Can PDFIum edit PDF files?

[尚二蛋]

• Why did I only find the load interface(FPDF_LoadDocument) and not the save interface????

[Lei Zhang]

Please take a look in public/fpdf_save.h. I would also suggest looking
through the other headers in the same directory to see all the
available public APIs.

On Mon, Oct 25, 2021 at 8:50 AM 尚二蛋 <shan...@gmail.com> wrote:
>
> Why did I only find the load interface(FPDF_LoadDocument) and not the save interface????
>

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[尚二蛋]

thanks for your reply.

It is now can  save, but file contents not the same as the source file.

show my code

-------------------------------my code begin------------------------------------

void SavePDF(

  const void* pData,

  unsigned long size) {

  char filename[256]{"E:\\hello_world_test.pdf"};

  FILE* fp = fopen(filename, "w");

  if (!fp) {

    fprintf(stderr, "Failed to open %s for output\n", filename);

    return;

  }

  if (fwrite(pData, size, 1, fp) != 1) {

    fprintf(stderr, "Failed to write to %s\n", filename);

    (void)fclose(fp);

    return;

  }

  (void)fclose(fp);

}

int FakeBlockWriter(FPDF_FILEWRITE* pThis,

  const void* pData,

  unsigned long size) {

  SavePDF(pData, size);

  return size;

}

test () {

  std::string filename = "E:\\src\\pdf\\test\\data\\helloworld.pdf";

  ScopedFPDFDocument doc;

  const char* password = nullptr;

  doc.reset(FPDF_LoadDocument(filename.c_str(), password));

  FPDF_FILEWRITE writer;

  writer.version = 1;

  writer.WriteBlock = FakeBlockWriter;

  FPDF_SaveAsCopy(doc.get(), &writer, 0);

}

----------------------------------------------my code end-------------------

soruce pdf file

%PDF-1.1

%忏嫌

1 0 obj 

<<

/Kids [2 0 R]

/Count 1

/Type /Pages

>>

endobj 

2 0 obj 

<<

/Parent 1 0 R

/Resources 3 0 R

/MediaBox [0 0 612 792]

/Contents [4 0 R]

/Type /Page

>>

endobj 

3 0 obj 

<<

/Font 

<<

/F0 

<<

/BaseFont /Times-Italic

/Subtype /Type1

/Type /Font

>>

>>

>>

endobj 

4 0 obj 

<<

/Length 65

>>

stream

1. 0. 0. 1. 50. 700. cm

BT

  /F0 36. Tf

  (Hello, World!) Tj

ET 

endstream 

endobj 

5 0 obj 

<<

/Pages 1 0 R

/Type /Catalog

>>

endobj xref

0 6

0000000000 65535 f 

0000000015 00000 n 

0000000074 00000 n 

0000000182 00000 n 

0000000281 00000 n 

0000000399 00000 n 

trailer

<<

/Root 5 0 R

/Size 6

>>

startxref

449

%%EOF

---------------------------------------------

save new file

%PDF-1.1

%〕抛

1 0 obj

<</Count 1/Kids[ 2 0 R ]/Type/Pages>>

endobj

2 0 obj

<</Contents[ 4 0 R ]/MediaBox[ 0 0 612 792]/Parent 1 0 R /Resources 3 0 R /Type/Page>>

endobj

3 0 obj

<</Font<</F0<</BaseFont/Times-Italic/Subtype/Type1/Type/Font>>>>>>

endobj

4 0 obj

<</Filter/FlateDecode/Length 65>>stream

x?許0 #C= S en $抯箿B? 糨 屚?B襽

徳湝| 咅?EM厫,.? . 琸 2

endstream

endobj

5 0 obj

<</Pages 1 0 R /Type/Catalog>>

endobj

xref

0 6

0000000000 65535 f

0000000017 00000 n

0000000073 00000 n

0000000178 00000 n

0000000263 00000 n

0000000399 00000 n

trailer

<</Root 5 0 R /Size 6/ID[<3077DC735BA531D26EAAA4D886B9D42B><3077DC735BA531D26EAAA4D886B9D42B>]>>

startxref

448

%%EOF

[Lei Zhang]

Please send PDFs as email attachments and not inline, so they remain
intact. To be clear, are you saying the issue is FPDF_SaveAsCopy()'s
output is not exactly the same as the input, or that the output PDF
renders incorrectly?

> To view this discussion on the web visit https://groups.google.com/d/msgid/pdfium/617632f4-0ead-4a9a-b897-6d1c5f016d1fn%40googlegroups.com.