13 Commits

Author SHA1 Message Date
Raph Levien
bb601b67dd Make font runs less sticky
Fixes b/15734816 In the text "Wi-Fi", "-Fi" appears bolder than "Wi"

The problem was caused by "stickiness" in choosing fonts, where layout
would prefer using a font used for preceding characters as long as it
mapped the following characters in a run, in favor of the "best match"
rules. This patch adds a whitelist for making the stickiness more
conservative, only applying it for characters necessary for correct
shaping (ZWJ and ZWNJ in particular) and basic punctuation, where it is
desirable to match the style of the preceding text.

Change-Id: I1cf116879f074a5a71c351846707bfdd07b0d320
2014-06-19 09:03:01 -07:00
Raph Levien
bd36ec766a Fix missing text on nonexistent font file
Fix for bug 15570313 "Missing text on nonexistent font file"

This patch makes sure that the lastChar and mInstances arrays are in
sync with each other even when a FontFamily being added has no valid
fonts in it. Previously, when they got out of sync, unicode coverage
calculation would be wrong, resulting in missing text.

Change-Id: I69c727ef69e2c61e2b2d6b81d5a28c806327f865
2014-06-11 16:03:49 -07:00
Raph Levien
9a5f713add Support for fake bold and italics
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
2014-06-10 11:59:29 -07:00
Raph Levien
89566f0ada Add baseFont method to FontCollection
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
2014-06-06 17:03:33 +00:00
Raph Levien
066e8575af Fix ZWJ not working for Indic fonts
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
2014-05-29 15:16:32 -07:00
Raph Levien
7b221d97b7 Language and variant selection
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
2014-05-29 15:16:32 -07:00
Raph Levien
4d4e6bc811 Caching for layouts and harfbuzz faces
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
2014-05-27 15:39:33 +00:00
Raph Levien
72fe9422c8 Fix native crash in Latin-1 typefaces
This is a fix for bug 15171911 Timely crashes (native crash in
libminikin) when I go to add a new alarm

This patch fixes an off-by-one error that caused typefaces with only one
page of Unicode coverage (ASCII or Latin-1) to have nPages = 0 instead
of the correct value of 1 in the corresponding FontCollection.

Change-Id: Id8be0c9e5713b8af22d863992921ee6382416a34
2014-05-23 22:44:35 -07:00
Raph Levien
c31e388345 Fix incomplete refcounting and locking
These changes were supposed to be committed in the previous patch
"Better refcounting and locking" but seem to have gotten lost in a
rebase. It fixes a memory leak and some possible race conditions.

Change-Id: I54ca1e37500ec49756fe317cc6d6d03da9911501
2014-05-19 14:01:37 -07:00
Raph Levien
b80c1f19c5 Better refcounting and locking
All major externally accessible objects (especially FontFamily and
FontCollection) are now reference counted. In addition, there is a
global lock intended to make operations thread-safe.

WIP notice: in this version of the patch, not all external API entry
points are protected by the lock. That should be fixed.

Change-Id: I14106196e99eb101e8bf1bcb4b81359759d2086c
2014-05-12 10:28:15 -07:00
Raph Levien
ecc2d34ac2 A basket of features: itemization, bounds, refcount
This patch improves script run itemization and also exposes metrics
and bounds for layouts. In addition, there is a fair amount of internal
cleanup, including ref counting, and making the MinikinFont abstraction
strong enough to support both FreeType and Skia implementations. There
is also a sample implementation using Skia, in the sample directory.

As part of its functionality, his patch measures the bounds of the
layout and gives access through Layout::GetBounds().  The corresponding
method is not implemented in the FreeType-only implementation of
MinikinFont, so that will probably have to be fixed.

Change-Id: Ib1a3fe9d7c90519ac651fb4aa957848e4bb758ec
2014-05-12 09:08:15 -07:00
Raph Levien
bcc3dc5a25 Introduce MinikinFont abstraction
This commit removes the direct dependency on FreeType and replaces it
with a MinikinFont abstraction, which is designed to support both
FreeType and Skia fonts (and possibly others in the future).

Also adds a "total advance" to the Layout, with an API for retrieving
it.

Change-Id: If20f92db9a43fd15b0fe9794b761ba00fb21338c
2013-06-14 11:22:35 -07:00
Raph Levien
9cc9bbe146 Initial commit of Minikin library
This is the initial draft of Minikin, a library intended to perform text
layout functions. This version does basic weight selection and font runs
for scripts, and also has a simple renderer for drawing into bitmaps,
but is lacking measurement, line breaking, and a number of other
important features. It also lacks caching and other performance
refinements.

Change-Id: I789a2e47d11d71202dc84b4751b51a5e2cd9c451
2013-04-25 12:23:57 -07:00