================
Machine Controls
================

We want all `ActionButtons` in VCP to have a minimum height and width of 50
pixels and the font size to be 14pt so in the stylesheet for the `QMainWindow`
put the following.
::

    ActionButton {
    min-height: 50px;
    min-width: 50px;
    font: 14pt "DejaVu Sans";
    }

.. image:: images/vcp1-designer-08.png
   :align: center
   :scale: 40 %

Now add three action buttons in the bottom frame and from left to right add the
following to the `actionName` of each button.
::

    machine.estop.toggle
    machine.power.toggle
    machine.home.all


Name the left button `E Stop` and the middle button `Power`. The `Home All`
button will get its name from the rule.

Make sure you check off the `checkable` box for E Stop and Power buttons, this
makes them a toggle button.

Now we need to add a couple of rules to the `Home` button. The first rule will
set the text of the button based on if all the joints are homed or not. Double
click on the button to open the `Rules Editor` and add a new rule. The
`Property` is Text. Click in the blue channel box and type `s` now pick
`status:all_axes_homed` from the list. Notice the type is `bool` which is a true
false type and that is what we want for this.
::

    status:all_axes_homed

The expression to change the text of the button is::

    'Homed' if ch[0] else 'Home\nAll'

Notice that 'Home\\nAll' has a new line character `\\n` in it.

.. image:: images/vcp1-designer-09.png
   :align: center
   :scale: 60 %

The second rule will have the same channel but the property will be for the
`Style Sheet` with the following expression::

    'background-color:rgb(138, 226, 52)' if ch[0]else ''

.. image:: images/vcp1-designer-10.png
   :align: center
   :scale: 60 %

Now when we run the VCP you can see the buttons in action.

.. image:: images/vcp1-run-04.png
   :align: center
   :scale: 60 %

To see the styles for `machine.estop` and `machine.power` buttons look in
`vcp1/vcp1/ui/style.css and you can see the how the styles are applied using the
style.qss file. For example the style for the E Stop button is applied with the
following. Notice that the type of widget is an `ActionButton` and the specfic
button has the `actionName` machine.estop.toggle. and the state is `checked`.
::

    ActionButton[actionName="machine.estop.toggle"]:checked{
        background: rgb(239, 41, 41);
    }

Now lets add the rest of the machine buttons so add five more `ActionButtons` to
the right of the Home button and name them Run, Step, Pause, Resume, and Abort.

The `actionNames` are::

    program.run
    program.step
    program.pause
    program.resume
    program.abort

Now we have the machine buttons complete.

.. image:: images/vcp1-run-05.png
   :align: center
   :scale: 60 %

The program buttons will not be enabled until we load a program.