Generic Function

Summary

Calls a function on each of a pane's children.

Package

capi

Signature

map-pane-children pane function &key visible test reverse

Arguments

pane

A CAPI pane.

function

A function of one argument.

visible

A boolean. The default value is nil.

test

A function of one argument, or nil. The default is nil.

reverse

A boolean. The default value is nil.

Description

The function map-pane-children applies function to pane 's immediate children.

If visible is true, then function is applied only to the visible children.

If test is non-nil, it is a function which is applied first to each child, and only those for which test returns a true value are then passed to function .

If reverse is non-nil, the order in which the children are processed is reversed.

Example

This example constructs a pinboard containing random ellipses. A repainting function is mapped over them, restricted to those with width greater than height.

(defun random-color () 

  (aref #(:red :blue :green :yellow :cyan 

          :magenta :pink :purple :black :white) 

        (random 10)))

(defun random-origin () 

  (list (random 350) (random 250)))

(defun random-size () 

  (list (+ 10 (random 40)) 

        (+ 10 (random 40))))

(setf ellipses

      (capi:contain 

       (make-instance 

        'capi:pinboard-layout 

        :children 

        (loop for i below 40

              for origin = (random-origin)

              for size = (random-size)

              collect 

              (make-instance 'capi:ellipse 

                             :x (first origin) 

                             :y (second origin)

                             :width (first size) 

                             :height (second size)

                             :graphics-args 

                             (list :foreground 

                                   (random-color)) 

                             :filled t)))))

(defun repaint (ellipse) 

  (setf (capi:pinboard-object-graphics-args ellipse)

       (list :foreground (random-color)))

  (capi:redraw-pinboard-object ellipse t))

(defun widep (ellipse)

  (capi:with-geometry ellipse

      (> capi:%width% capi:%height%)))

(capi:map-pane-children ellipses 'repaint :test 'widep)

See also

map-pane-descendant-children
Hierarchy of panes