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Search found 52 results on 3 pages for 'cgbitmapcontextcreate'.

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• iPhone SDK - CGBitmapContextCreate

  - by nax_

  Hi, I would like to create an image of my own. I already know its width (320*2 = 640) and height (427). So I have some raw data : unsigned char *rawImg = malloc(height * width * 4 *2 ); Then, I will fill it :) Then, I have to do something like that to get a bitmap and return a (UIImage *) : ctx =…

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• CGBitmapContextCreate: unsupported parameter combination

  - by tarmes

  I'm getting this error when creating a bitmap context: CGBitmapContextCreate: unsupported parameter combination: 8 integer bits/component; 24 bits/pixel; 3-component color space; kCGImageAlphaNone; 7936 bytes/row. Here's the code (note that the context is based on the parameters of an existing CGImage:…

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• CGBitmapContextCreate on the iPhone/iPad

  - by toastie

  Hello, I have a method that needs to parse through a bunch of large PNG images pixel by pixel (the PNGs are 600x600 pixels each). It seems to work great on the Simulator, but on the device (iPad), i get an EXC_BAD_ACCESS in some internal memory copying function. It seems the size is the culprit because…

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• CGBitmapContextCreate issue while trying to resize images

  - by Jeff

  Hello! I'm running into an issue when I try to create a CGContextRef while attempting to resize some images: There are the errors Sun May 16 20:07:18 new-host.home app [7406] <Error>: Unable to create bitmap delegate device Sun May 16 20:07:18 new-host.home app [7406] <Error>:…

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• How to create a CGBitmapContext which works for Retina display and not wasting space for regular display?

  - by ????

  Is it true that if it is in UIKit, including drawRect, the HD aspect of Retina display is automatically handled? So does that mean in drawRect, the current graphics context for a 1024 x 768 view is actually a 2048 x 1536 pixel Bitmap context? (is there a way to print this size out to…

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• iPhone: Changing CGImageAlphaInfo of CGImage

  - by TechZen

  I have a PNG image that has an unsupported bitmap graphics context pixel format. Whenever I attempt to resize the image, CGBitmapContextCreate() chokes on the unsupported format (Error formatted for easy reading): CGBitmapContextCreate: unsupported parameter combination: 8…

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• Error With CBitmapContextCreate, CGContextDrawImage, CGBitmapContextCreateImage

  - by wsidell

  Error: CGBitmapContextCreate: invalid data bytes/row: should be at least 400 for 8 integer bits/component, 3 components, kCGImageAlphaNoneSkipFirst. Error: CGContextDrawImage: invalid context Error: CGBitmapContextCreateImage: invalid context Currently, I have in application…

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• A scheme to show picture

  - by luoliyong

  I have a requirement that need me to show picture using one canvas. All the operation will be done on this canvas, include change the picture (This picture is made of lines, rectangular and so on. Draw these lines or rectangular will use the base method). In China, we called…

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• UIView: how to do non-destructive drawing?

  - by Caffeine Coma

  My original question: I'm creating a simple drawing application and need to be able to draw over existing, previously drawn content in my drawRect. What is the proper way to draw on top of existing content without entirely replacing it? Based on answers received…

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• iPhone - UIImage Leak, CGBitmapContextCreateImage Leak

  - by bbullis21

  Alright I am having a world of difficulty tracking down this memory leak. When running this script I do not see any memory leaking, but my objectalloc is climbing. Instruments points to CGBitmapContextCreateImage create_bitmap_data_provider malloc, this takes up 60% of my…

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• iPhone Image Processing--matrix convolution

  - by James

  I am implementing a matrix convolution blur on the iPhone. The following code converts the UIImage supplied as an argument of the blur function into a CGImageRef, and then stores the RGBA values in a standard C char array. CGImageRef imageRef = imgRef.CGImage; int…

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• How can we change color of a text programmatically ?

  - by user297535

  My code is -(UIImage *)addText:(UIImage *)img text:(NSString *)text1{ int w = img.size.width; int h = img.size.height; CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); CGContextRef context = CGBitmapContextCreate(NULL, w, h, 8, 4 * w,…

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• UIImagePickerController, UIImage, Memory and More!

  - by Itay

  I've noticed that there are many questions about how to handle UIImage objects, especially in conjunction with UIImagePickerController and then displaying it in a view (usually a UIImageView). Here is a collection of common questions and their answers. Feel free…

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• iPhone: CMYK Supported Pixel Formats woes

  - by user219393

  I am trying to create a image sized 1X1 in CMYK color space. as first step I am creating bitmapContext as CGColorSpaceRef cmykcolorSpace = CGColorSpaceCreateDeviceCMYK(); CGContextRef currentcontext = CGBitmapContextCreate(NULL, …

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• How to crop the UIImage?

  - by Rajendra Bhole

  Hi, I develop an application in which i process the image using its pixels but in that image processing it takes a lot of time. Therefore i want to crop UIImage (Only middle part of image i.e. removing/croping bordered part of image).I have the develop code are,…

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• Create new UIImage by adding shadow to existing UIImage

  - by Tom Irving

  I've taken a look at this question: http://stackoverflow.com/questions/962827/uiimage-shadow But the accepted answer didn't work for me. What I'm trying to do is take a UIImage and add a shadow to it, then return a whole new UIImage, shadow and all. This is…

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• CoreGraphics on iPhone. What is the proper way to load a PNG file with pre-multiplied alpha?

  - by dugla

  For my iPhone 3D apps I am currently using CoreGraphics to load png files that have pre-multiplied alpha. Here are the essentials: // load a 4-channel rgba png file with pre-multiplied alpha. CGContextRef context = CGBitmapContextCreate(data, width, height,…

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• How can I tell when a UIWebView has finished drawing to a context?

  - by phopkins

  In my code I'm trying to show a UIWebView as a page is loading, and then, when it's done, capture an image from the web view to cache and display later (so I don't have to reload and render the web page). I have something along the lines of: CGContextRef…

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• How to get rid of previous reflection when reflecting a UIImageView (with changing pictures)?

  - by epale

  Hi everyone, I have managed to use the reflection sample app from apple to create a reflection from a UIImageView. But the problem is that when I change the picture inside the UIImageView, the reflection from the previous displayed picture remains on the…

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• Creating a mask from a graphics context

  - by Magic Bullet Dave

  I want to be able to create a greyscale image with no alpha from a png in the app bundle. This works, and I get an image created: // Create graphics context the size of the overlapping rectangle UIGraphicsBeginImageContext(rectangleOfOverlap.size);…

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• How i store the images pixels in matrix form?

  - by Rajendra Bhole

  Hi, I developing an application in which the pixelize image i want to be store in matrix format. The code is as follows. struct pixel { //unsigned char r, g, b,a; Byte r, g, b; int count; }; (NSInteger) processImage1: (UIImage*) image {…

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• iOS - pass UIImage to shader as texture

  - by martin pilch

  I am trying to pass UIImage to GLSL shader. The fragment shader is: varying highp vec2 textureCoordinate; uniform sampler2D inputImageTexture; uniform sampler2D inputImageTexture2; void main() { highp vec4 color = texture2D(inputImageTexture,…

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• Rendering Texture Quad to Screen or FBO (OpenGL ES)

  - by Usman.3D

  I need to render the texture on the iOS device's screen or a render-to-texture frame buffer object. But it does not show any texture. It's all black. (I am loading texture with image myself for testing purpose) //Load texture data UIImage…

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• memory warning, generating UIImagefrom pdf files in objective-c

  - by favo

  When converting PDF Pages into UIImages I receive memory warnings all the time. It seems there is either some leak or something else that eats my memory. Using instruments didn't give me any helpful details. I'm using the following…

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• UIImage Shadow Trouble

  - by Brandon Schlenker

  I'm trying to add a small shadow to an image, much like the icon shadows in the App Store. Right now I'm using the following code to round the corners of my images. Does anyone know how I can adapt it to add a small shadow? -…

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