This code places five Elementary clock widgets on a window, each of them exemplifying a part of the widget's API. Before explaining each clock to be more didatical let's start with the basics.
The first part consists of including the headers. In this case we are only working with the Elementary C++ binding and thus we need only to include him.
- Attention
- If necessary the C and/or the C++ headers should be include here as well.
Now we need to actually start the code and set the elm_policy, which defines for a given policy group/identifier a new policy's value, respectively. In this example the only policy we need to set a value for is ELM_POLICY_QUIT, possibles values for it are:
ELM_POLICY_QUIT_NONE:Never quit the application automatically;
ELM_POLICY_QUIT_LAST_WINDOW_CLOSED:quit when the application's last window is closed;
ELM_POLICY_QUIT_LAST_WINDOW_HIDDEN: quit when the application's last window is hidden;
As you can see, the policy we chose was to quit when the last win is hidden as opose to examples with the C bindings where we perpetually set it to quit when last win was closed. This changed was necessary because in C++ binding as the elm mainloop stop running all object are destroyed, references are unreferenced and events are stopped at ELM_MAIN().
- See also
- For more details consult elm_policy_set
Next step is creating an Elementary window, in this example we use the C++ binding method with the elm_win_util_standard_add that is a elm_win_legacy function, better explained below. And then we set the autohide state for it.
elm_win_util_standard_add (const char *name, const char *tittle) Adds a window object with standard setup. Parameters:
name- The name of the window;
title- The title for the window.
This creates a window but also puts in a standard background with elm_bg_add(), as well as setting the window title to title. The window type created is of type ELM_WIN_BASIC, with the NULL as the parent widget. Returns the created object or NULL on failure.
And we also set the autohide state for win, autohide works similarly to autodel, automatically handling "delete,request" signals when set to true, with the difference that it will hide the window, instead of destroying it.
It is specially designed to work together with ELM_POLICY_QUIT_LAST_WINDOW_HIDDEN which allows exiting Elementary's main loop when all the windows are hidden.
- Note
autodeland autohide are not mutually exclusive. The window will be destructed if both autodel and autohide is set toEINA_TRUEortrue.
- See also
- For more details consult elm::win::autohide_set().
A box arranges objects in a linear fashion, governed by a layout function that defines the details of this arrangement. The box will use an internal function to set the layout to a single row, vertical by default.
Now let's create the box with the C++ binding method, passing our window object as parent.
To better understand, the function size_hint_weight_set for C++ bindings originated from C bindings function evas_object_size_hint_weight_set, that is EFL Evas type function. With this function we set the hints for an object's weight. The parameters are:
- x - Nonnegative double value to use as horizontal weight hint.
- y - Nonnegative double value to use as vertical weight hint.
This is not a size enforcement in any way, it's just a hint that should be used whenever appropriate. This is a hint on how a container object should resize a given child within its area.
Containers may adhere to the simpler logic of just expanding the child object's dimensions to fit its own (see the EVAS_HINT_EXPAND helper weight macro in the EFL Evas Documentation) or the complete one of taking each child's weight hint as real weights to how much of its size to allocate for them in each axis. A container is supposed to, after normalizing the weights of its children (with weight hints), distribute the space it has to layout them by those factors – most weighted children get larger in this process than the least ones.
- Note
- Default weight hint values are 0.0, for both axis.
Then we add the box as a resize-object to win informing that when the size of the win changes so should the box's size. Remember always to set the box visibility to true.
We create each clock with the C++ binding method, passing our window object as parent. The first of them is the pristine clock, using the defaults for a clock, which are military time with no seconds shown.
When using the elm::box the packing method of the subobj - clock in this case - should be defined. There are four possible methods:
pack_start(subobj_)- Add an object to the beginning of the pack list. Packsubobj_into the box obj, placing it first in the list of children objects. The actual position the object will get on screen depends on the layout used. If no custom layout is set, it will be at the top or left, depending if the box is vertical or horizontal, respectively.
pack_end(subobj_)- Add an object at the end of the pack list. Packsubobj_into the box obj, placing it last in the list of children objects. The actual position the object will get on screen depends on the layout used. If no custom layout is set, it will be at the bottom or right, depending if the box is vertical or horizontal, respectively.
pack_before(subobj_, before_)- Adds an object to the box before the indicated object. This will add thesubobj_to the box indicated before the object indicated withbefore_. If before is not already in the box, results are undefined. Before means either to the left of the indicated object or above it depending on orientation.
pack_after(subobj_, after_)- Adds an object to the box after the indicated object. This will add thesubobj_to the box indicated after the object indicated withafter_. If after is not already in the box, results are undefined. After means either to the right of the indicated object or below it depending on orientation.
In this and most examples we use pack_end by choice and practicality. In this part of the code we also make clock visible.
The second clock shows ther am/pm time, that we also create with the C++ binding method, passing our window object as parent. Setting show_am_pm to true and again choosing the packing method and making clock visible.
The third one will show the seconds digits, which will flip in synchrony with system time. Note, besides, that the time itself is different from the system's – it was customly set with time_set():
In both fourth and fifth ones, we turn on the edition mode. See how you can change each of the sheets on it, and be sure to try holding the mouse pressed over one of the sheet arrows. The forth one also starts with a custom time set:
The fifth, besides editable, has only the time units editable, for hours, minutes and seconds. This exemplifies edit_mode_set():
Finally we just have to make our window visible and then run the elm mainloop, starting to handle events and drawing operations.
See the full clock_cxx_example.cc, whose window should look like this picture:
