Class: Colormap

• Inheritance
• Description
• Related information
• Class protocol
  • instance creation
• Instance protocol
  • accessing
  • accessing-internals
  • converting
  • copying
  • misc
  • printing & storing
  • queries

Inheritance:

   Object
   |
   +--Collection
      |
      +--SequenceableCollection
         |
         +--Colormap
            |
            +--ColorPalette

Package:

stx:libview

Category:

Graphics-Images-Support

Version:

rev: 1.39 date: 2007/07/22 18:48:11

user: cg

file: Colormap.st directory: libview

module: stx stc-classLibrary: libview

Author:

Claus Gittinger

Description:

Colormaps are used with images (and Forms) to keep the byte-to-color mapping.
Externally, either colors or pixel values can be accessed.
Internally, the values are stored as 3 separate byte-arrays
(i.e. individual components can be 0..255).
This was done to avoid overhead due to allocation of many color instances.

Notice: Colormap is going to be obsoleted, and the functionality will
move to subclasses (MappedPalette etc.)

Related information:

    Color
    Image
    Form

Class protocol:

 fromColors: aColorArray

given a sequenceable collection of colors, return a new instance of myself.
Obsolete: use #withColors: for VW compatibility.

** This is an obsolete interface - do not use it (it may vanish in future versions) **

 new: numColors

^ self withColors:(Array new:numColors withAll:Color black)

 redVector: rV greenVector: gV blueVector: bV

given vectors of red/green/and blue pixelValues,
return a new instance of myself.
The values must be in the range 0..255.

 rgbBytesVector: rgbVector

given a single vector containing r-g-b byte values,
return a new instance of myself.
The values must be in the range 0..255.

 rgbValueVector: rgbValueVector

given a single vector containing r-g-b pixel-values,
return a new instance of myself.
The values must be of the rgb-form i.e. 16rRRGGBB

 withColors: aColorArray

given a sequenceable collection of colors, return a new instance
of myself. Renamed from #fromColors: for ST-80 compatibility.

Instance protocol:

 at: index

return the color for a index.
Notice that index range is 1...nColors

 at: index put: aColor

set the color for a index. Return aColor (sigh).
Notice that index range is 1...

 atPixelValue: pixelValue

return the color for a pixelValue.
Notice that pixelValue range is 0...nColors-1

 blueAt: index

return the blue component for some index.
The returned value is scaled from the internal 0.. 255 to
a percentage value 0..100.
Notice that index range is 1...

 colors

ST-80 compatibility: return a collection containing the colors I hold

 colors: aCollectionOfColors

setup the receiver from colors given in a sequenceable collection of colors

 greenAt: index

return the green component for some index.
The returned value is scaled from the internal 0.. 255 to
a percentage value 0..100.
Notice that index range is 1...

 redAt: index

return the red component for some index.
The returned value is scaled from the internal 0.. 255 to
a percentage value 0..100.
Notice that index range is 1...

 blueByteAt: index

return the blueByte component for some index.
The returned value is from the internal 0.. 255

 blueByteAt: index put: anInteger

change the internal blueByte component for some index.
The argument, anInteger should be from the internal 0.. 255.
Notice that index range is 1...

 blueVector

return the blueVector

 blueVector: something

set blueVector

 greenByteAt: index

return the greenByte component for some index.
The returned value is from the internal 0.. 255

 greenByteAt: index put: anInteger

change the internal greenByte component for some index.
The argument, anInteger should be from the internal 0.. 255.
Notice that index range is 1...

 greenVector

return greenVector

 greenVector: something

set greenVector

 redByteAt: index

return the redByte component for some index.
The returned value is from the internal 0.. 255

 redByteAt: index put: anInteger

change the internal redByte component for some index.
The argument, anInteger should be from the internal 0.. 255.
Notice that index range is 1...

 redVector

return redVector

 redVector: something

set redVector

 redVector: r greenVector: g blueVector: b

set the red, green and blueVectors

 asArray

return the receiver as an array containing my colors

 copyFrom: start to: stop

 postCopy

 grow: howBig

change the receivers size

 scaleValuesBy: scaleFactor

multiply all values by scaleFactor; finally round to integer.
This can be used to brighten/darken an images colormap

 storeOn: aStream

append a representation to aStream, from which the receiver
can be reconstructed

 indexOfPaintNearest: color

 isFixedPalette

 isGreyscaleColormap

return true, if the receiver is actually a greymap.
Could be used to convert images as read from imageFiles
(for example, GIF-files) automatically to greyScale (which is not yet done).

 size

return the number of colors in the receiver