Class: Depth1Image

• Inheritance
• Description
• Related information
• Class protocol
  • queries
• Instance protocol
  • accessing-pixels
  • converting
  • enumerating
  • magnification
  • private
  • queries

Inheritance:

   Object
   |
   +--Image
      |
      +--Depth1Image
         |
         +--ImageMask

Package:

stx:libview

Category:

Graphics-Images

Version:

rev: 1.57 date: 2009/11/05 14:37:53

user: stefan

file: Depth1Image.st directory: libview

module: stx stc-classLibrary: libview

Author:

Claus Gittinger

Description:

this class represents bilevel (1 bit / pixel) images.
It mainly consists of methods which are already implemented in Image,
but reimplemented here for more performance. If you plan to do heavy
image processing on bilevel images, you may want to add more
specialized methods here.

#blackIs0 / #whiteIs0 and #palette formats are supported here.

Related information:

    Depth2Image
    Depth4Image
    Depth8Image
    Depth16Image
    Depth24Image
    ImageReader

Class protocol:

 imageDepth

return the depth of images represented by instances of
this class - here we return 1

Instance protocol:

 pixelAtX: x y: y

retrieve a pixelValue at x/y; return a number.
The interpretation of the returned value depends on the photometric
and the colormap. See also Image>>atX:y:)
Pixels start at 0@0 for upper left pixel, end at
(width-1)@(height-1) for lower right pixel

 pixelAtX: x y: y put: aPixelValue

set a pixels value at x/y to aPixelValue.
Pixels start at x=0 , y=0 for upper left pixel, end at
x = width-1, y=height-1 for lower right pixel

 asFormOn: aDevice

convert a monochrome image to a device form

 greyImageAsFormOn: aDevice

convert a greyscale image to a device form

 greyImageAsMonoFormOn: aDevice

convert to a monochrome form - thats easy

 paletteImageAsMonoFormOn: aDevice

convert a palette image to a b&w monochrome device form

 paletteImageAsTrueColorFormOn: aDevice

since all devices must support monochrome images, and
a 2-entry colormap is implemented by ST/X's drawForm methods,
we can do this on all color devices as a palette image.

 colorsAtY: y from: xLow to: xHigh do: aBlock

perform aBlock for each pixel from x1 to x2 in row y.
The block is passed the color at each pixel.
This method allows slighly faster processing of an
image than using atX:y:, since some processing can be
avoided when going from pixel to pixel. However, for
real image processing, specialized methods should be written.

 valuesAtY: y from: xLow to: xHigh do: aBlock

perform aBlock for each pixelValue from x1 to x2 in row y.
The block is passed the color at each pixel.
This method allows slighly faster processing of an
image than using atX:y:, since some processing can be
avoided when going from pixel to pixel. However, for
real image processing, specialized methods should be written.

 hardMagnifiedBy: scalePoint

return a new image magnified by scalePoint, aPoint.
This is the general magnification method, handling non-integral values.
It is slower than the integral magnification method.

 magnifyRowFrom: srcBytes offset: srcStart into: dstBytes offset: dstStart factor: mX

magnify a single pixel row - can only magnify by integer factors.
This method has been specially tuned for magnification by 2 and 4.

 anyImageAsFormOn: aDevice

convert a monochrome image to a device form

 bitsPerPixel

return the number of bits per pixel

 bitsPerRow

return the number of bits in one scanline of the image

 bytesPerRow

return the number of bytes in one scanline of the image

 colorFromValue: pixelValue

given a pixel value, return the corresponding color.
Pixel values start with 0.

 rgbFromValue: pixelValue

given a pixel value, return the corresponding 24bit rgbValue (rrggbb, red is MSB).
Pixel values start with 0.

 usedColors

return a collection of colors used in the receiver.
For depth1 images, we return the colorMap here, assuming all
pixels are used ...
... which is not really true - it could be all-white or all-black

 usedValues

return a collection of color values used in the receiver.

 valueFromColor: aColor

given a color, return the corresponding pixel value.
Non-representable colors return nil.