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: 1.7 date: 2019/06/28 07:19:55

user: cg

file: ScaleTransform.st directory: libview

module: stx stc-classLibrary: libview

Author:

Claus Gittinger

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

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; openAndWait.
 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.