Custom cursors and high dpi (Windows and MacOS testers needed)

[vanuan]

Need help with custom cursors
https://forum.freecadweb.org/viewtopic.php?f=3&t=48681

Currently, those are defined as hard-coded 32x32 bitmaps, e.g.: src/Mod/Sketcher/Gui/CommandCreateGeo.cpp

As 4K displays become more common, cursor icons need to be scaled up to 200% or 300%.
Unfortunately, naive scaling makes cursor icons to be blurry/pixelated.

I can make a PR for crude scaling, but it would be much better to actually make higher resolution cursor.

Bitmaps look like this:

Code: Select all

"......+.........................",
"......+.........................",
"......+.........................",
"......+.........................",
"......+.........................",
"................................",
"+++++...+++++...................",
"................................",
"......+.........................",
"......+.........................",
"......+.........................",
"......+.........................",
"......+.........................",
"................................",
"................................",
"..........................###...",
"........###################.##..",
".......#..................###.#.",
"......#........................#",
".....#.........................#",
"....#.....###..................#",
"....#.....#.#..................#",
".....#....###.................#.",
"......#.......................#.",
".......#.....................#..",
"........#####################...",
"................................",
"................................",
"................................",
"................................",
"................................",
"................................"};

[openBrain]

Cursors are XPM but I guess it would be doable to define them as SVG then use BitmapFactory or some Qt graphics class to convert them.
To me a problem is to manage things correctly when viewport spans over a HiDpi display and a "standard" one.

[vanuan]

Let's solve the problems one by one. This one is about the discrepancy between standard cursors and custom ones.

Here's a solution without SVG files (results in blurred icons): https://github.com/FreeCAD/FreeCAD/pull/3712

[openBrain]

This is what I call solving problem half by half.

[vanuan]

This is what I call solving problem half by half.

I dare you to try it, maybe it's fully solved
If not, I'm waiting for feedback.
Unforutnately, I don't have access to a second monitor right now.

[openBrain]

I don't have HiDpi. The main problem with your PR is that it will scale cursor in every case, even if not needed. So everybody will get a blurred cursor, even those that don't deserve it.

[Kunda1]

What about looking at how other FOSS projects deal with this perhaps we can use their assets too?

[openBrain]

IMO, as cursor isn't generally the only implication (but also are icons, fonts, ...), we'd better use Qt abilities rather than some custom algorithm.

[vanuan]

I don't have HiDpi. The main problem with your PR is that it will scale cursor in every case, even if not needed. So everybody will get a blurred cursor, even those that don't deserve it.

Nope, if not needed, devicePixelRatio will return 1, so it would be of original size.

[vanuan]

IMO, as cursor isn't generally the only implication (but also are icons, fonts, ...), we'd better use Qt abilities rather than some custom algorithm.

My solution is based on the Qt documentation
https://doc.qt.io/qt-5/scalability.html ... n-platform

Code: Select all

if ( QGuiApplication::primaryScreen()->devicePixelRatio() >= 2 ) {
    imageVariant = "@2x";
} else {
    imageVariant = "";
}

This is for QML, but FreeCAD doesn't currently use QML, so I adapted accordingly.

The issue is that we don't have multiple icon sizes for different pixel ratios, hence why I asked for help. Is anybody familiar with Inkscape? Or could provide raster icons of 2X-4X size?