ITextSharp旋转页面上的所有文本关于点

Question

我刚刚烧了一个小时，找出解决方案，我肯定不是最好的;我很乐意听到有没有更好的解决方案。

我需要旋转页面上关于点的所有文本。我试图将点转化为原点，执行一个旋转然后变换回去，但是似乎最终的变换正在发生在相对于旋转变换（考虑它的意义是合理的）上。

这里是我的代码复杂度降低的版本：

imports itextsharp.text 

public class Example 

    public shared function RotateAboutPoint(byval sourceReader as pdf.pdfreader, byval rads as double, byval centreX as double, byval centreY as double) as pdf.pdfreader    

     Using ms As New System.IO.MemoryStream 
      Using doc As New Document 
       Using writer As pdf.PdfWriter = pdf.PdfWriter.GetInstance(doc, ms) 
        doc.Open() 
        For i As Integer = 1 To sourceReader.NumberOfPages 
         Dim p As pdf.PdfTemplate = writer.GetImportedPage(sourceReader, i) 

         dim trans as new itextsharp.awt.geom.affinetransform 
         trans.translate(-centrex, -centrey) 
         trans.rotate(-rads) 
         trans.translate(centerx, centery) 

         doc.setpagesize(sourcereader.getpagesizewithrotation(I)) 
         doc.newpage() 

         writer.DirectContent.AddTemplate(p, trans) 
        Next i 
        doc.Close() 
       End Using 
      End Using 
      sourceReader.Close() 
      sourceReader.Dispose() 
      return New pdf.PdfReader(ms.ToArray) 
     End Using 
    end function 
end class 

Answer 1

下面是我临到解决方案，基本上执行不用翻译旋转，然后通过添加两种载体，一种从获得翻译旋转原点到所需旋转中心和一个从（即所需旋转中心将已被旋转的地方）获取旋转原点

imports itextsharp.text 

public class Example 

    public shared function RotateAboutPoint(byval sourceReader as pdf.pdfreader, byval rads as double, byval centreX as double, byval centreY as double) as pdf.pdfreader    

     Using ms As New System.IO.MemoryStream 
      Using doc As New Document 
       Using writer As pdf.PdfWriter = pdf.PdfWriter.GetInstance(doc, ms) 
        doc.Open() 
        For i As Integer = 1 To sourceReader.NumberOfPages 
         Dim p As pdf.PdfTemplate = writer.GetImportedPage(sourceReader, i) 

         Dim transAdjust As New iTextSharp.awt.geom.AffineTransform 
         transAdjust.SetToIdentity() 
         transAdjust.Translate(centreX - ((centreX * System.Math.Cos(rads)) + (centreY * System.Math.Sin(rads))), centreY - ((centreX * -System.Math.Sin(rads)) + (centreY * System.Math.Cos(rads)))) 
         Dim transRotate As New iTextSharp.awt.geom.AffineTransform 
         transRotate.SetToIdentity() 
         transRotate.Rotate(-rads) 

         Dim finalTrans As New iTextSharp.awt.geom.AffineTransform 
         finalTrans.SetToIdentity() 
         finalTrans.Concatenate(transAdjust) 
         finalTrans.Concatenate(transRotate) 

         doc.setpagesize(sourcereader.getpagesizewithrotation(I)) 
         doc.newpage() 

         writer.DirectContent.AddTemplate(p, finalTrans) 
        Next i 
        doc.Close() 
       End Using 
      End Using 
      sourceReader.Close() 
      sourceReader.Dispose() 
      return New pdf.PdfReader(ms.ToArray) 
     End Using 
    end function 
end class 

感觉凌乱，但它的工作原理 - 我如果有的话，非常感兴趣使用变换和旋转组合的更简单的方法。