Enlightenment CVS committal
Author : ningerso
Project : e17
Module : libs/ewl
Dir : e17/libs/ewl/src/bin/tests/widget
Modified Files:
ewl_widget.c
Log Message:
Add tutorial for widget creation.
===================================================================
RCS file: /cvs/e/e17/libs/ewl/src/bin/tests/widget/ewl_widget.c,v
retrieving revision 1.3
retrieving revision 1.4
diff -u -3 -r1.3 -r1.4
--- ewl_widget.c 4 Jan 2007 07:49:23 -0000 1.3
+++ ewl_widget.c 7 Jan 2007 04:51:27 -0000 1.4
@@ -5,6 +5,104 @@
#include <string.h>
#include <stdlib.h>
+/**
+ * @addtogroup Ewl_Widget
+ * @section widget_tut Tutorial
+ *
+ * Small as small can be
+ * (originally at http://everburning.com/news/small-as-small-can-be)
+ *
+ * Whats the minimum amount of work you need to do to create your own EWL
+ * widget? Just want something you can build on but dont know where to start?
+ *
+ * Well, hopefully this should give you the base for starting your widget.
+ * Assuming youre creating a widget called My_Widget, the EWL convention is to
+ * have a my_widget.c and my_widget.h files. There are only a couple things you
+ * need to implement to get a working widget.
+ *
+ * First, my_widget.h.
+ *
+ * @code
+ * #ifndef MY_WIDGET_H
+ * #define MY_WIDGET_H
+ *
+ * #include <Ewl.h>
+ *
+ * #define MY_WIDGET(w) ((My_Widget *)w)
+ * #define MY_WIDGET_TYPE "my_widget"
+ *
+ * typedef struct My_Widget My_Widget;
+ * struct My_Widget
+ * {
+ * Ewl_Widget widget;
+ * };
+ *
+ * Ewl_Widget *my_widget_new(void);
+ * int my_widget_init(My_Widget *w);
+ *
+ * #endif
+ * @endcode
+ *
+ * That wasnt so bad. What have we got? Well, the MY_WIDGET(w) define gives us
a
+ * simple macro to cast other widgets to our widget. The second define,
+ * MY_WIDGET_TYPE, is a simple macro containing the type name of the widget.
+ * Well use that a bit later (and in any type checking we add to our widget.)
+ *
+ * We then create the widget structure. In this case were inheriting from
+ * Ewl_Widget so its the first item in our struct (and not a pointer, thats
+ * important). This is how EWLs inhertiance works. The widget youre inheriting
+ * from is the first item in the struct and not a pointer. You will now be able
+ * to call any of the methods of the inherited class on the new class.
+ *
+ * We then declare two methods. The convention in EWL is that the _new()
+ * function always takes no parameters (void). There is also always a _init()
+ * function that takes the widget as its only parameter and returns an int, if
+ * the initialization succeeded or failed.
+ *
+ * With that out of the way, lets take a look at my_widget.c.
+ *
+ * @code
+ * #include "my_widget.h"
+ *
+ * Ewl_Widget *
+ * my_widget_new(void)
+ * {
+ * Ewl_Widget *w;
+ *
+ * w = calloc(1, sizeof(My_Widget)));
+ * if (!w) return NULL;
+ *
+ * if (!my_widget_init(MY_WIDGET(w)))
+ * {
+ * free(w);
+ * return NULL;
+ * }
+ * return w;
+ * }
+ *
+ * int
+ * my_widget_init(My_Widget *w)
+ * {
+ * if (!ewl_widget_init(EWL_WIDGET(w)))
+ * return 0;
+ *
+ * ewl_widget_appearance_set(EWL_WIDGET(w), MY_WIDGET_TYPE);
+ * ewl_widget_inherit(EWL_WIDGET(w), MY_WIDGET_TYPE);
+ *
+ * return 1;
+ * }
+ * @endcode
+ *
+ * Thats pretty simple. We create a new widget, initialize it and thats about
+ * it. In my_widget_init() we make sure we call ewl_widget_init() as thats the
+ * widget we are inheriting from and we then set our inheritance and appearance
+ * strings (notice the use of our type define from earlier).
+ *
+ * With that youve got a simple widget. It doesnt do much, but it exists. Build
+ * on as you will.
+ *
+ */
+
static int create_test(Ewl_Container *box);
static void ewl_widget_cb_toggle(Ewl_Widget *w, void *ev, void *data);
static void ewl_widget_cb_first_click(Ewl_Widget *w, void *ev, void *data);
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