Files
atom/src/lines-yardstick.coffee
2016-01-13 12:17:01 -07:00

111 lines
3.8 KiB
CoffeeScript

TokenIterator = require './token-iterator'
{Point} = require 'text-buffer'
{isPairedCharacter} = require './text-utils'
module.exports =
class LinesYardstick
constructor: (@model, @lineNodesProvider, grammarRegistry) ->
@tokenIterator = new TokenIterator({grammarRegistry})
@rangeForMeasurement = document.createRange()
@invalidateCache()
invalidateCache: ->
@leftPixelPositionCache = {}
measuredRowForPixelPosition: (pixelPosition) ->
targetTop = pixelPosition.top
row = Math.floor(targetTop / @model.getLineHeightInPixels())
row if 0 <= row <= @model.getLastScreenRow()
screenPositionForPixelPosition: (pixelPosition) ->
targetTop = pixelPosition.top
targetLeft = pixelPosition.left
row = Math.floor(targetTop / @model.getLineHeightInPixels())
targetLeft = 0 if row < 0
targetLeft = Infinity if row > @model.getLastScreenRow()
row = Math.min(row, @model.getLastScreenRow())
row = Math.max(0, row)
lineNode = @lineNodesProvider.lineNodeForScreenRow(row)
return Point(row, 0) unless lineNode
textNodes = @lineNodesProvider.textNodesForScreenRow(row)
lineOffset = lineNode.getBoundingClientRect().left
targetLeft += lineOffset
textNodeStartColumn = 0
for textNode in textNodes
{length: textNodeLength, textContent: textNodeContent} = textNode
textNodeRight = @clientRectForRange(textNode, 0, textNodeLength).right
if textNodeRight > targetLeft
characterIndex = 0
while characterIndex < textNodeLength
if isPairedCharacter(textNodeContent, characterIndex)
nextCharacterIndex = characterIndex + 2
else
nextCharacterIndex = characterIndex + 1
rangeRect = @clientRectForRange(textNode, characterIndex, nextCharacterIndex)
if rangeRect.right > targetLeft
if targetLeft <= ((rangeRect.left + rangeRect.right) / 2)
return Point(row, textNodeStartColumn + characterIndex)
else
return Point(row, textNodeStartColumn + nextCharacterIndex)
else
characterIndex = nextCharacterIndex
textNodeStartColumn += textNodeLength
Point(row, textNodeStartColumn)
pixelPositionForScreenPosition: (screenPosition) ->
targetRow = screenPosition.row
targetColumn = screenPosition.column
top = targetRow * @model.getLineHeightInPixels()
left = @leftPixelPositionForScreenPosition(targetRow, targetColumn)
{top, left}
leftPixelPositionForScreenPosition: (row, column) ->
lineNode = @lineNodesProvider.lineNodeForScreenRow(row)
lineId = @lineNodesProvider.lineIdForScreenRow(row)
return 0 unless lineNode?
if cachedPosition = @leftPixelPositionCache[lineId]?[column]
return cachedPosition
textNodes = @lineNodesProvider.textNodesForScreenRow(row)
textNodeStartColumn = 0
for textNode in textNodes
textNodeEndColumn = textNodeStartColumn + textNode.textContent.length
if textNodeEndColumn > column
indexInTextNode = column - textNodeStartColumn
break
else
textNodeStartColumn = textNodeEndColumn
if textNode?
indexInTextNode ?= textNode.textContent.length
lineOffset = lineNode.getBoundingClientRect().left
if indexInTextNode is 0
leftPixelPosition = @clientRectForRange(textNode, 0, 1).left
else
leftPixelPosition = @clientRectForRange(textNode, 0, indexInTextNode).right
leftPixelPosition -= lineOffset
@leftPixelPositionCache[lineId] ?= {}
@leftPixelPositionCache[lineId][column] = leftPixelPosition
leftPixelPosition
else
0
clientRectForRange: (textNode, startIndex, endIndex) ->
@rangeForMeasurement.setStart(textNode, startIndex)
@rangeForMeasurement.setEnd(textNode, endIndex)
@rangeForMeasurement.getBoundingClientRect()