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| author | Fabien Costantini <fabien@onepost.net> | 2008-10-14 22:12:25 +0000 |
|---|---|---|
| committer | Fabien Costantini <fabien@onepost.net> | 2008-10-14 22:12:25 +0000 |
| commit | 497afccb07164373e0de6639e754d7d691f1926f (patch) | |
| tree | 449d0b92ceb05f39617fe8fc2876d16eecde7460 /documentation/events.html | |
| parent | e08fffdfe08bbc9320e39a15d162b6501abd4925 (diff) | |
Doxygen pdf man: First version added in documentation/fltk.pdf, old doc removed, images, dox files moved to a new src directory.
git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@6431 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
Diffstat (limited to 'documentation/events.html')
| -rw-r--r-- | documentation/events.html | 394 |
1 files changed, 0 insertions, 394 deletions
diff --git a/documentation/events.html b/documentation/events.html deleted file mode 100644 index d6717de89..000000000 --- a/documentation/events.html +++ /dev/null @@ -1,394 +0,0 @@ -<HTML> -<HEAD> - <TITLE>6 - Handling Events</TITLE> -</HEAD> -<BODY> - -<H1 ALIGN="RIGHT"><A NAME="events">6 - Handling Events</A></H1> - -<P>This chapter discusses the FLTK event model and how to handle -events in your program or widget. - -<H2>The FLTK Event Model</H2> - -<P>Every time a user moves the mouse pointer, clicks a button, -or presses a key, an event is generated and sent to your -application. Events can also come from other programs like the -window manager. - -<P>Events are identified by the integer argument passed to the -<A href="subclassing.html#handle"><TT>Fl_Widget::handle()</TT></A> virtual -method. Other information about the most recent event is stored in -static locations and acquired by calling the <A -href="#event_xxx"><TT>Fl::event_*()</TT></A> methods. This static -information remains valid until the next event is read from the window -system, so it is ok to look at it outside of the <TT>handle()</TT> -method. - -<H2>Mouse Events</H2> - -<H3>FL_PUSH</H3> - -<P>A mouse button has gone down with the mouse pointing at this -widget. You can find out what button by calling <A -href="Fl.html#Fl.event_button"><TT> -Fl::event_button()</TT></A>. You find out the mouse position by -calling <A -href="Fl.html#Fl.event_x"><TT>Fl::event_x()</TT></A> and <A -href="Fl.html#Fl.event_y"> <TT>Fl::event_y()</TT></A>. - -<P>A widget indicates that it "wants" the mouse click -by returning non-zero from its <A -href="subclassing.html#handle"><TT>handle()</TT></A> method. It -will then become the <A href="Fl.html#Fl.pushed"><TT> -Fl::pushed()</TT></A> widget and will get <TT>FL_DRAG</TT> and -the matching <TT>FL_RELEASE</TT> events. If <TT>handle()</TT> -returns zero then FLTK will try sending the <TT>FL_PUSH</TT> to -another widget. </P> - -<H3>FL_DRAG</H3> - -<P>The mouse has moved with a button held down. The current -button state is in <a -href="Fl.html#Fl.event_state"><tt>Fl::event_state()</tt></a>. -The mouse position is in <a -href="Fl.html#Fl.event_x"><tt>Fl::event_x()</tt></a> and <a -href="Fl.html#Fl.event_y"><tt>Fl::event_y()</tt></a>. - -<P>In order to receive <TT>FL_DRAG</TT> events, the widget must -return non-zero when handling <TT>FL_PUSH</TT>.</P> - -<H3>FL_RELEASE</H3> - -<P>A mouse button has been released. You can find out what -button by calling <A -href="Fl.html#Fl.event_button"><TT>Fl::event_button()</TT></A>. - -<P>In order to receive the <TT>FL_RELEASE</TT> event, the widget must -return non-zero when handling <TT>FL_PUSH</TT>.</P> - -<H3>FL_MOVE</H3> - -<P>The mouse has moved without any mouse buttons held down. -This event is sent to the <A -href="Fl.html#Fl.belowmouse"><TT>Fl::belowmouse()</TT></A> -widget.</P> - -<P>In order to receive <TT>FL_MOVE</TT> events, the widget must -return non-zero when handling <TT>FL_ENTER</TT>.</P> - -<H3>FL_MOUSEWHEEL</H3> - -<P>The user has moved the mouse wheel. The <A -HREF="Fl.html#Fl.event_dx"><TT>Fl::event_dx()</TT></A> and <A -HREF="Fl.html#Fl.event_dy"><TT>Fl::event_dy()</TT></A> methods -can be used to find the amount to scroll horizontally and -vertically. - -<H2>Focus Events</H2> - -<H3>FL_ENTER</H3> - -<P>The mouse has been moved to point at this widget. This can -be used for highlighting feedback. If a widget wants to -highlight or otherwise track the mouse, it indicates this by -returning non-zero from its <A -href="Fl.html#Fl.handle"><TT>handle()</TT></A> method. It then -becomes the <A -href="Fl.html#Fl.belowmouse"><TT>Fl::belowmouse()</TT></A> -widget and will receive <TT>FL_MOVE</TT> and <TT>FL_LEAVE</TT> -events. - -<H3>FL_LEAVE</H3> - -<P>The mouse has moved out of the widget. - -<P>In order to receive the <TT>FL_LEAVE</TT> event, the widget must -return non-zero when handling <TT>FL_ENTER</TT>.</P> - -<H3>FL_FOCUS</H3> - -<P>This indicates an <I>attempt</I> to give a widget the -keyboard focus. - -<P>If a widget wants the focus, it should change itself to -display the fact that it has the focus, and return non-zero from -its <A -href="Fl_Widget.html#Fl_Widget.handle"><TT>handle()</TT></A> -method. It then becomes the <A -href="Fl.html#Fl.focus"><TT>Fl::focus()</TT></A> widget and gets -<TT>FL_KEYDOWN</TT>, <TT>FL_KEYUP</TT>, and <TT>FL_UNFOCUS</TT> -events. - -<P>The focus will change either because the window manager -changed which window gets the focus, or because the user tried -to navigate using tab, arrows, or other keys. You can check <A -href="Fl.html#Fl.event_key"><TT>Fl::event_key()</TT></A> to -figure out why it moved. For navigation it will be the key -pressed and interaction with the window manager it will be -zero. - -<H3>FL_UNFOCUS</H3> - -<P>This event is sent to the previous <A -href="Fl.html#Fl.focus"><TT>Fl::focus()</TT></A> widget when -another widget gets the focus or the window loses focus. - -<H2>Keyboard Events</H2> - -<H3>FL_KEYDOWN, FL_KEYUP</H3> - -<P>A key was pressed or released. The key can be found in <A -href="Fl.html#Fl.event_key"><TT>Fl::event_key()</TT></A>. The -text that the key should insert can be found with <A -href="Fl.html#Fl.event_text"><TT>Fl::event_text()</TT></A> and -its length is in <A -href="Fl.html#Fl.event_length"><TT>Fl::event_length()</TT></A>. -If you use the key <TT>handle()</TT> should return 1. If you -return zero then FLTK assumes you ignored the key and will -then attempt to send it to a parent widget. If none of them want -it, it will change the event into a <TT>FL_SHORTCUT</TT> event. - -<P>To receive <CODE>FL_KEYBOARD</CODE> events you must also -respond to the <CODE>FL_FOCUS</CODE> and <CODE>FL_UNFOCUS</CODE> -events. - -<P>If you are writing a text-editing widget you may also want to -call the <a href="Fl.html#Fl.compose"><TT>Fl::compose()</TT></a> -function to translate individual keystrokes into foreign -characters. - -<P><code>FL_KEYUP</code> events are sent to the widget that -currently has focus. This is not necessarily the same widget -that received the corresponding <code>FL_KEYDOWN</code> event -because focus may have changed between events. - -<H3>FL_SHORTCUT</H3> - -<P>If the <A href="Fl.html#Fl.focus"><TT>Fl::focus()</TT></A> -widget is zero or ignores an <TT>FL_KEYBOARD</TT> event then -FLTK tries sending this event to every widget it can, until one -of them returns non-zero. <TT>FL_SHORTCUT</TT> is first sent to -the <TT>Fl::belowmouse()</TT> widget, then its parents and -siblings, and eventually to every widget in the window, trying -to find an object that returns non-zero. FLTK tries really hard -to not to ignore any keystrokes! - -<P>You can also make "global" shortcuts by using <A -href="Fl.html#Fl.add_handler"><TT>Fl::add_handler()</TT></A>. A -global shortcut will work no matter what windows are displayed -or which one has the focus.</P> - -<H2>Widget Events</H2> - -<H3>FL_DEACTIVATE</H3> - -<P>This widget is no longer active, due to <A -href="Fl_Widget.html#Fl_Widget.deactivate"><TT>deactivate()</TT></A> -being called on it or one of its parents. <TT> active()</TT> may -still be true after this, the widget is only active if -<TT>active()</TT> is true on it and all its parents (use <TT>active_r()</TT> to check this). - -<H3>FL_ACTIVATE</H3> - -<P>This widget is now active, due to <A -href="Fl_Widget.html#Fl_Widget.activate"><TT>activate()</TT></A> -being called on it or one of its parents. - -<H3>FL_HIDE</H3> - -<P>This widget is no longer visible, due to <A -href="Fl_Widget.html#Fl_Widget.hide"><tt>hide()</tt></a> being -called on it or one of its parents, or due to a parent window -being minimized. <tt>visible()</tt> may still be true after -this, but the widget is visible only if <tt>visible()</tt> is -true for it and all its parents (use <tt>visible_r()</tt> to -check this). - -<h3>FL_SHOW</h3> - -<P>This widget is visible again, due to <a -href="Fl_Widget.html#Fl_Widget.show"><TT>show()</TT></A> being -called on it or one of its parents, or due to a parent window -being restored. <I>Child <TT>Fl_Window</TT>s respond to this by -actually creating the window if not done already, so if you -subclass a window, be sure to pass <TT>FL_SHOW</TT> to the base -class <TT>handle()</TT> method!</I> - -<H2>Clipboard Events</H2> - -<H3>FL_PASTE</H3> - -<P>You should get this event some time after you call <A -href="Fl.html#Fl.paste"><TT>Fl::paste()</TT></A>. The contents -of <A href="Fl.html#Fl.event_text"><TT>Fl::event_text()</TT></A> -is the text to insert and the number of characters is in <A -href="Fl.html#Fl.event_length"><TT>Fl::event_length()</TT></A>. - -<H3>FL_SELECTIONCLEAR</H3> - -<P>The <A -href="Fl.html#Fl.selection_owner"><TT>Fl::selection_owner()</TT></A> -will get this event before the selection is moved to another -widget. This indicates that some other widget or program has -claimed the selection. Motif programs used this to clear the -selection indication. Most modern programs ignore this. - -<H2><A NAME="dnd">Drag And Drop Events</A></H2> - -<P>FLTK supports drag and drop of text and files from any -application on the desktop. Text is transfered using -the current code page. Files are received as a list of full path -and file names, seperated by newline. On some platforms, path -names are prepended with <tt>file://</tt>. - -<P>The drag and drop data is available in <tt>Fl::event_text()</tt> -at the concluding <tt>FL_PASTE</tt>. On some platforms, the -event text is also available for the <tt>FL_DND_*</tt> events, -however application must not depend on that behavior because it -depends on the protocol used on each platform. - -<P><tt>FL_DND_*</tt> events cannot be used in widgets derived -from <tt>Fl_Group</tt> or <tt>Fl_Window</tt>. - -<H3>FL_DND_ENTER</H3> - -<P>The mouse has been moved to point at this widget. A widget -that is interested in receiving drag'n'drop data must return 1 -to receive FL_DND_DRAG, FL_DND_LEAVE and FL_DND_RELEASE events. - -<H3>FL_DND_DRAG</H3> - -<P>The mouse has been moved inside a widget while dragging data. -A widget that is interested in receiving drag'n'drop data should -indicate the possible drop position. - -<H3>FL_DND_LEAVE</H3> - -<P>The mouse has moved out of the widget. - -<H3>FL_DND_RELEASE</H3> - -<P>The user has released the mouse button dropping data into -the widget. If the widget returns 1, it will receive the data in -the immediatly following FL_PASTE event. - -<!-- NEED 6in --> - -<H2><A name="event_xxx">Fl::event_*() methods</A></H2> - -<P>FLTK keeps the information about the most recent event in -static storage. This information is good until the next event is -processed. Thus it is valid inside <TT>handle()</TT> and -<TT>callback()</TT> methods. - -<P>These are all trivial inline functions and thus very fast and small: </P> - -<UL> - - <LI><A HREF="Fl.html#Fl.event_button"><TT>Fl::event_button</TT></A></LI> - - <LI><A HREF="Fl.html#Fl.event_clicks"><TT>Fl::event_clicks</TT></A></LI> - - <LI><A HREF="Fl.html#Fl.event_dx"><TT>Fl::event_dx</TT></A></LI> - - <LI><A HREF="Fl.html#Fl.event_dy"><TT>Fl::event_dy</TT></A></LI> - - <LI><A HREF="Fl.html#Fl.event_inside"><TT>Fl::event_inside</TT></A></LI> - - <LI><A HREF="Fl.html#Fl.event_is_click"><TT>Fl::event_is_click</TT></A></LI> - - <LI><A HREF="Fl.html#Fl.event_key"><TT>Fl::event_key</TT></A></LI> - - <LI><A HREF="Fl.html#Fl.event_length"><TT>Fl::event_length</TT></A></LI> - - <LI><A HREF="Fl.html#Fl.event_state"><TT>Fl::event_state</TT></A></LI> - - <LI><A HREF="Fl.html#Fl.event_text"><TT>Fl::event_text</TT></A></LI> - - <LI><A HREF="Fl.html#Fl.event_x"><TT>Fl::event_x</TT></A></LI> - - <LI><A HREF="Fl.html#Fl.event_x_root"><TT>Fl::event_x_root</TT></A></LI> - - <LI><A HREF="Fl.html#Fl.event_y"><TT>Fl::event_y</TT></A></LI> - - <LI><A HREF="Fl.html#Fl.event_y_root"><TT>Fl::event_y_root</TT></A></LI> - - <LI><A HREF="Fl.html#Fl.get_key"><TT>Fl::get_key</TT></A></LI> - - <LI><A HREF="Fl.html#Fl.get_mouse"><TT>Fl::get_mouse</TT></A></LI> - - <LI><A HREF="Fl.html#Fl.test_shortcut"><TT>Fl::test_shortcut</TT></A></LI> - -</UL> - -<H2><A name=propagation>Event Propagation</A></H2> - -<P>FLTK follows very simple and unchangeable rules for sending -events. The major innovation is that widgets can indicate (by -returning 0 from the <TT>handle()</TT> method) that they are not -interested in an event, and FLTK can then send that event -elsewhere. This eliminates the need for "interests" -(event masks or tables), and this is probably the main reason -FLTK is much smaller than other toolkits. - -<P>Most events are sent directly to the <TT>handle()</TT> method -of the <TT>Fl_Window</TT> that the window system says they -belong to. The window (actually the <TT>Fl_Group</TT> that -<TT>Fl_Window</TT> is a subclass of) is responsible for sending -the events on to any child widgets. To make the -<TT>Fl_Group</TT> code somewhat easier, FLTK sends some events -(<TT>FL_DRAG</TT>, <TT>FL_RELEASE</TT>, <TT>FL_KEYBOARD</TT>, -<TT>FL_SHORTCUT</TT>, <TT>FL_UNFOCUS</TT>, and -<TT>FL_LEAVE</TT>) directly to leaf widgets. These procedures -control those leaf widgets: - -<UL> - - <LI><A HREF="Fl.html#Fl.add_handler"><TT>Fl::add_handler</TT></A></LI> - - <LI><A HREF="Fl.html#Fl.belowmouse"><TT>Fl::belowmouse</TT></A></LI> - - <LI><A HREF="Fl.html#Fl.focus"><TT>Fl::focus</TT></A></LI> - - <LI><A HREF="Fl.html#Fl.grab"><TT>Fl::grab</TT></A></LI> - - <LI><A HREF="Fl.html#Fl.modal"><TT>Fl::modal</TT></A></LI> - - <LI><A HREF="Fl.html#Fl.pushed"><TT>Fl::pushed</TT></A></LI> - - <LI><A HREF="Fl.html#Fl.release"><TT>Fl::release</TT></A></LI> - - <LI><A HREF="Fl_Widget.html#Fl_Widget.take_focus"><TT>Fl_Widget::take_focus</TT></A></LI> - -</UL> - -<H2><A name="compose">FLTK Compose-Character Sequences</A></H2> - -<P>The foreign-letter compose processing done by the <A -href="Fl_Input.html#compose"><tt>Fl_Input</tt></a> widget is provided in -a function that you can call if you are writing your own text editor -widget. - -<p>FLTK uses its own compose processing to allow "preview" of -the partially composed sequence, which is impossible with the -usual "dead key" processing. - -<p>Although currently only characters in the ISO-8859-1 -character set are handled, you should call this in case any -enhancements to the processing are done in the future. The -interface has been designed to handle arbitrary UTF-8 encoded -text. - -<P>The following methods are provided for character composition: - -<UL> - - <LI><A HREF="Fl.html#Fl.compose"><TT>Fl::compose()</TT></A></LI> - - <LI><A HREF="Fl.html#Fl.compose_reset"><TT>Fl::compose_reset()</TT></A></LI> - -</UL> - -</BODY> -</HTML> |