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[evas] More love to a given example's text. 

SVN revision: 61536
This commit is contained in:
Gustavo Lima Chaves 2011-07-20 17:58:56 +00:00
parent 859c4bd33d
commit 0b7d33e3df
2 changed files with 107 additions and 62 deletions
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138
legacy/evas/doc/examples.dox
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@ -169,74 +169,114 @@
* @page Example_Evas_Events Evas events (canvas and object ones) and some canvas operations example
* @dontinclude evas-events.c
*
* In this example we illustrate how to interact with canvas' (and
* its objects') events and other canvas operations.
* In this example we illustrate how to interact with canvas' (and its
* objects') events, including the key input ones. We also demonstrate
* precise point collision on objects and canvas "obscured regions",
* here.
*
* After we grab our canvas pointer, we registrate two event callbacks on it:
* The example application consists of a window with a white
* background and an image -- the Enlightenment logo. The application
* begins with this image switching back and forth into two sizes: the
* exact canvas' size and one quarter of it (when it's placed on the
* top left quadrant). Thus, we'll have an @b animation going on,
* with image states set to change each 2 elapsed seconds.
*
* There's a global variable to aid accessing our desired context
* variables from anywhere in the code:
* @dontinclude evas-events.c
* @skip test_data
* @until {0}
*
* What interests us there are the @c canvas pointer, our image handle
* -- @c img -- and the background one, @c bg.
*
* The first interesting thing on the example is the registration of a
* callback on each canvas resizing event, where we put our canvas'
* size and the background rectangle's one in synchrony, so that we
* don't get bogus content on rendering with canvas resizes:
* @dontinclude evas-events.c
* @skip resize_set
* @until resize_set
* @dontinclude evas-events.c
* @skip here to keep
* @until }
*
* Than, after grabbing our canvas pointer from the Ecore Evas helper
* infrastructure, we registrate an event callbacks on it:
* @skip evas_event_callback_add(d.canvas, EVAS_CALLBACK_RENDER_FLUSH_PRE,
* @until two canvas event callbacks
* The first of them, which has the following code,
* @dontinclude evas-events.c
* @skip render flush callback
* @until }
* will be called whenever our canvas has to flush its rendering pipeline.
* In this example, two ways of observing that message which is printed in
* the cited callback are:
* It will be called whenever our canvas has to flush its rendering
* pipeline. In this example, two ways of observing that message
* which is printed in the cited callback are:
* - to resize the example's window (thus resizing the canvas' viewport)
* - let the animation run
*
* When one resizes the canvas, there's at least one operation it has
* to do which will require new calculation for rendering: the
* resizing of the background rectangle:
* resizing of the background rectangle, in a callback we already
* shown you.
*
* The creation of our background rectangle is so that we give it a @b name,
* via evas_object_name_set() and we give it the canvas @b focus:
* @dontinclude evas-events.c
* @skip here just to keep
* @skip bg = evas_object_rectangle_add
* @until focus_set
*
* Still exempliflying events and callbacks, we register a callback on
* the canvas event of an object being focused:
* @dontinclude evas-events.c
* @skip add(d.canvas, EVAS_CALLBACK_CANVAS_OBJECT_FOCUS
* @until }
* The animation we talked about comes from a timer we register just before
* we start the example's main loop:
* @dontinclude evas-events.c
* @skip called when
* @until }
*
* In that call, @c event_info is going to be the focused object's
* handle, in this case our background rectangle. We print its name,
* so you can check it's the same. We check that pointer is the same
* reported by Evas' API with regard to the newest focused
* object. Finally, we check whether that object is really flagged as
* focused, now using an Evas object API function.
*
* The animation we talked about comes from a timer we register just
* before we start the example's main loop. As we said, the resizing
* of the image will also force the canvas to repaint itself, thus
* flushing the rendering pipeline whenever the timer ticks:
* @dontinclude evas-events.c
* @skip d.resize_timer = ecore
* @until d.resize_timer = ecore
* being the timer's callback what follows:
* @dontinclude evas-events.c
* @skip put some action
* @until }
* As you see, the resizing of the image will also force the canvas to
* repaint itself, thus flushing the rendering pipeline whenever the
* timer ticks. When you start this example, this animation will be
* When you start this example, this animation will be
* running, by default. To interact with the program, there's a
* command line interface. A help string can be asked for with the
* 'h' key:
* @dontinclude evas-events.c
* @skip if (strcmp(ev->keyname, "h") == 0)
* @until }
* @skip static const char *commands
* @until ;
* These are the commands the example will accept at any time, except
* when one triggers the 'f' one:
* when one triggers the 'f' one. This command will exemplify
* evas_event_freeze(), which interrupts @b all input events
* processing for the canvas (in the example, just for 3 seconds). Try
* to issue events for it during that freeze time:
* @dontinclude evas-events.c
* @skip if (strcmp(ev->keyname, "f") == 0)
* @until }
* This command will exemplify evas_event_freeze(), which interrupts
* @b all input events processing for the canvas (in the example, just
* for 3 seconds). Try to issue events for it during that freeze time.
* The 'd' command will unregister those two canvas callbacks for you,
* so you won't see the messages about the focused object and the
* rendering process anymore:
* @dontinclude evas-events.c
* @skip if (strcmp(ev->keyname, "d") == 0)
* @until }
* The second of those callbacks has the following code:
* @dontinclude evas-events.c
* @skip called when our rectangle gets focus
* In this example, we start using a focused object to handle the input
* events -- the background rectangle. We register a callback on an key input
* event occurring on it, so that we can act on each key stroke:
* @skip object_event_callback_add
* @until }
* It will take place whenever an object in the canvas receives
* focus. In this example, we use the focus to handle the input
* events:
* @skip so we get input events
* @until }
* The background rectangle is the chosen object to receive the
* focus. This also illustrates the use of
* evas_object_event_callback_add(), which registers an event callback
* on an Evas @b object (in this case, the event of a key being
* pressed down). On this callback, we examine each key pressed and,
* if they match one between the expected, we take some actions:
* @dontinclude evas-events.c
* @skip examine the keys pressed
* @until key grab
@ -246,7 +286,7 @@
* example -- evas_object_key_grab(). The 'c' command will, when
* firstly used, @b unfocus the background rectangle. Unfocused
* objects on an Evas canvas will @b never receive key events. We
* grab, then, the keys we're interested at, to the object forcefully:
* grab, then, the keys we're interested at to the object forcefully:
* @skip if (d.focus)
* @until got here by key grabs
* This shows how one can handle input not depending on focus issues
@ -254,10 +294,10 @@
* forced key grabbing with the 'c' key, and observe the messages
* printed about the focused object. Observe, also, that we register
* two more @b object callbacks, this time on the image object
* (Enlightenment logo):
* (Enlightenment logo), where we just print messages telling the mouse
* pointer has entered or exited it area:
* @skip evas_object_show(d.img);
* @until mouse_out, NULL
* The code code blocks for those callbacks are
* @dontinclude evas-events.c
* @skip mouse enters the object's area
* @until mouse exits the object's area
@ -266,25 +306,25 @@
* experience). When you start the example, Evas will consider this
* area by being the whole boundary rectangle around the picture. If
* you issue the 'p' command, though, you get a demonstration of Evas'
* precise point collision detection on objects:
* precise point collision detection on objects. With
* evas_object_precise_is_inside_get(), one can make Evas consider the
* transparent areas of an object (the middle of the logo's E letter,
* in the case) as not belonging to it when calculating mouse
* in/out/up/down events:
* @dontinclude evas-events.c
* @skip if (strcmp(ev->keyname, "p") == 0)
* @until }
* With evas_object_precise_is_inside_get(), one can make Evas
* consider the transparent areas of an object (the middle of the
* logo's E letter, in the case) as not belonging to it when
* calculating mouse in/out/up/down events. To finish the example, try
* the command bound to Cotrol + 'o':
* @skip mods = evas_key_modifier_get(evas);
* @until end of obscured region command
* It exemplifies Evas' <b>obscured regions</b>. When firstly pressed,
* you'll get the same contents, in a region in the middle of the
* canvas, at the time the key was pressed, until you toggle the
* To finish the example, try the command bound to Control + 'o',
* which exemplifies Evas' <b>obscured regions</b>. When firstly
* pressed, you'll get the same contents, in a region in the middle of
* the canvas, at the time the key was pressed, until you toggle the
* effect off again (make sure the animation is running on to get the
* idea better). When you toggle this effect off, we also demonstrate
* the use of evas_render_updates(), which will force immediate
* updates on the canvas rendering, bringing back the obscured
* region's contents to normal.
* @skip mods = evas_key_modifier_get(evas);
* @until end of obscured region command
*
* What follows is the complete code for this example.
*

31
legacy/evas/src/examples/evas-events.c
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@ -31,6 +31,16 @@
static const char *img_path = PACKAGE_EXAMPLES_DIR "/enlightenment.png";
static const char *commands = \
"commands are:\n"
"\ta - toggle animation timer\n"
"\tc - cycle between focus and key grabs for key input\n"
"\td - delete canvas callbacks\n"
"\tf - freeze input for 3 seconds\n"
"\tp - toggle precise point collision detection on image\n"
"\tControl + o - add an obscured rectangle\n"
"\th - print help\n";
struct test_data
{
Ecore_Evas *ee;
@ -42,7 +52,7 @@ struct test_data
static struct test_data d = {0};
/* here just to keep our example's window size and background image's
/* here to keep our example's window size and background image's
* size in synchrony */
static void
_canvas_resize_cb(Ecore_Evas *ee)
@ -69,7 +79,8 @@ _object_focus_in_cb(void *data __UNUSED__,
"OK!" : "Oops, something is bad.");
}
static void /* render flush callback */
/* render flush callback */
static void
_render_flush_cb(void *data __UNUSED__,
Evas *e __UNUSED__,
void *event_info __UNUSED__)
@ -94,8 +105,8 @@ _resize_cb(void *data __UNUSED__)
return EINA_TRUE; /* re-issue the timer */
}
static Eina_Bool
/* let's have our events back */
static Eina_Bool
_thaw_cb(void *data __UNUSED__)
{
fprintf(stdout, "Canvas was frozen %d times, now thawing.\n",
@ -104,7 +115,8 @@ _thaw_cb(void *data __UNUSED__)
return EINA_FALSE; /* do not re-issue the timer */
}
static void /* mouse enters the object's area */
/* mouse enters the object's area */
static void
_on_mouse_in(void *data __UNUSED__,
Evas *evas __UNUSED__,
Evas_Object *o __UNUSED__,
@ -138,15 +150,7 @@ _on_keydown(void *data __UNUSED__,
if (strcmp(ev->keyname, "h") == 0) /* print help */
{
fprintf(stdout,
"commands are:\n"
"\ta - toggle animation timer\n"
"\tc - cycle between focus and key grabs for key input\n"
"\td - delete canvas callbacks\n"
"\tf - freeze input for 3 seconds\n"
"\tp - toggle precise point collision detection on image\n"
"\tControl + o - add an obscured rectangle\n\n"
"\th - print help\n");
fprintf(stdout, commands);
return;
}
@ -393,6 +397,7 @@ main(void)
d.resize_timer = ecore_timer_add(2, _resize_cb, NULL);
fprintf(stdout, commands);
ecore_main_loop_begin();
ecore_evas_free(d.ee);