Saving a PDF to web-server: how can I covert a PGraphics object into a byte[]

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almost_sc..

Saving a PDF to web-server: how can I covert a PGraphics object into a byte[]

in Programming Questions • 1 year ago

Hi!

I'm woking off the code found here ( http://wiki.processing.org/w/Saving_files_to_a_web-server) to write some PDFs to web-server and running into some trouble.

I'm created my PDFs off screen using createGraphics() to create a PGraphics object.

Based on the code snippet from the link above:

             
              void postData(String title, String ext, String folder, byte[] bytes, boolean popup)
              {
               try{
               URL u = new URL(url+"saveFile.php?title="+title+"&ext="+ext+"&folder="+folder); 
                  URLConnection c = u.openConnection(); 
              ......

I need to pass this function a byte[] not a PGraphics object.

I can't seem to figure out how to covert the PGraphics to a byte[]

Any thoughts?

Thanks in advance!

Replies(4)

PhiLho

Re: Saving a PDF to web-server: how can I covert a PGraphics object into a byte[]

1 year ago

The postToWeb library, based on some code I wrote ( in the old forum) which in turn is based on the wiki article you mention just does that. Just use the library or get inspiration on its design.

almost_sc..

Re: Re: Saving a PDF to web-server: how can I covert a PGraphics object into a byte[]

1 year ago

HI Phi.lho

So I'm looking through the docs for postToWeb and I don't see a way either set the size of the pdf or use offscreen drawing, both of which I need to do.

It looks like I can modify startRecording() in PDFToWeb.java to take any width and height, but what is the best way to handel offscreen drawing?

Also, when I run the example I get this error:

java.lang.StringIndexOutOfBoundsException: String index out of range: 4

import processing.pdf.*;
import org.seltar.Bytes2Web.*;
PDFToWeb pdf;
void setup()
{
size(800,600);
pdf = new PDFToWeb(this);
}
void draw()
{
background(0);
stroke(255);
line(random(width),random(height),random(width),random(height));
pdf.addPage(); // if you want each frame to be on it's own page
}
void keyPressed()
{
String url = "http://www.almostscientific.com.com/Upload.php";
if(key == 'p'){
if(!pdf.isRecording()){
pdf.startRecording();
}else{
pdf.save("pdf");
pdf.post("PDFs",url,"pdf-test",true);
}
}
}

Thanks

PhiLho

Re: Saving a PDF to web-server: how can I covert a PGraphics object into a byte[]

1 year ago

Note that the in memory PDF I see in postToWeb-0.5 (the version I have) is an old version I made when PGraphicsPDF was difficult to extend. Since then, this class has been improved and the extension is much easier to do:

public class InMemoryPGraphicsPDF extends PGraphicsPDF
{
@Override
protected void allocate() // Called by PGraphics in setSize()
{
output = new ByteArrayOutputStream(16384);
}
public byte[] getBytes()
{
return ((ByteArrayOutputStream) output).toByteArray();
}
}

After that, with getBytes(), you have an array of bytes you can pass to UploadBinaryData().
I will see if I can improve my ImageUpload sketch to include my InMemoryPDF.
Note that PGraphicsPDF has already off-screen rendering capability, see the PDF library page for example.

almost_sc..

Re: Saving a PDF to web-server: how can I covert a PGraphics object into a byte[]

1 year ago

Okay I got this to work!

Here is how I did if for future folks trying the same thing.

1- import InMemoryPGraphicsPDF.java to you sketch, from the post above

2- add the UploadBinaryData class to your sketch.

Then create you PDFs for off screen drawing like this:

PGraphics pdfLay = createGraphics(W, H, "InMemoryPGraphicsPDF");
beginRecord(pdfLay);
DRAW YOU STUFF...

Since I had a lot of PDFs to write I made this function:

String writePDFToWeb(String name, PGraphics thePDF){
InMemoryPGraphicsPDF impgpdf = (InMemoryPGraphicsPDF) thePDF; // Get the real renderer
byte[] pdfData = impgpdf.getBytes();
DataUpload du=new DataUpload();
du.UploadBinaryData(name, "PDF", pdfData);
return du.GetServerFeedback();
}

I then used a modified version of Upload.php to handel my filenames and paths they way I wanted.

And it worked!

Thanks Phi.lho!

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