rsc3/doc-schelp/HelpSource/Classes/GridLayout.schelp

186 lines
6.6 KiB
Text

CLASS:: GridLayout
summary:: A layout that organizes views in a grid
categories:: GUI>Layout
related:: Classes/HLayout, Classes/VLayout, Classes/StackLayout, Guides/GUI-Layout-Management
DESCRIPTION::
GridLayout distributes its space into a strong::grid of rows and columns::, where each item can occupy strong::one or more cells::.
You can construct the layout in two ways using link::#*rows:: and link::#*columns::. In the former constructor you pass arrays of items by rows, and in the latter by columns. Items can also be added later using link::#-add:: and link::#-addSpanning::. To remove an item, simply use link::Classes/View#-remove:: for views, or link::Classes/QObject#-destroy:: for views or layouts.
It is possible to add more than one view into the same cell. The last added view will be the top-most. However, it is most probably more convenient to use a link::Classes/StackLayout:: for that purpose.
The layout manages the grid size automatically: you can add an item at any row and cell number. When items are added or removed, the grid will re-adjust according to the last occupied row and column.
subsection:: Fine tuning
Each item can be assigned an strong::alignment:: either at layout link::#*rows#construction:: or later using link::#-setAlignment::. An item will then get at most its default size, if available (see: link::Classes/View#-sizeHint::), and will be aligned within its cell according to the specified alignment.
Each row or column can be assigned a strong::stretch factor:: using link::#-setRowStretch:: and link::#-setColumnStretch::. Rows or columns that would otherwise get equal space are then distributed according to the relative proportions of their stretch factors.
Each row or column can also be assigned a strong::minimum:: size using link::#-setMinRowHeight:: and link::#-setMinColumnWidth::, to override the size constraints imposed by the contained views.
In addition to adjusting the spacing between cells using link::Classes/Layout#-spacing:: you can control the spacing between rows and between columns separately using link::#-hSpacing:: and link::#-vSpacing::.
subsection:: Leaving empty space
You can leave any cell empty by not placing any item into it, or at link::#*rows#construction:: using code::nil:: instead of a view or another layout. Note though that the empty cells will always be regarded as freely stretchable and will not impose any constraints on space distribution.
CLASSMETHODS::
PRIVATE:: key
PRIVATE:: qtClass
METHOD:: rows
Creates a GridLayout and fills each row with an array of items given as arguments.
argument:: ... rows
Each argument is an Array of items to form a consecutive row. An item can be a strong::view::, another strong::layout::, or strong::nil:: for an empty cell.
discussion::
You can make an item span more than one cell by wrapping it into an Array, followed by pairs of (\rows, number) and/or (\columns, number). You can also assign an alignment to an item by following it with a pair of (\align, alignment). \rows, \columns, and \align can be abbreviated with \r, \c, and \a, respectively. For possible alignment values see link::Reference/gui_alignments::.
The simplified syntax for placing key-value pairs into an array comes handy (see link::Reference/Syntax-Shortcuts#Creating Arrays with key-value pairs::, and the example below).
Example:
Code::
(
w=Window().layout_( GridLayout.rows(
[Slider2D(), Slider2D(), [Slider(), rows:2]],
[Slider2D(), Slider2D()],
[[Slider().orientation_(\horizontal), columns:2]]
)).front;
)
::
METHOD:: columns
Creates a GridLayout and fills each column with an array of items given as arguments.
argument:: ... cols
Each argument is an Array of items to form a consecutive column. An item can be a strong::view::, another strong::layout::, or strong::nil:: for an empty cell.
discussion::
To make an item span several cells, or assign an alignment to it, the same instructions as for link::#*rows:: apply.
INSTANCEMETHODS::
METHOD:: add
Adds an item into the cell at specified row and column.
argument:: item
The item can be a strong::view:: or another strong::layout::.
argument:: row
The row index.
argument:: column
The column index.
argument:: align
A symbol denoting the alignment, or nil. See link::Reference/gui_alignments:: for possible values.
METHOD:: addSpanning
Adds an item into the grid so as to occupy several cells.
argument:: item
The item can be a strong::view:: or another strong::layout::.
argument:: row
The row index.
argument:: column
The column index.
argument:: rowSpan
The amount of cells to occupy in vertical direction.
argument:: columnSpan
The amount of cells to occupy in horizontal direction.
argument:: align
A symbol denoting the alignment, or nil. See link::Reference/gui_alignments:: for possible values.
METHOD:: hSpacing
The spacing between columns, in Integer amount of pixels.
METHOD:: vSpacing
The spacing between rows, in Integer amount of pixels.
METHOD:: setRowStretch
Sets the stretch factor of a row. By default rows have a stretch factor of 0. If a larger factor is assigned to a row, rows will get their space redistributed according to the relative proportions of their factors.
argument:: row
The index of a row.
argument:: factor
An Integer.
METHOD:: setColumnStretch
Sets the stretch factor of a column. By default columns have a stretch factor of 0. If a larger factor is assigned to a column, columns will get their space redistributed according to the relative proportions of their factors.
argument:: column
The index of a column.
argument:: factor
An Integer.
METHOD:: setAlignment
Sets the alignment of an item managed by the layout.
argument:: item
A view or a layout managed by this layout, or a Point of which x denotes the column index and y the row index of an item.
argument:: align
A symbol denoting the alignment. See link::Reference/gui_alignments:: for possible values.
METHOD:: minRowHeight
Gets the minimum height assigned to a row.
argument:: row
The index of a row.
METHOD:: setMinRowHeight
Sets the minimum height of row.
argument:: row
The index of a row.
argument:: height
An Integer amount of pixels.
METHOD:: minColumnWidth
Gets the minimum width assigned to a column.
argument:: column
The index of a column.
METHOD:: setMinColumnWidth
Sets the minimum width of a column.
argument:: column
The index of a column.
argument:: width
An Integer amount of pixels.