Package net.paulhertz.pixelaudio

Class PixelMapGen

java.lang.Object
net.paulhertz.pixelaudio.PixelMapGen
Direct Known Subclasses:
BuildFromPathGen, DiagonalZigzagGen, HilbertGen, MooreGen, MultiGen
public abstract class PixelMapGen extends Object

Abstract class for handling coordinates and LUT generation for PixelAudioMapper. PixelAudioMapper is designed to be independent of any specific mapping between its audio and pixel arrays. It uses PixelMapGen classes as plug-ins to obtain values for its LUTs. Keeping the LUT generation class outside PixelAudioMapper removes dependencies on the particular mapping.

The PixelAudioMapper class handles the combinatorial math for mapping between two arrays whose elements are in one-to-one correspondence but in different orders. PixelMapGen generates the mapping between the two arrays. PixelAudioMapper, as its name suggests, considers one array to be floating point audio samples and other to be RGBA integer pixel data, but of course the relationship is completely arbitrary as far as the mapping goes. The mapping was given its own class precisely because it is generalizable, though PixelMapGen does assume that the cardinality of its arrays can be factored by width and height.

The following short program shows the typical initialization of PixelAudio classes in Processing: 

   import net.paulhertz.pixelaudio.*;
   
   PixelAudio pixelaudio;
   HilbertGen hGen;
   PixelAudioMapper mapper;
   PImage mapImage;
   int[] colors;
   
   public void setup() {
     size(512, 512);
     pixelaudio = new PixelAudio(this);
     hGen = new HilbertGen(width, height);
     mapper = new PixelAudioMapper(hGen);
     mapImage = createImage(width, height, RGB);
     mapImage.loadPixels();
     mapper.plantPixels(getColors(), mapImage.pixels, 0, 0, mapper.getSize());
     mapImage.updatePixels();
   }
   
   public int[] getColors() {
     int[] colorWheel = new int[mapper.getSize()];
     pushStyle();
     colorMode(HSB, colorWheel.length, 100, 100);
     int h = 0;
     for (int i = 0; i < colorWheel.length; i++) {
       colorWheel[i] = color(h, 66, 66);
       h++;
     }
     popStyle();
     return colorWheel;
   }
   
   public void draw() {
     image(mapImage, 0, 0);
   }

If you create your own PixelMapGen subclass, please follow the convention of generating the first coordinate at (0,0). This allows for consistent behavior when coordinates and LUTs undergo the transforms implemented in the BitmapTransform class.

  • Field Details

    • w

      public int w

    • h

      public int h

    • size

      public int size

    • pixelMap

      public int[] pixelMap

    • sampleMap

      public int[] sampleMap

    • coords

      public ArrayList<int[]> coords

    • transformType

      public AffineTransformType transformType

    • description

      public static final String description
      See Also:

  • Constructor Details

    • PixelMapGen

      public PixelMapGen(int width, int height, AffineTransformType type)
      Constructor for classes that extend PixelMapGen. You will need to create you own constructor for your class, but it can just call super(width, height) if everything it does can be handled in your generate() method. Note that generate() should be called on the last line of your constructor, after any additional initializations or calculations required for your class. See DiagonalZigzagGen and HilbertGen for examples of how to organize and initialize your own PixelMapGen class.
      Parameters:
      width -
      height -

    • PixelMapGen

      public PixelMapGen(int width, int height)
      Constructor for classes that extend PixelMapGen. You will need to create you own constructor for your class, but it can just call super(width, height) if everything it does can be handled in your generate() method. Note that generate() should be called on the last line of your constructor, after any additional initializations or calculations required for your class. See DiagonalZigzagGen and HilbertGen for examples of how to organize and initialize your own PixelMapGen class.
      Parameters:
      width -
      height -

  • Method Details

    • describe

      public abstract String describe()
      Returns:
      A String describing the mapping generated by your class and any initialization requirements.

    • validate

      public abstract boolean validate(int width, int height)
      Parameters:
      width -
      height -
      Returns:
      true if the width and height parameters are valid for creating a mapping with this generator, otherwise, false.

    • generate

      public abstract int[] generate()

      Initialization method that sets this.coords, and then this.pixelMap and this.sampleMap: this.coords is a list of coordinate pairs representing the signal path, the (x,y) pixel locations along a path that visits every pixel in a bitmap exactly once. Once you have created it, you can call setMapsFromCoords() to set this.pixelMap and this.sampleMap automatically.

      generate() must be called from your class, so that you can initialize any local variables before generating coordinates and LUTs. The best place to call it is typically on the last line of the constructor for your class, after calling super() on the first line and after initializing any local variables needed to generate your coordinates and LUTs. You must initialize this.coords, this.pixelMap, and this.sampleMap within generate(). See DiagonalZigzagGen or HilbertGen for sample code.

      Returns:
      this.pixelMap, the value for PixelAudioMapper.signalToImageLUT.

    • setMapsFromCoords

      public int[] setMapsFromCoords(ArrayList<int[]> coordinates)
      Sets this.coords, this.pixelMap and this.sampleMap instance variables from coordinates ArrayList argument. This method is provided as a convenience: all you have to do in a child class is set the coordinates of the signal path as it steps through a bitmap of dimensions this.w * this.h.
      Parameters:
      coordinates - a list of coordinate pairs representing the signal path, the (x,y) pixel locations along a path that visits every pixel in a bitmap exactly once. This should be created within your generate() method in your child class that extends PixelMapGen.
      Returns:
      the pixelMap value, which has already been set in this method and may be ignored

    • transformCoords

      public void transformCoords(ArrayList<int[]> coordinates, AffineTransformType type)

    • loadIndexMaps

      public void loadIndexMaps()

    • getWidth

      public int getWidth()
      Returns:
      Width of the bitmap associated with this PixelMapGen.

    • getHeight

      public int getHeight()
      Returns:
      Height of the bitmap associated with this PixelMapGen.

    • getSize

      public int getSize()
      Returns:
      Size (width * height) of the bitmap associated with this PixelMapGen.

    • getPixelMap

      public int[] getPixelMap()
      Returns:
      pixelMap array, which steps through the signal and returns indexes to each pixel in the corresponding bitmap

    • getPixelMapCopy

      public int[] getPixelMapCopy()
      Returns:
      a copy of the pixelMap array

    • getSampleMap

      public int[] getSampleMap()
      Returns:
      the sampleMap array, which steps through the bitmap and returns indexes to each sample in the corresponding signal

    • getSampleMapCopy

      public int[] getSampleMapCopy()
      Returns:
      a copy of the sampleMap

    • getCoordinates

      public ArrayList<int[]> getCoordinates()
      Returns:
      this.coords, the array of coordinate pairs that mark a path (the "signal path") through every pixel in a bitmap.

    • getCoordinatesCopy

      public ArrayList<int[]> getCoordinatesCopy()
      Returns:
      a copy of this.coords

    • getTransformType

      public AffineTransformType getTransformType()
      Returns:
      the AffineTransformType associated with this PixelMapGen

    • setTransformType

      public void setTransformType(AffineTransformType transformType)
      Sets the AffineTransformType associated with this PixelMapGen and transforms its coordinates and associated sampleMap and pixelMap fields.
      Parameters:
      transformType - an AffineTransformType

    • isPowerOfTwo

      public static boolean isPowerOfTwo(int n)

    • findPowerOfTwo

      public static int findPowerOfTwo(int n)

    • findNearestPowerOfTwoLessThan

      public static int findNearestPowerOfTwoLessThan(int n)

    • getPixelMapFromCoordinatess

      public static int[] getPixelMapFromCoordinatess(ArrayList<int[]> coordsList, int w)
      Parameters:
      coordsList - a list of coordinate pairs representing the (x,y) pixel locations along a path that visits every pixel in a bitmap
      w - the width of the bitmap
      Returns:
      the bitmap index numbers of the coordinates

    • getInversMapFromPixelArray

      public static int[] getInversMapFromPixelArray(int[] pixelArr)