bug#49937: 28.0.50; feature/pgtk: tetris blocks are comparatively larger

[Robert Pluim]

>>>>> On Tue, 10 Aug 2021 14:51:44 +0200, Lars Ingebrigtsen <larsi@gnus.org> 
>>>>> said:

    Lars> Alan Third <alan@idiocy.org> writes:
    >> They're images, ostensibly 7mm in height but it appears on X (and NS)
    >> they're much smaller. I imagine it depends on the screen's reported
    >> DPI since the gamegrid code appears to calculate the size using it.

    Lars> I think this is bug#47039 -- pgtk scales images correctly, which 
images
    Lars> found via `find-image' are not scaled correctly on the trunk.

The images in this case are created on the fly by gamegrid.el, which
uses 'display-mm-height', which gives the wrong answer under X:

ELISP> (display-mm-height)
572

In pgtk itʼs correct:

ELISP> (display-mm-height)
190 (#o276, #xbe)

We could change gamegrid.el to use 'display-monitor-attributes-list'
instead, that gives the right values under both:

X:

ELISP> (display-monitor-attributes-list)
(((name . "XWAYLAND0")
  (geometry 0 0 3840 2160)
  (workarea 0 26 3840 2100)
  (mm-size 350 190)
  (frames #<frame *ielm* - GNU Emacs at rltb 0x564418c8a710>)
  (source . "Gdk")))

pgtk under wayland:

ELISP> (display-monitor-attributes-list)
(((name . "0x1431")
  (geometry 0 0 3840 2160)
  (workarea 0 0 3840 2160)
  (mm-size 350 190)
  (scale-factor . 1.0)
  (frames #<frame *ielm* - GNU Emacs at rltb 0x561d802c4670>)
  (source . "Gdk")))

Robert
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