children-on ( rect gadget -- seq )
Factor handbook » UI framework » Building user interfaces » Gadget geometry

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Vocabulary
ui.gadgets

Inputs

rect	a rect
gadget	a gadget

Outputs

seq	a sequence of gadgets

Generic word contract
Outputs a sequence of gadgets which potentially intersect a rectangle in the coordinate system of the gadget.

Notes
This does not have to be an accurate intersection test, and simply returning children>> is a valid implementation. However, an accurate intersection test reduces the amount of work done when drawing this gadget if it is partially clipped and not all children are visible.

Definition

IN: ui.gadgets

GENERIC: children-on ( rect gadget -- seq )

Methods

USING: accessors kernel ui.gadgets ;

M: gadget children-on nip children>> ;


USING: accessors kernel math.vectors sequences ui.gadgets
ui.gadgets.grids ;

M: grid children-on
    dup children>> empty?
    [ 2drop f ] [
        [ { 0 1 } ] dip [ grid>> ] [ dim>> ] bi
        [ [ loc>> vmin ] reduce ] curry fast-children-on concat
    ] if ;


USING: accessors kernel ui.gadgets ui.gadgets.packs ;

M: pack children-on
    [ orientation>> ] [ children>> ] bi
    [ loc>> ] fast-children-on ;


USING: accessors kernel ui.gadgets ui.gadgets.worlds ;

M: world children-on nip children>> ;