[gtk3] Drawing canvas is blurry/low-resolution on HiDPI/Retina configuration

[Brion Vibber]

GTK+ 3.10 and later support a scaled rendering mode for hi-DPI devices such as Apple's "Retina" displays and other vendors' 2560x1440+ laptop displays.

In addition to providing higher-resolution icons for toolbars etc, it'll be necessary to make sure that Inkscape's drawing surface is done at the appropriate scale.

Currently, on a GTK3 build on Fedora 20, with scaling on, the basic UI components render nicely (except for icons) but the drawing surface is blurry and low-resolution.

See https://wiki.gnome.org/BrionVibber/HiDpiNotes for some background and related issues with other apps.

In addition to Linux, full HiDPI support will be wanted for Mac OS X: https://bugs.launchpad.net/inkscape/+bug/1216795 ... In theory the same stuff done for Linux GTK3 should work on OS X w/ native GTK3 backend.

[Fernando (fcuencamargalef)]

Not only for retina.

I have a Toshiba Satellite P50t, with UHD resolution in 15.6'', with Ubuntu 14.10. And I can not use inkscape with native resolution. With high dpi resolutions the UI shows icons, texts, menus, toolbars, cursors... too small.

I think this request must be prioritary, because Inkscape is a tool for designers, and designers we love hidpi monitors :-D

Next year 4k and UHD monitors will be more and more common, and Inkscape is far to be ready.

[Andreas E. (andreas-e)]

I have been using Inkscape on high dpi for over a year.
I get not only a blurry canvas, but also drawing artifacts (this 1 screen pixel thick lines) between re-rendered areas of the canvas.
I see Inkscape frequently pushing updates to the inkscape.dev ppa, but no improvements in this regard?

[Matthieu James (tiheum)]

I tried the GTK3 build on my brand new XPS 13 (2015) and have the same artifacts as described above. This issue makes the software almost unsuable so at the moment I keep on using the GTK2 version despite the tiny icons.

[davidgf (david-davidgf)]

Same issues here! (Same picture as Patryk Hes shows).
Is it gonna be fixed soon? I mean, GTK3 is quite old already :D

[shinyblue (shinyblue)]

+1 4h HDPI laptop screen, can't see the icons/cursors.

[Issa Mahasneh (issa86)]

+1
I have installed the GTK+ 3 port on a device with HiDPI (2560x1440) resolution, and I can confirm both the blurry drawing surface and the lines that remain after re-rendering on the canvas.

[Randal (randal.junior)]

Same problem on Windows 10.

[Patrick Storz (ede123)]

Issue also affects MSYS2 builds of master.

While gtk2 builds of 0.92.x use the native display resolution when the application manifest declares "dpiAware" [1] , gtk3 builds of master show a blurry canvas [2].

I think this should be considered a high priority for 0.93; regressing one of the most basics aspects of Inkscape (on-canvas rendering) is unacceptable (maybe this should even be a blocker).

[1] https://inkscape.org/en/~eduard.braun/%E2%98%85inkscape_092x_dpiawarenon-dpiaware_200png
[2] https://inkscape.org/en/~eduard.braun/%E2%98%85inkscape_master_dpiawarenon-dpiaware_200png

[Tavmjong Bah (tavmjong-free)]

Fedora 25. Enabling HiDP scaling factor 2 via Tweektool, Inkscape does not scale at all.

[Tavmjong Bah (tavmjong-free)]

I've done a lot more experimenting. See: http://wiki.inkscape.org/wiki/index.php/HiDPI

[Tavmjong Bah (tavmjong-free)]

A HiDPI canvas branch in now on GitLab. See the link in the previous entry.

[robis24 (robis24)]

After trying inkscape-trunk build from the ppa, I have successfully build your HIDPI inkscape version, but no success still blurry on my HIDPI display . On ubuntu 16.10 - 64bit, GNOME Shell 3.20.4, X11, tweaktool scale=2, Intel® HD Graphics 515 (Skylake GT2) , laptop-display: 13,3" - 16:9 - 3200 x 1800 . Do you have any suggestions for me? I love inkscape but I can no longer use it in this state. :( , thanks in advance

[Norbert Nemec (nnemec)]

HiDPI works quite well for me on Windows with the current development preview build. What does not work, yet, is dynamically changing DPI. This comes up frequently when working in a multi-screen setting with the screens at different DPI values.

Generally, Windows deals with the really nicely, either informing the application about the changed DPI or, if the the application does not support that, automatically scaling the window (resulting in blurry, but acceptable display)

With the new build of inkscape, Windows believes that the application can deal with the changing DPI, but inkscape respects the changed DPI value only partially, leaving some of the window in the original DPI setting and ultimately resulting in a totally messed up window layout.

Not sure whether dynamic HiDPI should still be considered part of this ticket or whether is should be split out as a separate bug ticket.

[Patrick Storz (ede123)]

Likely it should be split out.
First task is to figure out if the toolkit itself (GTK+) supports different DPI per monitor. Last time I checked this did not seem to be the case, which makes it almost impossible to implement this properly in Inkscape.

[Norbert Nemec (nnemec)]

I just created https://bugs.launchpad.net/inkscape/+bug/1789696 to track this separately.

Note that inkscape does appear to react to the signal that the DPI has changed, so GTK-3 seems to offer some kind of support for this feature. My guess is that inkscape's layout calculations are not correctly triggered on that event.

[Shawn Landden (scientes)]

This is still broken in Ubuntu 19.10