I want to draw on an existing image to achieve the accumulation effect. Currently, the only way I found is: UIGraphicsBeginImageContext(rect.size); CGContextRef context = UIGraphicsGetCurrentContext(); ... // draw the existing image // draw other things ... UIImage *color = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImage...
I am getting EXEC_BAD_ACCESS errors in a CGContextDrawImage call and trying to trace it back. I have a PNG image and running a UIImagePNGRepresentation o it gives me NSData instance. I need to convert this to CGImageRef instance, so I can run the CGImageCreateWithPNGDataProvider method with this CGImageRef. I tried two ways: 1) To cast...
I've looked around everywhere to no avail. I'm doing some image loading in a thread and since UIKit is not thread safe I'm going to have to store the images as CGImageRefs but I can't figure out how to do this. I haven't played with any of the Quartz stuff before so it's confusing me. Basically I just need to load a JPG from the disk int...
I have an application that draws images from a CGImage. The CImage itself is loaded using a CGImageSourceCreateImageAtIndex to create an image from a PNG file. This forms part of a sprite engine - there are multiple sprite images on a single PNG file, so each sprite has a CGRect defining where it is found on the CGImage. The problem i...
I'm using CGImageCreateWithImageInRect to do a magnifying effect, and it works beautifully, except when I get close to the edges of my view. In that case, clipping causes the image to be distorted. Right now I grab a 72x72 chunk of the view, apply a round mask to it, and then draw the masked image, and a circle on top. When the copied...
I'd like to multiply r, g, b and a values of two CGImages, to use a single image as both a mask (in its alpha channel) and tint (in the rgb channels). I first tried simply: CGContextDrawImage(context, CGRectMake(0, 0, _w, _h), handle()); CGContextSetBlendMode(context, kCGBlendModeMultiply); CGContextDrawImage(context, CGRectMake(0, 0, o...
I've got a function that returns a std::string object. I'm working with Cocoa/CoreGraphics and I need a way to get the data from that string into a CFData object so that I can feed that into a CGDataProviderCreateWithCFData object to make a CGImage. The CreateCFData function wants a const UInt8* object (UInt8 being a typedef for unsign...
I have code something like this... CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); CGContextRef ctx = CGBitmapContextCreate(pixelArray, width, height, 8, 4 * width, colorSpace, kCGImageAlphaNoneSkipLast); CGImageRef createdImage = CGBitmapContextCreateImage (ctx); uiImage = [[UIImage imageWithCGImage:createdImage] retain];...
This project is a generic C++ plugin with core-graphics support. I am unable to convert a PicHandle to CGImageRef successfully. Saving off image from CFDataRef results in a bad image. if(pic) { Handle thePictureFileHandle; thePictureFileHandle = NewHandleClear(512); HandAndHand((Handle)pic,thePictureFileHandle); d...
Hi All, I any one have idea about taking snapshot from iphone application through coding. means. I am developing an iphone application where there will be two images dynamically comes. There will be a text view with clear color on those particular images. users will be able to write any text on the images and click save button. Then t...
Hi All, In my iPhone application, i am using the following code to get a snap shot from the iphone application. -(UIImage *)captureView:(UIView *)view { CGRect screenRect = [view bounds]; UIGraphicsBeginImageContext(screenRect.size); CGContextRef ctx = UIGraphicsGetCurrentContext(); [[UIColor clearColor] set]; CGContextFillRect(c...
I'm trying to implement a very simple drawing view in my app. This is only a small part of my app but it's turning into a real hassle. This is what I have so far, but all it's displaying right now is morse code like dots and lines. - (void)viewDidLoad { [super viewDidLoad]; self.view.backgroundColor = [UIColor whiteColor...
I'd LOVE to know what I'm doing wrong here. I'm a bit of a newbie with CGImageRefs so any advice would help. I'm trying to create a bitmap image that has as it's pixel values a weighted sum of the pixels from another bitmap, and both bitmaps are 16bits per channel. For some reason I had no trouble getting this to work with 8bit images b...
Hi, I want to write all frames to disk using QTKit.framework for camera input. But all the images I get are half transparent and without some colors, maybe colorspace problem? ;( They seem good in the preview View but when I write them "something" happens. I wonder what it that. -(void)savePNGImage:(CGImageRef)imageRef path:(NSString *)...
I'm trying to get an image of an offscreen window to use in a CALayer-based animation, but no matter which method I try I cannot get an image out the other side. Here is the code I've been using on a custom NSWindow subclass in my project: CGImageRef windowImage = CGWindowListCreateImage(CGRectNull, ...
Hi. I am trying to work with images in Cocoa - open images and manipulate with them. I take ImageApp as example . All work fine, but I need to save images in lower quality -(8, 4, 2, 1 bits per pixel - 256, 16, 4, 2 colors respectively). According to documentation, the "lowest" pixel format is Gray 8 bpp, 8 bpc,kCGImageAlphaNone and i...