diff options
| author | Albrecht Schlosser <albrechts.fltk@online.de> | 2008-09-13 15:55:32 +0000 |
|---|---|---|
| committer | Albrecht Schlosser <albrechts.fltk@online.de> | 2008-09-13 15:55:32 +0000 |
| commit | 8416a4012ecb985d150fad566659cf59ee1dc3aa (patch) | |
| tree | a0b52461eeeaf926de99392145c087e96f6c36e1 /documentation/basics.dox | |
| parent | 054d25081a74d504eb38042ffbd9acf70be4de1d (diff) | |
Doxygen documentation - WP12 and WP13 - first step.
Converted the descriptive chapters of the html docs to doxygen format
and modified index.dox accordingly.
This checkin includes only trivial reformatting, no major rewriting.
Added a chapter "Migrating Code from FLTK 1.1 to 1.3".
All links on the main page are working now.
Todo:
- Check doxygen error messages, rewrite pages (html tags, contents).
- Fill the new "Migrating..." chapter.
git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@6224 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
Diffstat (limited to 'documentation/basics.dox')
| -rw-r--r-- | documentation/basics.dox | 362 |
1 files changed, 362 insertions, 0 deletions
diff --git a/documentation/basics.dox b/documentation/basics.dox new file mode 100644 index 000000000..3c330f907 --- /dev/null +++ b/documentation/basics.dox @@ -0,0 +1,362 @@ +/** + + \page basics 2 - FLTK Basics + + <P>This chapter teaches you the basics of compiling programs +that use FLTK.</P> + +<H2>Writing Your First FLTK Program</H2> + +<P>All programs must include the file <TT><FL/Fl.H></TT>. +In addition the program must include a header file for each +FLTK class it uses. Listing 1 shows a simple "Hello, +World!" program that uses FLTK to display the window.</P> + +<UL> +<P><I>Listing 1 - "hello.cxx"</I> +<PRE> +#include <FL/Fl.H> +#include <FL/Fl_Window.H> +#include <FL/Fl_Box.H> + +int main(int argc, char **argv) { + <A href="Fl_Window.html">Fl_Window</A> *window = new <A href="Fl_Window.html#Fl_Window.Fl_Window">Fl_Window</A>(300,180); + <A href="Fl_Box.html">Fl_Box</A> *box = new <A href="Fl_Box.html#Fl_Box.Fl_Box">Fl_Box</A>(20,40,260,100,"Hello, World!"); + box-><A href="Fl_Widget.html#Fl_Widget.box">box</A>(<A href="common.html#boxtypes">FL_UP_BOX</A>); + box-><A href="Fl_Widget.html#Fl_Widget.labelsize">labelsize</A>(36); + box-><A href="Fl_Widget.html#Fl_Widget.labelfont">labelfont</A>(<A href="drawing.html#fonts">FL_BOLD</A>+<A href="drawing.html#fonts">FL_ITALIC</A>); + box-><A href="Fl_Widget.html#Fl_Widget.labeltype">labeltype</A>(<A href="common.html#labels">FL_SHADOW_LABEL</A>); + window-><A href="Fl_Group.html#Fl_Group.end">end</A>(); + window-><A href="Fl_Window.html#Fl_Window.show">show</A>(argc, argv); + return <A href="Fl.html#Fl.run">Fl::run</A>(); +} +</PRE></UL> + +<!-- NEED 2in --> + +<P>After including the required header files, the program then creates a +window. All following widgets will automatically be children of this window.</P> + +<UL><PRE> +Fl_Window *window = new <A href="Fl_Window.html#Fl_Window">Fl_Window</A>(300,180); +</PRE></UL> + +<P>Then we create a box with the "Hello, World!" string in it. FLTK automatically adds +the new box to <tt>window</tt>, the current grouping widget.</P> + +<UL><PRE> +Fl_Box *box = new <A href="Fl_Box.html#Fl_Box">Fl_Box</A>(20,40,260,100,"Hello, World!"); +</PRE></UL> + +<P>Next, we set the type of box and the size, font, and style of the label:</P> + +<UL><PRE> +box-><A href="Fl_Widget.html#Fl_Widget.box">box</A>(FL_UP_BOX); +box-><A href=Fl_Widget.html#Fl_Widget.labelsize>labelsize</A>(36); +box-><A href=Fl_Widget.html#Fl_Widget.labelfont>labelfont</A>(FL_BOLD+FL_ITALIC); +box-><A href=Fl_Widget.html#Fl_Widget.labeltype>labeltype</A>(FL_SHADOW_LABEL); +</PRE></UL> + +<P>We tell FLTK that we will not add any more widgets to <tt>window</tt>.</P> + +<UL><PRE> +window-><A href=Fl_Group.html#Fl_Group.end>end</A>(); +</PRE></UL> + +<P>Finally, we show the window and enter the FLTK event loop:</P> + +<UL><PRE> +window-><A href=Fl_Window.html#Fl_Window.show>show</A>(argc, argv); +return <A href="Fl.html#Fl.run">Fl::run</A>(); +</PRE></UL> + +<P>The resulting program will display the window in Figure 2-1. +You can quit the program by closing the window or pressing the +<KBD>ESC</KBD>ape key.</P> + +<P ALIGN="CENTER"><IMG src="hello.C.gif" alt="Hello, World! Window"><BR> +<I>Figure 2-1: The Hello, World! Window</I></P> + +<H3>Creating the Widgets</H3> + +<P>The widgets are created using the C++ <TT>new</TT> operator. For +most widgets the arguments to the constructor are:</P> + +<UL><PRE> +Fl_Widget(x, y, width, height, label) +</PRE></UL> + +<P>The <TT>x</TT> and <TT>y</TT> parameters determine where the +widget or window is placed on the screen. In FLTK the top left +corner of the window or screen is the origin (i.e. x = 0, y = +0) and the units are in pixels.</P> + +<P>The <TT>width</TT> and <TT>height</TT> parameters determine +the size of the widget or window in pixels. The maximum widget +size is typically governed by the underlying window system or +hardware.</P> + +<P><tt>label</tt> is a pointer to a character string to label +the widget with or <tt>NULL</tt>. If not specified the label +defaults to <tt>NULL</tt>. The label string must be in static +storage such as a string constant because FLTK does not make a +copy of it - it just uses the pointer.</P> + +<H3>Creating Widget hierarchies</H3> + +<P>Widgets are commonly ordered into functional groups, which +in turn may be grouped again, creating a hierarchy of widgets. +FLTK makes it easy to fill groups by automatically adding all widgets +that are created between a <tt>myGroup->begin()</tt> and +<tt>myGroup->end()</tt>. In this example, <tt>myGroup</tt> +would be the <i>current</i> group.</P> + +<P>Newly created groups and their derived widgets implicitly call +<tt>begin()</tt> in the constructor, effectively adding all +subsequently created widgets to itself until <tt>end()</tt> +is called.</P> + +<P>Setting the current group to <tt>NULL</tt> will stop automatic +hierarchies. New widgets can now be added manually using +<tt>Fl_Group::add(...)</tt> and <tt>Fl_Group::insert(...)</tt>.</P> + +<H3>Get/Set Methods</H3> + +<P><tt>box->box(FL_UP_BOX)</tt> sets the type of box the +Fl_Box draws, changing it from the default of +<tt>FL_NO_BOX</tt>, which means that no box is drawn. In our +"Hello, World!" example we use <TT>FL_UP_BOX</TT>, +which means that a raised button border will be drawn around +the widget. You can learn more about boxtypes in +<A href="common.html#boxtypes">Chapter 3</A>.</P> + +<P>You could examine the boxtype in by doing +<tt>box->box()</tt>. FLTK uses method name overloading to make +short names for get/set methods. A "set" method is always of +the form "void name(type)", and a "get" method is always +of the form "type name() const".</P> + +<H3>Redrawing After Changing Attributes</H3> + +<P>Almost all of the set/get pairs are very fast, short inline +functions and thus very efficient. However, <i>the "set" methods +do not call <TT>redraw()</TT></i> - you have to call it +yourself. This greatly reduces code size and execution time. The +only common exceptions are <tt>value()</tt> which calls +<TT>redraw()</TT> and <tt>label()</tt> which calls +<TT>redraw_label()</TT> if necessary.</P> + +<H3>Labels</H3> + +<P>All widgets support labels. In the case of window widgets, +the label is used for the label in the title bar. Our example +program calls the <A href=Fl_Widget.html#Fl_Widget.labelfont> +<TT>labelfont</TT></A>, +<A href=Fl_Widget.html#Fl_Widget.labelsize><TT> labelsize</TT></A>, +and <A href=Fl_Widget.html#Fl_Widget.labeltype><TT>labeltype</TT></A> +methods.</P> + +<P>The <TT>labelfont</TT> method sets the typeface and style +that is used for the label, which for this example we are using +<TT>FL_BOLD</TT> and <TT>FL_ITALIC</TT>. You can also specify +typefaces directly. </P> <P>The <TT>labelsize</TT> method sets +the height of the font in pixels. </P> <P>The <TT>labeltype</TT> +method sets the type of label. FLTK supports normal, embossed, +and shadowed labels internally, and more types can be added as +desired.</P> + +<P>A complete list of all label options can be found in +<A href="common.html#labels">Chapter 3</A>.</P> + +<H3>Showing the Window</H3> + +<P>The <TT>show()</TT> method shows the widget or window. For windows +you can also provide the command-line arguments to allow users to +customize the appearance, size, and position of your windows.</P> + +<H3>The Main Event Loop</H3> + +<P>All FLTK applications (and most GUI applications in general) +are based on a simple event processing model. User actions such +as mouse movement, button clicks, and keyboard activity generate +events that are sent to an application. The application may then +ignore the events or respond to the user, typically by redrawing +a button in the "down" position, adding the text to an input +field, and so forth.</P> + +<P>FLTK also supports idle, timer, and file pseudo-events that +cause a function to be called when they occur. Idle functions +are called when no user input is present and no timers or files +need to be handled - in short, when the application is not doing +anything. Idle callbacks are often used to update a 3D display +or do other background processing.</P> + +<P>Timer functions are called after a specific amount of time +has expired. They can be used to pop up a progress dialog after +a certain amount of time or do other things that need to happen +at more-or-less regular intervals. FLTK timers are not 100% +accurate, so they should not be used to measure time intervals, +for example.</P> + +<P>File functions are called when data is ready to read or +write, or when an error condition occurs on a file. They are +most often used to monitor network connections (sockets) for +data-driven displays.</P> + +<P>FLTK applications must periodically check +(<TT>Fl::check()</TT>) or wait (<TT>Fl::wait()</TT>) for events +or use the <A href="Fl.html#Fl.run"><TT>Fl::run()</TT></A> +method to enter a standard event processing loop. Calling +<TT>Fl::run()</TT> is equivalent to the following code:</P> + +<UL><PRE> +while (Fl::wait()); +</PRE></UL> + +<P><TT>Fl::run()</TT> does not return until all of the windows +under FLTK control are closed by the user or your program.</P> + +<H2>Compiling Programs with Standard Compilers</H2> + +<P>Under UNIX (and under Microsoft Windows when using the GNU development +tools) you will probably need to tell the compiler where to find the +header files. This is usually done using the <TT>-I</TT> option:</P> + +<UL><PRE> +CC -I/usr/local/include ... +gcc -I/usr/local/include ... +</PRE></UL> + +<P>The <TT>fltk-config</TT> script included with FLTK can be +used to get the options that are required by your compiler:</P> + +<UL><PRE> +CC `fltk-config --cxxflags` ... +</PRE></UL> + +<P>Similarly, when linking your application you will need to tell the +compiler to use the FLTK library:</P> + +<UL><PRE> +CC ... -L/usr/local/lib -lfltk -lXext -lX11 -lm +gcc ... -L/usr/local/lib -lfltk -lXext -lX11 -lm +</PRE></UL> + +<P>Aside from the "fltk" library, there is also a "fltk_forms" +library for the XForms compatibility classes, "fltk_gl" for the +OpenGL and GLUT classes, and "fltk_images" for the image file +classes, <A +HREF="Fl_Help_Dialog.html#Fl_Help_Dialog"><CODE>Fl_Help_Dialog</CODE></A> +widget, and system icon support. + +<CENTER><TABLE WIDTH="80%" BORDER="1" CELLPADDING="10" BGCOLOR="#cccccc"> +<TR> + <TD><B>Note:</B> + <P>The libraries are named "fltk.lib", "fltkgl.lib", "fltkforms.lib", + and "fltkimages.lib", respectively under Windows. + </TD> +</TR> +</TABLE></CENTER> + +<P>As before, the <TT>fltk-config</TT> script included with FLTK can be +used to get the options that are required by your linker:</P> + +<UL><PRE> +CC ... `fltk-config --ldflags` +</PRE></UL> + +<!-- NEED 2in --> + +<P>The forms, GL, and images libraries are included with the "--use-foo" +options, as follows: + +<UL><PRE> +CC ... `fltk-config --use-forms --ldflags` +CC ... `fltk-config --use-gl --ldflags` +CC ... `fltk-config --use-images --ldflags` +CC ... `fltk-config --use-forms --use-gl --use-images --ldflags` +</PRE></UL> + +<P>Finally, you can use the <TT>fltk-config</TT> script to +compile a single source file as a FLTK program: + +<UL><PRE> +fltk-config --compile filename.cpp +fltk-config --use-forms --compile filename.cpp +fltk-config --use-gl --compile filename.cpp +fltk-config --use-images --compile filename.cpp +fltk-config --use-forms --use-gl --use-images --compile filename.cpp +</PRE></UL> + +<P>Any of these will create an executable named <TT>filename</TT>. + +<H2>Compiling Programs with Microsoft Visual C++</H2> + +<P>In Visual C++ you will need to tell the compiler where to +find the FLTK header files. This can be done by selecting +"Settings" from the "Project" menu and then +changing the "Preprocessor" settings under the +"C/C++" tab. You will also need to add the FLTK and +WinSock (WSOCK32.LIB) libraries to the "Link" +settings.</P> + +<P>You can build your Microsoft Windows applications as Console or +WIN32 applications. If you want to use the standard C <TT>main()</TT> +function as the entry point, FLTK includes a <TT>WinMain()</TT> +function that will call your <TT>main()</TT> function for you.</P> + +<P><I>Note: The Visual C++ 5.0 optimizer is known to cause problems with +many programs. We only recommend using the "Favor Small Code" +optimization setting.</I> The Visual C++ 6.0 optimizer seems to be much +better and can be used with the "optimized for speed" setting.</P> + +<H2>Naming</H2> + +<P>All public symbols in FLTK start with the characters 'F' and 'L':</P> + +<UL> + + <LI>Functions are either <TT>Fl::foo()</TT> or + <TT>fl_foo()</TT>.</LI> + + <LI>Class and type names are capitalized: + <TT>Fl_Foo</TT>.</LI> + + <LI><A href="enumerations.html">Constants and + enumerations</A> are uppercase: <TT>FL_FOO</TT>.</LI> + + <LI>All header files start with <TT><FL/...></TT>. + </LI> + +</UL> + +<!-- NEED 5in --> + +<H2>Header Files</H2> + +<P>The proper way to include FLTK header files is:</P> + +<UL><PRE> +#include <FL/Fl_xyz.H> +</PRE></UL> + +<CENTER><TABLE BORDER="1" CELLPADDING="10" BGCOLOR="#cccccc"> +<TR> + <TD><B>Note:</B> + + <P>Case <I>is</I> significant on many operating systems, + and the C standard uses the forward slash (/) to + separate directories. <i>Do not use any of the following + include lines:</i></P> + + <UL><PRE> + #include <FL\Fl_xyz.H> + #include <fl/fl_xyz.h> + #include <Fl/fl_xyz.h> + </PRE></UL> + + </TD> +</TR> +</TABLE></CENTER> + +*/ |