Class: LayoutOrigin

• Inheritance
• Description
• Class protocol
  • instance creation
• Instance protocol
  • accessing
  • comparing
  • computing
  • converting
  • initialization
  • printing & storing
  • queries
• Examples

Inheritance:

   Object
   |
   +--Layout
      |
      +--LayoutOrigin
         |
         +--AlignmentOrigin
         |
         +--LayoutFrame

Package:

stx:libview2

Category:

Graphics-Geometry

Version:

rev: 1.35 date: 2022/01/12 17:32:51

user: cg

file: LayoutOrigin.st directory: libview2

module: stx stc-classLibrary: libview2

Description:

This class is provided to make porting of existing ST-80 applications
easier. Instances can be used to control the geometry of a subview, within
its superview. It provides the same functionality as a relative origin
combined with insets.
A layoutOrigin controls the origin of a subcomponent, given a fractional
component and an offset component.

Notice: 
    this class was implemented using protocol information
    from alpha testers - it may not be complete or compatible to
    the corresponding ST-80 class. 
    If you encounter any incompatibilities, please forward a note 
    describing the incompatibility verbal (i.e. no code) to the ST/X team.

copyright
COPYRIGHT (c) 1995 by Claus Gittinger
             All Rights Reserved

This software is furnished under a license and may be used
only in accordance with the terms of that license and with the
inclusion of the above copyright notice.   This software may not
be provided or otherwise made available to, or used by, any
other person.  No title to or ownership of the software is
hereby transferred.

Class protocol:

 fractionalFromPoint: aPoint

given a point, create a layoutOrigin representing the same
relative origin.

Usage example(s):

LayoutOrigin fractionalFromPoint:0.5@0.5

 fromPoint: aPoint

return a new LayoutOrigin from aPoint.
If the coordinates are between 0 and 1,
take them as fractional parts (relative to superview).
Otherwise, treat them as absolute offsets.

Usage example(s):

LayoutOrigin fromPoint:100@100 LayoutOrigin fromPoint:0.5@0.5 LayoutOrigin fromPoint:0.5@100

 offsetFromPoint: aPoint

given a point, create a layoutOrigin representing the same
absolute (pixel) origin.

Usage example(s):

LayoutOrigin offsetFromPoint:100@100

Instance protocol:

 leftFraction

return leftFraction

 leftFraction: aFraction

set leftFraction (0..1)

 leftFraction: aFraction offset: o

set leftFraction (0..1) and offset in pixels

 leftFraction: lF offset: lO topFraction: tF offset: tO

set leftFraction (0..1), leftOffset, topFraction (0..1) and topOffset

 leftFraction: newLeft topFraction: newTop

set leftFraction (0..1) and topFraction (0..1)

 leftInset: pixels

set leftOffset for an inset at the left

 leftOffset

return leftOffset

 leftOffset: something

set leftOffset

 leftOffset: newLeft topOffset: newTop

set leftOffset and topOffset

 offset: aPoint

set both left and top offsets

 topFraction

return topFraction

 topFraction: aFraction

set topFraction (0..1)

 topFraction: aFraction offset: o

set topFraction (0..1) and offset

 topInset: pixels

set topOffset for an inset at the top

 topOffset

return topOffset

 topOffset: something

set topOffset

 = anObject

(comment from inherited method)
return true if the receiver and the arg have the same structure.
Notice:
This method is partially open coded (inlined) by the compiler(s)
identical objects are always considered equal.
redefining it may not work as expected.

 hash

(comment from inherited method)
return an Integer useful as a hash key for the receiver.
This hash should return same values for objects with same
contents (i.e. use this to hash on structure)

 rectangleRelativeTo: superRectangle preferred: prefRectHolder

compute the rectangle represented by the receiver,
given the superView's rectangle and the view's preferredExtent.

Usage example(s):

|superRect lO| superRect := 0@0 corner:100@100. lO := (LayoutOrigin new). lO leftFraction:0.5; topFraction:0.5. lO rectangleRelativeTo:superRect preferred:(0@0 corner:30@30)

 asAlignmentOrigin

return an equivalent alignmentOrigin

 fromLiteralArrayEncoding: encoding

read my values from an encoding.
The encoding is supposed to be of the form:
(#LayoutOrigin orgOffsX relOrgX orgOffsY relOrgY)
This is the reverse operation to #literalArrayEncoding.

Usage example(s):

LayoutOrigin new fromLiteralArrayEncoding:#(#LayoutOrigin 70 0 2 0)

 literalArrayEncoding

encode myself as an array, from which a copy of the receiver
can be reconstructed with #decodeAsLiteralArray.
The encoding is:
(#LayoutOrigin orgOffsX relOrgX orgOffsY relOrgY)

Usage example(s):

LayoutOrigin new fromLiteralArrayEncoding:#(#LayoutOrigin 70 0 2 0) (LayoutOrigin new leftOffset:10; leftFraction:0.2; topOffset:20; topFraction:0.4) literalArrayEncoding

 initialize

(comment from inherited method)
setup the instance - to be redefined by concrete subclasses

 displayOn: aGCOrStream

return a printed representation of the receiver for displaying

 isLayoutOrigin

return true, if this is a layoutOrigin

 origin

Examples:

    |top button|

    top := StandardSystemView new.
    top extent:300@300.

    button := Button label:'component'.
    top add:button in:(LayoutOrigin new
                            leftFraction:0.5;
                            topFraction:0.5).

    top open

    |top button|

    top := StandardSystemView new.
    top extent:300@300.

    button := Button label:'component'.
    top add:button in:(LayoutOrigin new
                            leftFraction:0.5;
                            topFraction:0.5;
                            leftOffset:10;
                            topOffset:20).

    top open