Reference

Layout

Guietta uses a grid layout (QGridLayout). Number of rows and columns is automatically calculated from the input. There is typically one widget per grid cell ( _ will result in an empty cell), but widgets may span multiple rows and/or columns as described below.

Syntax

To create a layout, instantiate a guietta.Gui object and pass it a series of lists. Each list corresponds to a row of widgets. All lists must have the same length.

As a special case, if a list contains a single widget, the widget will be expanded to fill the whole row. This is useful for titles and horizontal separators.

Widgets

Here is the complete widget set:

from guietta import Gui, B, E, L, HS, VS, HSeparator, VSeparator
from guietta import Yes, No, Ok, Cancel, Quit, _, ___, III

gui = Gui(

   [ '<center>A big GUI with all of Guietta''s widgets</center>'],
   [ HSeparator ],

  [ 'Label'    , 'imagelabel.jpeg' , L('another label')  , VS('slider1')],
  [  _         ,     ['button']    , B('another button') ,     III      ],
  [ '__edit__' ,  E('an edit box') , _                   ,   VSeparator ],
  [   Quit     ,        Ok         , Cancel              ,     III      ],
  [    Yes     ,        No         , _                   ,     III      ],
  [  HS('slider2'),    ___         , ___                 ,      _       ] )

gui.show()
Syntax Equivalent Qt widget Event name
_ nothing (empty layout cell) none
‘text’
L(‘text’)
 QLabel(‘text’) ‘text’
‘image.jpg’
L(‘image.jpg’)
 QLabel with QPixmap(‘image.jpg’) ‘image’
[‘text’]
B(‘text’)
 QPushButton(‘text’) ‘text’
[‘image.jpg’]
B(‘image.jpg’)
 QPushButton(QIcon(‘image.jpg’), ‘’) ‘image’
‘__name__’ QLineEdit(‘’), name set to ‘name’ ‘name’
E(‘text’) QLineEdit(‘text’) ‘text’
C(‘text’) QCheckBox(‘text’) ‘text’
R(‘text’) QRadioButton(‘text’) ‘text’
P(‘name’) QProgressBar() ‘name’
HS(‘name’) QSlider(Qt::Horizontal) ‘name’
VS(‘name’) QSlider(Qt::Horizontal) ‘name’
HSeparator Horizontal separator  
VSeparator Vertical separator  
M(‘name’) Matplotlib FigureCanvas*  
widget any valid QT widget none
(widget, ‘name’) any valid QT widget ‘name’
  • Matplotlib will only be imported if the M() widget is used. Matplotlib is not installed automatically toegher with guietta. If the M() widget is used, the user must install matplotlib manually.

Buttons support both images and texts at the same time:

Syntax Equivalent Qt widget Event name
[‘image.jpg’, ‘text’]
B(‘image.jpg’, ‘text’)
 QPushButton() with image and text ‘text’

Continuations

How to extend widgets over multiple rows and/or columns:

from guietta import Gui, HS, VS, _, ___, III

gui = Gui(

   [ 'Big label', ___ , ___ , 'xxx' , VS('s1') ],
   [    III     , III , III , 'xxx' ,   III    ],
   [    III     , III , III , 'xxx' ,   III    ],
   [     _      ,  _  ,  _  , 'xxx' ,   III    ],
   [  HS('s2')  , ___ , ___ ,  ___  ,    _     ])
Syntax Meaning
_ nothing (empty layout cell)
___ (three underscores) Horizontal widget span
III (three capital letters i) vertical widget span

Rules:

  • all grid cells must contain either a widget, one of ___ or III, or _ if the cell is empty. Other values will cause a ValueError exception. Empty elements are not allowed by the Python list syntax and will cause a SyntaxError.
  • ___ can only be used to the right of a widget to extend it
  • III can only be used below a widget to extend it
  • ___ and III can be combined to form big rectangular widgets, with the widget to be extended in the top-left corner.

Signals

Signals can be connected with gui.events() where each widget has:

Syntax Meaning
_ no connection
slot reference to Python callable, using the default widget signal (if pre-defined, otherwise ValueError)
(‘textEdited’, slot) tuple(signal name, Python callable)

Table of default signals:

Widget Signal
QPushButton clicked(bool)
QLineEdit returnPressed()
QCheckBox stateChanged(int)
QRadioButton toggled())
QAbstractSlider (QSlider, QDial, QScrollBar) QProgressBar valueChanged(int)
QListWidget currentTextChanged
QComboBox textActivated

Widgets not listed in this table must be connected using the tuple syntax.

Properties

Table of properties created for each widget type:

Widget Read property type Write property type
QLabel, QLineEdit str str
QAbstractButton (QPushButton, QCheckBox, QRadioButton) widget instance callable
QAbstractSlider (QSlider, QDial, QScrollBar) QProgressBar int int
QAbstractItemView (QListWidget) list of str list of str
QComboBox dict{str: any} dict{str: any}
Everything else widget instance raises an exception

Exception catching in slots

When a slot is called, they will be enclosed in a “try - except Exception” block. What happens in the except clause depends on the “exceptions” keyword parameter of the GUI constructor, which accepts the following enums:

Enum Exception handling
Exceptions.OFF nothing, exception is re-raised
Exceptions.POPUP (default) popup a QMessageBox.warning with the exception string
Exceptions.PRINT exception string printed on stdout
Exceptions.SILENT nothing, exception is “swallowed”