Files
atom/src/display-buffer.coffee
Nathan Sobo 314e082f1d Clean up max scroll margin code
Previously we were attempting the same computation twice, once
incorrectly when returning the scroll margins as integers and then doing
the same thing in terms of pixels. This just cleans up the original
calculation. It’s *slightly* different because it takes the floor to
continue returning integers, but the behavior is extremely close.
2015-08-27 17:40:01 -06:00

1396 lines
48 KiB
CoffeeScript

_ = require 'underscore-plus'
Serializable = require 'serializable'
{CompositeDisposable, Emitter} = require 'event-kit'
{Point, Range} = require 'text-buffer'
Grim = require 'grim'
TokenizedBuffer = require './tokenized-buffer'
RowMap = require './row-map'
Fold = require './fold'
Model = require './model'
Token = require './token'
Decoration = require './decoration'
Marker = require './marker'
class BufferToScreenConversionError extends Error
constructor: (@message, @metadata) ->
super
Error.captureStackTrace(this, BufferToScreenConversionError)
module.exports =
class DisplayBuffer extends Model
Serializable.includeInto(this)
verticalScrollMargin: 2
horizontalScrollMargin: 6
scopedCharacterWidthsChangeCount: 0
changeCount: 0
constructor: ({tabLength, @editorWidthInChars, @tokenizedBuffer, buffer, ignoreInvisibles, @largeFileMode}={}) ->
super
@emitter = new Emitter
@disposables = new CompositeDisposable
@tokenizedBuffer ?= new TokenizedBuffer({tabLength, buffer, ignoreInvisibles, @largeFileMode})
@buffer = @tokenizedBuffer.buffer
@charWidthsByScope = {}
@markers = {}
@foldsByMarkerId = {}
@decorationsById = {}
@decorationsByMarkerId = {}
@overlayDecorationsById = {}
@disposables.add @tokenizedBuffer.observeGrammar @subscribeToScopedConfigSettings
@disposables.add @tokenizedBuffer.onDidChange @handleTokenizedBufferChange
@disposables.add @buffer.onDidCreateMarker @handleBufferMarkerCreated
@disposables.add @buffer.onDidUpdateMarkers => @emitter.emit 'did-update-markers'
@foldMarkerAttributes = Object.freeze({class: 'fold', displayBufferId: @id})
folds = (new Fold(this, marker) for marker in @buffer.findMarkers(@getFoldMarkerAttributes()))
@updateAllScreenLines()
@decorateFold(fold) for fold in folds
subscribeToScopedConfigSettings: =>
@scopedConfigSubscriptions?.dispose()
@scopedConfigSubscriptions = subscriptions = new CompositeDisposable
scopeDescriptor = @getRootScopeDescriptor()
oldConfigSettings = @configSettings
@configSettings =
scrollPastEnd: atom.config.get('editor.scrollPastEnd', scope: scopeDescriptor)
softWrap: atom.config.get('editor.softWrap', scope: scopeDescriptor)
softWrapAtPreferredLineLength: atom.config.get('editor.softWrapAtPreferredLineLength', scope: scopeDescriptor)
softWrapHangingIndent: atom.config.get('editor.softWrapHangingIndent', scope: scopeDescriptor)
preferredLineLength: atom.config.get('editor.preferredLineLength', scope: scopeDescriptor)
subscriptions.add atom.config.onDidChange 'editor.softWrap', scope: scopeDescriptor, ({newValue}) =>
@configSettings.softWrap = newValue
@updateWrappedScreenLines()
subscriptions.add atom.config.onDidChange 'editor.softWrapHangingIndent', scope: scopeDescriptor, ({newValue}) =>
@configSettings.softWrapHangingIndent = newValue
@updateWrappedScreenLines()
subscriptions.add atom.config.onDidChange 'editor.softWrapAtPreferredLineLength', scope: scopeDescriptor, ({newValue}) =>
@configSettings.softWrapAtPreferredLineLength = newValue
@updateWrappedScreenLines() if @isSoftWrapped()
subscriptions.add atom.config.onDidChange 'editor.preferredLineLength', scope: scopeDescriptor, ({newValue}) =>
@configSettings.preferredLineLength = newValue
@updateWrappedScreenLines() if @isSoftWrapped() and atom.config.get('editor.softWrapAtPreferredLineLength', scope: scopeDescriptor)
subscriptions.add atom.config.observe 'editor.scrollPastEnd', scope: scopeDescriptor, (value) =>
@configSettings.scrollPastEnd = value
@updateWrappedScreenLines() if oldConfigSettings? and not _.isEqual(oldConfigSettings, @configSettings)
serializeParams: ->
id: @id
softWrapped: @isSoftWrapped()
editorWidthInChars: @editorWidthInChars
scrollTop: @scrollTop
scrollLeft: @scrollLeft
tokenizedBuffer: @tokenizedBuffer.serialize()
largeFileMode: @largeFileMode
deserializeParams: (params) ->
params.tokenizedBuffer = TokenizedBuffer.deserialize(params.tokenizedBuffer)
params
copy: ->
newDisplayBuffer = new DisplayBuffer({@buffer, tabLength: @getTabLength(), @largeFileMode})
newDisplayBuffer.setScrollTop(@getScrollTop())
newDisplayBuffer.setScrollLeft(@getScrollLeft())
for marker in @findMarkers(displayBufferId: @id)
marker.copy(displayBufferId: newDisplayBuffer.id)
newDisplayBuffer
updateAllScreenLines: ->
@maxLineLength = 0
@screenLines = []
@rowMap = new RowMap
@updateScreenLines(0, @buffer.getLineCount(), null, suppressChangeEvent: true)
onDidChangeSoftWrapped: (callback) ->
@emitter.on 'did-change-soft-wrapped', callback
onDidChangeGrammar: (callback) ->
@tokenizedBuffer.onDidChangeGrammar(callback)
onDidTokenize: (callback) ->
@tokenizedBuffer.onDidTokenize(callback)
onDidChange: (callback) ->
@emitter.on 'did-change', callback
onDidChangeCharacterWidths: (callback) ->
@emitter.on 'did-change-character-widths', callback
onDidChangeScrollTop: (callback) ->
@emitter.on 'did-change-scroll-top', callback
onDidChangeScrollLeft: (callback) ->
@emitter.on 'did-change-scroll-left', callback
observeScrollTop: (callback) ->
callback(@scrollTop)
@onDidChangeScrollTop(callback)
observeScrollLeft: (callback) ->
callback(@scrollLeft)
@onDidChangeScrollLeft(callback)
observeDecorations: (callback) ->
callback(decoration) for decoration in @getDecorations()
@onDidAddDecoration(callback)
onDidAddDecoration: (callback) ->
@emitter.on 'did-add-decoration', callback
onDidRemoveDecoration: (callback) ->
@emitter.on 'did-remove-decoration', callback
onDidCreateMarker: (callback) ->
@emitter.on 'did-create-marker', callback
onDidUpdateMarkers: (callback) ->
@emitter.on 'did-update-markers', callback
emitDidChange: (eventProperties, refreshMarkers=true) ->
@emit 'changed', eventProperties if Grim.includeDeprecatedAPIs
@emitter.emit 'did-change', eventProperties
if refreshMarkers
@refreshMarkerScreenPositions()
@emit 'markers-updated' if Grim.includeDeprecatedAPIs
@emitter.emit 'did-update-markers'
updateWrappedScreenLines: ->
start = 0
end = @getLastRow()
@updateAllScreenLines()
screenDelta = @getLastRow() - end
bufferDelta = 0
@emitDidChange({start, end, screenDelta, bufferDelta})
# Sets the visibility of the tokenized buffer.
#
# visible - A {Boolean} indicating of the tokenized buffer is shown
setVisible: (visible) -> @tokenizedBuffer.setVisible(visible)
getVerticalScrollMargin: ->
maxScrollMargin = Math.floor(((@getHeight() / @getLineHeightInPixels()) - 1) / 2)
Math.min(@verticalScrollMargin, maxScrollMargin)
setVerticalScrollMargin: (@verticalScrollMargin) -> @verticalScrollMargin
getVerticalScrollMarginInPixels: -> @getVerticalScrollMargin() * @getLineHeightInPixels()
getHorizontalScrollMargin: -> Math.min(@horizontalScrollMargin, Math.floor(((@getWidth() / @getDefaultCharWidth()) - 1) / 2))
setHorizontalScrollMargin: (@horizontalScrollMargin) -> @horizontalScrollMargin
getHorizontalScrollMarginInPixels: -> scrollMarginInPixels = @getHorizontalScrollMargin() * @getDefaultCharWidth()
getHorizontalScrollbarHeight: -> @horizontalScrollbarHeight
setHorizontalScrollbarHeight: (@horizontalScrollbarHeight) -> @horizontalScrollbarHeight
getVerticalScrollbarWidth: -> @verticalScrollbarWidth
setVerticalScrollbarWidth: (@verticalScrollbarWidth) -> @verticalScrollbarWidth
getHeight: ->
if @height?
@height
else
if @horizontallyScrollable()
@getScrollHeight() + @getHorizontalScrollbarHeight()
else
@getScrollHeight()
setHeight: (@height) -> @height
getClientHeight: (reentrant) ->
if @horizontallyScrollable(reentrant)
@getHeight() - @getHorizontalScrollbarHeight()
else
@getHeight()
getClientWidth: (reentrant) ->
if @verticallyScrollable(reentrant)
@getWidth() - @getVerticalScrollbarWidth()
else
@getWidth()
horizontallyScrollable: (reentrant) ->
return false unless @width?
return false if @isSoftWrapped()
if reentrant
@getScrollWidth() > @getWidth()
else
@getScrollWidth() > @getClientWidth(true)
verticallyScrollable: (reentrant) ->
return false unless @height?
if reentrant
@getScrollHeight() > @getHeight()
else
@getScrollHeight() > @getClientHeight(true)
getWidth: ->
if @width?
@width
else
if @verticallyScrollable()
@getScrollWidth() + @getVerticalScrollbarWidth()
else
@getScrollWidth()
setWidth: (newWidth) ->
oldWidth = @width
@width = newWidth
@updateWrappedScreenLines() if newWidth isnt oldWidth and @isSoftWrapped()
@setScrollTop(@getScrollTop()) # Ensure scrollTop is still valid in case horizontal scrollbar disappeared
@width
getScrollTop: -> @scrollTop
setScrollTop: (scrollTop) ->
scrollTop = Math.round(Math.max(0, Math.min(@getMaxScrollTop(), scrollTop)))
unless scrollTop is @scrollTop
@scrollTop = scrollTop
@emitter.emit 'did-change-scroll-top', @scrollTop
@scrollTop
getMaxScrollTop: ->
@getScrollHeight() - @getClientHeight()
getScrollBottom: -> @scrollTop + @getClientHeight()
setScrollBottom: (scrollBottom) ->
@setScrollTop(scrollBottom - @getClientHeight())
@getScrollBottom()
getScrollLeft: -> @scrollLeft
setScrollLeft: (scrollLeft) ->
scrollLeft = Math.round(Math.max(0, Math.min(@getScrollWidth() - @getClientWidth(), scrollLeft)))
unless scrollLeft is @scrollLeft
@scrollLeft = scrollLeft
@emitter.emit 'did-change-scroll-left', @scrollLeft
@scrollLeft
getMaxScrollLeft: ->
@getScrollWidth() - @getClientWidth()
getScrollRight: -> @scrollLeft + @width
setScrollRight: (scrollRight) ->
@setScrollLeft(scrollRight - @width)
@getScrollRight()
getLineHeightInPixels: -> @lineHeightInPixels
setLineHeightInPixels: (@lineHeightInPixels) -> @lineHeightInPixels
getDefaultCharWidth: -> @defaultCharWidth
setDefaultCharWidth: (defaultCharWidth) ->
if defaultCharWidth isnt @defaultCharWidth
@defaultCharWidth = defaultCharWidth
@computeScrollWidth()
defaultCharWidth
getCursorWidth: -> 1
getScopedCharWidth: (scopeNames, char) ->
@getScopedCharWidths(scopeNames)[char]
getScopedCharWidths: (scopeNames) ->
scope = @charWidthsByScope
for scopeName in scopeNames
scope[scopeName] ?= {}
scope = scope[scopeName]
scope.charWidths ?= {}
scope.charWidths
batchCharacterMeasurement: (fn) ->
oldChangeCount = @scopedCharacterWidthsChangeCount
@batchingCharacterMeasurement = true
fn()
@batchingCharacterMeasurement = false
@characterWidthsChanged() if oldChangeCount isnt @scopedCharacterWidthsChangeCount
setScopedCharWidth: (scopeNames, char, width) ->
@getScopedCharWidths(scopeNames)[char] = width
@scopedCharacterWidthsChangeCount++
@characterWidthsChanged() unless @batchingCharacterMeasurement
characterWidthsChanged: ->
@computeScrollWidth()
@emit 'character-widths-changed', @scopedCharacterWidthsChangeCount if Grim.includeDeprecatedAPIs
@emitter.emit 'did-change-character-widths', @scopedCharacterWidthsChangeCount
clearScopedCharWidths: ->
@charWidthsByScope = {}
getScrollHeight: ->
lineHeight = @getLineHeightInPixels()
return 0 unless lineHeight > 0
scrollHeight = @getLineCount() * lineHeight
if @height? and @configSettings.scrollPastEnd
scrollHeight = scrollHeight + @height - (lineHeight * 3)
scrollHeight
getScrollWidth: ->
@scrollWidth
# Returns an {Array} of two numbers representing the first and the last visible rows.
getVisibleRowRange: ->
return [0, 0] unless @getLineHeightInPixels() > 0
startRow = Math.floor(@getScrollTop() / @getLineHeightInPixels())
endRow = Math.ceil((@getScrollTop() + @getHeight()) / @getLineHeightInPixels()) - 1
endRow = Math.min(@getLineCount(), endRow)
[startRow, endRow]
intersectsVisibleRowRange: (startRow, endRow) ->
[visibleStart, visibleEnd] = @getVisibleRowRange()
not (endRow <= visibleStart or visibleEnd <= startRow)
selectionIntersectsVisibleRowRange: (selection) ->
{start, end} = selection.getScreenRange()
@intersectsVisibleRowRange(start.row, end.row + 1)
scrollToScreenRange: (screenRange, options) ->
verticalScrollMarginInPixels = @getVerticalScrollMarginInPixels()
horizontalScrollMarginInPixels = @getHorizontalScrollMarginInPixels()
{top, left} = @pixelRectForScreenRange(new Range(screenRange.start, screenRange.start))
{top: endTop, left: endLeft, height: endHeight} = @pixelRectForScreenRange(new Range(screenRange.end, screenRange.end))
bottom = endTop + endHeight
right = endLeft
if options?.center
desiredScrollCenter = (top + bottom) / 2
unless @getScrollTop() < desiredScrollCenter < @getScrollBottom()
desiredScrollTop = desiredScrollCenter - @getHeight() / 2
desiredScrollBottom = desiredScrollCenter + @getHeight() / 2
else
desiredScrollTop = top - verticalScrollMarginInPixels
desiredScrollBottom = bottom + verticalScrollMarginInPixels
desiredScrollLeft = left - horizontalScrollMarginInPixels
desiredScrollRight = right + horizontalScrollMarginInPixels
if options?.reversed ? true
if desiredScrollBottom > @getScrollBottom()
@setScrollBottom(desiredScrollBottom)
if desiredScrollTop < @getScrollTop()
@setScrollTop(desiredScrollTop)
if desiredScrollRight > @getScrollRight()
@setScrollRight(desiredScrollRight)
if desiredScrollLeft < @getScrollLeft()
@setScrollLeft(desiredScrollLeft)
else
if desiredScrollTop < @getScrollTop()
@setScrollTop(desiredScrollTop)
if desiredScrollBottom > @getScrollBottom()
@setScrollBottom(desiredScrollBottom)
if desiredScrollLeft < @getScrollLeft()
@setScrollLeft(desiredScrollLeft)
if desiredScrollRight > @getScrollRight()
@setScrollRight(desiredScrollRight)
scrollToScreenPosition: (screenPosition, options) ->
@scrollToScreenRange(new Range(screenPosition, screenPosition), options)
scrollToBufferPosition: (bufferPosition, options) ->
@scrollToScreenPosition(@screenPositionForBufferPosition(bufferPosition), options)
pixelRectForScreenRange: (screenRange) ->
if screenRange.end.row > screenRange.start.row
top = @pixelPositionForScreenPosition(screenRange.start).top
left = 0
height = (screenRange.end.row - screenRange.start.row + 1) * @getLineHeightInPixels()
width = @getScrollWidth()
else
{top, left} = @pixelPositionForScreenPosition(screenRange.start, false)
height = @getLineHeightInPixels()
width = @pixelPositionForScreenPosition(screenRange.end, false).left - left
{top, left, width, height}
# Retrieves the current tab length.
#
# Returns a {Number}.
getTabLength: ->
@tokenizedBuffer.getTabLength()
# Specifies the tab length.
#
# tabLength - A {Number} that defines the new tab length.
setTabLength: (tabLength) ->
@tokenizedBuffer.setTabLength(tabLength)
setIgnoreInvisibles: (ignoreInvisibles) ->
@tokenizedBuffer.setIgnoreInvisibles(ignoreInvisibles)
setSoftWrapped: (softWrapped) ->
if softWrapped isnt @softWrapped
@softWrapped = softWrapped
@updateWrappedScreenLines()
softWrapped = @isSoftWrapped()
@emit 'soft-wrap-changed', softWrapped if Grim.includeDeprecatedAPIs
@emitter.emit 'did-change-soft-wrapped', softWrapped
softWrapped
else
@isSoftWrapped()
isSoftWrapped: ->
if @largeFileMode
false
else
@softWrapped ? @configSettings.softWrap ? false
# Set the number of characters that fit horizontally in the editor.
#
# editorWidthInChars - A {Number} of characters.
setEditorWidthInChars: (editorWidthInChars) ->
if editorWidthInChars > 0
previousWidthInChars = @editorWidthInChars
@editorWidthInChars = editorWidthInChars
if editorWidthInChars isnt previousWidthInChars and @isSoftWrapped()
@updateWrappedScreenLines()
# Returns the editor width in characters for soft wrap.
getEditorWidthInChars: ->
width = @width ? @getScrollWidth()
width -= @getVerticalScrollbarWidth()
if width? and @defaultCharWidth > 0
Math.max(0, Math.floor(width / @defaultCharWidth))
else
@editorWidthInChars
getSoftWrapColumn: ->
if @configSettings.softWrapAtPreferredLineLength
Math.min(@getEditorWidthInChars(), @configSettings.preferredLineLength)
else
@getEditorWidthInChars()
# Gets the screen line for the given screen row.
#
# * `screenRow` - A {Number} indicating the screen row.
#
# Returns {TokenizedLine}
tokenizedLineForScreenRow: (screenRow) ->
if @largeFileMode
if line = @tokenizedBuffer.tokenizedLineForRow(screenRow)
if line.text.length > @maxLineLength
@maxLineLength = line.text.length
@longestScreenRow = screenRow
line
else
@screenLines[screenRow]
# Gets the screen lines for the given screen row range.
#
# startRow - A {Number} indicating the beginning screen row.
# endRow - A {Number} indicating the ending screen row.
#
# Returns an {Array} of {TokenizedLine}s.
tokenizedLinesForScreenRows: (startRow, endRow) ->
if @largeFileMode
@tokenizedBuffer.tokenizedLinesForRows(startRow, endRow)
else
@screenLines[startRow..endRow]
# Gets all the screen lines.
#
# Returns an {Array} of {TokenizedLine}s.
getTokenizedLines: ->
if @largeFileMode
@tokenizedBuffer.tokenizedLinesForRows(0, @getLastRow())
else
new Array(@screenLines...)
indentLevelForLine: (line) ->
@tokenizedBuffer.indentLevelForLine(line)
# Given starting and ending screen rows, this returns an array of the
# buffer rows corresponding to every screen row in the range
#
# startScreenRow - The screen row {Number} to start at
# endScreenRow - The screen row {Number} to end at (default: the last screen row)
#
# Returns an {Array} of buffer rows as {Numbers}s.
bufferRowsForScreenRows: (startScreenRow, endScreenRow) ->
if @largeFileMode
[startScreenRow..endScreenRow]
else
for screenRow in [startScreenRow..endScreenRow]
@rowMap.bufferRowRangeForScreenRow(screenRow)[0]
# Creates a new fold between two row numbers.
#
# startRow - The row {Number} to start folding at
# endRow - The row {Number} to end the fold
#
# Returns the new {Fold}.
createFold: (startRow, endRow) ->
unless @largeFileMode
foldMarker =
@findFoldMarker({startRow, endRow}) ?
@buffer.markRange([[startRow, 0], [endRow, Infinity]], @getFoldMarkerAttributes())
@foldForMarker(foldMarker)
isFoldedAtBufferRow: (bufferRow) ->
@largestFoldContainingBufferRow(bufferRow)?
isFoldedAtScreenRow: (screenRow) ->
@largestFoldContainingBufferRow(@bufferRowForScreenRow(screenRow))?
# Destroys the fold with the given id
destroyFoldWithId: (id) ->
@foldsByMarkerId[id]?.destroy()
# Removes any folds found that contain the given buffer row.
#
# bufferRow - The buffer row {Number} to check against
unfoldBufferRow: (bufferRow) ->
fold.destroy() for fold in @foldsContainingBufferRow(bufferRow)
return
# Given a buffer row, this returns the largest fold that starts there.
#
# Largest is defined as the fold whose difference between its start and end points
# are the greatest.
#
# bufferRow - A {Number} indicating the buffer row
#
# Returns a {Fold} or null if none exists.
largestFoldStartingAtBufferRow: (bufferRow) ->
@foldsStartingAtBufferRow(bufferRow)[0]
# Public: Given a buffer row, this returns all folds that start there.
#
# bufferRow - A {Number} indicating the buffer row
#
# Returns an {Array} of {Fold}s.
foldsStartingAtBufferRow: (bufferRow) ->
for marker in @findFoldMarkers(startRow: bufferRow)
@foldForMarker(marker)
# Given a screen row, this returns the largest fold that starts there.
#
# Largest is defined as the fold whose difference between its start and end points
# are the greatest.
#
# screenRow - A {Number} indicating the screen row
#
# Returns a {Fold}.
largestFoldStartingAtScreenRow: (screenRow) ->
@largestFoldStartingAtBufferRow(@bufferRowForScreenRow(screenRow))
# Given a buffer row, this returns the largest fold that includes it.
#
# Largest is defined as the fold whose difference between its start and end rows
# is the greatest.
#
# bufferRow - A {Number} indicating the buffer row
#
# Returns a {Fold}.
largestFoldContainingBufferRow: (bufferRow) ->
@foldsContainingBufferRow(bufferRow)[0]
# Returns the folds in the given row range (exclusive of end row) that are
# not contained by any other folds.
outermostFoldsInBufferRowRange: (startRow, endRow) ->
folds = []
lastFoldEndRow = -1
for marker in @findFoldMarkers(intersectsRowRange: [startRow, endRow])
range = marker.getRange()
if range.start.row > lastFoldEndRow
lastFoldEndRow = range.end.row
if startRow <= range.start.row <= range.end.row < endRow
folds.push(@foldForMarker(marker))
folds
# Public: Given a buffer row, this returns folds that include it.
#
#
# bufferRow - A {Number} indicating the buffer row
#
# Returns an {Array} of {Fold}s.
foldsContainingBufferRow: (bufferRow) ->
for marker in @findFoldMarkers(intersectsRow: bufferRow)
@foldForMarker(marker)
# Given a buffer row, this converts it into a screen row.
#
# bufferRow - A {Number} representing a buffer row
#
# Returns a {Number}.
screenRowForBufferRow: (bufferRow) ->
if @largeFileMode
bufferRow
else
@rowMap.screenRowRangeForBufferRow(bufferRow)[0]
lastScreenRowForBufferRow: (bufferRow) ->
if @largeFileMode
bufferRow
else
@rowMap.screenRowRangeForBufferRow(bufferRow)[1] - 1
# Given a screen row, this converts it into a buffer row.
#
# screenRow - A {Number} representing a screen row
#
# Returns a {Number}.
bufferRowForScreenRow: (screenRow) ->
if @largeFileMode
screenRow
else
@rowMap.bufferRowRangeForScreenRow(screenRow)[0]
# Given a buffer range, this converts it into a screen position.
#
# bufferRange - The {Range} to convert
#
# Returns a {Range}.
screenRangeForBufferRange: (bufferRange, options) ->
bufferRange = Range.fromObject(bufferRange)
start = @screenPositionForBufferPosition(bufferRange.start, options)
end = @screenPositionForBufferPosition(bufferRange.end, options)
new Range(start, end)
# Given a screen range, this converts it into a buffer position.
#
# screenRange - The {Range} to convert
#
# Returns a {Range}.
bufferRangeForScreenRange: (screenRange) ->
screenRange = Range.fromObject(screenRange)
start = @bufferPositionForScreenPosition(screenRange.start)
end = @bufferPositionForScreenPosition(screenRange.end)
new Range(start, end)
pixelRangeForScreenRange: (screenRange, clip=true) ->
{start, end} = Range.fromObject(screenRange)
{start: @pixelPositionForScreenPosition(start, clip), end: @pixelPositionForScreenPosition(end, clip)}
pixelPositionForScreenPosition: (screenPosition, clip=true) ->
screenPosition = Point.fromObject(screenPosition)
screenPosition = @clipScreenPosition(screenPosition) if clip
targetRow = screenPosition.row
targetColumn = screenPosition.column
defaultCharWidth = @defaultCharWidth
top = targetRow * @lineHeightInPixels
left = 0
column = 0
iterator = @tokenizedLineForScreenRow(targetRow).getTokenIterator()
while iterator.next()
charWidths = @getScopedCharWidths(iterator.getScopes())
valueIndex = 0
value = iterator.getText()
while valueIndex < value.length
if iterator.isPairedCharacter()
char = value
charLength = 2
valueIndex += 2
else
char = value[valueIndex]
charLength = 1
valueIndex++
return {top, left} if column is targetColumn
left += charWidths[char] ? defaultCharWidth unless char is '\0'
column += charLength
{top, left}
screenPositionForPixelPosition: (pixelPosition) ->
targetTop = pixelPosition.top
targetLeft = pixelPosition.left
defaultCharWidth = @defaultCharWidth
row = Math.floor(targetTop / @getLineHeightInPixels())
targetLeft = 0 if row < 0
targetLeft = Infinity if row > @getLastRow()
row = Math.min(row, @getLastRow())
row = Math.max(0, row)
left = 0
column = 0
iterator = @tokenizedLineForScreenRow(row).getTokenIterator()
while iterator.next()
charWidths = @getScopedCharWidths(iterator.getScopes())
value = iterator.getText()
valueIndex = 0
while valueIndex < value.length
if iterator.isPairedCharacter()
char = value
charLength = 2
valueIndex += 2
else
char = value[valueIndex]
charLength = 1
valueIndex++
charWidth = charWidths[char] ? defaultCharWidth
break if targetLeft <= left + (charWidth / 2)
left += charWidth
column += charLength
new Point(row, column)
pixelPositionForBufferPosition: (bufferPosition) ->
@pixelPositionForScreenPosition(@screenPositionForBufferPosition(bufferPosition))
# Gets the number of screen lines.
#
# Returns a {Number}.
getLineCount: ->
if @largeFileMode
@tokenizedBuffer.getLineCount()
else
@screenLines.length
# Gets the number of the last screen line.
#
# Returns a {Number}.
getLastRow: ->
@getLineCount() - 1
# Gets the length of the longest screen line.
#
# Returns a {Number}.
getMaxLineLength: ->
@maxLineLength
# Gets the row number of the longest screen line.
#
# Return a {}
getLongestScreenRow: ->
@longestScreenRow
# Given a buffer position, this converts it into a screen position.
#
# bufferPosition - An object that represents a buffer position. It can be either
# an {Object} (`{row, column}`), {Array} (`[row, column]`), or {Point}
# options - A hash of options with the following keys:
# wrapBeyondNewlines:
# wrapAtSoftNewlines:
#
# Returns a {Point}.
screenPositionForBufferPosition: (bufferPosition, options) ->
throw new Error("This TextEditor has been destroyed") if @isDestroyed()
{row, column} = @buffer.clipPosition(bufferPosition)
[startScreenRow, endScreenRow] = @rowMap.screenRowRangeForBufferRow(row)
for screenRow in [startScreenRow...endScreenRow]
screenLine = @tokenizedLineForScreenRow(screenRow)
unless screenLine?
throw new BufferToScreenConversionError "No screen line exists when converting buffer row to screen row",
softWrapEnabled: @isSoftWrapped()
foldCount: @findFoldMarkers().length
lastBufferRow: @buffer.getLastRow()
lastScreenRow: @getLastRow()
bufferRow: row
screenRow: screenRow
displayBufferChangeCount: @changeCount
tokenizedBufferChangeCount: @tokenizedBuffer.changeCount
bufferChangeCount: @buffer.changeCount
maxBufferColumn = screenLine.getMaxBufferColumn()
if screenLine.isSoftWrapped() and column > maxBufferColumn
continue
else
if column <= maxBufferColumn
screenColumn = screenLine.screenColumnForBufferColumn(column)
else
screenColumn = Infinity
break
@clipScreenPosition([screenRow, screenColumn], options)
# Given a buffer position, this converts it into a screen position.
#
# screenPosition - An object that represents a buffer position. It can be either
# an {Object} (`{row, column}`), {Array} (`[row, column]`), or {Point}
# options - A hash of options with the following keys:
# wrapBeyondNewlines:
# wrapAtSoftNewlines:
#
# Returns a {Point}.
bufferPositionForScreenPosition: (screenPosition, options) ->
{row, column} = @clipScreenPosition(Point.fromObject(screenPosition), options)
[bufferRow] = @rowMap.bufferRowRangeForScreenRow(row)
new Point(bufferRow, @tokenizedLineForScreenRow(row).bufferColumnForScreenColumn(column))
# Retrieves the grammar's token scopeDescriptor for a buffer position.
#
# bufferPosition - A {Point} in the {TextBuffer}
#
# Returns a {ScopeDescriptor}.
scopeDescriptorForBufferPosition: (bufferPosition) ->
@tokenizedBuffer.scopeDescriptorForPosition(bufferPosition)
bufferRangeForScopeAtPosition: (selector, position) ->
@tokenizedBuffer.bufferRangeForScopeAtPosition(selector, position)
# Retrieves the grammar's token for a buffer position.
#
# bufferPosition - A {Point} in the {TextBuffer}.
#
# Returns a {Token}.
tokenForBufferPosition: (bufferPosition) ->
@tokenizedBuffer.tokenForPosition(bufferPosition)
# Get the grammar for this buffer.
#
# Returns the current {Grammar} or the {NullGrammar}.
getGrammar: ->
@tokenizedBuffer.grammar
# Sets the grammar for the buffer.
#
# grammar - Sets the new grammar rules
setGrammar: (grammar) ->
@tokenizedBuffer.setGrammar(grammar)
# Reloads the current grammar.
reloadGrammar: ->
@tokenizedBuffer.reloadGrammar()
# Given a position, this clips it to a real position.
#
# For example, if `position`'s row exceeds the row count of the buffer,
# or if its column goes beyond a line's length, this "sanitizes" the value
# to a real position.
#
# position - The {Point} to clip
# options - A hash with the following values:
# wrapBeyondNewlines: if `true`, continues wrapping past newlines
# wrapAtSoftNewlines: if `true`, continues wrapping past soft newlines
# skipSoftWrapIndentation: if `true`, skips soft wrap indentation without wrapping to the previous line
# screenLine: if `true`, indicates that you're using a line number, not a row number
#
# Returns the new, clipped {Point}. Note that this could be the same as `position` if no clipping was performed.
clipScreenPosition: (screenPosition, options={}) ->
{wrapBeyondNewlines, wrapAtSoftNewlines, skipSoftWrapIndentation} = options
{row, column} = Point.fromObject(screenPosition)
if row < 0
row = 0
column = 0
else if row > @getLastRow()
row = @getLastRow()
column = Infinity
else if column < 0
column = 0
screenLine = @tokenizedLineForScreenRow(row)
unless screenLine?
error = new Error("Undefined screen line when clipping screen position")
Error.captureStackTrace(error)
error.metadata = {
screenRow: row
screenColumn: column
maxScreenRow: @getLastRow()
screenLinesDefined: @screenLines.map (sl) -> sl?
displayBufferChangeCount: @changeCount
tokenizedBufferChangeCount: @tokenizedBuffer.changeCount
bufferChangeCount: @buffer.changeCount
}
throw error
maxScreenColumn = screenLine.getMaxScreenColumn()
if screenLine.isSoftWrapped() and column >= maxScreenColumn
if wrapAtSoftNewlines
row++
column = @tokenizedLineForScreenRow(row).clipScreenColumn(0)
else
column = screenLine.clipScreenColumn(maxScreenColumn - 1)
else if screenLine.isColumnInsideSoftWrapIndentation(column)
if skipSoftWrapIndentation
column = screenLine.clipScreenColumn(0)
else
row--
column = @tokenizedLineForScreenRow(row).getMaxScreenColumn() - 1
else if wrapBeyondNewlines and column > maxScreenColumn and row < @getLastRow()
row++
column = 0
else
column = screenLine.clipScreenColumn(column, options)
new Point(row, column)
# Clip the start and end of the given range to valid positions on screen.
# See {::clipScreenPosition} for more information.
#
# * `range` The {Range} to clip.
# * `options` (optional) See {::clipScreenPosition} `options`.
# Returns a {Range}.
clipScreenRange: (range, options) ->
start = @clipScreenPosition(range.start, options)
end = @clipScreenPosition(range.end, options)
new Range(start, end)
# Calculates a {Range} representing the start of the {TextBuffer} until the end.
#
# Returns a {Range}.
rangeForAllLines: ->
new Range([0, 0], @clipScreenPosition([Infinity, Infinity]))
decorationForId: (id) ->
@decorationsById[id]
getDecorations: (propertyFilter) ->
allDecorations = []
for markerId, decorations of @decorationsByMarkerId
allDecorations.push(decorations...) if decorations?
if propertyFilter?
allDecorations = allDecorations.filter (decoration) ->
for key, value of propertyFilter
return false unless decoration.properties[key] is value
true
allDecorations
getLineDecorations: (propertyFilter) ->
@getDecorations(propertyFilter).filter (decoration) -> decoration.isType('line')
getLineNumberDecorations: (propertyFilter) ->
@getDecorations(propertyFilter).filter (decoration) -> decoration.isType('line-number')
getHighlightDecorations: (propertyFilter) ->
@getDecorations(propertyFilter).filter (decoration) -> decoration.isType('highlight')
getOverlayDecorations: (propertyFilter) ->
result = []
for id, decoration of @overlayDecorationsById
result.push(decoration)
if propertyFilter?
result.filter (decoration) ->
for key, value of propertyFilter
return false unless decoration.properties[key] is value
true
else
result
decorationsForScreenRowRange: (startScreenRow, endScreenRow) ->
decorationsByMarkerId = {}
for marker in @findMarkers(intersectsScreenRowRange: [startScreenRow, endScreenRow])
if decorations = @decorationsByMarkerId[marker.id]
decorationsByMarkerId[marker.id] = decorations
decorationsByMarkerId
decorateMarker: (marker, decorationParams) ->
marker = @getMarker(marker.id)
decoration = new Decoration(marker, this, decorationParams)
decorationDestroyedDisposable = decoration.onDidDestroy =>
@removeDecoration(decoration)
@disposables.remove(decorationDestroyedDisposable)
@disposables.add(decorationDestroyedDisposable)
@decorationsByMarkerId[marker.id] ?= []
@decorationsByMarkerId[marker.id].push(decoration)
@overlayDecorationsById[decoration.id] = decoration if decoration.isType('overlay')
@decorationsById[decoration.id] = decoration
@emit 'decoration-added', decoration if Grim.includeDeprecatedAPIs
@emitter.emit 'did-add-decoration', decoration
decoration
removeDecoration: (decoration) ->
{marker} = decoration
return unless decorations = @decorationsByMarkerId[marker.id]
index = decorations.indexOf(decoration)
if index > -1
decorations.splice(index, 1)
delete @decorationsById[decoration.id]
@emit 'decoration-removed', decoration if Grim.includeDeprecatedAPIs
@emitter.emit 'did-remove-decoration', decoration
delete @decorationsByMarkerId[marker.id] if decorations.length is 0
delete @overlayDecorationsById[decoration.id]
decorationsForMarkerId: (markerId) ->
@decorationsByMarkerId[markerId]
# Retrieves a {Marker} based on its id.
#
# id - A {Number} representing a marker id
#
# Returns the {Marker} (if it exists).
getMarker: (id) ->
unless marker = @markers[id]
if bufferMarker = @buffer.getMarker(id)
marker = new Marker({bufferMarker, displayBuffer: this})
@markers[id] = marker
marker
# Retrieves the active markers in the buffer.
#
# Returns an {Array} of existing {Marker}s.
getMarkers: ->
@buffer.getMarkers().map ({id}) => @getMarker(id)
getMarkerCount: ->
@buffer.getMarkerCount()
# Public: Constructs a new marker at the given screen range.
#
# range - The marker {Range} (representing the distance between the head and tail)
# options - Options to pass to the {Marker} constructor
#
# Returns a {Number} representing the new marker's ID.
markScreenRange: (args...) ->
bufferRange = @bufferRangeForScreenRange(args.shift())
@markBufferRange(bufferRange, args...)
# Public: Constructs a new marker at the given buffer range.
#
# range - The marker {Range} (representing the distance between the head and tail)
# options - Options to pass to the {Marker} constructor
#
# Returns a {Number} representing the new marker's ID.
markBufferRange: (range, options) ->
@getMarker(@buffer.markRange(range, options).id)
# Public: Constructs a new marker at the given screen position.
#
# range - The marker {Range} (representing the distance between the head and tail)
# options - Options to pass to the {Marker} constructor
#
# Returns a {Number} representing the new marker's ID.
markScreenPosition: (screenPosition, options) ->
@markBufferPosition(@bufferPositionForScreenPosition(screenPosition), options)
# Public: Constructs a new marker at the given buffer position.
#
# range - The marker {Range} (representing the distance between the head and tail)
# options - Options to pass to the {Marker} constructor
#
# Returns a {Number} representing the new marker's ID.
markBufferPosition: (bufferPosition, options) ->
@getMarker(@buffer.markPosition(bufferPosition, options).id)
# Public: Removes the marker with the given id.
#
# id - The {Number} of the ID to remove
destroyMarker: (id) ->
@buffer.destroyMarker(id)
delete @markers[id]
# Finds the first marker satisfying the given attributes
#
# Refer to {DisplayBuffer::findMarkers} for details.
#
# Returns a {Marker} or null
findMarker: (params) ->
@findMarkers(params)[0]
# Public: Find all markers satisfying a set of parameters.
#
# params - An {Object} containing parameters that all returned markers must
# satisfy. Unreserved keys will be compared against the markers' custom
# properties. There are also the following reserved keys with special
# meaning for the query:
# :startBufferRow - A {Number}. Only returns markers starting at this row in
# buffer coordinates.
# :endBufferRow - A {Number}. Only returns markers ending at this row in
# buffer coordinates.
# :containsBufferRange - A {Range} or range-compatible {Array}. Only returns
# markers containing this range in buffer coordinates.
# :containsBufferPosition - A {Point} or point-compatible {Array}. Only
# returns markers containing this position in buffer coordinates.
# :containedInBufferRange - A {Range} or range-compatible {Array}. Only
# returns markers contained within this range.
#
# Returns an {Array} of {Marker}s
findMarkers: (params) ->
params = @translateToBufferMarkerParams(params)
@buffer.findMarkers(params).map (stringMarker) => @getMarker(stringMarker.id)
translateToBufferMarkerParams: (params) ->
bufferMarkerParams = {}
for key, value of params
switch key
when 'startBufferRow'
key = 'startRow'
when 'endBufferRow'
key = 'endRow'
when 'startScreenRow'
key = 'startRow'
value = @bufferRowForScreenRow(value)
when 'endScreenRow'
key = 'endRow'
value = @bufferRowForScreenRow(value)
when 'intersectsBufferRowRange'
key = 'intersectsRowRange'
when 'intersectsScreenRowRange'
key = 'intersectsRowRange'
[startRow, endRow] = value
value = [@bufferRowForScreenRow(startRow), @bufferRowForScreenRow(endRow)]
when 'containsBufferRange'
key = 'containsRange'
when 'containsBufferPosition'
key = 'containsPosition'
when 'containedInBufferRange'
key = 'containedInRange'
when 'containedInScreenRange'
key = 'containedInRange'
value = @bufferRangeForScreenRange(value)
when 'intersectsBufferRange'
key = 'intersectsRange'
when 'intersectsScreenRange'
key = 'intersectsRange'
value = @bufferRangeForScreenRange(value)
bufferMarkerParams[key] = value
bufferMarkerParams
findFoldMarker: (attributes) ->
@findFoldMarkers(attributes)[0]
findFoldMarkers: (attributes) ->
@buffer.findMarkers(@getFoldMarkerAttributes(attributes))
getFoldMarkerAttributes: (attributes) ->
if attributes
_.extend(attributes, @foldMarkerAttributes)
else
@foldMarkerAttributes
refreshMarkerScreenPositions: ->
for marker in @getMarkers()
marker.notifyObservers(textChanged: false)
return
destroyed: ->
fold.destroy() for markerId, fold of @foldsByMarkerId
marker.disposables.dispose() for id, marker of @markers
@scopedConfigSubscriptions.dispose()
@disposables.dispose()
@tokenizedBuffer.destroy()
logLines: (start=0, end=@getLastRow()) ->
for row in [start..end]
line = @tokenizedLineForScreenRow(row).text
console.log row, @bufferRowForScreenRow(row), line, line.length
return
getRootScopeDescriptor: ->
@tokenizedBuffer.rootScopeDescriptor
handleTokenizedBufferChange: (tokenizedBufferChange) =>
@changeCount = @tokenizedBuffer.changeCount
{start, end, delta, bufferChange} = tokenizedBufferChange
@updateScreenLines(start, end + 1, delta, refreshMarkers: false)
@setScrollTop(Math.min(@getScrollTop(), @getMaxScrollTop())) if delta < 0
updateScreenLines: (startBufferRow, endBufferRow, bufferDelta=0, options={}) ->
return if @largeFileMode
return if @isDestroyed()
startBufferRow = @rowMap.bufferRowRangeForBufferRow(startBufferRow)[0]
endBufferRow = @rowMap.bufferRowRangeForBufferRow(endBufferRow - 1)[1]
startScreenRow = @rowMap.screenRowRangeForBufferRow(startBufferRow)[0]
endScreenRow = @rowMap.screenRowRangeForBufferRow(endBufferRow - 1)[1]
{screenLines, regions} = @buildScreenLines(startBufferRow, endBufferRow + bufferDelta)
screenDelta = screenLines.length - (endScreenRow - startScreenRow)
_.spliceWithArray(@screenLines, startScreenRow, endScreenRow - startScreenRow, screenLines, 10000)
@checkScreenLinesInvariant()
@rowMap.spliceRegions(startBufferRow, endBufferRow - startBufferRow, regions)
@findMaxLineLength(startScreenRow, endScreenRow, screenLines, screenDelta)
return if options.suppressChangeEvent
changeEvent =
start: startScreenRow
end: endScreenRow - 1
screenDelta: screenDelta
bufferDelta: bufferDelta
@emitDidChange(changeEvent, options.refreshMarkers)
buildScreenLines: (startBufferRow, endBufferRow) ->
screenLines = []
regions = []
rectangularRegion = null
foldsByStartRow = {}
for fold in @outermostFoldsInBufferRowRange(startBufferRow, endBufferRow)
foldsByStartRow[fold.getStartRow()] = fold
bufferRow = startBufferRow
while bufferRow < endBufferRow
tokenizedLine = @tokenizedBuffer.tokenizedLineForRow(bufferRow)
if fold = foldsByStartRow[bufferRow]
foldLine = tokenizedLine.copy()
foldLine.fold = fold
screenLines.push(foldLine)
if rectangularRegion?
regions.push(rectangularRegion)
rectangularRegion = null
foldedRowCount = fold.getBufferRowCount()
regions.push(bufferRows: foldedRowCount, screenRows: 1)
bufferRow += foldedRowCount
else
softWraps = 0
if @isSoftWrapped()
while wrapScreenColumn = tokenizedLine.findWrapColumn(@getSoftWrapColumn())
[wrappedLine, tokenizedLine] = tokenizedLine.softWrapAt(
wrapScreenColumn,
@configSettings.softWrapHangingIndent
)
break if wrappedLine.hasOnlySoftWrapIndentation()
screenLines.push(wrappedLine)
softWraps++
screenLines.push(tokenizedLine)
if softWraps > 0
if rectangularRegion?
regions.push(rectangularRegion)
rectangularRegion = null
regions.push(bufferRows: 1, screenRows: softWraps + 1)
else
rectangularRegion ?= {bufferRows: 0, screenRows: 0}
rectangularRegion.bufferRows++
rectangularRegion.screenRows++
bufferRow++
if rectangularRegion?
regions.push(rectangularRegion)
{screenLines, regions}
findMaxLineLength: (startScreenRow, endScreenRow, newScreenLines, screenDelta) ->
oldMaxLineLength = @maxLineLength
if startScreenRow <= @longestScreenRow < endScreenRow
@longestScreenRow = 0
@maxLineLength = 0
maxLengthCandidatesStartRow = 0
maxLengthCandidates = @screenLines
else
@longestScreenRow += screenDelta if endScreenRow <= @longestScreenRow
maxLengthCandidatesStartRow = startScreenRow
maxLengthCandidates = newScreenLines
for screenLine, i in maxLengthCandidates
screenRow = maxLengthCandidatesStartRow + i
length = screenLine.text.length
if length > @maxLineLength
@longestScreenRow = screenRow
@maxLineLength = length
@computeScrollWidth() if oldMaxLineLength isnt @maxLineLength
computeScrollWidth: ->
@scrollWidth = @pixelPositionForScreenPosition([@longestScreenRow, @maxLineLength]).left
@scrollWidth += 1 unless @isSoftWrapped()
@setScrollLeft(Math.min(@getScrollLeft(), @getMaxScrollLeft()))
handleBufferMarkerCreated: (textBufferMarker) =>
if textBufferMarker.matchesParams(@getFoldMarkerAttributes())
fold = new Fold(this, textBufferMarker)
fold.updateDisplayBuffer()
@decorateFold(fold)
if marker = @getMarker(textBufferMarker.id)
# The marker might have been removed in some other handler called before
# this one. Only emit when the marker still exists.
@emit 'marker-created', marker if Grim.includeDeprecatedAPIs
@emitter.emit 'did-create-marker', marker
decorateFold: (fold) ->
@decorateMarker(fold.marker, type: 'line-number', class: 'folded')
foldForMarker: (marker) ->
@foldsByMarkerId[marker.id]
decorationDidChangeType: (decoration) ->
if decoration.isType('overlay')
@overlayDecorationsById[decoration.id] = decoration
else
delete @overlayDecorationsById[decoration.id]
checkScreenLinesInvariant: ->
return if @isSoftWrapped()
return if _.size(@foldsByMarkerId) > 0
screenLinesCount = @screenLines.length
tokenizedLinesCount = @tokenizedBuffer.getLineCount()
bufferLinesCount = @buffer.getLineCount()
atom.assert screenLinesCount is tokenizedLinesCount, "Display buffer line count out of sync with tokenized buffer", (error) ->
error.metadata = {screenLinesCount, tokenizedLinesCount, bufferLinesCount}
atom.assert screenLinesCount is bufferLinesCount, "Display buffer line count out of sync with buffer", (error) ->
error.metadata = {screenLinesCount, tokenizedLinesCount, bufferLinesCount}
if Grim.includeDeprecatedAPIs
DisplayBuffer.properties
softWrapped: null
editorWidthInChars: null
lineHeightInPixels: null
defaultCharWidth: null
height: null
width: null
scrollTop: 0
scrollLeft: 0
scrollWidth: 0
verticalScrollbarWidth: 15
horizontalScrollbarHeight: 15
EmitterMixin = require('emissary').Emitter
DisplayBuffer::on = (eventName) ->
switch eventName
when 'changed'
Grim.deprecate("Use DisplayBuffer::onDidChange instead")
when 'grammar-changed'
Grim.deprecate("Use DisplayBuffer::onDidChangeGrammar instead")
when 'soft-wrap-changed'
Grim.deprecate("Use DisplayBuffer::onDidChangeSoftWrap instead")
when 'character-widths-changed'
Grim.deprecate("Use DisplayBuffer::onDidChangeCharacterWidths instead")
when 'decoration-added'
Grim.deprecate("Use DisplayBuffer::onDidAddDecoration instead")
when 'decoration-removed'
Grim.deprecate("Use DisplayBuffer::onDidRemoveDecoration instead")
when 'decoration-changed'
Grim.deprecate("Use decoration.getMarker().onDidChange() instead")
when 'decoration-updated'
Grim.deprecate("Use Decoration::onDidChangeProperties instead")
when 'marker-created'
Grim.deprecate("Use Decoration::onDidCreateMarker instead")
when 'markers-updated'
Grim.deprecate("Use Decoration::onDidUpdateMarkers instead")
else
Grim.deprecate("DisplayBuffer::on is deprecated. Use event subscription methods instead.")
EmitterMixin::on.apply(this, arguments)
else
DisplayBuffer::softWrapped = null
DisplayBuffer::editorWidthInChars = null
DisplayBuffer::lineHeightInPixels = null
DisplayBuffer::defaultCharWidth = null
DisplayBuffer::height = null
DisplayBuffer::width = null
DisplayBuffer::scrollTop = 0
DisplayBuffer::scrollLeft = 0
DisplayBuffer::scrollWidth = 0
DisplayBuffer::verticalScrollbarWidth = 15
DisplayBuffer::horizontalScrollbarHeight = 15