# scaling.tcl --
#
# Contains scaling-related utility procedures.
#
# Copyright © 2022 Csaba Nemethi <[email protected]>
# ::tk::ScalingPct --
#
# Returns the display's "scaling percentage" (the display resolution expressed
# as a percentage of 96dpi), rounded to the nearest multiple of 25 that is at
# least 100.
#
# On X11 systems (but not on SDL systems that claim to be X11), the first call
# of the command also sets [tk scaling] and ::tk::fontScalingFactor to values
# extracted from the X11 configuration.
#
# The command is called during Tk initialization, from icons.tcl, when the
# latter is sourced by tk.tcl.
proc ::tk::ScalingPct {} {
set pct [expr {[tk scaling] * 75}]
variable doneScalingInitX11
if {![info exists doneScalingInitX11]} {
set pct [::tk::ScalingInitX11 $pct]
set doneScalingInitX11 1
}
#
# Save the value of pct rounded to the nearest multiple
# of 25 that is at least 100, in the variable scalingPct.
# See "man n tk_scalingPct" for use of ::tk::scalingPct.
#
variable scalingPct
for {set scalingPct 100} {1} {incr scalingPct 25} {
if {$pct < $scalingPct + 12.5} {
break
}
}
return $scalingPct
}
proc ::tk::ScalingInitX11 {pct} {
set onX11 [expr {[tk windowingsystem] eq "x11"}]
set usingSDL [expr {[info exists ::tk::sdltk] && $::tk::sdltk}]
if {$onX11 && !$usingSDL} {
set origPct $pct
#
# Try to get the window scaling factor (1 or 2), partly
# based on https://wiki.archlinux.org/title/HiDPI
#
set winScalingFactor 1
variable fontScalingFactor 1 ;# needed in the file ttk/fonts
if {[catch {exec ps -e | grep xfce4-session}] == 0} { ;# Xfce
if {[catch {exec xfconf-query -c xsettings \
-p /Gdk/WindowScalingFactor} result] == 0} {
set winScalingFactor $result
if {$winScalingFactor >= 2} {
set fontScalingFactor 2
}
}
#
# The DPI value can be set in the "Fonts" tab of the "Appearance"
# dialog or (on Linux Lite 5+) via the "HiDPI Settings" dialog.
#
} elseif {[catch {exec ps -e | grep mate-session}] == 0} { ;# MATE
if {[catch {exec gsettings get org.mate.interface \
window-scaling-factor} result] == 0} {
if {$result == 0} { ;# means: "Auto-detect"
#
# Try to get winScalingFactor from the cursor size
#
if {[catch {exec xrdb -query | grep Xcursor.size} result]
== 0 &&
[catch {exec gsettings get org.mate.peripherals-mouse \
cursor-size} defCursorSize] == 0} {
set cursorSize [lindex $result 1]
set winScalingFactor \
[expr {($cursorSize + $defCursorSize - 1) /
$defCursorSize}]
}
} else {
set winScalingFactor $result
}
}
#
# The DPI value can be set via the "Font Rendering Details"
# dialog, which can be opened using the "Details..." button
# in the "Fonts" tab of the "Appearance Preferences" dialog.
#
} elseif {[catch {exec ps -e | grep gnome-session}] == 0 &&
[catch {exec gsettings get \
org.gnome.settings-daemon.plugins.xsettings overrides} \
result] == 0 &&
[set idx \
[string first "'Gdk/WindowScalingFactor'" $result]] >= 0} {
scan [string range $result $idx end] "%*s <%d>" winScalingFactor
}
#
# Get the scaling percentage
#
if {$winScalingFactor >= 2} {
set pct 200
} elseif {[catch {exec xrdb -query | grep Xft.dpi} result] == 0} {
#
# Derive the value of pct from that of the font DPI
#
set dpi [lindex $result 1]
set pct [expr {100.0 * $dpi / 96}]
} elseif {[catch {exec ps -e | grep gnome-session}] == 0 &&
![info exists ::env(WAYLAND_DISPLAY)] &&
[catch {exec xrandr | grep " connected"} result] == 0 &&
[catch {open $::env(HOME)/.config/monitors.xml} chan] == 0} {
#
# Update pct by scanning the file ~/.config/monitors.xml
#
ScanMonitorsFile $result $chan pct
}
if {($pct != 100) && ($pct != $origPct) && (![interp issafe])} {
#
# Set Tk's scaling factor according to $pct
#
tk scaling [expr {$pct / 75.0}]
}
}
return $pct
}
# ::tk::ScaleNum --
#
# Scales an integer according to the display's current scaling percentage.
#
# Arguments:
# num - An integer.
proc ::tk::ScaleNum num {
return [expr {round($num * [tk scaling] * 0.75)}]
}
# ::tk::FontScalingFactor --
#
# Accessor command for variable ::tk::fontScalingFactor.
proc ::tk::FontScalingFactor {} {
variable fontScalingFactor
if {[info exists fontScalingFactor]} {
return $fontScalingFactor
} else {
return 1
}
}
# ::tk::ScanMonitorsFile --
#
# Updates the scaling percentage by scanning the file ~/.config/monitors.xml.
#
# Arguments:
# xrandrResult - The output of 'xrandr | grep " connected"'.
# chan - Returned from 'open ~/.config/monitors.xml'.
# pctName - The name of a variable containing the scaling percentage.
proc ::tk::ScanMonitorsFile {xrandrResult chan pctName} {
upvar $pctName pct
#
# Get the list of connected outputs reported by xrandr
#
set outputList {}
foreach line [split $xrandrResult "\n"] {
set idx [string first " " $line]
set output [string range $line 0 [incr idx -1]]
lappend outputList $output
}
set outputList [lsort $outputList]
#
# Get the content of the file ~/.config/monitors.xml
#
set str [read $chan]
close $chan
#
# Run over the file's "configuration" sections
#
set idx 0
while {[set idx2 [string first "<configuration>" $str $idx]] >= 0} {
set idx2 [string first ">" $str $idx2]
set idx [string first "</configuration>" $str $idx2]
set config [string range $str [incr idx2] [incr idx -1]]
#
# Get the list of connectors within this configuration
#
set connectorList {}
foreach {dummy connector} [regexp -all -inline \
{<connector>([^<]+)</connector>} $config] {
lappend connectorList $connector
}
set connectorList [lsort $connectorList]
#
# If $outputList and $connectorList are identical then set the
# variable pct to 100, 200, 300, 400, or 500, depending on the
# max. scaling within this configuration, and exit the loop
#
if {$outputList eq $connectorList} {
set maxScaling 1.0
foreach {dummy scaling} [regexp -all -inline \
{<scale>([^<]+)</scale>} $config] {
if {$scaling > $maxScaling} {
set maxScaling $scaling
}
}
foreach n {4 3 2 1 0} {
if {$maxScaling > $n} {
set pct [expr {($n + 1) * 100}]
break
}
}
break
}
}
}
