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the friday prophets @ soundcloud

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~/Library/Preferences/com.apple.dt.Xcode.plist

but to no effect. when i checked the crash log i saw that i got some ui-based reason:

...
ASSERTION FAILURE in /SourceCache/DVTKit/DVTKit-907/Framework/Classes/Tabs/DVTTabBarView.m:1532
Details:  Assertion failed: maxX >= minX
...

so i figured i’d check out what my workspace file (or actually folder) contained. after firing up iTerm and navigating to

<project-dir>/<project-name>.xcworkspace/xcuserdata/<username>.xcuserdatad/

i found the file UserInterfaceState.xcuserstate. having had a few beers i didn’t feel like going thru a gazillion rows of apple-xml just to fix some layout-crap so i simply (re)moved it. This fixed the problem.

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next time i post it’ll be the new uvc-ctrl comming out.

update: still some kinks to work out.. but here’s a sneek preview

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Through work i found the need to display an IplImage in cocoa.. after looking at CVOCV, James Hurleys example and a couple of other snippets i remembered that opencv can be built for iOS and started browsing through the source. Inside OpenCV-2.4.1/modules/highgui/src/window_cocoa.mm i found what i was looking for (CVView). i rewrote it a bit and came up with the following NSView subclass:

MyCVView.h

#import <Foundation/Foundation.h>
#import <opencv/cv.h>


@interface MyCVView : NSView {
@private
	NSBitmapImageRep *bm;
@public
}
@property (nonatomic, retain) NSImage *image;

- (void)setImagePrefs:(int)width		// image width
			   height:(int)height		// " height
			 channels:(int)nChannels	// usually 4/3/1 (rgba/rgb/monochrome)
			widthStep:(int)widthStep	// usually width*nChannels
			    depth:(int)depth;
- (void)setImageData:(IplImage *)img
   releaseWhenCopied:(BOOL)shouldRelease;
- (void)drawRect:(NSRect)rect;

@end

MyCVView.m:

#import "MyCVView.h"

@implementation MyCVView 

@synthesize image;

- (id)init {
	if((self = [super init])) [self setCanDrawConcurrently:true];
	return self;
}

- (void)setImagePrefs:(int)width
			   height:(int)height
			 channels:(int)nChannels
			widthStep:(int)widthStep
			    depth:(int)depth
{
	if(bm) [bm release];
	bm = [[NSBitmapImageRep alloc] initWithBitmapDataPlanes: NULL
												 pixelsWide: width
												 pixelsHigh: height
											  bitsPerSample: 8	// i only use IPL_DEPTH_8U, if you use others set it as an arg..
											samplesPerPixel: nChannels
												   hasAlpha: NO
												   isPlanar: NO
											 colorSpaceName: (nChannels == 1 ? NSDeviceWhiteColorSpace :  NSDeviceRGBColorSpace)
												bytesPerRow: widthStep
											   bitsPerPixel: nChannels*depth];
	if(image) [image release];
	image = [[NSImage alloc] init];
	[image addRepresentation:bm];
}

- (void)setImageData:(IplImage *)img
   releaseWhenCopied:(BOOL)shouldRelease
{
	if(!bm) [self setImagePrefs:img->width
						 height:img->height
					   channels:img->nChannels
					  widthStep:img->widthStep
					      depth:img->depth];
	unsigned char *src = (unsigned char *)img->imageData;
	unsigned char *dst = [bm bitmapData];
	if(img->nChannels == 1) memcpy(dst, src, (img->width*img->height));
	else
	{	// red-blue swap and flip incorporated
		for(int i = img->width * img->height - 1; i >= 0; i--)
		{
			dst[i * 4 + 0] = src[2];
			dst[i * 4 + 1] = src[1];
			dst[i * 4 + 2] = src[0];
			src += ((CvMat *)img)->step - ((CvMat *)img)->cols;
		}
	}
	[self setNeedsDisplay:YES];
	if(shouldRelease) cvReleaseImage(&img);
}

- (void)drawRect:(NSRect)rect {
	[super drawRect:rect];
	// autoscaling - if you don't want it replace second part with comment below 
	NSRect ir = {{0,0}, {[self bounds].size.width, [self bounds].size.height}};
						// {[image size].width, [image size].height}};
	if(image != nil)
	{
		[image drawInRect: ir
				 fromRect: NSZeroRect
				operation: NSCompositeSourceOver
				 fraction: 1.0];
	}
}

- (void)dealloc
{
	if(bm) [bm release];
	if(image) [image release];
    [super dealloc];
}

@end

This was built without warnings in xcode 4 on snow leopard and saves some cpu-cycles compared to the original version since the rb-swap and flip is stuffed into a the data-copy-loop. Note that you should not call it CVView (will cause a crash) since opencv already contains a class with that name.

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• could not claim interface: access denied error fixed. settings are still reset when some progs are started but they can now be set whilst running e.g. skype.
• show configuration works again.
• power line frequency control (manual 50/60Hz anti-flicker setting) added.

This version is also compatible with Klaus’ gui.

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mv uvc-ctrl uvc-ctrl-GUI.app/Contents/MacOS/

and then hit enter.
Thank you Klaus for you awesome work!

note libusb is still required.

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the binary included is “universal” (i386/x86_64) and have been tested on both os x 10.6 and 10.7 (thanks to Arvid). the source has also been compiled on freebsd9. it does not require python as that was only the gui. it does however require libusb.

known bugs (thank you Matthew and F-red for the reports)

• interactive session can’t take negative values
• auto-exposure value description in wrong order
• show configuration segfaults

update thanks to Klaus’ report it seems possible to fix the problem with programs resetting settings made by uvc-ctrl. if you have this trouble: try starting the program that resets your settings, from within it switch to your iSight, update the settings you want with uvc-ctrl on your other cam and then switch back. your settings should now still be in place.

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