I represent displayable text that has been decoraged with margin alignment, line leading, and tab settings.

	alignment
	centered justified leftFlush rightFlush toggleAlignment

	character location
	characterBlockAtPoint: characterBlockForIndex: defaultCharacterBlock

	composition
	composeAll wrappingBox:clippingBox:

	converting
	asForm asString asText

	display box access
	boundingBox computeBoundingBox

	displaying
	displayOn: displayOn:at: displayOn:at:clippingBox:rule:fillColor: displayOn:transformation:clippingBox:align:with:rule:fillColor:

	indicating
	flash outline

private

bottomAtLineIndex: compositionRectangle:text:style:offset: compositionRectangleDelta displayLines: displayLines:affectedRectangle: displayOn:lines: leftMarginForCompositionForLine: leftMarginForDisplayForLine: lineAt:put: lineIndexOfCharacterIndex: lineIndexOfTop: lines moveBy: rightMarginForComposition rightMarginForDisplay setWithText:style: setWithText:style:compositionRectangle:clippingRectangle: setWithText:style:compositionRectangle:clippingRectangle:foreColor:backColor: topAtLineIndex: topAtLineIndex:using:and: trimLinesTo: updateCompositionHeight withClippingRectangle:do:

	scrolling
	scrollBy: scrollBy:withSelectionFrom:to: scrollDelta scrollUncheckedBy:withSelectionFrom:to:

	selecting
	caretFormForDepth: clickAt:for:controller: extendSelectionAt:endBlock: hiliteRect: mouseMovedFrom:pivotBlock:showingCaret: mouseSelect mouseSelect: reverseFrom:to: selectionRectsFrom:to:

	utilities
	clearVisibleRectangle deepCopy destinationForm: fit lines: visibleRectangle

	instance creation
	new withText: withText:style: withText:style:compositionRectangle:clippingRectangle:foreColor:backColor:

	accessing	top
	backgroundColor
	clippingRectangle Answer the rectangle, defined in absolute coordinates, whose intersection with the destinationForm is the area in which the characters are constrained to display.
	clippingRectangle:
	compositionRectangle Answer the rectangle whose width is the dimension, modified by indents and tabsLevels, against which line wraparound is measured. The height of the compositionRectangle is reset each time recomposition is required.
	compositionRectangle: Set the rectangle whose width is the dimension, modified by indents and tabsLevels, against which line wraparound is measured.
	destinationForm Answer the Form into which the characters are scanned.
	fillColor Answer the Form with which each character is combined by the scanner before applying the rule for display.
	fillColor: Set the argument, maskForm, to be the form with which each character is combined by the scanner before applying the rule for display.
	height Answer the height of the composition rectangle.
	indentationOfLineIndex:ifBlank: Answer the number of leading tabs in the line at lineIndex. If there are no visible characters, pass the number of tabs to aBlock and return its value. If the line is word-wrap overflow, back up a line and recur.
	mask Answer the Form with which each character is combined by the scanner before applying the rule for display.
	numberOfLines Answer the number of lines of text in the receiver.
	replaceFrom:to:with:displaying: Replace the receiver's text starting at position start, stopping at stop, by the characters in aText. It is expected that most requirements for modifications to the receiver will call this code. Certainly all cut's or paste's.
	rule Answer the rule according to which character display behaves. For example, rule may equal over, under, reverse.
	rule: Set the rule according to which character display behaves.
	stringAtLineNumber:
	text: Set the argument, aText, to be the text for the receiver.

	alignment	top
	centered Set the alignment for the style with which the receiver displays its text so that text is centered in the composition rectangle.
	justified Set the alignment for the style with which the receiver displays its text so that the characters in each of text end on an even border in the composition rectangle.
	leftFlush Set the alignment for the style with which the receiver displays its text so that the characters in each of text begin on an even border in the composition rectangle. This is also known as ragged-right.
	rightFlush Set the alignment for the style with which the receiver displays its text so that the characters in each of text end on an even border in the composition rectangle but the beginning of each line does not. This is also known as ragged-left.
	toggleAlignment Set the alignment for the style with which the receiver displays its text so that it moves from centered to justified to leftFlush to rightFlush and back to centered again.

	character location	top
	characterBlockAtPoint: Answer a CharacterBlock for characters in the text at point aPoint. It is assumed that aPoint has been transformed into coordinates appropriate to the receiver's destinationForm rectangle and the compositionRectangle.
	characterBlockForIndex: Answer a CharacterBlock for character in the text at targetIndex. The coordinates in the CharacterBlock will be appropriate to the intersection of the destinationForm rectangle and the compositionRectangle.
	defaultCharacterBlock

	composition	top
	composeAll Compose a collection of characters into a collection of lines.
	wrappingBox:clippingBox: Set the composition rectangle for the receiver so that the lines wrap within the rectangle, compositionRect, and the display of the text is clipped by the rectangle, clippingRect.

	converting	top
	asForm Answer a Form made up of the bits that represent the receiver's displayable text.
	asString Answer the string of characters of the receiver's text.
	asText Answer the receiver's text.

	display box access	top
	boundingBox Refer to the comment in DisplayObject|boundingBox.
	computeBoundingBox Compute minimum enclosing rectangle around characters.

	displaying	top
	displayOn: Because Paragraphs cache so much information, computation is avoided and displayAt: 0@0 is not appropriate here.
	displayOn:at: Use internal clippingRect; destination cliping is done during actual display.
	displayOn:at:clippingBox:rule:fillColor: Default display message when aDisplayPoint is in absolute screen coordinates.
	displayOn:transformation:clippingBox:align:with:rule:fillColor: Assumes offset has been set!!!!!

	indicating	top
	flash Complement twice the visible area in which the receiver displays.
	outline Display a border around the visible area in which the receiver presents its text.

	private	top
	bottomAtLineIndex: Answer the bottom y of given line.
	compositionRectangle:text:style:offset:
	compositionRectangleDelta A handy number -- mostly for scrolling.
	displayLines:
	displayLines:affectedRectangle: This is the first level workhorse in the display portion of the TextForm routines. It checks to see which lines in the interval are actually visible, has the CharacterScanner display only those, clears out the areas in which display will occur, and clears any space remaining in the visibleRectangle following the space occupied by lastLine.
	displayOn:lines:
	leftMarginForCompositionForLine: Build the left margin for composition of a line. Depends upon marginTabsLevel and the indent.
	leftMarginForDisplayForLine: Build the left margin for display of a line. Depends upon leftMarginForComposition, compositionRectangle left and the alignment.
	lineAt:put: Store a line, track last, and grow lines if necessary.
	lineIndexOfCharacterIndex: Answer the line index for a given characterIndex.
	lineIndexOfTop: Answer the line index at a given top y.
	lines
	moveBy:
	rightMarginForComposition Build the right margin for a line. Depends upon compositionRectangle width, marginTabsLevel, and right indent.
	rightMarginForDisplay Build the right margin for a line. Depends upon compositionRectangle rightSide, marginTabsLevel, and right indent.
	setWithText:style: Set text and adjust bounding rectangles to fit.
	setWithText:style:compositionRectangle:clippingRectangle: Set text and using supplied parameters. Answer max composition width.
	setWithText:style:compositionRectangle:clippingRectangle:foreColor:backColor: Set text and using supplied parameters. Answer max composition width.
	topAtLineIndex: Answer the top y of given line.
	topAtLineIndex:using:and: Answer the top y of given line.
	trimLinesTo:
	updateCompositionHeight Mainly used to insure that intersections with compositionRectangle work.
	withClippingRectangle:do:

	scrolling	top
	scrollBy:
	scrollBy:withSelectionFrom:to: Translate the composition rectangle up (dy<0) by heightToMove. Repainting text as necessary, and selection if blocks not nil. Return true unless scrolling limits have been reached.
	scrollDelta By comparing this before and after, you know if scrolling happened
	scrollUncheckedBy:withSelectionFrom:to: Scroll by the given amount. Copy bits where possible, display the rest. If selection blocks are not nil, then select the newly visible text as well.

	selecting	top
	caretFormForDepth: Return a caret form for the given depth.
	clickAt:for:controller: Give sensitive text a chance to fire. Display flash: (100@100 extent: 100@100).
	extendSelectionAt:endBlock: Answer with an Array of two CharacterBlocks that represent the text selection that the user makes.
	hiliteRect:
	mouseMovedFrom:pivotBlock:showingCaret:
	mouseSelect Answer with an Array of two CharacterBlocks that represent the text selection that the user makes. Return quickly if the button is noticed up to make double-click more responsive.
	mouseSelect: Track text selection and answer with an Array of two CharacterBlocks.
	reverseFrom:to: Reverse area between the two character blocks given as arguments.
	selectionRectsFrom:to: Return an array of rectangles representing the area between the two character blocks given as arguments.

	utilities	top
	clearVisibleRectangle Display the area in which the receiver presents its text so that the area is all one tone--in this case, all white.
	deepCopy Don't want to copy the destForm (Display) or fonts in the TextStyle. 9/13/96 tk
	destinationForm:
	fit Make the bounding rectangle of the receiver contain all the text without changing the width of the receiver's composition rectangle.
	lines:
	visibleRectangle May be less than the clippingRectangle if text ends part way down. Also some fearful history includes Display intersection; it shouldn't be necessary

	examples	top
	example This simple example illustrates how to display a few lines of text on the screen at the current cursor point. Fixed.

	instance creation	top
	new Do not allow an uninitialized view. Create with text that has no characters.
	withText: Answer an instance of me with text set to aText and style set to the system's default text style.
	withText:style: Answer an instance of me with text set to aText and style set to aTextStyle.
	withText:style:compositionRectangle:clippingRectangle:foreColor:backColor: Answer an instance of me with text set to aText and style set to aTextStyle, composition rectangle is compRect and the clipping rectangle is clipRect.