tree b852defac79a73fd0d58c72d4bf162592a8c02b4
parent e74192103c15f0000eefd1b4bacd9fa82b0ec749
author Mike Reed <reed@google.com> 1555344439 -0400
committer Skia Commit-Bot <skia-commit-bot@chromium.org> 1555356959 +0000

use slope-guess for faster charToGlyph

Made up a threshold between linear and slope searching.
For a count of 100 here are the before and after timings.
The first two lines are being changed. The latter 2 are
the native look-ups for mac.

Before

  15/15  MB	115	2.33µs	2.34µs	2.34µs	2.34µs	0%	▆▁▄█▇▇▂▄█▆	nonrendering	cmap_findcache_charToGlyph
  15/15  MB	66	3.47µs	3.48µs	3.49µs	3.55µs	1%	█▁▁▁▂▁▁▁▁▄	nonrendering	cmap_addcache_charToGlyph
  15/15  MB	1	1.1µs	1.13µs	1.21µs	1.98µs	22%	█▂▁▁▁▁▁▁▁▂	nonrendering	cmap_face_charToGlyph
  15/15  MB	190	1.09µs	1.1µs	1.19µs	1.64µs	17%	▁▁▁▆█▁▁▁▁▁	nonrendering	cmap_font_charToGlyph

After

  15/15  MB	447	448ns	449ns	448ns	449ns	0%	▂▅█▅▁▆█▂▁▆	nonrendering	cmap_findcache_charToGlyph
  15/15  MB	95	2.79µs	3.03µs	3µs	3.06µs	3%	▇▇▇▇▇███▄▁	nonrendering	cmap_addcache_charToGlyph
  15/15  MB	1	1.15µs	1.16µs	1.25µs	1.99µs	21%	█▂▁▁▁▁▁▁▁▁	nonrendering	cmap_face_charToGlyph
  15/15  MB	186	1.09µs	1.1µs	1.12µs	1.27µs	5%	█▁▁▁▂▁▁▁▁▁	nonrendering	cmap_font_charToGlyph


Bug: skia:
Change-Id: If7da4eef3cce248393815071f342607f0c8140bb
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/208044
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Mike Reed <reed@google.com>