This example shows how to manipulate a dragable part through the edje_object_part_drag API.
First, in the edc code, we are declaring a part which will be our movable part, called "knob". It is a normal rectangle, which contains a block called "dragable", that will define the area where this rectangle can be moved, and in which axis it can be moved.
This is our part:
Notice that it defines, through its "x:" and "y:' properties, that the
part will be only moved on the y axis (vertical). Check the edc reference
docs for more info about this.
Now, in our example C code, we just do the same as on the other examples,
setting some global data on a structure, load the edje file and so:
@dontinclude edje-drag.c
@skip static const char *PARTNAME
@until ;
@skip main(int argc __UNUSED__, char *argv[])
@until evas_object_show
We want to use the drag_page and drag_step functions, and in order to do so we
need to define the step size and page size of our dragable part. They are
defined as float values which represent a portion of the entire size of the
dragable area:
@until drag page step
We are going to use the keyboard to move the @c knob part, through the key
down callback @c _bg_key_down, but we also want to know when the user has
moved the knob by using the mouse (which is possible, since we defined that
this part will receive mouse events). Thus, we set a callback for the signal
"drag", which comes from the dragable part:
@dontinclude edje-drag.c
@skipline evas_object_event_callback_add
@skipline edje_object_signal_callback_add
Now, let's take a look at our key down callback:
@dontinclude edje-drag.c
@skip _on_bg_key_down
@until }
@skip else
@until }
@skip else
@until }
@skip else
@until }
@skip else
@until }
@skip else
@until }
@skip else
@until }
@skip else
@until }
On this callback we define that the user will use the "up" and "down" arrows
to move the dragable part, respectively, -1.0 and 1.0 times the step size.
And that the "Page Up" (Prior) and "Page Down" (Next) keys will move -1.0 and
1.0 times the page size. Both of these will occur on the vertical axis, since
we pass 0.0 as value to the respective horizontal axis parameters. And our
dragable part also only supports being moved in the vertical axis (defined in
the edc).
We also define that the "m" key will be used to explicitly position the knob
part in the middle of the dragable area.
And here is the callback for the @c "drag" signal that is received from the
theme:
@dontinclude edje-drag.c
@skip _on_knob_moved
@until }
The example's window should look like this picture:
@image html edje-drag-example.png
@image rtf edje-drag-example.png
@image latex edje-drag-example.eps width=\textwidth
The full source code follows:
@include edje-drag.c
To compile use this command:
@verbatim
* gcc -o edje-drag edje-drag.c -DPACKAGE_BIN_DIR=\"/Where/enlightenment/is/installed/bin\" -DPACKAGE_LIB_DIR=\"/Where/enlightenment/is/installed/lib\"
* -DPACKAGE_DATA_DIR=\"/Where/enlightenment/is/installed/share\"