Lets Make a List of ToDos and RoadMap file

[bawarkamalqader]

Just wanted to ask if it was possible to make a ToDo list , so that new contributors will be able to know where to start, and what to do , like a ROADMAP.

things like ::

• GPOS Table Writing
• GSUB Subtables Writing : 2,5,6,7,8,9
• others ...

[brawer]

Fix test failures?

[bawarkamalqader]

that goes into implementing remaining tables, currently 17 tables are supported, we need to add the remaining tables ::

Remaining Tables : TrueType Font Tables : 'acnt' , 'ankr' , 'avar' , 'bdat' , 'bhed' , 'bloc' , 'bsln' , 'cvar' , 'cvt ' , 'EBSC' , 'fdsc' , 'feat' , 'fmtx' , 'fond' , 'fpgm' , 'gasp' , 'gcid' , 'gvar' , 'hdmx' , 'just' , 'kerx' , 'lcar' , 'mort' , 'morx' , 'opbd' , 'prep' , 'prop' , 'sbix' , 'trak' , 'vhea' , 'vmtx' , 'xref' , 'Zapf' ,

Important Opentype Tables BASE,CBDT,CBLC,COLR,CPAL,DSIG,EBDT,EBLC,GDEF,HVAR,JSTF,LTSH,MATH,MERG

[bawarkamalqader]

we need to sort the remaining tables by priority , i mean the tables that need to be supported earlier and implemented immediately .

[brawer]

I'm in no position to define a roadmap, but personally I'd recommend starting with the missing parts of cmap; then fixing shaping (GSUB/GPOS). The latter will need GDEF (easy), various barely-documented script-specific shaping engines (painful) plus the Universal Shaping Engine USE. The fontkit project has ported HarfBuzz to JavaScript, so have a look at the fontkit sources. Once all that is done, OpenType.js will be able to correctly render Unicode text.

Personally, I would recommend looking at variable fonts (gvar, hvar, avar, HVAR), color fonts, AAT tables, etc. only after the basics of text rendering are working without bugs. Just my personal two cents of course; others might have different opinions.

[Jolg42]

Having a list sorted by priority would be great indeed! Thanks @brawer for your input.

@bawarkamalqader are you interested in something specific?

Adding (and first finding) good fonts with the associated tables to the list would be great as well to make sure everything works well.

About cmap adding the missing parts will probably need some refactoring but not for GSUB. So starting there will be easier. Also I recommend to start on the implementing reading first and then writing, both with tests.

[solomancode]

I was able to compose an overview of the current library status, what's been done and what needs to be done. each item has a severity value to indicate the importance of this item. I slightly adjusted Jakob's Nielsen Severity Scale to match the context of this document.

Severity Scale

0 = I don't agree that this is a usability problem at all 1 = Need not be fixed unless extra time is available 2 = Minor usability problem: fixing this should be given low priority 3 = Major usability problem: important to fix, so should be given high priority 4 = Usability catastrophe: imperative to fix this before product can be released

Required Tables

description	status
cmap character to glyph mapping	✔️
head font header	✔️
hhea horizontal header	✔️
hmtx horizontal metrics	✔️
loca index to location	✔️
maxp maximum profile	✔️
name naming	✔️
post PostScript	✔️

---

Optional Tables

description	status	severity	reference
cvt control value	missing	2	reference
fpgm font program	missing	2	reference
hdmx horizontal device metrics	missing	2	reference
kern kerning	✔️	4
OS/2 OS/2	✔️	3
prep control value program	missing	2	reference
VORG Vertical Origin	missing	2	reference
gasp Grid-fitting/Scan-conversion	missing	2	reference
DSIG Digital signature	missing	1	reference
LTSH Linear threshold data	missing	2	reference
MERG Merge	missing	2	reference
meta Metadata	missing	1	reference
STAT Style attributes	missing	3	reference
PCLT PCL 5 data	missing	0	reference
VDMX Vertical device metrics	missing	1	reference
vhea Vertical Metrics header	missing	2	reference
vmtx Vertical Metrics	missing	2	reference

---

Outlines Tables

description	status
glyf glyph data for TrueType	✔️
CFF Compact Font Format 1.0	✔️
CFF2 Compact Font Format 2.0	✔️

---

Font Variations Tables

description	status	severity	reference
avar Axis variations	missing	3	reference
cvar CVT variations (TrueType outlines only)	missing	3	reference
fvar Font variations	✔️
gvar Glyph variations (TrueType outlines only)	missing	3	reference
HVAR Horizontal metrics variations	missing	3	reference
MVAR Metrics variations	missing	3	reference
STAT Style attributes (required for variable fonts, optional for non-variable fonts)	missing	3	reference
VVAR Vertical metrics variations	missing	3	reference

---

Advanced Typographic Tables

description	status	severity	reference
BASE Baseline data	missing	4	reference
GDEF Glyph definition data	missing	4	reference
GPOS Glyph positioning data	partial	4	reference
GSUB Glyph substitution data	partial	4	reference
JSTF Justification data	missing	3	reference
MATH Math layout data	missing	2	reference

---

GSUB table status

description	status	severity	reference
1.1 Single Substitution format 1	missing	4	reference
1.2 Single Substitution format 2	✔️
2.1 Multiple Substitution format 1	✔️
3.1 Alternate Substitution	missing	4	reference
4.1 Ligature Substitution	missing	4	reference
5.1 Context Substitution Format 1	missing	4	reference
5.1 Context Substitution Format 2	missing	4	reference
5.1 Context Substitution Format 3	missing	4	reference
6.1 Chaining Context Substitution Format 1	missing	4	reference
6.2 Chaining Context Substitution Format 2	missing	4	reference
6.3 Chaining Context Substitution Format 3	✔️

---

GPOS table status

description	status	severity	reference
1 Single adjustment	✔️
2 Pair adjustment	✔️
3 Cursive attachment	missing	4	reference
4 MarkToBase attachment	missing	4	reference
5 MarkToLigature attachment	missing	4	reference
6 MarkToMark attachment	missing	4	reference
7 Context positioning	missing	4	reference
8 Chained Context positioning	missing	4	reference
9 Extension positioning	missing	4	reference

---

Color Fonts & Bitmap Glyphs Tables

description	status	severity	reference
COLR Color table	missing	2	reference
CPAL Color palette table	missing	2	reference
CBDT Color bitmap data	missing	2	reference
CBLC Color bitmap location data	missing	2	reference
sbix Standard bitmap graphics	missing	2	reference
SVG The SVG (Scalable Vector Graphics) table	missing	2	reference
EBDT Embedded bitmap data	missing	2	reference
EBLC Embedded bitmap location data	missing	2	reference
EBSC Embedded bitmap scaling data	missing	2	reference

---

• (!) Hint,

  Some tables like GSUB and GPOS requires multiple steps to be completed in a certain order, for example For a certain feature in GSUB table to be fully implemented, the library should support

  1. parsing ( reading data from font file )

  2. re-structuring data for future lookups

  3. the lookup logic that handles data retrieval to be used in rendering, ... etc.

  please make sure that you don't repeat yourself as some features has been already implemented and you can use it's existing logic or refactor it if you think you can do better.

---

Tooling

description	status	severity
Glyph Inspector Find a glyph by name, unicode or index	missing	3
Glyph Inspector Add sidebearing marks	missing	2
Glyph Inspector Fonts presets to easily inspect multiple languages	missing	4
Font Inspector Add formatting and syntax highlighting to GSUB and cmap table data	missing	4

---

Technical

• I recommend using Typescript 3.0

  using typescript will ensure that typings are synced with implementation unlike JSDocs. plus all the gains of using JSDocs. and it'll greatly improve code quality. what I propose is removing JSDocs type annotations while keeping description blocks and use typescript annotations instead.

---

I believe I didn't cover everything, please feel free to update existing items or add more items.

[yisibl]

Is there a plan to support Color Fonts?

[kontur]

woff2 decompression would be great (to be on the list).

[cmloegcmluin]

I'm very new to this world, so forgive me if I'm off-base. But I think I'm experiencing a problem using opentype.js because my font contains some GSUB lookup tables of type 7, extension substitution, which seem to be something like wrappers around lookup tables of other types (in my case, type 4, ligatures, which are otherwise working fine). Is there any plan to support GSUB type 7? Perhaps @bawarkamalqader was referring to this in the first post here, but @solomancode 's table cut off at 6.

[cmloegcmluin]

Ah, apologies. I was looking at a version of opentype.js that was a couple years old. It looks like extension substitution lookup tables may already be supported now. Thank you.

[Connum]

I added the Release 2.0.0 milestone, so we can re-evaluate the status quo. We should especially

• update the nice overview in https://github.com/opentypejs/opentype.js/issues/374#issuecomment-485134088 and port it over to a more prominent place in either the Discussions or a new Wiki
• have https://rawgit.com/unicode-org/text-rendering-tests/master/reports/OpenType.js.html updated with either a pre-release of 2.0.0 or at least 2.0.0 itself, so we can get a clearer perspective of what's next moving on from there

[ILOVEPIE]

woff2 decompression would be great (to be on the list).

Woff2 decompression is out of scope for the library, you can use other libraries to do the decompression and then pass the results to opentype.js see https://github.com/opentypejs/opentype.js/issues/183#issuecomment-1147228025

[Connum]

I made a repository where I will store test reports from that tool for different versions and commits from the master branch. The reports are directly available to view on GitHub Pages here: https://connum.github.io/opentypejs-reports/