puglSetSizeHint with PUGL_CURRENT_SIZE doesn't work on X11/KDE

[swesterfeld]

I am on KUbuntu 24.04, using KDE with pugl from main. If I run examples/pugl_window_demo and use Shift+LEFT, Shift+RIGHT, ... nothing happens (this should change the window size). It works if I add a call XSetWMNormalHints to puglSetWindowSize like this:

PuglStatus
puglSetWindowSize(PuglView* const view,
                  const unsigned  width,
                  const unsigned  height)
{
  //- HACK: change size hints before resizing ------------------------------
  XSizeHints *hints = XAllocSizeHints();
  hints->min_width = width;
  hints->min_height = height;
  hints->max_width = width;
  hints->max_height = height;
  hints->flags = PMaxSize | PMinSize;

  XSetWMNormalHints(view->world->impl->display, view->impl->win, hints);
  //------------------------------------------------------------------------

  return puglX11Status(
    XResizeWindow(view->world->impl->display, view->impl->win, width, height));
}

I know that this is probably not the right thing to do, but I'm not sure what is the right thing to do.

[drobilla]

Did you run it with -r? If not, what happens (without the hack in place) if you do?

[swesterfeld]

If I run it with -r resizing works properly. In my liquidsfz lv2 plugin, I now use this:

PuglStatus
puglSetWindowSize(PuglView* const view,
                  const unsigned  width,
                  const unsigned  height)
{
  if (!view->hints[PUGL_RESIZABLE])
    puglUpdateSizeHints (view);

  return puglX11Status(
    XResizeWindow(view->world->impl->display, view->impl->win, width, height));
}

Note the two lines checking for PUGL_RESIZABLE were added. In case you wonder why I want to resize a non-resizable window: I create a UI for my plugin, and then ask for puglGetScaleFactor (view) - after this I need to change the window size according to the scale factor. The user cannot resize the window afterwards.

[drobilla]

I see (I don't have a KDE-on-X11 installation handy to check myself). It's not surprising that trying to resize a non-resizable window doesn't work or work well, but being X11 it will be weird and broken in different ways on different systems.

The scale thing is a known problem, yeah. The scale factor is internally available before creating the view, but doing this properly in the API (kinda sorta probably maybe) means dealing with multiple displays there as well so it's not so trivial. See #108

This needs to get sorted out, but I don't personally have any projects to drive/test it (converting the LV2 examples to pugl is on my TODO list but I haven't gotten around to it). I think puglGetScaleFactor should work before realizing the view, though, so maybe you can get the scale factor very early and set the view up properly to begin with? (doing it right first instead of trying to change things later is generally a pretty common theme with making UIs work, e.g. reparenting is a nightmare). I'm not sure though