| Allegro CL version 8.2 Unrevised from 8.1 to 8.2. 8.1 version |
A grid-row
that is an instance of this class allows the user to interactively
change the width of grid-column
s where they cross the
grid-row
. The
resizable
property of a column must also be true before interactive resizing is
possible for that column. In other words, a column may be
interactively resized at a particular cell if the column is a resizable one and the row
at that cell is an instance of column-sizing-row-mixin
.
This feature is typically used only in a row that serves as a set of column headers, so that the special column-sizing mouse cursor does not appear frequently as the user moves the mouse over the body of the grid (which might be distracting), and/or to prevent the user from inadvertantly resizing a column slightly if they click too near a cell's border when they mean to click in its interior. Nevertheless, it may sometimes be desirable to use this class for multiple rows, or even every row, of a grid.
The user uses this feature by moving the mouse cursor to the righthand
border of a cell in a resizable column where it crosses a
column-sizing-row-mixin
row. The
mouse cursor will change to indicate where resizing may be initiated;
this area ranges from the rightmost edge of the border to *grid-border-mouse-slack*
pixels to
the left of that. The user may click and drag horizontally in this
area to resize the grid-column
. If the uniform-resizing property
of the grid section is true, then all of the columns in the clicked
grid-column-section
will be sized to the specified size, though if the control key is held
down then the behavior of the uniform-resizing property is
reversed. The drag may be canceled either by pressing the Escape key
before releasing the mouse button or by releasing the mouse button to
the left of the left side of the column (which would otherwise makes
its width be negative).
This class must be mixed with grid-row
(or one of its subclasses)
to make an instantiable class. It is best to specify such mixin
classes ahead of the grid-row
class in the list of
superclasses for a new class, so that the small amount of special
behavior from the mixin class will override the more general behavior
of the grid-row
class. For example:
(defclass my-column-sizing-row (column-sizing-row-mixin grid-row)())
The above default mouse click behavior may be overridden by custom cell-click methods.
The width of a grid-column
is stored as its
section-size
property. See also stretch-subsection.
See the grid-widget
class
for an overview of writing grid-widget code.
Copyright (c) 1998-2016, Franz Inc. Oakland, CA., USA. All rights reserved.
This page was not revised from the 8.1 page.
Created 2010.1.21.
| Allegro CL version 8.2 Unrevised from 8.1 to 8.2. 8.1 version |