Fix text displaying bug for browsers that block canvas data extraction #5342
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
bigtimebuddy
reviewed
Jan 9, 2019
ivanpopelyshev
approved these changes
Jan 9, 2019
|
right, Comodo |
themoonrat
approved these changes
Jan 9, 2019
|
This thread has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs. |
Sign up for free
to subscribe to this conversation on GitHub.
Already have an account?
Sign in.
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Description of change
There is some privacy-focused browsers(Firefox 58+, Tor) that disallow canvas data extraction(toDataURL, getImageData) by default(not really disallow, just return white picture), i.e. they ask for permission to do so(although i don't have a permission request on localhost). TextMetrics.js is using getImageData in static function called measureFont to calculates the ascent, descent and font size of a font-style, but when user decline permission request or just ignore it function return zeroes for ascent, descent and font size, then text element became 1px tall(not visible on screen). No need to use measureFont if we can't, there is fallback in commit that allow to show text if we can't extract canvas data.
Pre-Merge Checklist
npm run lint)npm run test)