Type Layoutf

   object --+        
            |        
       Object --+    
                |    
LayoutConstraints --+
                    |
                   Layoutf

The class Layoutf(wxLayoutConstraints) presents a simplification of the wxLayoutConstraints syntax. The name Layoutf is choosen because of the similarity with C's printf function.

Quick Example:

lc = Layoutf('t=t#1;l=r10#2;r!100;h%h50#1', (self, self.panel))

is equivalent to

lc = wxLayoutContraints() lc.top.SameAs(self, wxTop) lc.left.SameAs(self.panel, wxRight, 10) lc.right.Absolute(100) lc.height.PercentOf(self, wxHeight, 50)

Usage:

You can give a constraint string to the Layoutf constructor,

or use the 'pack' method. The following are equivalent:

lc = Layoutf('t=t#1;l=r#2;r!100;h%h50#1', (self, self.panel))

and

lc = Layoutf() lc.pack('t=t#1;l=r#2;r!100;h%h50#1', (self, self.panel))

Besides 'pack' there's also 'debug_pack' which does not set

constraints, but prints traditional wxLayoutConstraint calls to stdout.

The calls to the Layoutf constructor and pack methods have

the following argument list:

(constraint_string, objects_tuple)

Constraint String syntax:

Constraint directives are separated by semi-colons. You

generally (always?) need four directives to completely describe a subwindow's location.

A single directive has either of the following forms:

1. <own attribute><compare operation>[numerical argument] for example r!100 -> lc.right.Absolute(100) ) and w* -> lc.width.AsIs()

2. <own attribute><compare operation>[numerical argument] #<compare object nr.>

for example t_10#2 (lc.top.Below(<second obj>, 10)

3. <own attribute><compare operation><compare attribute> [numerical argument]#<compare object nr.>

for example w%h50#2 ( lc.width.PercentOf(<second obj>, wxHeight, 50) and t=b#1 ( lc.top.SameAs(<first obj>, wxBottom) )

Which one you need is defined by the <compare operation>

type. The following take type 1 (no object to compare with):

'!': 'Absolute', '?': 'Unconstrained', '*': 'AsIs'

These take type 2 (need to be compared with another object)

'<': 'LeftOf', '>': 'RightOf', '^': 'Above', '_': 'Below'

These take type 3 (need to be compared to another object attribute)

'=': 'SameAs', '%': 'PercentOf'

For all types, the <own attribute> letter can be any of

't': 'top', 'l': 'left', 'b': 'bottom', 'r': 'right', 'h': 'height', 'w': 'width', 'x': 'centreX', 'y': 'centreY'

If the operation takes an (optional) numerical argument, place it in [numerical argument]. For type 3 directives, the <compare attribute> letter can be any of

't': 'wxTop', 'l': 'wxLeft', 'b': 'wxBottom' 'r': 'wxRight', 'h': 'wxHeight', 'w': 'wxWidth', 'x': 'wxCentreX', 'y': 'wxCentreY'

Note that these are the same letters as used for <own attribute>, so you'll only need to remember one set. Finally, the object whose attribute is refered to, is specified by #<compare object nr>, where <compare object nr> is the 1-based (stupid, I know, but I've gotten used to it) index of the object in the objects_tuple argument.

Bugs:

Not entirely happy about the logic in the order of arguments after the <compare operation> character.

Not all wxLayoutConstraint methods are included in the syntax. However, the type 3 directives are generally the most used. Further excuse: wxWindows layout constraints are at the time of this writing not documented.