myLocationTextExtractionStrategyクラスはexample Projectから質問"how to highlight a text or word in a pdf file using iTextsharp?"にhis answerに共有スタックオーバーフローユーザーJcisを取っているように見えます。
彼はVB.Netでそれを書いています：
Public Class myLocationTextExtractionStrategy
Implements ITextExtractionStrategy
'* set to true for debugging
Private _UndercontentCharacterSpacing = 0
Private _UndercontentHorizontalScaling = 0
Private ThisPdfDocFonts As SortedList(Of String, DocumentFont)
Public Shared DUMP_STATE As Boolean = False
'* a summary of all found text
Private locationalResult As New List(Of TextChunk)()
'*
' * Creates a new text extraction renderer.
'
Public Sub New()
ThisPdfDocFonts = New SortedList(Of String, DocumentFont)
End Sub
'*
' * @see com.itextpdf.text.pdf.parser.RenderListener#beginTextBlock()
'
Public Overridable Sub BeginTextBlock() Implements ITextExtractionStrategy.BeginTextBlock
End Sub
'*
' * @see com.itextpdf.text.pdf.parser.RenderListener#endTextBlock()
'
Public Overridable Sub EndTextBlock() Implements ITextExtractionStrategy.EndTextBlock
End Sub
'*
' * @param str
' * @return true if the string starts with a space character, false if the string is empty or starts with a non-space character
'
Private Function StartsWithSpace(ByVal str As [String]) As Boolean
If str.Length = 0 Then
Return False
End If
Return str(0) = " "c
End Function
'*
' * @param str
' * @return true if the string ends with a space character, false if the string is empty or ends with a non-space character
'
Private Function EndsWithSpace(ByVal str As [String]) As Boolean
If str.Length = 0 Then
Return False
End If
Return str(str.Length - 1) = " "c
End Function
Public Property UndercontentCharacterSpacing
Get
Return _UndercontentCharacterSpacing
End Get
Set(ByVal value)
_UndercontentCharacterSpacing = value
End Set
End Property
Public Property UndercontentHorizontalScaling
Get
Return _UndercontentHorizontalScaling
End Get
Set(ByVal value)
_UndercontentHorizontalScaling = value
End Set
End Property
Public Overridable Function GetResultantText() As [String] Implements ITextExtractionStrategy.GetResultantText
If DUMP_STATE Then
DumpState()
End If
locationalResult.Sort()
Dim sb As New StringBuilder()
Dim lastChunk As TextChunk = Nothing
For Each chunk As TextChunk In locationalResult
If lastChunk Is Nothing Then
sb.Append(chunk.text)
Else
If chunk.SameLine(lastChunk) Then
Dim dist As Single = chunk.DistanceFromEndOf(lastChunk)
If dist < -chunk.charSpaceWidth Then
sb.Append(" "c)
' we only insert a blank space if the trailing character of the previous string wasn't a space, and the leading character of the current string isn't a space
ElseIf dist > chunk.charSpaceWidth/2.0F AndAlso Not StartsWithSpace(chunk.text) AndAlso Not EndsWithSpace(lastChunk.text) Then
sb.Append(" "c)
End If
sb.Append(chunk.text)
Else
sb.Append(ControlChars.Lf)
sb.Append(chunk.text)
End If
End If
lastChunk = chunk
Next
Return sb.ToString()
End Function
Public Function GetTextLocations(ByVal pSearchString As String, ByVal pStrComp As System.StringComparison) As List(Of iTextSharp.text.Rectangle)
Dim FoundMatches As New List(Of iTextSharp.text.Rectangle)
Dim sb As New StringBuilder()
Dim ThisLineChunks As List(Of TextChunk) = New List(Of TextChunk)
Dim bStart As Boolean, bEnd As Boolean
Dim FirstChunk As TextChunk = Nothing, LastChunk As TextChunk = Nothing
Dim sTextInUsedChunks As String = vbNullString
For Each chunk As TextChunk In locationalResult
If ThisLineChunks.Count > 0 AndAlso Not chunk.SameLine(ThisLineChunks.Last) Then
If sb.ToString.IndexOf(pSearchString, pStrComp) > -1 Then
Dim sLine As String = sb.ToString
'Check how many times the Search String is present in this line:
Dim iCount As Integer = 0
Dim lPos As Integer
lPos = sLine.IndexOf(pSearchString, 0, pStrComp)
Do While lPos > -1
iCount += 1
If lPos + pSearchString.Length > sLine.Length Then Exit Do Else lPos = lPos + pSearchString.Length
lPos = sLine.IndexOf(pSearchString, lPos, pStrComp)
Loop
'Process each match found in this Text line:
Dim curPos As Integer = 0
For i As Integer = 1 To iCount
Dim sCurrentText As String, iFromChar As Integer, iToChar As Integer
iFromChar = sLine.IndexOf(pSearchString, curPos, pStrComp)
curPos = iFromChar
iToChar = iFromChar + pSearchString.Length - 1
sCurrentText = vbNullString
sTextInUsedChunks = vbNullString
FirstChunk = Nothing
LastChunk = Nothing
'Get first and last Chunks corresponding to this match found, from all Chunks in this line
For Each chk As TextChunk In ThisLineChunks
sCurrentText = sCurrentText & chk.text
'Check if we entered the part where we had found a matching String then get this Chunk (First Chunk)
If Not bStart AndAlso sCurrentText.Length - 1 >= iFromChar Then
FirstChunk = chk
bStart = True
End If
'Keep getting Text from Chunks while we are in the part where the matching String had been found
If bStart And Not bEnd Then
sTextInUsedChunks = sTextInUsedChunks & chk.text
End If
'If we get out the matching String part then get this Chunk (last Chunk)
If Not bEnd AndAlso sCurrentText.Length - 1 >= iToChar Then
LastChunk = chk
bEnd = True
End If
'If we already have first and last Chunks enclosing the Text where our String pSearchString has been found
'then it's time to get the rectangle, GetRectangleFromText Function below this Function, there we extract the pSearchString locations
If bStart And bEnd Then
FoundMatches.Add(GetRectangleFromText(FirstChunk, LastChunk, pSearchString, sTextInUsedChunks, iFromChar, iToChar, pStrComp))
curPos = curPos + pSearchString.Length
bStart = False : bEnd = False
Exit For
End If
Next
Next
End If
sb.Clear()
ThisLineChunks.Clear()
End If
ThisLineChunks.Add(chunk)
sb.Append(chunk.text)
Next
Return FoundMatches
End Function
Private Function GetRectangleFromText(ByVal FirstChunk As TextChunk, ByVal LastChunk As TextChunk, ByVal pSearchString As String, _
ByVal sTextinChunks As String, ByVal iFromChar As Integer, ByVal iToChar As Integer, ByVal pStrComp As System.StringComparison) As iTextSharp.text.Rectangle
'There are cases where Chunk contains extra text at begining and end, we don't want this text locations, we need to extract the pSearchString location inside
'for these cases we need to crop this String (left and Right), and measure this excedent at left and right, at this point we don't have any direct way to make a
'Transformation from text space points to User Space units, the matrix for making this transformation is not accesible from here, so for these special cases when
'the String needs to be cropped (Left/Right) We'll interpolate between the width from Text in Chunk (we have this value in User Space units), then i'll measure Text corresponding
'to the same String but in Text Space units, finally from the relation betweeenthese 2 values I get the TransformationValue I need to use for all cases
'Text Width in User Space Units
Dim LineRealWidth As Single = LastChunk.PosRight - FirstChunk.PosLeft
'Text Width in Text Units
Dim LineTextWidth As Single = GetStringWidth(sTextinChunks, LastChunk.curFontSize, _
LastChunk.charSpaceWidth, _
ThisPdfDocFonts.Values.ElementAt(LastChunk.FontIndex))
'TransformationValue value for Interpolation
Dim TransformationValue As Single = LineRealWidth/LineTextWidth
'In the worst case, we'll need to crop left and right:
Dim iStart As Integer = sTextinChunks.IndexOf(pSearchString, pStrComp)
Dim iEnd As Integer = iStart + pSearchString.Length - 1
Dim sLeft As String
If iStart = 0 Then sLeft = vbNullString Else sLeft = sTextinChunks.Substring(0, iStart)
Dim sRight As String
If iEnd = sTextinChunks.Length - 1 Then sRight = vbNullString Else sRight = sTextinChunks.Substring(iEnd + 1, sTextinChunks.Length - iEnd - 1)
'Measure cropped Text at left:
Dim LeftWidth As Single = 0
If iStart > 0 Then
LeftWidth = GetStringWidth(sLeft, LastChunk.curFontSize, _
LastChunk.charSpaceWidth, _
ThisPdfDocFonts.Values.ElementAt(LastChunk.FontIndex))
LeftWidth = LeftWidth * TransformationValue
End If
'Measure cropped Text at right:
Dim RightWidth As Single = 0
If iEnd < sTextinChunks.Length - 1 Then
RightWidth = GetStringWidth(sRight, LastChunk.curFontSize, _
LastChunk.charSpaceWidth, _
ThisPdfDocFonts.Values.ElementAt(LastChunk.FontIndex))
RightWidth = RightWidth * TransformationValue
End If
'LeftWidth is the text width at left we need to exclude, FirstChunk.distParallelStart is the distance to left margin, both together will give us this LeftOffset
Dim LeftOffset As Single = FirstChunk.distParallelStart + LeftWidth
'RightWidth is the text width at right we need to exclude, FirstChunk.distParallelEnd is the distance to right margin, we substract RightWidth from distParallelEnd to get RightOffset
Dim RightOffset As Single = LastChunk.distParallelEnd - RightWidth
'Return this Rectangle
Return New iTextSharp.text.Rectangle(LeftOffset, FirstChunk.PosBottom, RightOffset, FirstChunk.PosTop)
End Function
Private Function GetStringWidth(ByVal str As String, ByVal curFontSize As Single, ByVal pSingleSpaceWidth As Single, ByVal pFont As DocumentFont) As Single
Dim chars() As Char = str.ToCharArray()
Dim totalWidth As Single = 0
Dim w As Single = 0
For Each c As Char In chars
w = pFont.GetWidth(c)/1000
totalWidth += (w * curFontSize + Me.UndercontentCharacterSpacing) * Me.UndercontentHorizontalScaling/100
Next
Return totalWidth
End Function
Private Sub DumpState()
For Each location As TextChunk In locationalResult
location.PrintDiagnostics()
Console.WriteLine()
Next
End Sub
Public Overridable Sub RenderText(ByVal renderInfo As TextRenderInfo) Implements ITextExtractionStrategy.RenderText
Dim segment As LineSegment = renderInfo.GetBaseline()
Dim location As New TextChunk(renderInfo.GetText(), segment.GetStartPoint(), segment.GetEndPoint(), renderInfo.GetSingleSpaceWidth())
With location
'Chunk Location:
Debug.Print(renderInfo.GetText)
.PosLeft = renderInfo.GetDescentLine.GetStartPoint(Vector.I1)
.PosRight = renderInfo.GetAscentLine.GetEndPoint(Vector.I1)
.PosBottom = renderInfo.GetDescentLine.GetStartPoint(Vector.I2)
.PosTop = renderInfo.GetAscentLine.GetEndPoint(Vector.I2)
'Chunk Font Size: (Height)
.curFontSize = .PosTop - segment.GetStartPoint()(Vector.I2)
'Use Font name and Size as Key in the SortedList
Dim StrKey As String = renderInfo.GetFont.PostscriptFontName & .curFontSize.ToString
'Add this font to ThisPdfDocFonts SortedList if it's not already present
If Not ThisPdfDocFonts.ContainsKey(StrKey) Then ThisPdfDocFonts.Add(StrKey, renderInfo.GetFont)
'Store the SortedList index in this Chunk, so we can get it later
.FontIndex = ThisPdfDocFonts.IndexOfKey(StrKey)
End With
locationalResult.Add(location)
End Sub
'*
' * Represents a chunk of text, it's orientation, and location relative to the orientation vector
'
Public Class TextChunk
Implements IComparable(Of TextChunk)
'* the text of the chunk
Friend text As [String]
'* the starting location of the chunk
Friend startLocation As Vector
'* the ending location of the chunk
Friend endLocation As Vector
'* unit vector in the orientation of the chunk
Friend orientationVector As Vector
'* the orientation as a scalar for quick sorting
Friend orientationMagnitude As Integer
'* perpendicular distance to the orientation unit vector (i.e. the Y position in an unrotated coordinate system)
' * we round to the nearest integer to handle the fuzziness of comparing floats
Friend distPerpendicular As Integer
'* distance of the start of the chunk parallel to the orientation unit vector (i.e. the X position in an unrotated coordinate system)
Friend distParallelStart As Single
'* distance of the end of the chunk parallel to the orientation unit vector (i.e. the X position in an unrotated coordinate system)
Friend distParallelEnd As Single
'* the width of a single space character in the font of the chunk
Friend charSpaceWidth As Single
Private _PosLeft As Single
Private _PosRight As Single
Private _PosTop As Single
Private _PosBottom As Single
Private _curFontSize As Single
Private _FontIndex As Integer
Public Property FontIndex As Integer
Get
Return _FontIndex
End Get
Set(ByVal value As Integer)
_FontIndex = value
End Set
End Property
Public Property PosLeft As Single
Get
Return _PosLeft
End Get
Set(ByVal value As Single)
_PosLeft = value
End Set
End Property
Public Property PosRight As Single
Get
Return _PosRight
End Get
Set(ByVal value As Single)
_PosRight = value
End Set
End Property
Public Property PosTop As Single
Get
Return _PosTop
End Get
Set(ByVal value As Single)
_PosTop = value
End Set
End Property
Public Property PosBottom As Single
Get
Return _PosBottom
End Get
Set(ByVal value As Single)
_PosBottom = value
End Set
End Property
Public Property curFontSize As Single
Get
Return _curFontSize
End Get
Set(ByVal value As Single)
_curFontSize = value
End Set
End Property
Public Sub New(ByVal str As [String], ByVal startLocation As Vector, ByVal endLocation As Vector, ByVal charSpaceWidth As Single)
Me.text = str
Me.startLocation = startLocation
Me.endLocation = endLocation
Me.charSpaceWidth = charSpaceWidth
Dim oVector As Vector = endLocation.Subtract(startLocation)
If oVector.Length = 0 Then
oVector = New Vector(1, 0, 0)
End If
orientationVector = oVector.Normalize()
orientationMagnitude = CInt(Math.Truncate(Math.Atan2(orientationVector(Vector.I2), orientationVector(Vector.I1)) * 1000))
Dim origin As New Vector(0, 0, 1)
distPerpendicular = CInt((startLocation.Subtract(origin)).Cross(orientationVector)(Vector.I3))
distParallelStart = orientationVector.Dot(startLocation)
distParallelEnd = orientationVector.Dot(endLocation)
End Sub
Public Sub PrintDiagnostics()
Console.WriteLine("Text (@" & Convert.ToString(startLocation) & " -> " & Convert.ToString(endLocation) & "): " & text)
Console.WriteLine("orientationMagnitude: " & orientationMagnitude)
Console.WriteLine("distPerpendicular: " & distPerpendicular)
Console.WriteLine("distParallel: " & distParallelStart)
End Sub
'*
' * @param as the location to compare to
' * @return true is this location is on the the same line as the other
'
Public Function SameLine(ByVal a As TextChunk) As Boolean
If orientationMagnitude <> a.orientationMagnitude Then
Return False
End If
If distPerpendicular <> a.distPerpendicular Then
Return False
End If
Return True
End Function
'*
' * Computes the distance between the end of 'other' and the beginning of this chunk
' * in the direction of this chunk's orientation vector. Note that it's a bad idea
' * to call this for chunks that aren't on the same line and orientation, but we don't
' * explicitly check for that condition for performance reasons.
' * @param other
' * @return the number of spaces between the end of 'other' and the beginning of this chunk
'
Public Function DistanceFromEndOf(ByVal other As TextChunk) As Single
Dim distance As Single = distParallelStart - other.distParallelEnd
Return distance
End Function
'*
' * Compares based on orientation, perpendicular distance, then parallel distance
' * @see java.lang.Comparable#compareTo(java.lang.Object)
'
Public Function CompareTo(ByVal rhs As TextChunk) As Integer Implements System.IComparable(Of TextChunk).CompareTo
If Me Is rhs Then
Return 0
End If
' not really needed, but just in case
Dim rslt As Integer
rslt = CompareInts(orientationMagnitude, rhs.orientationMagnitude)
If rslt <> 0 Then
Return rslt
End If
rslt = CompareInts(distPerpendicular, rhs.distPerpendicular)
If rslt <> 0 Then
Return rslt
End If
' note: it's never safe to check floating point numbers for equality, and if two chunks
' are truly right on top of each other, which one comes first or second just doesn't matter
' so we arbitrarily choose this way.
rslt = If(distParallelStart < rhs.distParallelStart, -1, 1)
Return rslt
End Function
'*
' *
' * @param int1
' * @param int2
' * @return comparison of the two integers
'
Private Shared Function CompareInts(ByVal int1 As Integer, ByVal int2 As Integer) As Integer
Return If(int1 = int2, 0, If(int1 < int2, -1, 1))
End Function
End Class
'*
' * no-op method - this renderer isn't interested in image events
' * @see com.itextpdf.text.pdf.parser.RenderListener#renderImage(com.itextpdf.text.pdf.parser.ImageRenderInfo)
' * @since 5.0.1
'
Public Sub RenderImage(ByVal renderInfo As ImageRenderInfo) Implements IRenderListener.RenderImage
' do nothing
End Sub
End Class
をスタックオーバーフローユーザーBorisは同じ質問にhis answerで、その中に小さな問題を解決したと主張しました。
さらに別の問題の文脈では、もう1つの問題が見つかりました。this answer;その答えの文脈で私はC＃への簡単な移植を行いました。あなたはその答えの付録として見つけることができます。
はい、それが見えます。 – criticalfix
戦略が – user6934713