| 1 | LIBGLADE |
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| 2 | ======== |
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| 3 | |
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| 4 | Author: James Henstridge <james@daa.com.au> |
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| 5 | |
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| 6 | This library allows you to load glade interface files in a program at |
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| 7 | runtime. It doesn't require GLADE to be used, but GLADE is by far the |
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| 8 | easiest way to create the interface files. |
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| 9 | |
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| 10 | For an idea of how to use the library, see test-libglade.c and |
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| 11 | glade/glade-xml.h. |
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| 12 | |
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| 13 | To compile, you will need the libxml2 package (aka the gnome-xml |
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| 14 | module in CVS) which can be found on the GNOME FTP site or its |
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| 15 | mirrors. If you want GNOME support, you will also need the gnome-libs |
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| 16 | package installed. |
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| 17 | |
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| 18 | |
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| 19 | LIBGLADE INTERNALS |
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| 20 | ================== |
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| 21 | |
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| 22 | If you are interested in how libglade works, here is a small |
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| 23 | description: |
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| 24 | |
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| 25 | When glade_xml_new is called, the XML file is loaded using libxml. |
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| 26 | Libglade uses the SAX interface because it is faster and allows me to |
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| 27 | store the data in a more compact representation. The data in the XML |
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| 28 | file is cached, so that if you load the interface again, the file does |
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| 29 | not need to be reparsed. If the file has changed though, it will be |
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| 30 | reparsed. |
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| 31 | |
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| 32 | Now glade_xml_build_widget is called for all the toplevel widgets in |
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| 33 | the interface (or if the second argument to glade_xml_new was non |
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| 34 | NULL, the widget it refers to is treated as the toplevel). |
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| 35 | |
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| 36 | For each of these widgets, they are created by a function specific to |
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| 37 | the widget type, and then glade_xml_build_widget is called for each |
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| 38 | child widget, which is then packed into its parent. This is done |
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| 39 | recursively, so the whole interface is constructed. |
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| 40 | |
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| 41 | New widget types are added to the widget class hash with the |
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| 42 | glade_register_widgets function. For an example, see the end of |
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| 43 | glade-gtk.c. |
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| 44 | |
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| 45 | The automatic signal connection system uses the introspective |
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| 46 | capabilities of dynamic linking. By openning a handle on NULL, we can |
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| 47 | get at all the global symbols (global functions, global variables) in |
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| 48 | the executable, and the libraries it is linked against. This is used |
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| 49 | to find the address of a signal handler from its name, so that |
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| 50 | gtk_signal_connect can be called automatically for you. |
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| 51 | |
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| 52 | Of course, there are other ways of connecting the signals if your |
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| 53 | platform doesn't support this feature. |
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