On Nov 19, 2009, at 4:37 PM, Chinh Nguyen wrote:
The conversion to screen coordinates is causing stair stepping in connected
lines and other oddities when exporting to PDF. As a temporary solution
until the code is rewritten, I've created a subclass of my view that's sized
at the large coordinate space's dimensions specifically for rendering the
image to PDF. However, I can't seem to resize the PDF data down to the more
manageable screen view's dimensions when saving to disk. I've tried creating
an NSPDFImageRep from the PDF data and resizing it but it has no effect on
the saved to disk image (I guess setSize: does not affect the original data).
What I end up with is a PDF file with large dimensions that overwhelms
whatever application I'm placing it into.
What I ended up doing is creating an NSView subclass that simply draws the
PDF at the size I want and returns the PDF data from that. This works but is
there a better way of resizing the dimensions of PDF data or is the size the
size that it's generated at and there's no changing it?
A PDF file has a number of rectangles that affect how and where it draws. I
would recommend looking at CGPDFContext. It gives you the ability to specify
the size of the PDF you are generating. You would basically use a combination
of changing the size of the PDF and using a coordinate transformation to scale
the PDF content to the size that you want.
Also, I allow the user to export the image as a bitmap and even override the
dimensions. I create an NSImage from the PDF data, resize the NSImage, then
save the TIFF representation to the bitmap format I want. This works in
Leopard but no longer works in Snow Leopard. I read the tech note about
changes to NSImage and caching but I had no luck with the different caching
methods. I ended up creating an NSImage at the desired size, locking the
focus, drawing the PDF data at the desired size, unlocking the focus, then
saving the TIFF representation. Is there a better way?
Your solution sounds OK. I tend to work at the CG Layer a lot so personally, I
would avoid NSImage altogether and drop down to the Core Graphics layer. I
would create a block of memory, use CGBitmapContextCreate to create a CG
context on that bitmap, draw the graphic into that context, construct a CGImage
and use Image I/O to export the image. The end result would be similar, but
I'd have to go through a lot more steps than you did.
And finally, is there a way to change the resolution of a bitmap from 72dpi
to say 300dpi? My users want to be able to specify the dimensions of the
exported bitmap in inches and the resolution. They want to be able to place
their 1800 pixel wide TIFF file into Word and it show up 6 inches wide (@
300dpi) instead of 25 inches wide (@ 72dpi). Not a huge deal because I still
recommend our users use PDF but some of them have legacy apps that don't
support PDF. The example I was able to find on this created a new
NSBitmapImageRep and copied the image data into it and then set the size.
This is one feature that Image I/O allows you to have control over. As you
export each image you can provide a dictionary of image attributes, one of
which is the desired image resolution.
Scott
___
Cocoa-dev mailing list (Cocoa-dev@lists.apple.com)
Please do not post admin requests or moderator comments to the list.
Contact the moderators at cocoa-dev-admins(at)lists.apple.com
Help/Unsubscribe/Update your Subscription:
http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com
This email sent to arch...@mail-archive.com
