Render arabic rtl text properly #361
Conversation
main components: Tokenizer: convert a string into a list of tokens FeatureQuery: query a feature and lookup a substitution Bidi: query, apply arabic features and adjust arabic layout Char: character class assertions supported gsub tables Single Substitution - lookup type 1, substFormat 2 Chaining Context Substitution - lookup type 6, substFormat 3 Ligature Substitution - lookup type 4, substFormat 1
…atures activation
Sync. opentype.js fork
| * and shouldn't be turned off when rendering arabic text. | ||
| */ | ||
| { script: 'arab', tags: ['init', 'medi', 'fina', 'rlig'] }, | ||
| { script: 'latn', tags: ['liga', 'rlig'] } |
There was a problem hiding this comment.
So if the font is not detected as Latin liga & rlig will be off?
Like if a font only supports emoji or a certain script?
There was a problem hiding this comment.
Yes, every registered feature is checked before application. If the script is missing or the font doesn't support this feature, It'll silently fail to apply this feature.
| * @param {any} options features options | ||
| */ | ||
| Font.prototype.updateFeatures = function (options) { | ||
| // TODO: update all features options not only 'latn'. |
There was a problem hiding this comment.
Do you plan to finish this TODO before merging this?
There was a problem hiding this comment.
Maybe later. But it'll not affect the current functionality at all. I need find a common model for updating features on UI controls changes / passed options to stringToGlyphs for all scripts.
|
👍 for all the gains! Just curious about what happens if a font script is not arab or latn? |
|
Just tested it now, Kerning is working fine for Latin script. as for other features. I'm not sure which features should be applied by default for other scripts. for now I added the required features for Arabic (init, medi, fina, rlig) and the most important features for Latin (liga, rlig). as for other scripts we might need some help from other contributors to understand which features to apply by default for which script. The latest defaults only applied liga and rlig for every script. what I did was to narrow down the application of these features to latin script/text only and I added required Arabic features as well. and of course all the tests for liga and rlig are passing. |
|
Take your time to make sure everything is fine before merging to master, If anything needs clarifying just leave me a comment. |
Refactor featureQuery.js implementation to favor functions composition over objects orientation
Gains:
Unify Substitution action + (class SubstitutionAction)
Gains:
Types of changes
Checklist:
npm run testand all tests passed green (including code styling checks).