The hb_font_t object holds on to tables of font data, acquired through
the MinikinFont::GetTable interface, which is based on copying data
into caller-owned buffers. Now that we're caching lots of hb_font_t's,
the cost of these buffers is significant.

This patch moves to a different interface, inspired by HarfBuzz's
hb_reference_table API, where the font can provide a pointer to the
actual font data (which will often be mmap'ed, so it doesn't even
consume physical RAM).

Bug: 27860101
Change-Id: Id766ab16a8d342bf7322a90e076e801271d527d4

Bug: http://b/26936282
Change-Id: I91b3bc246a4a8c45bde223cfc25df18ae9af8c5b

Bug: 24505153
Change-Id: If61c063c175086dec88cda187eafd9ce923e4cb1

It turned out that hb_font_t creation is not a lightweight operation.
Especially, Paint.hasGlyph creates hb_font_t for all existing fonts
every time. To improve the performance, cache hb_font_t instead
of hb_face_t.

Note that to calculate horizontal advance, MinikinPaint needs to be
associated with hb_font_t by calling hb_font_set_funcs. With this patch,
hb_font_set_funcs may be called multiple times for the same hb_font_t
object. However this is not an issue since MinikinPaint is unique
during layout.

Bug: 26784699

Change-Id: I516498ae9f0127d700fc9829327e9789845a1416

The intruduced method measureText can be used instead of
doLayout for text measurement purpose.

Bug: 24505153
Change-Id: Ic29bbb347daf18d1f6c13f86970dcdd11dd6a2bd

This is 2nd attempt of I8df992a6851021903478972601a9a5c9424b100c.

The main purpose of this CL is expanding FontLanguage to be able to
save full script tag. Previously, FontLangauge kept only limited script
tags. With this CL, FontLanguage keeps all script tags.

This CL contains the following changes:
- FontLanguage changes:
-- Moved to private directory not to be instantiated outside of Minikin.
-- Removed bool(), bits(), FontLanguage(uint32_t) methods which are no
   longer used.
-- Change the FontLanguage internal data structure.
-- Introduces script match logic.

- FontLanguages changes:
-- Moved to private directory not to be instantiated outside of Minikin.
-- This is now std::vector<FontLanguage>

- FontLanguageListCache changes:
-- Now FontLanguageListCache::getId through
   FontStyle::registerLanguageList is the only way to instantiate the
   FontLanguage.
-- Normalize input to be BCP47 compliant identifier by ICU.

Bug: 26168983
Change-Id: I431b3f361a7635497c05b85e8ecbeb48d9aef63e

This reverts commit 5e995fb8.

Change-Id: I761e0e41906742fbe3d3ac34170af3101e18042a

The main purpose of this CL is expanding FontLanguage to be able to
save full script tag. Previously, FontLangauge kept only limited script
tags. With this CL, FontLanguage keeps all script tags.

This CL contains the following changes:
- FontLanguage changes:
-- Moved to private directory not to be instantiated outside of Minikin.
-- Removed bool(), bits(), FontLanguage(uint32_t) methods which are no
   longer used.
-- Change the FontLanguage internal data structure.
-- Introduces script match logic.

- FontLanguages changes:
-- Moved to private directory not to be instantiated outside of Minikin.
-- This is now std::vector<FontLanguage>

- FontLanguageListCache changes:
-- Now FontLanguageListCache::getId through
   FontStyle::registerLanguageList is the only way to instantiate the
   FontLanguage.
-- Normalize input to be BCP47 compliant identifier by ICU.

Bug: 26168983
Change-Id: I8df992a6851021903478972601a9a5c9424b100c

FontLanguageListCache is an intentionally leaky singleton and its
internal cache won't be purged.

BUG: 25122318

Change-Id: I272097e979fe44b83fd86822235350e12eda8f51

This is 2nd trial of I30a0914a4633bd93eb60957cdf378770f04d8428

- To suppress noisy unused parameter warnings, comment out unused
  arguments.
- Add -Werror for suppressing further warning.
- Add -Wall -Wextra for safety.
- Use "z" prefix for format string of size_t.

Verified that compile succeeded on all arm,arm64,mips,x86,x86_64.

Change-Id: I7ad208464486b8a35da53929cb1cfe541ed0052f

This reverts commit 63635cff.

Change-Id: I2b4b10e8afedc85dbe2d07f3e47315652b65cd14

- To suppress noisy unused parameter warnings, comment out unused
  arguments.
- Add -Werror for suppressing further warning.
- Add -Wall -Wextra for safety.

Change-Id: I30a0914a4633bd93eb60957cdf378770f04d8428

This CL introduces new method hasVariationSelector into FontFamily but it
is not used in production code. So no behavior changes are expected.

This CL contains the following changes:
- Introduce hasVariationSelector which returns true if the corresponding
  font has a glyph for a code point and variation selector pair.
- Introduce purgeHbFontCache since hb_face_t won't be released by
  keeping hb_font_t.
- Introduce unit tests with self-built font.

Change-Id: I659a6d03d9ec446b409e1fba2758452abb9f44fa

This CL does following things:
- Extract hb_face_t object cache mechanism from Layout.cpp to be able to
  use it from other cpp file, especially from FontFamily.cpp.
  To address Bug 11256006 and Bug 17759267, need to touch
  hb_face_t from FontFamily.
- Make hb_face_t cache mechanism thread-safe.
- Add unit tests for HbFaceCache test cases.

Bug: 11256006
Bug: 17759267
Change-Id: Ic183634ef34326793bd9a32167236611d0af34d6

This doesn't change current behavior. It's a preparation
for the following CLs.

Bug: 22408712
Change-Id: Ic018422254aa3904655f499194caad74f0c0fc5d

Currently codepoint to glyph ID resolution is done through MinikinFont
interface. To support variation selector, use HarfBuzz API instead of
calling this interface since one of its implementation Skia doesn't
support variation selector.

On the other hand, we don't want to get glyph horizontal advance values
by HarfBuzz since HarfBuzz doesn't return correct values when the hinting
is active.

Thus, use ot_font as a parent font and override
glyph_h_advance/glyph_h_origin functions as is.

With this change, MinikinFont::GetGlyph is no longer necessary but not
removing in this CL for easy reverting since removing interface requires
multi-repository commit.

This is a base work of b/11256006 and this patch doesn't provide any
user visible changes.

Bug: 11256006
Change-Id: I061172c0b674bb649ce8bc013ffecf38708bdc41

This CL does:
1. Move the getNextWordBreak/getPrevWordBreak function to a separate source file.
2. Adding "ForCache" suffix for function name for making clear these function is
   for layout cache.
3. Introduce unit tests for them.

Bug: 11256006
Change-Id: I4138751a4570915f1a0d6c8921f89700f8ec7f35

Reported externally at https://code.google.com/p/android/issues/detail?id=167715.
Bug: 21498085

Change-Id: I73f22de03b0151ce31a6b3070d051a2a701b33d2

We bypass the word layout cache for "complex" cases, which includes
things like OpenType features. We were counting a hyphen edit as such
a case, but the problem is that we measure a _lot_ of these when
doing layout with hyphenation.

This patch adds plumbing for hyphen edits to the layout cache, so
that word fragments with hyphens can be cached as well.

Bug: 22378829

Change-Id: Idba4df4faa14f48a5faccc8a7a7955a36c19ef27

An incorrect cluster offset calculation was causing a lot of log
messages to appear. Separately, a confusion between #if and #ifdef was
causing unintended logging of line breaks. This patch fixes both.

Bug: 22178333
Change-Id: I2b3673ed66c784f5082fd127a8dc10bd3df6ed79

The appearance of letterspacing with scripts with cursive connections
is poor, so we simply disable letterspacing for those scripts. There
may be some cases where some form of letterspacing is desirable, but
this gives the highest likelihood that the final result will be good
without requiring additional work from clients.

Bug: 21935803
Change-Id: Ie25266249ac3a2605aa89ef5132e8edbe3a06d35

Previously, we just assumed the font in use had a U+2010 HYPHEN
character, resulting in a tofu (or an empty space) being shown when
U+2010 was not supported in the font used to render the hyphenated
word.

Now we try to fallback to U+002D HYPHEN-MINUS, which has a very good
chance of being available in at least any Latin font.

We still show a tofu when neither character is supported, to
intentionally alert that something is missing.

Bug: 20497913
Bug: 21088552
Bug: 21570828
Change-Id: Iff69bbc38836c03495e9124502b5207c39270da2

namespace naming collision. Move minikin's
Bitmap out of android:: and into minikin::

Change-Id: I5ae3925f81b848dc79576429ab55243b96f7fed2

This patch adds a LineBreaker class to Minikin, which will be used for
computing line breaks in StaticLayout. The version in this patch
contains basically the same functionality that existed before, but
hopefully better performance and an interface that's suitable for more
sophisticated paragraph layout.

Note that this version contains a high quality strategy, which mostly
works but doesn't respect varying line width.

Change-Id: I02485d58b1e52856296a72cdd4efd963bc572933

Adds a "HyphenEdit" field to the Minikin Paint object, which represents
an edit to the text to add a hyphen (and, in the future, other edits to
support nonstandard hyphenation).

Change-Id: Ib4ee690b0fe2137e1d1e2c9251e5526b274ec3a7

Previously, HarfBuzz's default fallback to compatibility
decompositions resulted in Mathematical Alphanumeric Symbols getting
rendered as normal letters and digits when there was no font
available to render them. This patch disables that fallback, to
ensure they are displayed as tofus.

Based on a patch by Behdad Esfahbod.

Bug: 19202569
Change-Id: I357f172302448d4ab0b24efc86119f1977b5996b

For build-system CFLAGS clean-up, fix unused variables.

Reorder initializer list to initialize in the order of member
declarations.

Change-Id: I64358b2dcf0e39d0f4e18fdc3473de867f84fcba

Bug: 15193147
Change-Id: I5e15c95415c39515340e2663acd5fd26666db720

Fractional advance widths were causing subtle problems with text
positioning when the same text was drawn with different spans in the
hwui renderer. Quantizing the coordinates on layout (as opposed to
waiting until the renderer draws the glyphs) solves the problem.

This patch also fixes a discrepancy between x position and advance
widths when letterspacing.

Bug: 17347779
Change-Id: Ia705944047408c2839d5ad078eefd6bbec446872

This reduces another allocation (last one?) we were doing when
fulfilling shaping requests from the cache.

Bug: 17111260
Change-Id: Ieb8ae1ccfcaacedb257e1e9263777f10623aaf98

C++ local var initialization always tricks me.  Previously, Layout
didn't have a constructor, which meant that defining it on the stack
left mAdvance uninitialized.  This was not an issue when we were doing
"new Layout()", since that invokes zero-initialization, but was an
issue for the skipCache path that was allocating layout on stack by
just "Layout l" instead of "Layout l = Layout()".  To avoid surprises,
add a constructors that clears everything.

Also adds reset() method to reset the layout for reuse.

Change-Id: I3e02f00da9dd7d360abe13f63c310f6882292d0a

Avoid copying the string for cache lookup.

Bug: 17111260
Change-Id: Ic220bfc991fc6b3dada197304aabdf72a8941bd7

Bug: 15246510
Change-Id: I544915d29b2be4fb9f82f1989188a3a918c50fbc

New API removes CSS string and directly takes needed objects.

Bug: 16651112
Change-Id: Ie5f7c2ab05be6cbd77cae0a5fd6bb453771ada59

All usage is ported to the new doLayout() API now.

Bug: 16651112
Change-Id: I2c959138a69853b5e30098889d771fe5f4cfaa66

Replaces invalid unicode with replacement character U+FFFD and always
makes forward progress.

Bug: 15849380

Change-Id: Ic59ef6c64b0f5c4450bcae61597adcc269d6e7c5

Extract language from FontStyle during shaping.  Don't attach CSS
to LayoutContext.

Change-Id: Ie621d3415410178d0d15fa7b810eb8e412342ab6

It has been unused outside minikin.

Change-Id: Iaa2237767d81c77f90d0264e633375e601dd72f1

After update to HarfBuzz 0.9.33 we don't need this anymore.  HarfBuzz takes care of invalid input and passes U+FFFD to us.

This reverts commit 4422f4dd.

Change-Id: Icfd0dc836a8d684fb1723fc215aa01f99639ff59

Bug: 15594400
Change-Id: Ied94d7674be4097b0f44c9b0770d3294dc6433c1