OSX: Bad kerning in disk image background #16836

The background image generated by make deploy for our OSX disk image has bad kerning at least for the OSX version I tested.

Software specs:

ProductName:    Mac OS X
ProductVersion: 10.14.6
BuildVersion:   18G87

Is this with gitian or a native build?

Is this with gitian or a native build?

Native build, perhaps we don't care that much about the disk image for native builds?

@dongcarl Do you have any more info? I have never seen this issue locally.

The background.svg image uses a font called Tuffy (I don't know why). This is probably suboptimal.

I guess @dongcarl's rsvg-convert has issues with either the font or with the general bitmapification of text.

What happens if you convert manually? rsvg-convert contrib/macdeploy/background.svg -f png -d 36 -p 36 -o test.png

@jonasschnelli Yes the kerning problem persists when I convert manually... Looking at Font Book on my system there doesn't seem to be a font named "Tuffy", which is probably the problem. Perhaps we could switch to something else?

It would seem that this is not due to missing fonts but rather a regression in rsvg-convert as @jonasschnelli and I discovered. This regression was introduced somewhere between rsvg-convert 2.40.16 and 2.46.0.

Looks like its related to the width="1000pt" height="640pt" part in the <svg> tag (changing from pt to px makes the kerning looks good, but unsure about the output image size).

Looks like the @2x image is fine (retina/HiDPI). Can you confirm @dongcarl ?

Looks like the @2x image is fine (retina/HiDPI). Can you confirm @dongcarl ?

Tested this issue using a retina display Macbook Pro running the same software specs, no kerning on my side which suggests the @2x image works as intended.

<img width="542" alt="bitcoin core" src="https://user-images.githubusercontent.com/31032215/65371043-6833c700-dc57-11e9-8c18-2e7a2f6cb452.png">

I also get the kerning if i convert manually using rsvg-convert contrib/macdeploy/background.svg -f png -d 36 -p 36 -o test.png

but not if i convert @2x manually using rsvg-convert contrib/macdeploy/background.svg -f png -d 72 -p 72 -o test.png

Software specs:

ProductName:    macOS Mojave
ProductVersion: 10.14.6
BuildVersion:   18G87

Looks like its related to the width="1000pt" height="640pt" part in the <svg> tag (changing from pt to px makes the kerning looks good, but unsure about the output image size). @jonasschnelli I've been playing around with this issue and as you mentioned changing from pt to px seems to solve the kerning issue.

However when using px instead of pt, the png outputs from the rsvg-convert seem to create the exact same file (regardless of the change in dpi) and therefor having the two different image output files (background.tiff.png and background.tiff@2x.png) would be pointless.

A potential solution would be to have two different background.svg files for each image resolution, however a solution that keeps it confined to one background.svg would seem more appropriate.

I'm willing to take on fixing this issue if nobody else already has, not sure of the best solution yet and your thoughts on this would be appreciated.

Also I'm fairly new around here so apologies if i haven't followed correct procedure or have put this in the wrong place (working my way through the contributing guide)

I've looked into this issue some more and provided upstream with a minimal reproducer: https://gitlab.gnome.org/GNOME/librsvg/issues/520

It appears to be an issue that only occurs on OSX.

Small update: seems to be a pango issue https://gitlab.gnome.org/GNOME/pango/issues/422

I've removed "Good first issue" and added upstream. I don't think fixing this a high priority.

Is this still an issue?

This is no longer an issue after #23909.