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

Bug: 22408712
Change-Id: Ic018422254aa3904655f499194caad74f0c0fc5d

Also handle the case of weird language code that we don't understand
properly better, by treating them not equal to each other.

Change-Id: Iaccb251fa38d700932f6eadac254d3d1fa09b3ea

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

Tuning for hyphenation parameters. We discourage hyphenation on the
last line, but offset this penalty by also applying a penalty for
each line, which optimizes for minimizing the number of lines. Thus,
when hyphenation can reduce the number of lines, it increases the
chance they're used.

There's probably more tuning and refinement that can be done, but
testing suggests that the tunable parameters are appropriate.

Bug: 20883322

Change-Id: Ida7eaf8aced109e426694f5a386924a842d29c4b

Three hyphenation frequencies are now supported:

kHyphenationFrequency_None, which turns off both automatic
hyphenation and soft hyphens.

kHyphenationFrequency_Normal, which has aconservative amount of
hyphenation useful as a conservative default.

kHyphenationFrequency_Full, which has a typographic-quality amount of
hyphenation useful for running text and tight screens.

Bug: 21038249
Change-Id: I2800f718c887c9389a1a059d7ec07d7fa2ca1dee

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

Change-Id: I5ae3925f81b848dc79576429ab55243b96f7fed2

New functions for computing the correspondence between cursor
position and advance, respecting grapheme boundaries.

Change-Id: I620378d5f64cd74300cd43db522adeb555825dff

The name "margin" conflicts with another meaning, so we're making the
name in the public api "idents" and the code consistent in naming.

Change-Id: I9170116b4d972e4b25f0f319e78376310288eb41

In order to support layout in non-rectangular regions, the LineWidths
object needs to accept an arbitrary array of margins. This is
implemented in addition to the existing firstWidthLineCount/restWidth
mechanism for convenience, though using only arrays would have the
same expressive power.

Bug: 20182243
Change-Id: Iea96bca1a92012314ac27e617c67f306c1f1b2f2

This reverts commit 0b25d5ac.

This reverts commit daf6a6bd.

Change-Id: I3fed65046274d3aeb748f0730585ab89927f5741

This patch adds hyphenation using the Liang hyphenation algorithm,
similar to TeX. It also improves the optimized line breaker so that
it works correctly and efficiently even when the line width is not
constant (there is a specialization for constant width, which is
probably worthwhile, but performance TODOs remain).

Still to be done:

* hyphenator has many shortcuts, only tested with English

* interaction between punctuation and hyphenation is problematic

Change-Id: I2d94a1668ebc536398b7c43fcf486333eeb7c6aa

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

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

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

Change-Id: I64358b2dcf0e39d0f4e18fdc3473de867f84fcba

This will significantly reduce memory usage and also speed the creation
of new font families. In particular, the coverage bitmaps for the fonts
in the fallback stack will be computed once in the Zygote, rather than
separately in each app process.

Bug: 17756900
Change-Id: I66f5706bddd4658d78fe5b709f7251ca9d2ff4f8

This will significantly reduce memory usage and also speed the creation
of new font families. In particular, the coverage bitmaps for the fonts
in the fallback stack will be computed once in the Zygote, rather than
separately in each app process.

Bug: 17756900
Change-Id: I66f5706bddd4658d78fe5b709f7251ca9d2ff4f8

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

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

We are stack-allocating MinikinPaint objects in Minikin clients, and
without a constructor adding new members to the struct cannot be done
without updating all clients (only one right now!).

Change-Id: I4170f16498bb6b07cb795495011aca58087ed0bd

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

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

Change-Id: Ie621d3415410178d0d15fa7b810eb8e412342ab6

It has been unused outside minikin.

Change-Id: Iaa2237767d81c77f90d0264e633375e601dd72f1

Bug: 15594400
Change-Id: Ied94d7674be4097b0f44c9b0770d3294dc6433c1

Expose a method to purge caches used for TextLayout, useful for low
memory conditions.

Change-Id: I92f41afe987b7be4af5ca0a0c50fb51be35a2758

This patch includes an implementation of grapheme cluster breaking,
which is especially useful for repositioning the cursor for left and
right arrow key presses. The implementation is closely based on Unicode
TR29, and uses the ICU grapheme cluster break property, but is tailored
to more closely match the existing implementation and expected behavior.

Part of a fix for b/15653110 Improve behavior of arrow keys in EditText

Change-Id: I8eb742f77039c9ab7b2838285018cf8a8fc88343

This patch adds support for computing when fake bold and fake italics
are needed (because the styles are requested but not provided by the
matching FontFamily), and providing them as part of the layout result.

Part of the fix for bug 15436379 Fake bold doesn't fully work (Minikin)

Change-Id: I180c034b559837943673b5c272c8e890178dff0d

This patch adds a method to retrieve the base font from a
FontCollection, which is useful when querying global font metrics.

Part of the fix for bug 15467288 "Inconsistent line heights on
Minikin builds"

Change-Id: I268ae5128d0852a020d746bc22af81fc1a623228

This patch adds support for computing when fake bold and fake italics
are needed (because the styles are requested but not provided by the
matching FontFamily), and providing them as part of the layout result.

Part of the fix for bug 15436379 Fake bold doesn't fully work (Minikin)

Change-Id: I180c034b559837943673b5c272c8e890178dff0d

This patch adds a method to retrieve the base font from a
FontCollection, which is useful when querying global font metrics.

Part of the fix for bug 15467288 "Inconsistent line heights on
Minikin builds"

Change-Id: I268ae5128d0852a020d746bc22af81fc1a623228

This patch completes support for adding context for complex script
layout, for example when a string with joins straddles two spans.

Part of the fix for 15431028: "Properly support context for joining
scripts (Minikin)"

Change-Id: I65b0833be92eb477aa531bbef0ac6eddeb3a962a

Change internal plumbing of paint flags (including CssParse) to uint32_t
consistently, to match the type used in the client. This will probably
prevent compiler warnings. Also renames "float" to "double" to avoid
confusion about precision.

Change-Id: I80374712c4067ca9e7711cc2d4ec33c440ab9c7c

Adds pseudo-css properties for scaleX and skewX, as well as paint flags,
and plumb them through to the MinikinPaint abstraction and to Harfbuzz,
to support nontrivial scale and stretch of text.

This is the Minikin part of the fix for bug 15186705 "Usability of the
suggestion strip in recent OTA's is severely reduced"

Change-Id: Ifa60355e086e4691ff92c5d50d84eb7cea0fea95

This is a fix for bug 15185229 ZWJ not working in Sinhala and Kannada.

Indic fonts (unlike Arabic) require the entire string, including ZWJ,
to be passed to Harfbuzz; it's not enough for the ZWJ to be present in
the context. The solution is to be "sticky" in font itemization,
continuing to use the same font as long as it has Unicode coverage.

Change-Id: I7673bc56fbda09f1e1a4582e8d88342343b706f1

This patch adds a "lang" pseudo-CSS property and uses it both to select
an appropriate font and control the "locl" OpenType feature to get the
most appropriate rendering for the langauge and script.  In addition,
the "-minikin-variant" property selects between "compact" and "elegant"
variants of a font, as the former is needed for vertically cramped
spaces.

This is part of the fix for bug 15179652 "Japanese font isn't shown on
LMP".

Change-Id: I7fab23c12d4c797a6d339a16e497b79a3afe9df1

This patch adds caching for both layouts and for HarfBuzz face objects.
The granularity of the cache for layouts is words, so it splits the
input string at word boundaries (using a heuristic). There are is also
some refactoring to reduce the amount of allocation and copying, and
movement towards properly supporting contexts.

The size of the caches is a fixed number of entries; thus, it is
possible to consume a large amount of memory by filling the cache with
lots of large strings. This should be refined towards a scheme that
bounds the total memory used by the cache.

This patch fixes bug 15237293 "Regression: Measure performance is
significantly slower with minikin".

Change-Id: Ie8176857e2d78656ce5479a7c04969819ef2718d

This is a fix for bug 15130102 "Language name for Hebrew displayed the
wrong way around on keyboard".

This patch extends the previous BiDi support (when the direction for the
entire string was given by the caller) to run the BiDi algorithm
(provided by ICU) over the string to break it into BiDi runs. Thus, it
handles mixed LTR and RTL strings in a single layout, and also respects
heuristics for inferring the paragraph direction from the string.

Change-Id: Ia4b869de3c139c5a7d16b8ce7766870b98a815ea
(cherry picked from commit 4b3a9411)