Will It 'Buzz?

This tool will compare the browser's native complex-shaping against HarfBuzz and identify differences.

Load up:

• A word list
• A font to test
• Click "Process"

And the tool will compare each word, producing a list of differences.

Live Page

https://mattmatic.github.io/will-it-buzz/

How it works

• The font is dynamically loaded into the css space
• HarfBuzzJS is used to shape and obtain the paths for each glyph

For each word:

• The word is filled to canvas in red.
• The word is stroked to canvas in black with a 1.5 wide line (this avoids aliasing issues in the overlap)
• The HarfBuzz shaping is pathed to the canvas in blue.
• The canvas bitmap is read, and a threshold of red pixels are detected as a failure

Downloads

The failed list of words can be downloaded as a UTF8 text file.

Additionally, the rendering of Browser (red) vs HarfBuzz (blue) can be saved as a ZIP file. The image renderings are in the png\ folder, with the image index matching the line number of the data\fail.txt file.

The PNG folder is limited to the first 4000 images.