Re: Optimizing PDFKit
Re: Optimizing PDFKit
- Subject: Re: Optimizing PDFKit
- From: Shaun Wexler <email@hidden>
- Date: Wed, 5 Oct 2005 02:59:37 -0700
On Oct 4, 2005, at 2:11 PM, Ricky Sharp wrote:
All images for my app are now PDF and I'd like to encrypt them to
protect my artwork.
Anyhow, I wanted to make sure my image loading times would not
suffer. I kept all my PDFs unencrypted and changed this line:
NSImage* theImage = [[NSImage alloc]
initWithContentsOfFile:theImagePath];
to...
NSURL* thePDFURL = [[[NSURL alloc]
initFileURLWithPath:theImagePath] autorelease];
PDFDocument* thePDFDocument = [[[PDFDocument alloc]
initWithURL:thePDFURL] autorelease];
if ([thePDFDocument isEncrypted])
{
// not yet implemented
}
NSImage* theImage = [[NSImage alloc] initWithData:
[thePDFDocument dataRepresentation]];
For the same run of a test script, the PDFKit code is a full order
of magnitude slower. I'm running 10.4.2 on a dual 2GHz G5 and am
concerned about users with slower machines.
You're performing two stages of unnecessary+expensive data conversion!!!
Does anyone know of a different (faster) path to decrypt PDFs and
ultimately create NSImage instances out of them?
All you need to do is sniff the raw data and decrypt the binary if
necessary:
NSData *data = [NSMutableData dataWithContentsOfFile:theImagePath];
NSImage *theImage = nil;
UInt32 magic, *bytes;
if ((bytes = [data bytes])) {
if ((magic = *bytes) == NSSwapBigIntToHost('cryp')) {
theImage = [[NSImage alloc] initWithEncryptedData:data]; // my
method
} else // if (magic == NSSwapBigIntToHost('%PDF')) {
theImage = [[NSImage alloc] initWithData:data];
// }
}
Email me if you need me to write you an implementation, plus my
encrypting tool (which you can script into a Deployment build phase).
--
Shaun Wexler
MacFOH
http://www.macfoh.com
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