Drawing in an NSImage: how maintain resolution independence?

[Just]

Here's what I'm trying to do:

- create an NSImage
- draw in it using NSBezierPaths
- draw it into a custom NSView
- then later I want to save the existing NSImage to a PDF file

I currently do the latter by sending dataWithPDFInsideRect: to the view.
But: I keep getting a bitmapped PDF, whereas I want a vector PDF. I've
been fiddling with representations and various image options
(setUsesEPSOnResolutionMismatch:, setPrefersColorMatch: and
setCacheMode:) to no avail. If I send bestRepresentationForDevice: nil
to the image I always get a chached bitmap representation and never an
NSPDFImageRep.

I've been trying to add an (empty) NSPDFImageRep to the image manually
and that doesn't help either. Then I googled and googled, but still
found nothing. Now, I've learned that if something seems hard with
Cocoa, I'm probably doing things the wrong way... Is there something I
overlooked? I'd really like to avoid creating the image twice, I want to
draw once, and use the image both on screen and in a resolution independ
way. Is that possible at all?

Feeling rather clueless today...

Just

[Per Bull Holmen]

Just <just@xs4all.nl> wrote:

> I've been trying to add an (empty) NSPDFImageRep to the image manually
> and that doesn't help either.

Did you try...

- (void) lockFocusOnRepresentation: (NSImageRep *) imageRepresentation

....rather than just lockFocus? Just checking to make sure, but
unfortunately I think it will still create an NSCachedImageRep and draw
it into a bitmap. Also you may try an NSEPSImageRep, but I don't think
it will actually help. Sorry.... :(

Per

[Just]

In article <1g1ubir.1kmk9nt10ibj6iN%pbh_news@yahoo.com>,
[email]pbh_news@yahoo.com[/email] (Per Bull Holmen) wrote:

> Just <just@xs4all.nl> wrote:
>

> > I've been trying to add an (empty) NSPDFImageRep to the image manually
> > and that doesn't help either.

>
> Did you try...
>
> - (void) lockFocusOnRepresentation: (NSImageRep *) imageRepresentation
>
> ...rather than just lockFocus? Just checking to make sure, but
> unfortunately I think it will still create an NSCachedImageRep and draw
> it into a bitmap. Also you may try an NSEPSImageRep, but I don't think
> it will actually help. Sorry.... :(

Thanks for the suggestion. It indeed doesn't seem to have any effect...
I'm creating an empty NSPDFImageRep with a new NSMutableData instance,
but that doesn't seem to be the right way to do it: the data remains
empty. It seems NSPDFImageRep is not meant to _create_ PDF data.

I've also been fighting with NSGraphicsContext, creating a PDF-based
context, but I haven't been able to invoke the right magic incantations
to get it to do what I want.

I guess the core question is: how do I make a vector-based PDF in Cocoa
from scratch?

Just

[Per Bull Holmen]

Just <just@xs4all.nl> wrote:

> I guess the core question is: how do I make a vector-based PDF in Cocoa
> from scratch?

I think you'll have to use CoreGraphics. Check out the documentation on
your HD (CoreTechnologies -> Quartz2D).

That is if you need to do it that way. Otherwise, make sure to draw with
the bezierpath inside drawRect.

Per

[Just]

In article <1g1uxcy.cp06fcxltwz8N%pbh_news@yahoo.com>,
[email]pbh_news@yahoo.com[/email] (Per Bull Holmen) wrote:

> > I guess the core question is: how do I make a vector-based PDF in Cocoa
> > from scratch?

>
> I think you'll have to use CoreGraphics. Check out the documentation on
> your HD (CoreTechnologies -> Quartz2D).
>
> That is if you need to do it that way. Otherwise, make sure to draw with
> the bezierpath inside drawRect.

Yeah, that's what I'm doing now. Having worked with QD PICTs in the past
(yuck!) I (probably mistakenly) thought/hoped NSImage could do vector
based image recording. I gave up on that, so I wrote my own recorder.
Luckily, no need to use CoreGraphics directly... Thanks for your help.

Just

[Per Bull Holmen]

Just <just@xs4all.nl> wrote:

> In article <1g1uxcy.cp06fcxltwz8N%pbh_news@yahoo.com>,
> [email]pbh_news@yahoo.com[/email] (Per Bull Holmen) wrote:
>

> > > I guess the core question is: how do I make a vector-based PDF in Cocoa
> > > from scratch?

> >
> > I think you'll have to use CoreGraphics. Check out the documentation on
> > your HD (CoreTechnologies -> Quartz2D).
> >
> > That is if you need to do it that way. Otherwise, make sure to draw with
> > the bezierpath inside drawRect.

>
> Yeah, that's what I'm doing now. Having worked with QD PICTs in the past
> (yuck!) I (probably mistakenly) thought/hoped NSImage could do vector
> based image recording. I gave up on that, so I wrote my own recorder.
> Luckily, no need to use CoreGraphics directly... Thanks for your help.

You're welcome.

Too bad NSImage can't fix it, cause it's already implemented in
CoreGraphics. All it lacks is the object oriented wrapping in an
NSImage/NSPDFImageRep.

Per