Open mathieureguer opened 1 year ago
I guess this is indeed a quartz issue. I have a hunch the screen you render on is important: could you check the resolution of the images inside the pdf? I assume the source is 72dpi, you have a retina screen and the final pdf has images with a higher resolution.
Oh, that would be an interesting plot twist!
I am not sure how to test the screen influence on this. I have a lower resolution screen hooked up to my retina laptop but the output is the same no matter what screen I run drawBot on (maybe this makes sense, the retina screen must be considered the main screen by the system…).
You are right, I should have inspected the image inside the pdf. It gives a much better picture as to what is happening:
It looks like all the images are converted to 72 dpi, but with no resampling, as their dimension change accordingly. I don't think that is a problem, as I guess no information is lost and no data is added or removed here.
Looking further into the images in the pdfs, it seems they are all encoded with ZIP/Flate compression (FlateDecode)
no matter the input image format (jpeg, tiff, pngs…).
Using a quartz filter to convert them to jpg brings the pdfs to a reasonable size, much closer to the original images files.
It would be awesome if dawBot pdfs could just keep the original compression (and resolution?) of the input images but I understand this is a quartz thing and it is probably not drawBot main focus anyway.
No image information is lost, so pdfs can be post processed outside of drawBot if compression is needed 🙂️
I noticed placing a jpg in a DrawBot document usually results in a saved pdf with a file size quite larger than the image file itself.
Will print:
Experimenting with other image formats (tiff, png), it seems the resulting pdf is always roughly the same size. Does that mean something is converting the images to a specific format when exporting pdfs? I understand this is probably a Quartz thing and not a drawBot thing, but if there is indeed a conversion, is there a way to control its settings somehow? I am trying to have pdfs as small as possible and even tiny images bloat them very fast 😅
Weirdly enough, cmyk images tends to result in smaller size pdfs.