Ok, it appears that the I'm creating a PDFDocument where pixelWidth is incorrect in the images that I created. So the question becomes: How do I get the correct resolution into the image?
I start with bitmap data from a scanner. I'm doing this:
CGDataProviderRef provider= CGDataProviderCreateWithData(NULL (UInt8*)data, bytesPerRow * length, NULL);
CGImageRef cgImg = CGImageCreate (
width,
length,
bitsPerComponent,
bitsPerPixel,
bytesPerRow,
colorspace,
bitmapinfo, // ? CGBitmapInfo bitmapInfo,
provider, //? CGDataProviderRef provider,
NULL, //const CGFloat decode[],
true, //bool shouldInterpolate,
kCGRenderingIntentDefault // CGColorRenderingIntent intent
);
/* CGColorSpaceRelease(colorspace); */
NSData* imgData = [NSMutableData data];
CGImageDestinationRef dest = CGImageDestinationCreateWithData
(imgData, kUTTypeTIFF, 1, NULL);
CGImageDestinationAddImage(dest, cgImg, NULL);
CGImageDestinationFinalize(dest);
NSImage* img = [[NSImage alloc] initWithData: imgData];
there doesn't appear to be anywhere in there to include the actual width/height in inches or points, nor the actual resolution, which I DO know at this point... how am I supposed to do this?
If you've got a chunk of data, the easiest way to turn it into an NSImage
is to use NSBitmapImageRep
. Specifically something like:
NSData * byteData = [NSData dataWithBytes:data length:length];
NSBitmapImageRep * imageRep = [NSBitmapImageRep imageRepWithData:byteData];
NSSize imageSize = NSMakeSize(CGImageGetWidth([imageRep CGImage]), CGImageGetHeight([imageRep CGImage]));
NSImage * image = [[NSImage alloc] initWithSize:imageSize];
[image addRepresentation:imageRep];
...use image