diff options
Diffstat (limited to 'doc/tkvars.n')
| -rw-r--r-- | doc/tkvars.n | 66 |
1 files changed, 62 insertions, 4 deletions
diff --git a/doc/tkvars.n b/doc/tkvars.n index 5ffa40a..e211575 100644 --- a/doc/tkvars.n +++ b/doc/tkvars.n @@ -10,7 +10,7 @@ .BS '\" Note: do not modify the .SH NAME line immediately below! .SH NAME -geometry, tk_library, tk_patchLevel, tk_strictMotif, tk_version \- Variables used or set by Tk +geometry, tk_library, tk_patchLevel, tk::scalingPct, tk_strictMotif, tk::svgFmt, tk_version \- Variables used or set by Tk .BE .SH DESCRIPTION .PP @@ -50,7 +50,42 @@ it uniquely identifies an official version of Tk. .RS .PP This value is normally the same as the result of -.QW "\fBpackage require\fR \fBTk\fR" . +.QW "\fBpackage require\fR \fBtk\fR" . +.RE +.TP +\fBtk::scalingPct\fR +. +Tk sets this variable at initialization time to the scaling percentage +corresponding to the display's DPI scaling level. This value is at least +100 and is restricted to multiples of 25 (100, 125, 150, 175, 200, +225, ...). The sizes and various attributes of the Tk core and Ttk +widgets and their components, as well as the sizes of the images used by +Tk are chosen according to the scaling percentage, and this is +recommended for applications and library packages, too. +.RS +.PP +Note that any access to this variable is supposed to be strictly +read-only! Note also that whenever the scaling factor used to convert +between physical units and pixels is changed via \fBtk scaling\fR, the +value of the variable \fBtk::scalingPct\fR is automatically updated. +.PP +On the windowing systems \fBwin32\fR and \fBaqua\fR the scaling +percentage is computed by rounding [\fBtk scaling\fR] * 75 to the +nearest multiple of 25 that is at least 100. (On \fBaqua\fR the result +is always 100, and the desktop engine automatically scales everything as +needed.) On \fBx11\fR, deriving the scaling percentage from +[\fBtk scaling\fR] is done as fallback method only, because the +implementation of display scaling is highly dependent on the desktop +environment and it mostly manipulates system resources that are resident +outside of Xlib, which Tk is based on. Moreover, for technical reasons, +the value assigned to the variable \fBtk::scalingPct\fR can be different +from the one selected in the system settings (e.g., 200 rather than 125, +150, or 175 when running GNOME on Xorg or the Cinnamon desktop). On +\fBx11\fR the scaling percentage is computed mostly (but not +exclusively) from the value of the X resource Xft.dpi, and, as an +additional step, Tk synchronizes the scaling factor used to convert +between physical units and pixels with the scaling percentage, with the +aid of the \fBtk scaling\fR command. .RE .TP \fBtk_strictMotif\fR @@ -61,7 +96,30 @@ closely as possible to Motif look-and-feel standards. For example, active elements such as buttons and scrollbar sliders will not change color when the pointer passes over them. Modern applications should not normally set this variable. -.TP 15 +.TP +\fBtk::svgFmt\fR +. +This variable is set at Tk initialization time to +.RS +.RS 4 +.PP +[\fBlist svg \-scale\fR [\fBexpr\fR {$\fBtk::scalingPct\fR / 100.0}]] +.RE +.PP +Typical values are {\fBsvg \-scale\fR 1.0}, {\fBsvg \-scale\fR 1.25}, +{\fBsvg \-scale\fR 2.0}, etc. It is recommended to pass the value of +this variable to the commands \fBimage create photo\fR, \fIimageName\fB +configure\fR, \fIimageName\fB put\fR, and \fIimageName\fB read\fR as the +value of their \fB\-format\fR option when creating or manipulating SVG +images, to make sure that their sizes will correspond to the display's +DPI scaling level. +.PP +Note that any access to this variable is supposed to be strictly +read-only! Note also that whenever the scaling factor used to convert +between physical units and pixels is changed via \fBtk scaling\fR, the +value of the variable \fBtk::svgFmt\fR is automatically updated. +.RE +.TP \fBtk_version\fR . Tk sets this variable in the interpreter for each application. @@ -96,7 +154,7 @@ used by Tk's test suite. The following variables are only guaranteed to exist in \fBwish\fR executables; the Tk library does not define them itself but many Tk environments do. -.TP 6 +.TP \fBgeometry\fR . If set, contains the user-supplied geometry specification to use for |