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1 | \section{\class{wxBoxSizer}}\label{wxboxsizer} |
2 | ||
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3 | The basic idea behind a box sizer is that windows will most often be laid out in rather |
4 | simple basic geomerty, typically in a row or a column or several hierachies of either. | |
5 | ||
6 | As an exmaple, we will construct a dialog that will contain a text field at the top and | |
7 | two buttons at the bottom. This can be seen as a top-hierarchy column with the text at | |
8 | the top and buttons at the bottom and a low-hierchary row with an OK button to the left | |
9 | and a Cancel button to the right. In many cases (particulary dialogs under Unix and | |
10 | normal frames) the main window will be resizable by the user and this change of size | |
11 | will have to get propagated to its children. In our case, we want the text area to grow | |
12 | with the dialog, whereas the button shall have a fixed size. In addition, there will be | |
13 | a thin border around all controls to make the dialog look nice and - to make matter worse - | |
14 | the buttons shall be centred as the width of the dialog changes. | |
15 | ||
16 | It is the unique feature of a box sizer, that it can grow in both directions (height and | |
17 | width) but can distribute its growth in the main direction (horizontal for a row) {\it unevenly} | |
18 | among its children. In our example case, the vertical sizer is supposed to propagate all its | |
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19 | height changes to only the text area, not to the button area. This is determined by the {\it option} parameter |
20 | when adding a window (or another sizer) to a sizer. It is interpreted | |
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21 | as a weight factor, i.e. it can be zero, indicating that the window may not be resized |
22 | at all, or above zero. If several windows have a value above zero, the value is interpreted | |
23 | relative to the sum of all weight factors of the sizer, so when adding two windows with | |
24 | a value of 1, they will both get resized equally much and each half as much as the sizer | |
25 | owning them. Then what do we do when a column sizer changes its width? This behaviour is | |
26 | controlled by {\it flags} (the second parameter of the Add() function): Zero or no flag indicates that | |
27 | the window will get aligned at the left (in a column sizer) and the top (row sizer), whereas | |
28 | wxALIGN\_RIGHT and wxALIGN\_BOTTOM will do what they say. The item can also be centered | |
29 | using the wxCENTRE flag (same as wxCENTER) or it can be forced to grow with the sizer (using | |
30 | the wxGROW flag (same as wxEXPAND)). | |
31 | ||
32 | As mentioned above, any window belonging to a sizer may have border, and it can be specified | |
33 | which of the four sides may have this border, using the wxTOP, wxLEFT, wxRIGHT and wxBOTTOM | |
34 | constants or wxALL for all directions (and you may also use wxNORTH, wxWEST etc instead). These | |
35 | flags can be used in combintaion with the alignement flags above as the second paramter of the | |
36 | Add() method using the binary or operator |. The sizer of the border also must be made known, | |
37 | and it is the third parameter in the Add() method. This means, that the entire behaviour of | |
38 | a sizer and its children can be controlled by the three parameters of the Add() method. | |
39 | ||
40 | \begin{verbatim} | |
41 | // we want to get a dialog that is stretchable because it | |
42 | // has a text ctrl at the top and two buttons at the bottom | |
43 | ||
44 | MyDialog::MyDialog(wxFrame *parent, wxWindowID id, const wxString &title ) : | |
45 | wxDialog( parent, id, title, wxDefaultPosition, wxDefaultSize, wxDIALOG_STYLE | wxRESIZE_BORDER ) | |
46 | { | |
47 | wxBoxSizer *topsizer = new wxBoxSizer( wxVERTICAL ); | |
48 | ||
49 | // create text ctrl with minimal size 100x60 | |
50 | topsizer->Add( | |
51 | new wxTextCtrl( this, -1, "My text.", wxDefaultPosition, wxSize(100,60), wxTE_MULTILINE), | |
52 | 1, // make vertically stretchable | |
53 | wxEXPAND | // make horizontally stretchable | |
54 | wxALL, // and make border all around | |
55 | 10 ); // set border width to 10 | |
56 | ||
57 | ||
58 | wxBoxSizer *button_sizer = new wxBoxSizer( wxHORIZONTAL ); | |
59 | button_sizer->Add( | |
60 | new wxButton( this, wxID_OK, "OK" ), | |
61 | 0, // make horizontally unstretchable | |
62 | wxALL, // make border all around (implicit top alignment) | |
63 | 10 ); // set border width to 10 | |
64 | button_sizer->Add( | |
65 | new wxButton( this, wxID_CANCEL, "Cancel" ), | |
66 | 0, // make horizontally unstretchable | |
67 | wxALL, // make border all around (implicit top alignment) | |
68 | 10 ); // set border width to 10 | |
69 | ||
70 | topsizer->Add( | |
71 | button_sizer, | |
72 | 0, // make vertically unstretchable | |
73 | wxCENTER ); // no border and centre horizontally | |
74 | ||
75 | SetAutoLayout( TRUE ); // tell dialog to use sizer | |
76 | SetSizer( topsizer ); // actually set the sizer | |
77 | ||
78 | topsizer->Fit( this ); // set size to minimum size as calculated by the sizer | |
79 | topsizer->SetSizeHints( this ); // set size hints to honour mininum size | |
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80 | } |
81 | \end{verbatim} | |
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83 | \wxheading{Derived from} |
84 | ||
36edded9 | 85 | \helpref{wxSizer}{wxsizer}\\ |
4130b487 | 86 | \helpref{wxObject}{wxobject} |
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87 | |
88 | \membersection{wxBoxSizer::wxBoxSizer}\label{wxboxsizerwxboxsizer} | |
89 | ||
90 | \func{}{wxBoxSizer}{\param{int }{orient}} | |
91 | ||
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92 | Constructor for a wxBoxSizer. {\it orient} may be either of wxVERTICAL |
93 | or wxHORIZONTAL for creating either a column sizer or a row sizer. | |
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94 | |
95 | \membersection{wxBoxSizer::RecalcSizes}\label{wxboxsizerrecalcsizes} | |
96 | ||
97 | \func{void}{RecalcSizes}{\void} | |
98 | ||
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99 | Implements the calculation of a box sizer's dimensions and then sets |
100 | the size of its its children (calling \helpref{wxWindow::SetSize}{wxwindowsetsize} | |
101 | if the child is a window). It is used internally only and must not be called | |
102 | by the users. Documented for information. | |
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103 | |
104 | \membersection{wxBoxSizer::CalcMin}\label{wxboxsizercalcmin} | |
105 | ||
106 | \func{wxSize}{CalcMin}{\void} | |
107 | ||
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108 | Implements the calculation of a box sizer's minimal. It is used internally |
109 | only and must not be called by the users. Documented for information. | |
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110 | |
111 | \membersection{wxBoxSizer::GetOrientation}\label{wxboxsizergetorientation} | |
112 | ||
113 | \func{int}{GetOrientation}{\void} | |
114 | ||
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115 | Returns the orientation of the boxsizer, either of wxVERTICAL |
116 | or wxHORIZONTAL. | |
117 |