Thanks Michael.
I took your advice and looked closer at PDFContentStreamProcessor.cs and
GraphicsState.cs, in fact, I downloaded the source and stepped through it as it
was processing the cm operators in my PDF. I guess I'm missing some
fundamental thing here because I still do not understand where my lines are
getting translated. In the (cm) ModifyCurrentTransformationMatrix function I
definitely see this happening:
float a = ((PdfNumber)operands[0]).FloatValue; float b =
((PdfNumber)operands[1]).FloatValue; float c =
((PdfNumber)operands[2]).FloatValue; float d =
((PdfNumber)operands[3]).FloatValue; float e =
((PdfNumber)operands[4]).FloatValue; float f =
((PdfNumber)operands[5]).FloatValue; Matrix matrix = new Matrix(a, b, c, d, e,
f); GraphicsState gs = processor.gsStack.Peek(); gs.ctm =
matrix.Multiply(gs.ctm);
The problem is that gs.ctm is always the identity matrix so the matrix.Multiply
just sets it to whatever operands were parsed out. I was expecting some actual
translation. I guess that is happening somewhere else at a later time.
Perhaps after all streams are parsed.
Am I just missing the boat here and looking in the wrong place or is this just
not possible with iText since it's almost more of a rendering thing -
translating what is in the PDF to actual coordinates after all translations are
applied?
Thanks for your help.
Darren
On Monday, September 1, 2014 7:47 AM, mkl <m...@wir-sind-cool.org> wrote:
Darren,
FDnC Red wrote
> I figured out I could setup a PDFContentStreamProcessor and get all line
> values from the Pdf operators like this snippet below. The only remaining
> problem is I can't get the CTM so my line coordinates are off.
>
> Listener listener = new Listener();
> PdfContentStreamProcessor processor = new
> PdfContentStreamProcessor(listener);
> CountOps counter = new CountOps(); //IContentOperator
> processor.RegisterContentOperator("q", counter);
> processor.RegisterContentOperator("cm", counter);
> processor.RegisterContentOperator("m", counter);
> processor.RegisterContentOperator("l", counter);
> processor.RegisterContentOperator("S", counter);
> processor.RegisterContentOperator("Q", counter);
>
> processor.ProcessContent(ContentByteUtils.GetContentBytesForPage(reader,
> 1), res);
>
>
> Is there any way to get the CTM in my IContentOperator class as the
> operators are found? I assume I need the CTM so then I can add the matrix
> found with the cm operator to find the real coordinates of the line.
As you already have found the PdfContentStreamProcessor class, you should
inspect it some more and look at its inner IContentOperator implementations
PushGraphicsState, PopGraphicsState, and ModifyCurrentTransformationMatrix
by default registered for q, Q, and cm, and the GraphicsState class. They
can serve as examples on how to process those operators and make the CTM
available (GraphicsState.GetCtm).
https://svn.code.sf.net/p/itextsharp/code/trunk/src/core/iTextSharp/text/pdf/parser/PdfContentStreamProcessor.cs
https://svn.code.sf.net/p/itextsharp/code/trunk/src/core/iTextSharp/text/pdf/parser/GraphicsState.cs
Regards, Michael
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