On the fly pdf creation with 16bit colour depth png support in php

Question

I'm trying to create pdf documents on the fly in an application, i.e. a user clicks a link and a pdf document is displayed to them with some text and some images.

I'm currently using FPDF v1.6 (http://www.fpdf.org/) which supports 24bit (true colour) png's but the problem I have is that this is a legacy application and there's 1000's of png's that are of 16bit colour depth which FPDF does not support and I can't simply convert due to other parts of the application using these images.

The only solutions I see are:

1. convert the 16bit png image on the fly and embed that into the pdf.
2. find a new class pdf class that will accept 16bit colour depth png's.

Anyone have any ideas?

Answer 1

Maybe you could try using TCPDF (never used it with 16bit PNGs but it should be easy to test it).

Answer 2

Fixed with this in python:

def fix_16_bit_depth_not_supported(raw_image_path):
    """
    fix
    RuntimeError: FPDF error: 16-bit depth not supported: test.png
    """
    new_file, filename = tempfile.mkstemp(suffix='.png')
    os.close(new_file)
    i = cv2.imread(raw_image_path, cv2.IMREAD_UNCHANGED)
    img = np.array(i, dtype=np.float32)
    convert = img / 255.
    cv2.imwrite(filename, convert)
    return filename