Class: ScaleTransform

• Inheritance
• Description
• Class protocol
  • instance creation
• Instance protocol
  • accessing
  • applying transform
  • printing & storing
  • private
  • testing
  • transformations
• Examples

Inheritance:

   Object
   |
   +--DisplayTransform
      |
      +--ScaleTransform
         |
         +--WindowingTransformation

Package:

stx:libview

Category:

Graphics-Transformations

Version:

rev: 1.10 date: 2023/11/21 14:45:39

user: stefan

file: ScaleTransform.st directory: libview

module: stx stc-classLibrary: libview

Description:

instances of ScaleTransform can be used to scale other objects in 2D space.
This one is used, if only a scale is applied, but no translation.
 
All 2-D objects are supposed to be able to be transformed using instances of me.  
Multiple instances of me can also be combined to form a single composite transformation.

[Instance variables:]
    scale           <Number> or <Point> representing a linear scaling factor.
                    nil is interpreted as 1@1

copyright
COPYRIGHT (c) 1992 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:

 scale: scaleFactor

 withScale: scaleFactor

Instance protocol:

 inverseTransformation

Return the inverse transformation of the receiver

 scale

return a copy of the Point that represents the
current scale of the receiver.

 scale: aScale

Set the receiver's scale to aScale, a Point or Number.

 scaleOfOne

Set the scale of the receiver to the identity scale

 scaleX

return the current x-scale of the receiver.

 scaleY

return the current x-scale of the receiver.

 translation

return a copy of the receiver's translation.

 translationX

return the x part of the receiver's translation.

 translationY

return the y part of the receiver's translation.

 applyInverseScaleX: aNumber

apply the scale only (if widths are to be transformed)

 applyInverseScaleY: aNumber

apply the scale only (if heights are to be transformed)

 applyInverseTo: anObject

Apply the inverse of the receiver to anObject
and return the result. This can be used to map back from logical
to physical coordinates, for example.

 applyInverseToX: aNumber

Apply the receiver to a number representing an x-coordinate
and return the result.

 applyInverseToY: aNumber

Apply the receiver to a number representing an y-coordinate
and return the result.

 applyScaleX: aNumber

apply the scale only (if widths are to be transformed)

 applyScaleY: aNumber

apply the scale only (if heights are to be transformed)

 transformPoint: p

Apply the receiver to a point, returning a new point.

 transformRectangle: aRectangle

Apply the receiver to a rectangle, returning a new rectangle.

 printOn: aStream

append a user printed representation of the receiver to aStream.
The format is suitable for a human - not meant to be read back.

 checkScale: aScale

Converts aScale to the internal format of a floating-point Point.

 inverseScale

return with a Point representing the inverse of my
scale.

 isIdentityTransformation

return true if this is an identity transformation;
return false, otherwise.

 isNoScale

return true if the identity scale is in effect (i.e. saleFactor is 1);
return false, otherwise.

 scaleBy: aScale

scale the receiver.
This is a destructive operation, modifying the transformation
represented by the receiver

 scaledBy: aScale

return a new WindowingTransformation with the scale and translation of
the receiver both scaled by aScale.

 translateBy: aTranslation

translate the receiver.
This is a destructive operation, modifying the transformation
represented by the receiver

 translatedBy: aPoint

return a new WindowingTransformation with the same scale and
rotations as the receiver and with a translation of the current
translation plus aPoint.

Examples:

 |v|

 v := View new extent:200@200; openAndWaitUntilVisible.
 v paint:Color green.
 v fillRectangle:(10@10 corner:40@40).
 v displayLineFrom:50@50 to:75@100. 

 v transformation:(ScaleTransform withScale:2).
 v paint:Color red.
 v fillRectangle:(10@10 corner:40@40).
 v displayLineFrom:50@50 to:75@100.