CMYK export from Processing - what's the latest?

norbert

I have a project that outputs geometry for print. I would like to output a PDF with print-ready CMYK colors. In my current workflow I have to use Adobe Illustrator simply to assign proper CMYK colors to the PDF output before print. I want Adobe out of my toolchain and I want my processing sketch to be able to output print-ready PDFs.

Andreas Gysin has created a solution for this, but it is no longer maintained and does not appear to work in Processing 3. I was hoping I could update it to work with Processing 3, but I don't know what I'm doing. There are lots of deprecated functions and changes and I don't understand the code well enough or the changes between P1, P2, P3...

I understand that Java supports CMYK color spaces and ICC profiles, but I am floundering with implementation. I haven't been able to get any of the example code running and I'm a bit out of my depth. Still haven't figured out how to instantiate a ColorSpace let alone use it for outputting colors to a PDF.

I thought I could export SVGs and use a text editor to replace the colors in the XML -- but SVG doesn't seem to support CMYK properly. I can kludge something together so I can use a non-Adobe editor, but the workflow becomes untenable.

I would be thrilled if anyone could give me some direction on this. What would I need to do to update Andreas Gysin's CMYK code for P3? Am I barking up the wrong tree with Java ColorSpace? Once I get a 4 component color model working, how do I ensure those colors are exported in the PDF? This seems like a simple problem, but no easy answers are forthcoming. Any avenues of research, high level code, suggestions or examples would really help me get past this roadblock. Thank you.

kfrajer

Andreas Gysin has created a solution for this

Can you provide a link to this reference?

Kf

koogs

google is your friend

https://github.com/ertdfgcvb/CMYK

koogs

that's doesn't look like a library but a class that you can just add to your sketch. the three directories there all contain the SAME PDF.pde file, which the other .pde file uses via something like

PDF pdf = new PDF(this, mm(210), mm(297), sketchPath(System.currentTimeMillis() + ".pdf")); 

koogs

which should make it easier to port to P3. that said, it is 5 years old.

jeremydouglass

The header notes on the PDF.pde class tab file says

A slightly modified PGraphicsPDF class

Perhaps diff Gysin's modifications

https://github.com/ertdfgcvb/CMYK/blob/master/cmyk/PDF.pde

...against the appropriate original version of PGraphics PDF from 2013

https://github.com/processing/processing/commits/master/java/libraries/pdf/src/processing/pdf/PGraphicsPDF.java

...and once you know what was changed, apply those changes to the latest version?

https://github.com/processing/processing/blob/master/java/libraries/pdf/src/processing/pdf/PGraphicsPDF.java

(I'm assuming these links are right based on a very quick search, but confirm that)

koogs

ok, so far i have:

added

import processing.awt.PGraphicsJava2D;

to the top of PDF.pde

added

super.setSize((int)w, (int)h);

to top of PDF.pde setSize(float w, float h) { because otherwise i was getting

java.lang.IllegalArgumentException: Width (0) and height (0) cannot be <= 0
    at java.awt.image.DirectColorModel.createCompatibleWritableRaster(DirectColorModel.java:1016)
    at java.awt.GraphicsConfiguration.createCompatibleImage(GraphicsConfiguration.java:186)
    at processing.awt.PGraphicsJava2D.checkImage(PGraphicsJava2D.java:328)
    at processing.awt.PGraphicsJava2D.beginDraw(PGraphicsJava2D.java:338)
    at cmyk$PDF.beginDraw(cmyk.java:585)

i also had to comment out allocate() method and the call to it in setSize() because it's no longer in the parent class

i'm currently getting

com.lowagie.text.exceptions.IllegalPdfSyntaxException: Unbalanced begin/end text operators.
    at com.lowagie.text.pdf.PdfContentByte.endText(Unknown Source)
    at com.lowagie.text.pdf.PdfDocument.newPage(Unknown Source)
    at com.lowagie.text.Document.newPage(Unknown Source)
    at cmyk$PDF.nextPage(cmyk.java:745)

koogs

as i said above, the github project is 3 directories, each a complete processing sketch. i'm using the cmyk directory for testing.

i'm getting a non-zero pdf as output, but nothing is displayed when i open it.

koogs

...and once you know what was changed, apply those changes to the latest version?

lots of style changes make this complicated... 8(

jeremydouglass

Oof. Yeah, the "diff" doesn't look simple to resolve at all.

Maybe reach out to the original author? Could be worth a shot....

• https://github.com/ertdfgcvb/CMYK/issues

koogs

actually, everything is nicely marked with his initials AG so it shouldn't be too hard just to copy the cmyk methods over to the new PGraphicsPDF file.

will try that tomorrow

koogs

actually, did it now. seems ok, but then i don't really know what i'm doing.

https://github.com/acdean/CMYK/blob/master/cmyk/PDF.pde

for an example see the cmyk.pde sketch in the same directory

koogs

Copied PDF.pde to the other two example project directories.

Replaced example outputs with newly generated files. (the font is missing so it uses the default, which isn't as nice, otherwise it looks identical).

https://github.com/acdean/CMYK

koogs

(i'm going to try and make the cmyk version extend the original PDF file, rather than copying 80% of the code)

jeremydouglass

Very cool that you are taking this on, @koogs. If it works it seems like it might even be a proposed pull request...? edit: by which I mean -- I wonder if this CMYK support could easily be pushed back upstream to the original Processing PDF.

norbert

Very cool indeed! Thank you! The code runs on P3 and the output displays proper 4-component and spot colors. I really appreciate your efforts on this!

kfrajer

@koogs Do you see it would be possible to be introduce in the current Processing core?

Kf