiles from the rounded ideal tile size,
tell the tile that it's upper left pixel is at the ideal location, and
then draw those tiles at the ideal locations. As a result, the tiles are
be out of phase with each other internally and then actually drawn at
the rounded pixel location instead of the ideal location.

The new behavior is to always round up to get the tile size, make the
tile translation an integer offset, and then draw at the exact pixel.

BUG=skia:5020
GOLD_TRYBOT_URL=
https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&is...
==========

[bungeman-skia, 2016-03-03 21:08:48]

Description was changed from

==========
Force tiles in SampleApp to integer boundaries.

The current behavior is to create tiles from the rounded ideal tile size,
tell the tile that it's upper left pixel is at the ideal location, and
then draw those tiles at the ideal locations. As a result, the tiles are
be out of phase with each other internally and then actually drawn at
the rounded pixel location instead of the ideal location.

The new behavior is to always round up to get the tile size, make the
tile translation an integer offset, and then draw at the exact pixel.

BUG=skia:5020
GOLD_TRYBOT_URL=
https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&is...
==========

to

==========
Force tiles in SampleApp to integer boundaries.

The current behavior is to create tiles from the rounded ideal tile size,
tell the tile that it's upper left pixel is at the ideal location, and
then draw those tiles at the ideal locations. As a result, the tiles are
be out of phase with each other internally and then actually drawn at
the rounded pixel location instead of the ideal location.

The new behavior is to always round up to get the tile size, make the
tile translation an integer offset, and then draw at the exact pixel.

This also modifies SampleApp to use the numeric keypad to
provide an extra manual 1/32 pixel translation for fine grained
movement.

BUG=skia:5020
==========

[bungeman-skia, 2016-03-03 21:09:11]

Description was changed from

==========
Force tiles in SampleApp to integer boundaries.

The current behavior is to create tiles from the rounded ideal tile size,
tell the tile that it's upper left pixel is at the ideal location, and
then draw those tiles at the ideal locations. As a result, the tiles are
be out of phase with each other internally and then actually drawn at
the rounded pixel location instead of the ideal location.

The new behavior is to always round up to get the tile size, make the
tile translation an integer offset, and then draw at the exact pixel.

This also modifies SampleApp to use the numeric keypad to
provide an extra manual 1/32 pixel translation for fine grained
movement.

BUG=skia:5020
==========

to

==========
Force tiles in SampleApp to integer boundaries.

The current behavior is to create tiles from the rounded ideal tile size,
tell the tile that it's upper left pixel is at the ideal location, and
then draw those tiles at the ideal locations. As a result, the tiles are
be out of phase with each other internally and then actually drawn at
the rounded pixel location instead of the ideal location.

The new behavior is to always round up to get the tile size, make the
tile translation an integer offset, and then draw at the exact pixel.

This also modifies SampleApp to use the numeric keypad to provide an
extra manual 1/32 pixel translation for fine grained movement.

BUG=skia:5020
==========

[bungeman-skia, 2016-03-03 21:09:22]

The CQ bit was checked by bungeman@google.com to run a CQ dry run

[commit-bot: I haz the power, 2016-03-03 21:09:30]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1763833002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1763833002/1

[bungeman-skia, 2016-03-03 21:14:19]

bungeman@google.com changed reviewers:
+ herb@google.com, reed@google.com

[bungeman-skia, 2016-03-03 21:14:20]

This corrects the issue in SampleApp, is it possible other tilers are running
into the same issue?

[reed1, 2016-03-03 21:23:37]

lgtm

[commit-bot: I haz the power, 2016-03-03 21:26:44]

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

[commit-bot: I haz the power, 2016-03-03 21:26:46]

Dry run: This issue passed the CQ dry run.

[bungeman-skia, 2016-03-03 21:31:40]

The CQ bit was checked by bungeman@google.com

[commit-bot: I haz the power, 2016-03-03 21:31:44]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1763833002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1763833002/1

[commit-bot: I haz the power, 2016-03-03 21:32:40]

Description was changed from

==========
Force tiles in SampleApp to integer boundaries.

The current behavior is to create tiles from the rounded ideal tile size,
tell the tile that it's upper left pixel is at the ideal location, and
then draw those tiles at the ideal locations. As a result, the tiles are
be out of phase with each other internally and then actually drawn at
the rounded pixel location instead of the ideal location.

The new behavior is to always round up to get the tile size, make the
tile translation an integer offset, and then draw at the exact pixel.

This also modifies SampleApp to use the numeric keypad to provide an
extra manual 1/32 pixel translation for fine grained movement.

BUG=skia:5020
==========

to

==========
Force tiles in SampleApp to integer boundaries.

The current behavior is to create tiles from the rounded ideal tile size,
tell the tile that it's upper left pixel is at the ideal location, and
then draw those tiles at the ideal locations. As a result, the tiles are
be out of phase with each other internally and then actually drawn at
the rounded pixel location instead of the ideal location.

The new behavior is to always round up to get the tile size, make the
tile translation an integer offset, and then draw at the exact pixel.

This also modifies SampleApp to use the numeric keypad to provide an
extra manual 1/32 pixel translation for fine grained movement.

BUG=skia:5020

Committed:
https://skia.googlesource.com/skia/+/ce56026db55d8585c2f920a6107a25b40fd5160a
==========

[commit-bot: I haz the power, 2016-03-03 21:32:41]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/ce56026db55d8585c2f920a6107a25b40fd5160a

[bungeman-skia, 2016-03-03 22:42:37]

https://codereview.chromium.org/1763833002/diff/1/samplecode/SampleApp.cpp
File samplecode/SampleApp.cpp (left):

https://codereview.chromium.org/1763833002/diff/1/samplecode/SampleApp.cpp#ol...
samplecode/SampleApp.cpp:1074: tileCanvas->translate(-x, -y);
Just to make things more clear, when x and y are not integers this means that
the pixel at the origin of the canvas is no longer at an integer position. Every
calculation will be shifted by the fractional part, resulting in rounding being
out of phase from the rounding if the same were drawn with a slightly different
fractional part.