diff options
Diffstat (limited to 'documentation/functions.html')
| -rw-r--r-- | documentation/functions.html | 46 |
1 files changed, 28 insertions, 18 deletions
diff --git a/documentation/functions.html b/documentation/functions.html index 162b89400..a79bdd1fd 100644 --- a/documentation/functions.html +++ b/documentation/functions.html @@ -282,8 +282,10 @@ in future versions, however. </LI> Adds a callback function that is called every time by <tt>Fl::wait()</tt> and also makes it act as though the timeout is -zero (so it just checks for events and returns immediately). This can -be used to get background processing done. +zero (this makes <tt>Fl::wait()</tt> return immediately, so if it is +in a loop it is called repeatedly, and thus the idle fucntion is +called repeatedly). The idle function can be used to get background +processing done. <P>You can have multiple idle callbacks. To remove an idle callback use <A href=#remove_idle><tt>Fl::remove_idle()</tt></A>. @@ -295,26 +297,34 @@ but <tt>Fl::ready()</tt> does not. <tt>Fl::wait()</tt>, <tt>Fl::check()</tt>, and <tt>Fl::ready()</tt>. Fltk will not recursively call the idle callback. -<h3><A name=add_timeout>static void Fl::add_timeout(float t, void -(*cb)(void*),void*v=0)</A></h3> +<h3><A name=add_timeout>static void Fl::add_timeout(float t, void (*cb)(void*),void*v=0)</A></h3> Add a one-shot timeout callback. The function will be called by -<tt>Fl::wait()</tt> at <i>t</i> seconds after this function is called -(except if you call this inside a timeout callback, then the time is -measured from when the callback was done, to allow accurate repeating -events). The optional <tt>void*</tt> argument is passed to the -callback. +<tt>Fl::wait()</tt> at <i>t</i> seconds after this function is called. +The optional <tt>void*</tt> argument is passed to the callback. -<P>This code will print "TICK" each second on stdout: +<h3><A name=add_interval_timeout>static void Fl::add_interval_timeout(float t, void (*cb)(void*),void*v=0)</A></h3> + +Add a one-shot timeout callback. The difference from <a +href=#add_timeout>add_timeout</a> is that the time is measured from +when the last timeout callback was called, rather than from the moment +this function is called (if no timeout has been called recently the +time is measured from the next call to Fl::wait). This is designed +for making regularly-spaced timeouts at high speed (like for movie +playback), it also has slightly less system-call overhead than +add_timeout. + +<P>This code will print "TICK" each second on stdout, with a +fair degree of accuracy: <UL><PRE>void callback(void*) { - printf("TICK\n"); - Fl::add_timeout(1.0,callback); + printf("TICK\n"); + Fl::add_interval_timeout(1.0,callback); } main() { - Fl::add_timeout(1.0,callback); - Fl::run(); + Fl::add_timeout(1.0,callback); + for (;;) Fl::wait(); }</PRE></UL> <h3><A name=arg>static int Fl::arg(int argc, char **argv, int &i)</A></h3> @@ -509,7 +519,7 @@ pick an item with a single click. Don't pass non-zero to this. <br><A name=get_key>int Fl::get_key(int)</A></h3> <tt>Fl::event_key()</tt> returns which key on the keyboard was last -pushed. +pushed. It returns zero if the last event was not a key press or release. <P><tt>Fl::event_key(int)</tt> returns true if the given key was held down (or pressed) <I>during</I> the last event. This is constant until @@ -955,9 +965,9 @@ Fl_Widget::test_shortcut()</tt></A>. <h3><A name=visual>static int Fl::visual(int)</A></h3> -Selects a visual so that your graphics are drawn correctly. You must -do this before calling show() on any windows. This does nothing if -the default visual satisfies the capabilities, or if no visual +Selects a visual so that your graphics are drawn correctly. This is +only allowed before you call show() on any windows. This does nothing +if the default visual satisfies the capabilities, or if no visual satisfies the capabilities, or on systems that don't have such brain-dead notions. |