How to I find out if a text element in PDF is filled or stroked?

[Support]

Q: Starting from your ElementEdit sample, I am trying to edit an
existing PDF document by changing all color spaces and all colorant to
gray (i.e. I want to change the entire colro PDF to grayscale PDF).
For some reason IsStroked()/IsFilled() is not working for text. How to
I find out if a text element is filled/stroked ? I develop in C++.

#include <PDF/PDFNet.h>
#include <PDF/PDFDoc.h>
#include <PDF/ElementWriter.h>
#include <PDF/ElementReader.h>
#include <PDF/Element.h>
#include <PDF/Font.h>
#include <Filters/FilterReader.h>
#include <PDF/Image/Image2RGB.h>

#include <iostream>
#include <assert.h>

using namespace std;

using namespace pdftron;
using namespace PDF;
using namespace SDF;
using namespace Common;
using namespace Filters;

char m_buf[4000];

int main(int argc, char *argv[])
{
int ret = 0;
PDFNet::Initialize();
PDFNet::SetResourcesPath("../../../resources");

// Relative path to the folder containing test files.
string input_path = "../../TestFiles/";
string output_path = "../../TestFiles/Output/";

try
{
PDFDoc doc((input_path + "foo.pdf").c_str());
doc.InitSecurityHandler();

int num_pages = doc.GetPageCount();

ElementWriter writer;
ElementReader reader;
Element element;

for(int i=1; i<=num_pages; ++i)
{
PageIterator itr = doc.GetPageIterator(i);
Page page = itr.Current();
reader.Begin(page);

Page new_page = doc.PageCreate();
PageIterator next_page = itr;
next_page.Next();
doc.PageInsert(next_page, new_page );

writer.Begin(new_page);
while (element = reader.Next()) // Read page
contents
{
GState gs;
switch(element.GetType())
{
case Element::e_path:
if(element.IsFilled())
{
gs = element.GetGState();
ColorSpace cs = gs.GetFillColorSpace
();
if(cs.GetType() !=
ColorSpace::e_device_gray)
{
ColorPt in = gs.GetFillColor
();
ColorPt out;
cs.Convert2Gray(in,out);
gs.SetFillColorSpace
(ColorSpace::CreateDeviceGray());
gs.SetFillColor(out);
}
}
if(element.IsStroked())
{
gs = element.GetGState();
ColorSpace cs =
gs.GetStrokeColorSpace();
if(cs.GetType() !=
ColorSpace::e_device_gray)
{
ColorPt in = gs.GetStrokeColor
();
ColorPt out;
cs.Convert2Gray(in,out);
gs.SetStrokeColorSpace
(ColorSpace::CreateDeviceGray());
gs.SetStrokeColor(out);
}
}
break;
case Element::e_text:
if(element.IsFilled())
{
gs = element.GetGState();
ColorSpace cs = gs.GetFillColorSpace
();
if(cs.GetType() !=
ColorSpace::e_device_gray)
{
ColorPt in = gs.GetFillColor
();
ColorPt out;
cs.Convert2Gray(in,out);
gs.SetFillColorSpace
(ColorSpace::CreateDeviceGray());
gs.SetFillColor(out);
}
}
if(element.IsStroked())
{
gs = element.GetGState();
ColorSpace cs =
gs.GetStrokeColorSpace();
if(cs.GetType() !=
ColorSpace::e_device_gray)
{
ColorPt in = gs.GetStrokeColor
();
ColorPt out;
cs.Convert2Gray(in,out);
gs.SetStrokeColorSpace
(ColorSpace::CreateDeviceGray());
gs.SetStrokeColor(out);
}
}
break;
}
//else if (element.GetType() ==
Element::e_image)
//{
// // remove all images
// continue;
//}

writer.WriteElement(element);
}

writer.End();
reader.End();
new_page.SetMediaBox(page.GetCropBox());
doc.PageRemove(doc.GetPageIterator(i));
}

doc.Save((output_path + "MA015RM.pdf").c_str(),
SDFDoc::e_remove_unused , 0);
// doc.Save((output_path + "newsletter_edited.pdf").c_str
(), Doc::e_linearized , 0);
cout << "Done. Result saved in newsletter_edited.pdf..."
<< endl;
}
catch(Common::Exception& e)
{
cout << e << endl;
ret = 1;
}
catch(...)
{
cout << "Unknown Exception" << endl;
ret = 1;
}

PDFNet::Terminate();
return ret;
}

-------
A: To find out if a text text element is filled, stroked, or clipped
use GetTextRenderingMode() in the graphics state. IsFiled()/IsStroked
() methods apply only to path elements.

case Element::e_text:
{
bool is_clipped, is_stroked, is_filled;
GState::TextRenderingMode tr = gs->GetTextRenderMode();
if (tr == GState::e_invisible_text) continue;
switch (tr)
{
case GState::e_clip_text :
is_clipped = true;
is_stroked = false;
is_filled = false;
break;
case GState::e_fill_clip_text:
is_clipped = true;
is_stroked = false;
is_filled = true;
break;
case GState::e_fill_stroke_clip_text:
is_clipped = true;
is_stroked = true;
is_filled = true;
break;
case GState::e_fill_stroke_text:
is_stroked = true;
is_filled = true;
break;
case GState::e_fill_text:
is_stroked = false;
is_filled = true;
break;
case GState::e_stroke_clip_text:
is_clipped = true;
is_stroked = true;
is_filled = false;
break;
case GState::e_stroke_text:
is_stroked = true;
is_filled = false;
break;
default: assert(false);
}

if(is_filled)
{
gs = element->GetGState();
ColorSpace cs = gs->GetFillColorSpace();
if(cs.GetType() != ColorSpace::e_device_gray)
{
ColorPt in = gs->GetFillColor();
ColorPt out;
cs.Convert2Gray(in,out);
gs->SetFillColorSpace(ColorSpace::CreateDeviceGray());
gs->SetFillColor(out);
}
}
if(is_stroked)
{
gs = element->GetGState();
ColorSpace cs = gs->GetStrokeColorSpace();
if(cs.GetType() != ColorSpace::e_device_gray)
{
ColorPt in = gs->GetStrokeColor();
ColorPt out;
cs.Convert2Gray(in,out);
gs->SetStrokeColorSpace(ColorSpace::CreateDeviceGray());
gs->SetStrokeColor(out);
}
}
}
break;
}