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Sun Mar 1 15:18:38 PST 1998 Shawn T. Amundson <amundson@gimp.org> * Required changes for version change to 0.99.4 * gtk/gtktree.[ch]: patch from J. Bolliet to correct some bugs * gtk/testgtk.c: added test here from J. Bolliet, removed testtree * gtk/clist: gtk-abilleira-981602-0, allows gtk_clist_set_pixmap and gtk_clist_set_pixtext to not require a mask * gdk/gdkdraw.c,gdk.h: gtk-trow-980217-0 adds gdk_draw_lines and fixes some things about gdk_draw_polygon
837 lines
31 KiB
Plaintext
837 lines
31 KiB
Plaintext
<!doctype linuxdoc system>
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<article>
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<!-- Title information -->
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<title>GTK+ FAQ
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<!-- NOTE: Use only one author tag, otherwise sgml2txt barfs - TRG -->
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<author>Nathan Froyd, Tony Gale, Shawn T. Amundson.
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<date>February 25th 1998
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<abstract>
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This document is intended to answer questions that are likely to be
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frequently asked by programmers using GTK+ or people who are just
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looking at using GTK+.
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</abstract>
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<!-- Table of contents -->
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<toc>
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<!-- Begin the document -->
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<!-- ***************************************************************** -->
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<sect>General Information
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<!-- ----------------------------------------------------------------- -->
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<sect1>Authors
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<p>
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The authors of GTK+ are:
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<itemize>
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<item>Peter Mattis (petm@xcf.berkeley.edu)
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<item>Spencer Kimball (spencer@xcf.berkeley.edu)
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<item>Josh MacDonald (jmacd@xcf.berkeley.edu)
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</itemize>
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GTK+ is distributed under the GNU Library General Public License
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<!-- ----------------------------------------------------------------- -->
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<sect1>What is GTK+?
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<p>
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GTK+ is a small and efficient widget set designed with the general look
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and feel of Motif. In reality, it looks much better than Motif. It
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contains common widgets and some more complex widgets such as a file
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selection, and color selection widgets.
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GTK+ provides some unique features. (At least, I know of no other widget
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library which provides them). For
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example, a button does not contain a label, it contains a child widget,
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which in most instances will be a label.
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However, the child widget can also be a pixmap, image or any combination
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possible the programmer desires.
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This flexibility is adhered to throughout the library.
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<!-- ----------------------------------------------------------------- -->
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<sect1>What is the + in GTK+?
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<P>
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Peter Mattis informed the gtk mailing list that:
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<quote>
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"I originally wrote gtk which included the three libraries, libglib,
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libgdk and libgtk. It featured a flat widget hierarchy. That is, you
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couldn't derive a new widget from an existing one. And it contained
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a more standard callback mechanism instead of the signal mechanism now
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present in gtk+. The + was added to distinguish between the original
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version of gtk and the new version. You can think of it as being an
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enhancement to the original gtk that adds object oriented features."
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</quote>
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<!-- ----------------------------------------------------------------- -->
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<sect1>Does the G in GTK+ stand for General, Gimp, or GNU?
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<p>
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Peter Mattis informed the gtk mailing list that:
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<quote>
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"I think the last time Spencer and I talked about it we decided on
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GTK = Gimp ToolKit. But I don't know for sure. Its definately not
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GNU, though."
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</quote>
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<!-- ----------------------------------------------------------------- -->
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<sect1>Where is the documentation for GTK+?
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<p>
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In the GTK+ distribution's doc/ directory you will find the
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reference material for both GTK and GDK, and this FAQ.
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There is also a GTK+ Tutorial which can be found at
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<htmlurl url="http://www.levien.com/~slow/gtk/"
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name="http://www.levien.com/~slow/gtk/">.
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The Tutorial and FAQ can also be found at
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<htmlurl url="http://www.geocities.com/ResearchTriangle/Lab/4299/"
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name="http://www.geocities.com/ResearchTriangle/Lab/4299/">.
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In addition, you can find links to all of these documents by going to
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<htmlurl url="http://www.gimp.org/gtk/docs"
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name="http://www.gimp.org/gtk/docs">.
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<!-- ----------------------------------------------------------------- -->
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<sect1>Is there a mailing list (or mailing list archive) for GTK+?
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<p>
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There are two mailing lists:
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<itemize>
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<item>A mailing list for discussion of development of GTK based applications
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is hosted at gtk-app-devel-list@redhat.com. To subscribe send an
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email message to <htmlurl url="mailto:gtk-app-devel-list-request@redhat.com"
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name="gtk-app-devel-list-request@redhat.com">
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with <em>subscribe</em> in the <bf>subject</bf>.
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<p>
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<item>A mailing list for discussion of development of GTK is hosted
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at gtk-list@redhat.com. To subscribe send an
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email message to <htmlurl url="mailto:gtk-list-request@redhat.com"
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name="gtk-list-request@redhat.com">
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with <em>subscribe</em> in the <bf>subject</bf>.
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<p>
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A searchable archive of the mailing list can be found at <htmlurl url="http://www.redhat.com/linux-info/gtk/gtk-list/index.html" name="http://www.redhat.com/linux-info/gtk/gtk-list/index.html">
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</itemize>
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<!-- ----------------------------------------------------------------- -->
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<sect1>The gtk-list hasn't had any traffic for days, is it dead?
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<p>
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No, everyone's just busy coding.
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<!-- ----------------------------------------------------------------- -->
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<sect1>How to get help with GTK+
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<p>
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First, make sure your question isn't answered in the documentation, this
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FAQ or the tutorial. Done that? You're sure you've done that, right? In
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that case, the best place to post questions is to the GTK+ mailing list.
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<!-- ----------------------------------------------------------------- -->
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<sect1>How to report bugs in GTK+
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<p>
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Bug reports should be sent to the GTK+ mailing list.
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<!-- ----------------------------------------------------------------- -->
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<sect1>What applications have been written with GTK+?
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<p>
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Some applications which use GTK+ are:
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<itemize>
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<item>GIMP (<htmlurl url="http://www.XCF.Berkeley.EDU/~gimp/"
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name="http://www.XCF.Berkeley.EDU/~gimp/"> ),
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an image manipulation program
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<item>Gsumi (<htmlurl url="http://www.msc.cornell.edu/~otaylor/gsumi/gsumi.html"
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name="http://www.msc.cornell.edu/~otaylor/gsumi/gsumi.html">),
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a fun B+W doodling program with XInput support.
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<item>GUBI (<htmlurl url="http://www.SoftHome.net/pub/users/timj/gubi/index.htm"
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name="http://www.SoftHome.net/pub/users/timj/gubi/index.htm">),
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a user interface builder
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<item>Gzilla (<htmlurl url="http://www.levien.com/gzilla/" name="http://www.levien.com/gzilla/">),
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a web browser
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<item>SANE (<htmlurl url="http://www.azstarnet.com/~axplinux/sane/" name="http://www.azstarnet.com/~axplinux/sane/"> ),
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a universal scanner interface
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<item>XQF (<htmlurl url="http://www.botik.ru/~roma/quake/" name="http://www.botik.ru/~roma/quake/">),
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a QuakeWorld/Quake2 server browser and launcher
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<item>ElectricEyes (<htmlurl url="http://www.labs.redhat.com/ee.shtml" name="http://www.labs.redhat.com/ee.shtml">),
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an image viewer that aims to be a free replacement for xv
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<item>GPK - the General Proxy Kit (<htmlurl url="http://www.humanfactor.com/gpk/" name="http://www.humanfactor.com/gpk/">),
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an add-on library to permit thread-safe access to GTK+
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<item>GCK - the General Convenience Kit (<htmlurl url="http://www.ii.uib.no/~tomb/gck.html" name="http://www.ii.uib.no/~tomb/gck.html">),
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miscellaneous functions intended to ease color handling, UI construction,
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vector operations, and math functions
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<item>GDK Imlib (<htmlurl url="http://www.labs.redhat.com/imlib/" name="http://www.labs.redhat.com/imlib/">),
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a fast image loading and manipulation library for GDK
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</itemize>
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<p>
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In addition to the above, the GNOME project (<htmlurl url="http://www.gnome.org"
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name="http://www.gnome.org">)
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is using GTK+ to build a free desktop for Linux. Many more programs can be found
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there.
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<!-- ***************************************************************** -->
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<sect>How to find, configure, install, and troubleshoot GTK+
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<!-- ***************************************************************** -->
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<!-- ----------------------------------------------------------------- -->
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<sect1>What do I need to run GTK+?
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<p>
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To compile GTK+, all you need is a C compiler (gcc) and the X Window System
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and associated libraries on your system.
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<!-- ----------------------------------------------------------------- -->
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<sect1>Where can I get GTK+?
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<p>
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The canonical site is:
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<verb>
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ftp://ftp.gimp.org/pub/gtk
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</verb>
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Of course, any mirrors of ftp.gimp.org should have the latest version, too.
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<sect1>How do I configure/compile GTK+?
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<p>
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Generally, all you will need to do is issue the commands:
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<verb>
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./configure
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make
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</verb>
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in the gtk+-version/ directory.
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<!-- ----------------------------------------------------------------- -->
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<sect1>When compiling GTK+ I get an error like:
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<tt/make: file `Makefile' line 456: Syntax error/
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<p>
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Make sure that you are using GNU make (use <tt/make -v/ to check). There are
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many weird and wonderful versions of make out there, and not all of them
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handle the automatically generated Makefiles.
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<!-- ----------------------------------------------------------------- -->
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<sect1>I've compiled and installed GTK+, but I can't get any programs to link
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with it!
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<p>
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This problem is most often encountered when the GTK+ libraries can't be
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found or are the wrong version. Generally, the compiler will complain about an
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'unresolved symbol'. There are two things you need to check:
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<itemize>
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<item>Make sure that the libraries can be found. You want to edit
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/etc/ld.so.conf to include /usr/local/lib (or whereever you installed GTK+),
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so it looks something like:
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<verb>
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/usr/X11R6/lib
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/usr/local/lib
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</verb>
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Then you need to run /sbin/ldconfig as root.
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<p>
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<item>Make sure the linker is finding the correct set of libraries. If you
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have a Linux distribution that installs GTK+ (e.g. RedHat 5.0) then this
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older version may be used. Now (assuming you have a RedHat
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system), issue the command
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<verb>
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rpm -e gtk gtk-devel
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</verb>
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You may also want to remove the packages that depend on gtk (rpm will tell you
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which ones they are). If you don't have a RedHat Linux system, check to make sure
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that neither <verb>/usr/lib</verb> or <verb>/usr/local/lib</verb> contain any of
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the libraries libgtk, libgdk, libglib, or libgck. If they do exist, remove them
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(and any gtk include files, such as /usr/include/gtk and /usr/include/gdk)
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and reinstall gtk+.
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</itemize>
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<!-- ***************************************************************** -->
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<sect>Development of GTK+
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<!-- ***************************************************************** -->
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<!-- ----------------------------------------------------------------- -->
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<sect1>When will it reach version 1.0?
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<p>
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The file 'TODO' in the gtk+ distribution lists the things that need to be done
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before version 1.0 is repleased. Not including bugs, this includes:
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<itemize>
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<item>New Features
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<itemize>
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<item>gdk_expose_compress: ala-Xt, this would really help for opaque moves and
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such
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</itemize>
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<p>
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<item>Widgets
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<itemize>
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<item>Column-list (Jay Painter)
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<item>Text widget (needs to be finished)
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<item>Entry should have a password mode (and it should show stars
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for user feedback)
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</itemize>
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<p>
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<item>Drag-and-Drop (DND)
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<itemize>
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<item> It seems to be having problems again. The way DND data types are set in
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GtkWidget really needs to be fixed. This is pretty high on my priority
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list, and I'll get to it as soon as the column list widget is done. The
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correct way dnd data needs to be set is to have a additional keyed data
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type with GtkWidget, which is applied to the widget's window upon realize.
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There also needs to be a way to set dnd-data on widget windows which are
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not the main window (for widgets that create more than one window).
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-- Jay Painter
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<item> DnD seems to work for me, but yes, there needs to be some sort of
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gtk_widget layer that makes it easier... Also, adding support for drop
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zones might be nice.
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-- Elliot
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</itemize>
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</itemize>
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<!-- ----------------------------------------------------------------- -->
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<sect1>How can I contribute to GTK+?
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<p>
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It's simple. If something doesn't work like you think it should in a program,
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check the documentation to make sure you're not missing something. If it is a true
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bug, track it down in the GTK+ source, change it, and then upload the patchfile to:
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<verb>
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ftp://ftp.gimp.org/incoming
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</verb>
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along with a README file. Make sure you follow the naming conventions or your
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will just be deleted! The filenames should be of this form:
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<verb>
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gtk-<username>-<date yymmdd-n>.patch.gz
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gtk-<username>-<date yymmdd-n>.patch.README
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</verb>
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The "n" in the date indicates a unique number (starting from 0)
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of patches you uploaded that day. It should be 0, unless you
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upload more than one patch in the same day.
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Example:
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<verb>
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gtk-gale-982701-0.patch.gz
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gtk-gale-982701-0.patch.README
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</verb>
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Once you upload <em>anything</em>, send the README to ftp-admin@gimp.org
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<!-- ----------------------------------------------------------------- -->
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<sect1>What is the policy on incorporating new widgets into the library?
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<p>
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This is up to the authors, so you will have to ask them once you
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are done with your widget. As a general guideline, widgets that are
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generally useful, work, and are not a disgrace to the widget set will
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gladly be included.
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<!-- ----------------------------------------------------------------- -->
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<sect1>Is anyone working on bindings for languages other than C?
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<p>
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Yes. There is
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<itemize>
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<item>a C++ wrapper for GTK+ called gtk--. You can find the home page at:
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<verb>
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http://www.cs.tut.fi/~p150650/gtk/gtk--.html
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</verb>
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The FTP site is:
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<verb>
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ftp://ftp.gimp.org/pub/gtk/gtk--/
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</verb>
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<p>
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<item>Perl bindings
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<verb>
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ftp://ftp.gimp.org/pub/gtk/perl
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</verb>
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<item>Guile bindings. The home page is at:
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<verb>
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http://www.ping.de/sites/zagadka/guile-gtk/
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</verb>
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By the way, Guile is the GNU Project's implemention of R4RS Scheme (the
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standard). If you like Scheme, you may want to take a look at this.
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<p>
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<item>David Monniaux reports:
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<quote>I've started a gtk-O'Caml binding system.
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The basics of the system, including callbacks, work fine.
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The current development is in
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http://www.ens-lyon.fr/~dmonniau/arcs/
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</quote>
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<item>
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Several python-gtk interfaces have been done. python-gtk is at:
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<verb>
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http://www.acs.ucalgary.cs/~nashceme/python-gtk/
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</verb>
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If you try python-gtk and don't like it, there's also pygtk located at:
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<verb>
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ftp://ftp.gimp.org/pub/gtk/python/
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</verb>
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<item>
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There's a OpenGL/Mesa widget available for GTK+. Grab it at:
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<verb>
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http://www.sakuranet.or.jp/~aozasa/shige/doc/comp/gtk/gtkGL/files-en.html
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</verb>
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</itemize>
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<!-- ***************************************************************** -->
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<sect>Development with GTK+
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<!-- ***************************************************************** -->
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<!-- ----------------------------------------------------------------- -->
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<sect1>How do I get started?
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<p>
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So, after you have installed GTK+ there are a couple of things that can
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ease you into developing applications with it. There is the
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GTK+ Tutorial <htmlurl url="http://www.levien.com/~slow/gtk/tutorial"
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name="<http://www.levien.com/~slow/gtk/tutorial>">, which is undergoing development. This will introduce you
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to writing applications using C.
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The Tutorial doesn't (yet) contain information on all of the widgets
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that are in GTK+. For example code on how to use the basics of all the
|
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GTK+ widgets you should look at the file gtk/testgtk.c (and associated
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source files) within the GTK+ distribution. Looking at these exmaples will
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give you a good grounding on what the widgets can do.
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<sect1>What widgets are in GTK?
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<p>
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The GTK+ Tutorial lists the following widgets:
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<verb>
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GtkObject
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+-- GtkData
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| \-- GtkAdjustment
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\-- GtkWidget
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+-- GtkContainer
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| +-- GtkBin
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| | +-- GtkAlignment
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| | +-- GtkFrame
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| | | *-- GtkAspectFrame
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| | |
|
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| | +-- GtkItem
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| | | +-- GtkListItem
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| | | +-- GtkMenuItem
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| | | | +-- GtkCheckMenuItem
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| | | | *-- GtkRadioMenuItem
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| | | |
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| | | *-- GtkTreeItem
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| | |
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| | +-- GtkViewport
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| | \-- GtkWindow
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| | +-- GtkDialog
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| | \-- GtkFileSelection
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| |
|
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| +-- GtkBox
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| | +-- GtkHBox
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| | \-- GtkVBox
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| | +-- GtkColorSelection
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| | \-- GtkCurve
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| |
|
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| +-- GtkButton
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| | +-- GtkOptionMenu
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| | \-- GtkToggleButton
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| | \-- GtkCheckButton
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| | \-- GtkRadioButton
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| |
|
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| +-- GtkList
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| +-- GtkMenuShell
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| | +-- GtkMenu
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| | \-- GtkMenuBar
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| |
|
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| +-- GtkNotebook
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| +-- GtkScrolledWindow
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| +-- GtkTable
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| \-- GtkTree
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+-- GtkDrawingArea
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+-- GtkEntry
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+-- GtkMisc
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| +-- GtkArrow
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| +-- GtkImage
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| +-- GtkLabel
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| \-- GtkPixmap
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+-- GtkPreview
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+-- GtkProgressBar
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+-- GtkRange
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| +-- GtkScale
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| | +-- GtkHScale
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| | \-- GtkVScale
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| |
|
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| \-- GtkScrollbar
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| +-- GtkHScrollbar
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| \-- GtkVScrollbar
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|
|
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+-- GtkRuler
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| +-- GtkHRuler
|
|
| \-- GtkVRuler
|
|
|
|
|
\-- GtkSeparator
|
|
+-- GtkHSeparator
|
|
\-- GtkVSeparator
|
|
</verb>
|
|
|
|
<!-- ----------------------------------------------------------------- -->
|
|
<sect1>How can I prevent redrawing and resizing while I change multiple widgets?
|
|
<p>
|
|
Use gtk_container_disable_resize and gtk_container_enable_resize around the
|
|
code where you are changing a lot of stuff. This will result in much faster
|
|
speed since it will prevent resizing of the entire widget hierarchy.
|
|
|
|
<!-- ----------------------------------------------------------------- -->
|
|
<sect1>How do I catch a double click event in a list widget?
|
|
<p>
|
|
Tim Janik wrote to gtk-list (slightly modified):
|
|
|
|
Define a signal handler:
|
|
|
|
<tscreen><verb>
|
|
gint
|
|
signal_handler_event(GtkWiget *widget, GdkEvenButton *event, gpointer func_data)
|
|
{
|
|
if (GTK_IS_LIST_ITEM(widget) &&
|
|
(event->type==GDK_2BUTTON_PRESS ||
|
|
event->type==GDK_3BUTTON_PRESS) ) {
|
|
printf("I feel %s clicked on button %d\",
|
|
event->type==GDK_2BUTTON_PRESS ? "double" : "triple",
|
|
event->button);
|
|
}
|
|
|
|
return FALSE;
|
|
}
|
|
</verb></tscreen>
|
|
|
|
And connect the handler to your object:
|
|
|
|
<tscreen><verb>
|
|
{
|
|
/* list, list item init stuff */
|
|
|
|
gtk_signal_connect(GTK_OBJECT(list_item),
|
|
"button_press_event",
|
|
GTK_SIGNAL_FUNC(signal_handler_event),
|
|
NULL);
|
|
|
|
/* and/or */
|
|
|
|
gtk_signal_connect(GTK_OBJECT(list_item),
|
|
"button_release_event",
|
|
GTK_SIGNAL_FUNC(signal_handler_event),
|
|
NULL);
|
|
|
|
/* something else */
|
|
}
|
|
</verb></tscreen>
|
|
|
|
<!-- ----------------------------------------------------------------- -->
|
|
<sect1>How do I find out about the selection of a GtkList?
|
|
<p>
|
|
|
|
Get the selection something like this:
|
|
<tscreen><verb>
|
|
GList *sel;
|
|
sel = GTK_LIST(list)->selection;
|
|
</verb></tscreen>
|
|
|
|
This is how GList is defined (quoting glist.h):
|
|
<tscreen><verb>
|
|
typedef struct _GList GList;
|
|
|
|
struct _GList
|
|
{
|
|
gpointer data;
|
|
GList *next;
|
|
GList *prev;
|
|
};
|
|
</verb></tscreen>
|
|
|
|
A GList structure is just a simple structure for doubly linked lists.
|
|
there exist several g_list_*() functions to modify a linked list in
|
|
glib.h. However the GTK_LIST(MyGtkList)->selection is maintained
|
|
by the gtk_list_*() functions and should not be modified.
|
|
|
|
The selection_mode of the GtkList determines the selection
|
|
facilities of a GtkList and therefore the contents
|
|
of GTK_LIST(AnyGtkList)->selection:
|
|
|
|
<verb>
|
|
selection_mode GTK_LIST()->selection contents
|
|
------------------------------------------------------
|
|
|
|
GTK_SELECTION_SINGLE) selection is either NULL
|
|
or contains a GList* pointer
|
|
for a single selected item.
|
|
|
|
GTK_SELECTION_BROWSE) selection is NULL if the list
|
|
contains no widgets, otherwise
|
|
it contains a GList* pointer
|
|
for one GList structure.
|
|
GTK_SELECTION_MULTIPLE) selection is NULL if no listitems
|
|
are selected or a a GList* pointer
|
|
for the first selected item. that
|
|
in turn points to a GList structure
|
|
for the second selected item and so
|
|
on
|
|
|
|
GTK_SELECTION_EXTENDED) selection is NULL.
|
|
</verb>
|
|
|
|
The data field of the GList structure GTK_LIST(MyGtkList)->selection points
|
|
to the first GtkListItem that is selected. So if you would like to determine
|
|
which listitems are selected you should go like this:
|
|
|
|
Upon Initialization:
|
|
<tscreen><verb>
|
|
{
|
|
gchar *list_items[]={
|
|
"Item0",
|
|
"Item1",
|
|
"foo",
|
|
"last Item",
|
|
};
|
|
guint nlist_items=sizeof(list_items)/sizeof(list_items[0]);
|
|
GtkWidget *list_item;
|
|
guint i;
|
|
|
|
list=gtk_list_new();
|
|
gtk_list_set_selection_mode(GTK_LIST(list), GTK_SELECTION_MULTIPLE);
|
|
gtk_container_add(GTK_CONTAINER(AnyGtkContainer), list);
|
|
gtk_widget_show (list);
|
|
|
|
for (i = 0; i < nlist_items; i++)
|
|
{
|
|
list_item=gtk_list_item_new_with_label(list_items[i]);
|
|
gtk_object_set_user_data(GTK_OBJECT(list_item), (gpointer)i);
|
|
gtk_container_add(GTK_CONTAINER(list), list_item);
|
|
gtk_widget_show(list_item);
|
|
}
|
|
}
|
|
</verb></tscreen>
|
|
|
|
To get known about the selection:
|
|
<tscreen><verb>
|
|
{
|
|
GList *items;
|
|
|
|
items=GTK_LIST(list)->selection;
|
|
|
|
printf("Selected Items: ");
|
|
while (items) {
|
|
if (GTK_IS_LIST_ITEM(items->data))
|
|
printf("%d ", (guint)
|
|
gtk_object_get_user_data(items->data));
|
|
items=items->next;
|
|
}
|
|
printf("\n");
|
|
}
|
|
</verb></tscreen>
|
|
<!-- ----------------------------------------------------------------- -->
|
|
<sect1>Is it possible to get some text displayed which is truncated to fit inside its allocation?
|
|
<p>
|
|
GTK's behavior (no clipping) is a consequence of its attempts to
|
|
conserve X resources. Label widgets (among others) don't get their own
|
|
X window - they just draw their contents on their parent's window.
|
|
While it might be possible to have clipping occur by setting the clip
|
|
mask before drawing the text, this would probably cause a substantial
|
|
performance penalty.
|
|
|
|
Its possible that, in the long term, the best solution to such
|
|
problems might be just to change gtk to give labels X windows.
|
|
A short term workaround is to put the label widget inside another
|
|
widget that does get it's own window - one possible candidate would
|
|
be the viewport widget.
|
|
|
|
<tscreen><verb>
|
|
viewport = gtk_viewport (NULL, NULL);
|
|
gtk_widget_set_usize (viewport, 50, 25);
|
|
gtk_viewport_set_shadow_type (GTK_VIEWPORT(viewport), GTK_SHADOW_NONE);
|
|
gtk_widget_show(viewport);
|
|
|
|
label = gtk_label ("a really long label that won't fit");
|
|
gtk_container_add (GTK_CONTAINER(viewport), label);
|
|
gtk_widget_show (label);
|
|
</verb></tscreen>
|
|
|
|
If you were doing this for a bunch of widgets, you might want to
|
|
copy gtkviewport.c and strip out the adjustment and shadow
|
|
functionality (perhaps you could call it GtkClipper).
|
|
|
|
<!-- ----------------------------------------------------------------- -->
|
|
<sect1>Why don't the contents of a button move when the button is pressed? Here's a patch to make it work that way...
|
|
<p>
|
|
From: Peter Mattis
|
|
|
|
The reason buttons don't move their child down and to the right when
|
|
they are depressed is because I don't think that's what is happening
|
|
visually. My view of buttons is that you are looking at them straight
|
|
on. That is, the user interface lies in a plane and you're above it
|
|
looking straight at it. When a button gets pressed it moves directly
|
|
away from you. To be absolutely correct I guess the child should
|
|
actually shrink a tiny amount. But I don't see why the child should
|
|
shift down and to the left. Remember, the child is supposed to be
|
|
attached to the buttons surface. Its not good for it to appear like
|
|
the child is slipping on the surface of the button.
|
|
|
|
On a more practical note, I did implement this at one point and
|
|
determined it didn't look good and removed it.
|
|
|
|
<!-- ----------------------------------------------------------------- -->
|
|
<sect1>How can I define a separation line in a menu?
|
|
<p>
|
|
See the <htmlurl url="http://www.levien.com/~slow/gtk/"
|
|
name="Tutorial"> for information on how to create menus.
|
|
However, to create a separation line in a menu, just insert an
|
|
empty menu item:
|
|
|
|
<tscreen><verb>
|
|
menuitem = gtk_menu_item_new();
|
|
gtk_menu_append(GTK_MENU(menu), menuitem);
|
|
gtk_widget_show(menuitem);
|
|
</verb></tscreen>
|
|
|
|
<!-- ***************************************************************** -->
|
|
<sect>About gdk
|
|
<!-- ***************************************************************** -->
|
|
|
|
<!-- ----------------------------------------------------------------- -->
|
|
<sect1>What is gdk?
|
|
<p>
|
|
gdk is basically a wrapper around the standard Xlib functions calls. If you are
|
|
at all familiar with Xlib, a lot of the functions in gdk will require little or no
|
|
getting used to. All functions are written to provide an easy way to access Xlib
|
|
functions in an easier an slightly more intuitive manner. In addition, since gdk
|
|
uses glib (see below), it will be more portable and safer to use on multiple platforms.
|
|
|
|
<!-- Examples, anybody? I've been mulling some over. NF -->
|
|
|
|
<sect1>How do I use color allocation?
|
|
<p>
|
|
One of the nice things about GDK is that it's based on top of Xlib; this is also
|
|
a problem, especially in the area of color management. If you want to use color
|
|
in your program (drawing a rectangle or such, your code should look something like
|
|
this:
|
|
<tscreen>
|
|
<verb>
|
|
{
|
|
GdkColor *color;
|
|
int width, height;
|
|
GtkWidget *widget;
|
|
|
|
...
|
|
|
|
/* first, create a GC to draw on */
|
|
gc = gdk_gc_new(widget->window);
|
|
|
|
/* find proper dimensions for rectangle */
|
|
gdk_window_get_size(widget->window, &width, &height);
|
|
|
|
/* the color we want to use */
|
|
color = (GdkColor *)malloc(sizeof(GdkColor));
|
|
|
|
/* red, green, and blue are passed values, indicating the RGB triple
|
|
* of the color we want to draw. Note that the values of the RGB components
|
|
* within the GdkColor are taken from 0 to 65535, not 0 to 255.
|
|
*/
|
|
color->red = red * (65535/255);
|
|
color->green = green * (65535/255);
|
|
color->blue = blue * (65535/255);
|
|
|
|
/* the pixel value indicates the index in the colormap of the color.
|
|
* it is simply a combination of the RGB values we set earlier
|
|
*/
|
|
color->pixel = (gulong)(red*65536 + green*256 + blue);
|
|
|
|
/* However, the pixel valule is only truly valid on 24-bit (TrueColor)
|
|
* displays. Therefore, this call is required so that GDK and X can
|
|
* give us the closest color available in the colormap
|
|
*/
|
|
gdk_color_alloc(gtk_widget_get_colormap(widget), color);
|
|
|
|
/* set the foreground to our color */
|
|
gdk_gc_set_foreground(gc, color);
|
|
|
|
/* draw the rectangle */
|
|
gdk_draw_rectangle(widget->window, gc, 1, 0, 0, width, height);
|
|
|
|
...
|
|
}
|
|
</verb>
|
|
</tscreen>
|
|
|
|
<!-- ***************************************************************** -->
|
|
<sect>About glib
|
|
<!-- ***************************************************************** -->
|
|
|
|
<!-- ----------------------------------------------------------------- -->
|
|
<sect1>What is glib?
|
|
<p>
|
|
glib is a library of useful functions and definitions available for use
|
|
when creating GDK and GTK applications. It provides replacements for some
|
|
standard libc functions, such as malloc, which are buggy on some systems.
|
|
<p>
|
|
It also provides routines for handling:
|
|
<itemize>
|
|
<item>Doubly Linked Lists
|
|
<item>Singly Linked Lists
|
|
<item>Timers
|
|
<item>String Handling
|
|
<item>A Lexical Scanner
|
|
<item>Error Functions
|
|
</itemize>
|
|
|
|
<!-- Some Examples might be useful here! NF -->
|
|
|
|
<!-- ----------------------------------------------------------------- -->
|
|
<sect1>Why use g_print, g_malloc, g_strdup and fellow glib functions ?
|
|
<p>
|
|
Thanks to Tim Janik who wrote to gtk-list: (slightly modified)
|
|
<quote>
|
|
Regarding g_malloc(), g_free() and siblings, these functions are much safer
|
|
than thier libc equivalences. For example, g_free() just returns if called
|
|
with NULL. Also, if USE_DMALLOC is defined, the definition for these
|
|
functions changes (in glib.h) to use MALLOC(), FREE() etc... If MEM_PROFILE
|
|
or MEM_CHECK are defined, there are even small statistics made counting
|
|
the used block sizes (shown by g_mem_profile() / g_mem_check()).
|
|
<p>
|
|
Considering the fact that glib provides an interface for memory chunks
|
|
to save space if you have lots of blocks that are always the same size
|
|
and to mark them ALLOC_ONLY if needed, it is just straight forward to
|
|
create a small saver (debug able) wrapper around the normal malloc/free
|
|
stuff as well - just like gdk covers Xlib. ;)
|
|
<p>
|
|
Using g_error() and g_warning() inside of applications like the GIMP
|
|
that fully rely on gtk even gives the opportunity to pop up a window
|
|
showing the messages inside of a gtk window with your own handler
|
|
(by using g_set_error_handler()) along the lines of gtk_print()
|
|
(inside of gtkmain.c).
|
|
</quote>
|
|
|
|
<!-- ***************************************************************** -->
|
|
<sect>GTK+ FAQ Contributions, Maintainers and Copyright
|
|
<p>
|
|
If you would like to make a contribution to the FAQ, send either one of us
|
|
an e-mail message with the exact text you think should be included (question and
|
|
answer). With your help, this document can grow and become more useful!
|
|
|
|
This document is maintained by Nathan Froyd
|
|
<htmlurl url="mailto:maestrox@geocities.com" name="<maestrox@geocities.com>">
|
|
and Tony Gale <htmlurl url="mailto:gale@gimp.org" name="<gale@gimp.org>">.
|
|
This FAQ was created by Shawn T. Amundson <htmlurl url="mailto:amundson@gimp.org"
|
|
name="<amundson@gimp.org>">who continues to provide support.
|
|
|
|
The GTK+ FAQ is Copyright (C) 1997,1998 by Shawn T. Amundson, Nathan Froyd and Tony Gale.
|
|
|
|
Permission is granted to make and distribute verbatim copies of this manual provided the
|
|
copyright notice and this permission notice are preserved on all copies.
|
|
|
|
Permission is granted to copy and distribute modified versions of this document under the conditions
|
|
for verbatim copying, provided that this copyright notice is included exactly as in the original,
|
|
and that the entire resulting derived work is distributed under the terms of a permission
|
|
notice identical to this one.
|
|
|
|
Permission is granted to copy and distribute translations of this document into another language,
|
|
under the above conditions for modified versions.
|
|
|
|
If you are intending to incorporate this document into a published work, please contact one of
|
|
the maintainers, and we will make an effort to ensure that you have the most up to date
|
|
information available.
|
|
|
|
There is no guarentee that this document lives up to its intended
|
|
purpose. This is simply provided as a free resource. As such,
|
|
the authors and maintainers of the information provided within can
|
|
not make any guarentee that the information is even accurate.
|
|
|
|
</article>
|