ColorForm is a normal Form plus a color map of up to 2^depth Colors. Typically, one reserves one entry in the color map for transparent. This allows 1, 3, 15, or 255 non-transparent colors in ColorForms of depths 1, 2, 4, and 8 bits per pixel. ColorForms don't support depths greater than 8 bits because that would require excessively large color maps with little real benefit, since 16-bit and 32-bit depths already support thousands and millions of colors.

ColorForms have several uses:
1) Precise colors. You can have up to 256 true colors, instead being limited to the 8-bit color palette.
2) Easy transparency. Just store (Color transparent) at the desired position in the color map.
3) Cheap color remapping by changing the color map.

A color map is an Array of up to 2^depth Color objects. A Bitmap colorMap is automatically computed and cached for rapid display. Note that if you change the color map, you must resubmit it via the colors: method to flush this cache.

ColorForms can be a bit tricky. Note that:
a) When you BitBlt from one ColorForm to another, you must remember to copy the color map of the source ColorForm to the destination ColorForm.
b) A ColorForm's color map is an array of depth-independent Color objects. BitBlt requires a BitMap of actual pixel values, adjusted to the destination depth. These are different things! ColorForms automatically maintain a cache of the BitBlt-style color map corresponding to the colors array for the last depth on which the ColorForm was displayed, so there should be little need for clients to work with BitBlt-style color maps.
c) The default map for 8 bit depth has black in the first entry, not transparent. Say (cform colors at: 1 put: Color transparent).

	color manipulation
	asGrayScale colormapIfNeededForDepth: colorsUsed ensureTransparentColor indexOfColor: mapColor:to: readFrom: replaceColor:with: replaceColorAt:with: replaceColorAtIndex:with: transparentAllPixelsLike: transparentColor: twoToneFromDisplay:backgroundColor:

	color mapping
	colormapIfNeededFor:

	copying
	asCursorForm blankCopyOf:scaledBy: copy: deepCopy

	displaying
	displayOn:at:clippingBox:rule:fillColor: displayOnPort:at:

	fileIn/Out
	encodeForRemoteCanvas hibernate storeOn: unhibernate

	pixel accessing
	colorAt: colorAt:put: isTransparentAt: pixelValueAt:

	postscript generation
	asFormWithSingleTransparentColors decodeArray encodePostscriptOn: getTransparencyUnificationLUT mapTransparencies: printPostscript: setColorspaceOn: transparentColorIndexes

	private
	clearColormapCache depth: ensureColorArrayExists setColors:cachedColormap:depth: setExtent:depth: unusedColormapEntry

	scaling, rotation
	flipBy:centerAt: scaledToSize:

	testing
	isColorForm

	accessing	top
	colors Return my color palette.
	colors: Set my color palette to the given collection.
	colorsFromArray:

	color manipulation	top
	asGrayScale Return a grayscale ColorForm computed by mapping each color into its grayscale equivalent
	colormapIfNeededForDepth: Return a colormap for displaying the receiver at the given depth, or nil if no colormap is needed.
	colorsUsed Return a list of the colors actually used by this ColorForm.
	ensureTransparentColor Ensure that the receiver (a) includes Color transparent in its color map and (b) that the entry for Color transparent is the first entry in its color map.
	indexOfColor: Return the index of aColor in my color array
	mapColor:to: Replace all occurances of the given color with the given new color in my color map.
	readFrom: Reads the receiver from the given binary stream with the format: depth, extent, offset, bits.
	replaceColor:with: Replace all occurances of the given color with the given new color in my color map.
	replaceColorAt:with: Replace a color map entry with newColor. The entry replaced is the one used by aPoint. If there are are two entries in the colorMap for the oldColor, just replace ONE!! There are often two whites or two blacks, and this is what you want, when replacing one.
	replaceColorAtIndex:with: Replace a color map entry with newColor.
	transparentAllPixelsLike: Make all occurances of the given pixel value transparent. Very useful when two entries in the colorMap have the same value. This only changes ONE.
	transparentColor: Make all occurances of the given color transparent. Note: for colors like black and white, which have two entries in the colorMap, this changes BOTH of them. Not always what you want.
	twoToneFromDisplay:backgroundColor: Copy one-bit deep ColorForm from the Display using a color map that maps all colors except the background color to black. Used for caching the contents of inactive MVC windows.

	color mapping	top
	colormapIfNeededFor: Return a ColorMap mapping from the receiver to destForm.

	copying	top
	asCursorForm
	blankCopyOf:scaledBy:
	copy: Return a new ColorForm containing the portion of the receiver delineated by aRect.
	deepCopy Answer a copy of the receiver with its own copy of each instance variable.

	displaying	top
	displayOn:at:clippingBox:rule:fillColor: This is the basic display primitive for graphic display objects. Display the receiver located at aDisplayPoint with rule, ruleInteger, and mask, aForm. Information to be displayed must be confined to the area that intersects with clipRectangle.
	displayOnPort:at:

	fileIn/Out	top
	encodeForRemoteCanvas encode into a bitstream for use with RemoteCanvas.
	hibernate Make myself take up less space. See comment in Form>hibernate.
	storeOn: Append to the argument aStream a sequence of characters that is an expression whose evaluation creates an object similar to the receiver.
	unhibernate If my bitmap has been compressed into a ByteArray, then expand it now, and return true.

	pixel accessing	top
	colorAt: Return the color of the pixel at aPoint.
	colorAt:put: Store the given color into the pixel at aPoint. The given color must match one of the colors in the receiver's colormap.
	isTransparentAt: Return true if the receiver is transparent at the given point.
	pixelValueAt: Return the raw pixel value at the given point. Typical clients use colorAt: to get a Color.

	postscript generation	top
	asFormWithSingleTransparentColors
	decodeArray
	encodePostscriptOn:
	getTransparencyUnificationLUT
	mapTransparencies:
	printPostscript:
	setColorspaceOn:
	transparentColorIndexes

	private	top
	clearColormapCache
	depth:
	ensureColorArrayExists Return my color palette.
	setColors:cachedColormap:depth: Semi-private. Set the color array, cached colormap, and cached colormap depth to avoid having to recompute the colormap when switching color palettes in animations.
	setExtent:depth: Create a virtual bit map with the given extent and bitsPerPixel.
	unusedColormapEntry Return the index of an unused color map entry, or zero if there isn't one.

	scaling, rotation	top
	flipBy:centerAt: Return a copy of the receiver flipped either #vertical or #horizontal.
	scaledToSize: super method did not seem to work so well on ColorForms

	testing	top
	isColorForm

	as yet unclassified	top
	mappingWhiteToTransparentFrom: Return a ColorForm copied from the given Form or Cursor with white mapped to transparent.
	twoToneFromDisplay:using:backgroundColor: Return a 1-bit deep ColorForm copied from the given rectangle of the display. All colors except the background color will be mapped to black.