I have a PDFDocument (made up of PDFPages ofcourse) and I need a CGImageRef to stick into my IKImageView.
Currently, I get the datarepresentation from the PDFPage, put it into an NSImage, then get the TIFFRepresentation of the NSImage, put it into a CGImageSource, and then get the CGImage out of the source.
That seemsneedlessly complicated, going through two NSData steps...
However, when I try to put the PDF data directly into the CGImageSource, even though that APPEARS to work, when I get the CGImage out, it is always NULL. is there something specific I should be doing to get this to work?
In Snow Leopard there is a method -[NSImage CGImageForProposedRect:context:hints:]. Or you could draw the page into a CGBitmapContext and use CGBitmapContextCreateImage.
Look at the CreatePDFPageImage function in my CGPDFAdditions code. I think that's exactly what you need.
Try feeding the data for the PDF document (as opposed to a single page) into the CGImageSource. Images from the source should correspond to pages in the document.
Related
I'm trying to figure an easy way to create screenshots at 1200x800 from nearly one hundred HTML files using QuickLook. This line pretty much sums up with I'm doing:
CGImageRef imageRef = QLThumbnailImageCreate(NULL, (__bridge CFURLRef) [NSURL fileURLWithPath:layoutHtml isDirectory:NO], CGSizeMake(1280 , 800), (__bridge CFDictionaryRef) #{ (NSString*) kQLThumbnailOptionIconModeKey:#(NO)});
Unfortunately the create image does not contain any images used in the HTML file, I only get the question mark "image not found" placeholder. When I use QuickLook from the Finder, images get loaded.
Any ideas on how I could convince QLThumbnailImageCreate to include images?
Thanks,
Ilja
I don't think this is possible unless there is hidden Preview Property.
The Generating Enriched HTML also does not mention anything about loading external resources, only kQLPreviewPropertyAttachmentsKey which requires the HTML to use the cid:identifier URL scheme.
There is webkit2png which is a python script that does what you need. Searching for WebKit screenshot solution also brings up some Cocoa code snippets.
I am trying to modify the Apple MultiGPUIOSurface sample (specifically the file http://developer.apple.com/library/mac/#samplecode/MultiGPUIOSurface/Listings/ServerOpenGLView_m.html) so that the server side will render to an IOSurface, without the need for a NSOpenGLView.
My modified version of that is at: http://pastebin.com/z3r715jJ
The difference in my approach is I'm rendering to the IOSurface based on a timer, and not in drawRect. I also am not using the NSOpenGlView's context.
The problem is that I see a corrupt view of the IOSurface in the client application. However if I set the NSOpenGLView's context to the one I created, or use the context from the NSOpenGLView, it works. This leads me to think that the NSOpenGLView is doing something extra that I also need to do, but I'm not sure what.
Found a solution (though I don't understand why): Create a pixelbuffer.
I found some discussion about offscreen buffers and the need for a drawable (http://www.mentby.com/Group/mac-opengl/opengl-offscreen-rendering-without-a-window.html)
Anyways, my fix was adding the lines:
NSOpenGLPixelBuffer* pbuf = [[NSOpenGLPixelBuffer alloc] initWithTextureTarget:GL_TEXTURE_RECTANGLE_EXT textureInternalFormat:GL_RGBA textureMaxMipMapLevel:0 pixelsWide:512 pixelsHigh:512];
[_nsContext setPixelBuffer:pbuf cubeMapFace:0 mipMapLevel:0 currentVirtualScreen:[_nsContext currentVirtualScreen]];
This has been driving me mad for months: I have a little app to preview camera raw images. As the files in question can be quite big and stored on a slow network drive I wanted to offer the user a chance to stop the loading of the image.
Handily I found this thread:
Cancel NSData initWithContentsOfURL in NSOperation
and am using Nick's great convenience method to cache the data and be able to issue a cancel request halfway through.
Anyway, once I have the data I use:
NSImage *sourceImage = [[NSImage alloc]initWithData:data];
The problem comes when looking at Nikon .NEF files; sourceImage returns only a thumbnail and not the full size. Displaying Canon .CR2 files and in fact, any other .TIFF's and .JPEG's seems fine and sourceImage is the expected size. I've checked the amount of data that is being loaded (with NSLog and [data length]) and it does seem that all of the Nikon files' 12mb is there for the -initWithData:
If I use
NSImage *sourceImage = [[NSImage alloc]initWithContentsOfURL:myNEFURL];
then I get the full sized image of the Nikon files but of course the app blocks.
So after poking around for what is beginning to feel like my entire life I think I know that the problem is related to the Nikon's metadata stating that the file's DPI is 300 whereas Canon et al is 72.
I hoped a solution would be to lazily access the file with:
NSImage*tempImg = [[NSImage alloc] initByReferencingURL:myNEFURL];
and having seen similar postings here and elsewhere I found a common possible answer of simply
[sourceImage setSize:tempImg.size];
but of course this just resizes the tiny thumbnail up to 3000x2000 or thereabouts.
I've been messing with the following hoping that they would provide a way to get the big picture from the .NEF:
CGImageSourceRef isr = CGImageSourceCreateWithData((__bridge CFDataRef)data, NULL);
CGImageRef isrRef = CGImageSourceCreateImageAtIndex(isr, 0, NULL);
and
NSBitmapImageRep *bitMapIR = [[NSBitmapImageRep alloc] initWithData:data];
But checking the sizes on these show similar thumbnail widths and heights. In fact, isrRef returns an even smaller thumbnail, one that is 4.2 times smaller. Perhaps worth noting that 300 / 72 == 4.2, so isrRef is taking account of the DPI on an image where the DPI (possibly) has already been observed.
Please! Can someone [nicely] put me out of my misery and help me get the full-sized image from the loaded data?!?! Currently, I'm special-case'ing the NEF files with a case insensitive search on the file extension and then loading the URL with the blocking methods. I have to take a hit on the app blocking and the search can't be fool-proof in the long run.
As an aside: is this actually a bug in the OS? It does seem like NSImage's -initWithData: and -initWithContentsOfURL: methods use different engines to actually render the image. Would it not be reasonable to have assumed that -initWithURL: simply loads the data which then gets rendered just as though it had been presented to the class with -initWithData: ?
It's a bug - confirmed when I did a DTS. Apparently I need to file a bug report. Currently the only way is to use the NSURL methods. Instead of checking the file extension I should probably traverse the meta dictionaries and check the manufacturer's entry for "Nikon", though...
If I create an NSImage via something like:
NSImage *icon = [NSImage imageNamed:NSImageNameUser];
it only has one representation, a NSCoreUIImageRep which seems to be a private class.
I'd like to archive this image as an NSData but if I ask for the TIFFRepresentation I get a
small icon when the real NSImage I originally created seemed to be vector and would scale up to fill my image views nicely.
I was kinda hoping images made this way would have a NSPDFImageRep I could use.
Any ideas how can I get an NSData (pref the vector version or at worse a large scale bitmap version) of this NSImage?
UPDATE
Spoke with some people on Twitter and they suggested that the real source of these images are multi resolution icns files (probably not vector at all). I couldn't find the location of these on disk but interesting to hear none-the-less.
Additionally they suggested I create the system NSImage and manually render it into a high res NSImage of my own. I'm doing this now and it's working for my needs. My code:
+ (NSImage *)pt_businessDefaultIcon
{
// Draws NSImageNameUser into a rendered bitmap.
// We do this because trying to create an NSData from
// [NSImage imageNamed:NSImageNameUser] directly results in a 32x32 image.
NSImage *icon = [NSImage imageNamed:NSImageNameUser];
NSImage *renderedIcon = [[NSImage alloc] initWithSize:CGSizeMake(PTAdditionsBusinessDefaultIconSize, PTAdditionsBusinessDefaultIconSize)];
[renderedIcon lockFocus];
NSRect inRect = NSMakeRect(0, 0, PTAdditionsBusinessDefaultIconSize, PTAdditionsBusinessDefaultIconSize);
NSRect fromRect = NSMakeRect(0, 0, icon.size.width, icon.size.width);;
[icon drawInRect:inRect fromRect:fromRect operation:NSCompositeCopy fraction:1.0];
[renderedIcon unlockFocus];
return renderedIcon;
}
(Tried to post this as my answer but I don't have enough reputation?)
You seem to be ignoring the documentation. Both of your major questions are answered there. The Cocoa Drawing Guide (companion guide linked from the NSImage API reference) has an Images section you really need to read thoroughly and refer to any time you have rep/caching/sizing/quality issues.
...if I ask for the TIFFRepresentation I get a small icon when the
real NSImage I originally created seemed to be vector and would scale
up to fill my image views nicely.
Relevant subsections of the Images section for this question are: How an Image Representation is Chosen, Images and Caching, and Image Size and Resolution. By default, the -cacheMode for a TIFF image "Behaves as if the NSImageCacheBySize setting were in effect." Also, for in-memory scaling/sizing operations, -imageInterpolation is important: "Table 6-4 lists the available interpolation settings." and "NSImageInterpolationHigh - Slower, higher-quality interpolation."
I'm fairly certain this applies to a named system image as well as any other.
I was kinda hoping images made [ by loading an image from disk ] would
have a NSPDFImageRep I could use.
Relevant subsection: Image Representations. "...with file-based images, most of the images you create need only a single image representation." and "You might create multiple representations in the following situations, however: For printing, you might want to create a PDF representation or high-resolution bitmap of your image."
You get the representation that suits the loaded image. You must create a PDF representation for a TIFF image, for example. To do so at high resolution, you'll need to refer back to the caching mode so you can get higher-res items.
There are a lot of fine details too numerous to list because of the high number of permutations of images/creation mechanisms/settings/ and what you want to do with it all. My post is meant to be a general guide toward finding the specific information you need for your situation.
For more detail, add specific details: the code you attempted to use, the type of image you're loading or creating -- you seemed to mention two different possibilities in your fourth paragraph -- and what went wrong.
I would guess that the image is "hard wired" into the graphics system somehow, and the NSImage representation of it is merely a number indicating which hard-wired graphic it is. So likely what you need to do is to draw it and then capture the drawing.
Very generally, create a view controller that will render the image, reference the VC's view property to cause the view to be rendered, extract the contentView of the VC, get the contentView.layer, render the layer into a UIGraphics context, get the UIImage from the context, extract whatever representation you want from the UIImage.
(There may be a simpler way, but this is the one I ended up using in one case.)
(And, sigh, I suppose this scheme doesn't preserve scaling either.)
I have a QTCaptureView and Im trying to save the view as a picture. So far I have this:
NSRect rect = [outputView bounds];
NSData *viewData = [outputView dataWithPDFInsideRect:rect];
[viewData writeToFile:#"/test.pdf" atomically:YES];
but for some reason when I save instead of seeing a picture of my vie (iSight Camera) I see a black pdf file.
Thanks for any help
QTCaptureView isn't meant to be used in this way due to the way it is optimized. You'll need to do single-frame-grabbing the QTKit way: Creating a Single-Frame Grabbing Application.