support for bleed

[typemytype]

https://developer.apple.com/documentation/coregraphics/kcgpdfcontextbleedbox?language=objc

requested here https://forum.drawbot.com/topic/183/is-there-a-way-to-build-bleed-into-a-file-for-printing

[typemytype]

proposal:

bleedRect(-10, -10, 10, 10) relative to the page size

or newPage((600, 600), bleed=(-10, -10, 10, 10)) as an extra argument when creating a new page.

[roberto-arista]

🥳

Roberto Arista
ಠ_ಠ

Sent from my mobile: +39 366 45 37 413

On 13 Aug 2019, at 19:02, Frederik Berlaen notifications@github.com wrote:

proposal:

bleedRect(-10, -10, 10, 10) relative to the page size

or newPage((600, 600), bleed=(-10, -10, 10, 10)) as an extra argument when creating a new page.

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[justvanrossum]

I suppose all bleed arguments can be positive, as you'd never want a negative bleed, no?

I'd be +1 for:

newPage((600, 600), bleed=(10, 10, 10, 10)) 

Perhaps also accepting:

newPage((600, 600), bleed=10)

[arrowtype]

I like this as an optional argument, and I like @justvanrossum's tweak to this proposal. I think of bleed as something that happens at each edge, rather than a big background rectangle.

[justvanrossum]

Also, are different bleed values for different edges even needed?

[justvanrossum]

Also 2, want to work on a PR?

[arrowtype]

are different bleed values for different edges even needed?

My guess is yes. In the circumstance of preparing a file with facing pages (e.g. a book), I think the edge of a page that is in the gutter probably shouldn't get a bleed.

want to work on a PR?

Possibly ... but I wouldn't really know where to start, so I'm not sure I'd be very efficient and may require some hand-holding. Is the newPage function here, or somewhere else? https://github.com/typemytype/drawbot/blob/33cb3d60afd30b33713e1d655dba8bfe09337d16/drawBot/drawBotDrawingTools.py#L263

If so, how does that connect to whatever actually creates the page (probably something in Core Graphics)?

[typemytype]

test script for reference, but cannot figure out what the correct values are

how to test if those values are set correctly?

import Quartz
import AppKit
import os

width, height = 500, 100
bleed = (10, 10, 10, 10)

mediaBox = Quartz.CGRectMake(0, 0, width, height)
bleedBox = Quartz.CGRectMake(-bleed[0], -bleed[1], bleed[2], bleed[3])

print(bleedBox)

auxiliaryInfo = dict()
auxiliaryInfo[Quartz.kCGPDFContextMediaBox] = mediaBox
auxiliaryInfo[Quartz.kCGPDFContextBleedBox] = bleedBox
# auxiliaryInfo[Quartz.kCGPDFContextCropBox]
# auxiliaryInfo[Quartz.kCGPDFContextTrimBox]
# auxiliaryInfo[Quartz.kCGPDFContextArtBox]

pdfData = Quartz.CFDataCreateMutable(None, 0)
dataConsumer = Quartz.CGDataConsumerCreateWithCFData(pdfData)

pdfContext = Quartz.CGPDFContextCreate(dataConsumer, mediaBox, None)

Quartz.CGPDFContextBeginPage(pdfContext, auxiliaryInfo)

Quartz.CGPDFContextEndPage(pdfContext)
Quartz.CGPDFContextClose(pdfContext)

path = os.path.expanduser('~/test--.pdf')
pdfData.writeToFile_atomically_(path, True)

[tetris-hermetris]

We can see it, for example, in Acrobat: In 'Output Preview,' you need to select 'Show art, trim, & bleed boxes.' If they are present, they will be displayed.

Also, in CLI, we can use mutool with mutool pages test.pdf. This will print something like

<page pagenum="1">
<BleedBox l="14.1732" b="14.1732" r="485.827" t="85.8268" />
</page>

if they are there, and

<page pagenum="1">
</page>

if they are not.

Well, for some reason, the script above did not successfully set the bleed in my case. Just wanted to mention it because I think having this feature is really great and super helpful for production purposes.