Really Miscellaneous Methods (Mastering Perl/Tk)

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13.24. Really Miscellaneous Methods

findINC returns the absolute pathname of a file:

$file = Tk->findINC("Xcamel.gif");

Tk->findINC searches for files in all Tk subdirectories of the current @INC path. This can also be a personal Tk directory, if it was added with use lib or push @INC,... earlier. If using the form Tk::findINC, then only @INC is searched, not the subdirectories.

FullScreen simply makes a Toplevel window as large as the display. On Win32, this does not include the taskbar area.

$mw->FullScreen;

Getimage looks for an image with the specified basename and returns the object reference. The subroutine appends extensions to the basename in the following order: xpm, gif, ppm, xbm until a valid image is found. If that fails, built-in images are searched.

$image = $widget->Getimage(name);

tainting returns a true value if the program is running with taint checks enabled.

$tainted = $widget->Tk::tainting;

scaling sets and queries the current scaling factor used by Tk to convert between physical units (for example, points, inches, or millimeters) and pixels. The number argument is a floating-point number that specifies the number of pixels per point on $widget's display. If the number argument is omitted, the current value of the scaling factor is returned.

A point is a unit of measurement equal to 1/72 inch. A scaling factor of 1.0 corresponds to 1 pixel per point, which is equivalent to a standard 72 dpi monitor. A scaling factor of 1.25 would mean 1.25 pixels per point, which is the setting for a 90 dpi monitor; setting the scaling factor to 1.25 on a 72 dpi monitor would cause everything in the application to be displayed 1.25 times larger than normal. The initial value for the scaling factor is set when the application starts, based on properties of the installed monitor (as reported via the window system), but it can be changed at any time. Measurements made after the scaling factor is changed will use the new scaling factor, but whether existing widgets will resize themselves dynamically to accommodate the new scaling factor is undefined.

$widget->scaling (number)

timeofday returns a floating-point number representing the universe's fractional time of the epoch. For most of us, the time is in the form ss.mmmmmm, where ss is seconds and mmmmmm is microseconds. If your operating system does not honor this, we apologize.

$self->{tm0} = Tk::timeofday;


13.23. Parsing Command-Line Options		14. Creating Custom Widgets in Pure Perl/Tk