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2014/10/15 ¤U¤È 10:03:34
iphone Programming Glossary: allocateHow to get the color of a pixel in an UIView? http://stackoverflow.com/questions/1160229/how-to-get-the-color-of-a-pixel-in-an-uiview improve this question It is pretty horrible and slow. Basically you create a bitmap context with a backing store you allocate so you can read the memory then you render the views layer in the context and read the appropriate point in ram. If you..
MKPinAnnotationView: Are there more than three colors available? http://stackoverflow.com/questions/1185611/mkpinannotationview-are-there-more-than-three-colors-available mapView MKMapView mapView viewForAnnotation id MKAnnotation annotation ... get the annotation delegate and allocate the MKAnnotationView annView if annotationDelegate.type localizedCaseInsensitiveCompare @ NeedsBluePin NSOrderedSame UIImage..
CGImage/UIImage lazily loading on UI thread causes stutter http://stackoverflow.com/questions/1815476/cgimage-uiimage-lazily-loading-on-ui-thread-causes-stutter it's a little more involved you need to create a color space figure out the right sized buffer to create and allocate it yourself . The CG methods are fine to run from a different thread. I'm not sure how you're initializing UIImage but if..
Create XML file dynamically in Iphone http://stackoverflow.com/questions/1825605/create-xml-file-dynamically-in-iphone iOS Written in Objective C a single .h. and .m file One @protocol for namespaces support and one for without Example allocate serializer XMLWriter xmlWriter XMLWriter alloc init start writing XML elements xmlWriter writeStartElement @ Root xmlWriter..
UITableView flexible/dynamic heightForRowAtIndexPath http://stackoverflow.com/questions/2213024/uitableview-flexible-dynamic-heightforrowatindexpath a couple of posts that said you don't want to do that but I don't really understand that. Yes I agree it will already allocate the cell but the heightForRowAtIndexPath delegate method is only called for the cells that will be visible so the cell will.. but the heightForRowAtIndexPath delegate method is only called for the cells that will be visible so the cell will be allocated anyway. If you properly use the dequeueReusableCellWithIdentifier the cell will not be allocated again in the cellForRowAtIndexPath.. so the cell will be allocated anyway. If you properly use the dequeueReusableCellWithIdentifier the cell will not be allocated again in the cellForRowAtIndexPath method instead a pointer is used and the properties are just adjusted. Then what's the..
Anyone know whether there is a 5-star rating component on iPhone? http://stackoverflow.com/questions/292137/anyone-know-whether-there-is-a-5-star-rating-component-on-iphone
http://stackoverflow.com/questions/3245733/apple-gyroscope-sample-code extra work which you might not need to do if you only instantiate your class once. Then in your init method you should allocate the motion manager object like so motionManager CMMotionManager alloc init referenceAttitude nil When you want to enable..
Detect retina screen/iPhone 4 in iPhone SDK http://stackoverflow.com/questions/3272752/detect-retina-screen-iphone-4-in-iphone-sdk device with a retina display. size_t size Set 'oldp' parameter to NULL to get the size of the data returned so we can allocate appropriate amount of space sysctlbyname hw.machine NULL size NULL 0 Allocate the space to store name char name malloc size..
Understanding the memory consumption on iPhone http://stackoverflow.com/questions/363493/understanding-the-memory-consumption-on-iphone memory go I would be glad to supply more details if this is not enough. Update I really tried to find where I could allocate so much memory but with no results. What drives me wild is the difference between the Object Allocations ~7 MB and real.. memory goes. The Object Alloc tool is almost useless for tracking the real memory usage. When I create a texture the allocated memory counter goes up for a while reading the texture into the memory then drops passing the texture data to OpenGL freeing.. after the texture has been passed on to OpenGL and freed from œmy memory. This means that the total amount of memory allocated as shown by the Object Alloc tool is smaller than the real total memory consumption but bigger than the real consumption..
What's the easiest way to get the current location of an iPhone? http://stackoverflow.com/questions/459355/whats-the-easiest-way-to-get-the-current-location-of-an-iphone alloc init return sharedInstance id alloc @synchronized self NSAssert sharedInstance nil @ Attempted to allocate a second instance of a singleton LocationController. sharedInstance super alloc return sharedInstance id init if self super..
Can you use cancel/isCancelled with GCD/dispatch_async? http://stackoverflow.com/questions/5449469/can-you-use-cancel-iscancelled-with-gcd-dispatch-async below whenever you break out of the bg process... you must clean up any variables you have open In my idiom you must allocate all variable contexts memory etc specifically in setUpHere . And you must release them in wrapUpHere . This idiom continues..
iPhone MKMapView - MKPolygon Issues http://stackoverflow.com/questions/5474299/iphone-mkmapview-mkpolygon-issues question The polygonWithCoordinates method wants a C array of CLLocationCoordinate2D structs. You can use malloc to allocate memory for the array and free to release the memory . Loop through your NSArray and set it each element in the struct array...
http://stackoverflow.com/questions/6942439/objectivec-ivars-or-property create @properties for each instance variable we define in header file. And actually I found out ivars easy to just allocate and release it after I use anywhere in the class for @properties I have to use autorealese or I have serious problems and.. I use anywhere in the class for @properties I have to use autorealese or I have serious problems and becareful how I allocate.. For instance for objects below @properties retain copy.. is not used in headers in many examples NSURLConnection connection.. just use simple ivars My only problem when using properties is not becuase I am lazy to define it but when I carefully allocate and init them in code I have to use autorelase and dont feel like I have the control when to release reset and allocate..
How to convert NSData to byte array in iPhone? http://stackoverflow.com/questions/724086/how-to-convert-nsdata-to-byte-array-in-iphone NSUInteger len data length Byte byteData Byte malloc len memcpy byteData data bytes len This code will dynamically allocate the array to the correct size you must free byteData when you're done and copy the bytes into it. You could also use getBytes..
Make Background of UIView a Gradient Without Sub Classing http://stackoverflow.com/questions/844710/make-background-of-uiview-a-gradient-without-sub-classing context CGContextRef bitmapContext CGBitmapContextCreate NULL 320 480 8 4 320 colorSpace kCGImageAlphaNoneSkipFirst allocate myGradient CGFloat locationList 0.0f 1.0f CGFloat colorList 0.0f 0.0f 0.0f 1.0f 0.0f 0.0f 0.0f 0.0f CGGradientRef myGradient..
View Controllers: How to switch between views programmatically? http://stackoverflow.com/questions/910994/view-controllers-how-to-switch-between-views-programmatically so on. Who or what or how would those methods be called if I do it my way without a tab bar controller I mean If I allocate that ViewController's class and the view get's visible would I have to take care about calling those methods How does it..
http://stackoverflow.com/questions/9797047/how-to-keep-data-associated-with-mkannotation-from-being-lost-after-a-callout-po method is called when you add a VoiceMemoryAnnotation to a map object. When this viewForAnnotation is called I simply allocate a MKPinAnnotationView object and return it. When the user taps this retuned pin they see the callout. As soon as they click..
http://stackoverflow.com/questions/11520815/nscache-is-not-evicting-data auto evict data in low memory situations or I am doing something wrong void viewDidLoad _testCache NSCache alloc init Allocate 600 MB of zeros and save to NSCache NSMutableData largeData NSMutableData alloc init largeData setLength 1024 1024 600 _testCache.. setLength 1024 1024 600 _testCache setObject largeData forKey @ original_Data IBAction buttonWasTapped id sender Allocate save to cache 300 MB each time the button is pressed NSMutableData largeData NSMutableData alloc init largeData setLength..
Writing video + generated audio to AVAssetWriterInput, audio stuttering http://stackoverflow.com/questions/12187124/writing-video-generated-audio-to-avassetwriterinput-audio-stuttering NULL audio_fmt_desc_ return self BOOL beginRecordingSession NSError error nil isAborted false abortCode No_Abort Allocate the video writer object. videoWriter AVAssetWriter alloc initWithURL self getVideoFileURLAndRemoveExisting recordingPath..
How do I synthesize sounds with CoreAudio on iPhone/Mac http://stackoverflow.com/questions/1361148/how-do-i-synthesize-sounds-with-coreaudio-on-iphone-mac AudioQueueNewOutput deviceFormat AudioQueueCallback NULL CFRunLoopGetCurrent kCFRunLoopCommonModes 0 audioQueue Allocate buffers for the AudioQueue and pre fill them. for int i 0 i BUFFER_COUNT i AudioQueueBufferRef mBuffer err AudioQueueAllocateBuffer.. buffers for the AudioQueue and pre fill them. for int i 0 i BUFFER_COUNT i AudioQueueBufferRef mBuffer err AudioQueueAllocateBuffer audioQueue BUFFER_SIZE mBuffer if err noErr break AudioQueueCallback NULL audioQueue mBuffer if err noErr err AudioQueueStart..
where to start with audio synthesis on iPhone http://stackoverflow.com/questions/2067267/where-to-start-with-audio-synthesis-on-iphone staticQueueCallback this NULL NULL 0 m_outAQ if result 0 printf ERROR d n int result return false Allocate buffers for the audio UInt32 bufferSizeBytes kBufferSizeInFrames m_outFormat.mBytesPerFrame for int buf 0 buf kNumBuffers.. kBufferSizeInFrames m_outFormat.mBytesPerFrame for int buf 0 buf kNumBuffers buf OSStatus result AudioQueueAllocateBuffer m_outAQ bufferSizeBytes m_buffers buf if result printf ERROR d n int result return false Prime the buffers queueCallback..
How i count red color pixel from the UIImage using objective-C in iphone? http://stackoverflow.com/questions/2342327/how-i-count-red-color-pixel-from-the-uiimage-using-objective-c-in-iphone and return the number of pure red pixels in it. NSUInteger processImage UIImage image NSUInteger numberOfRedPixels 0 Allocate a buffer big enough to hold all the pixels struct pixel pixels struct pixel calloc 1 image.size.width image.size.height..
Detect retina screen/iPhone 4 in iPhone SDK http://stackoverflow.com/questions/3272752/detect-retina-screen-iphone-4-in-iphone-sdk the size of the data returned so we can allocate appropriate amount of space sysctlbyname hw.machine NULL size NULL 0 Allocate the space to store name char name malloc size Get the platform name sysctlbyname hw.machine name size NULL 0 Place name..
Is it legal to use the well-known free memory code in ipad/iphone app? [closed] http://stackoverflow.com/questions/3823266/is-it-legal-to-use-the-well-known-free-memory-code-in-ipad-iphone-app pagesize natural_t mem_total mem_used mem_free NSLog @ used u free u total u mem_used mem_free mem_total Free memory Allocate the remaining amount of free memory minus 2 megs size_t size freemem 2 1024 1024 void allocation malloc size bzero allocation..
How to display an image on a MKOverlayView? http://stackoverflow.com/questions/3891850/how-to-display-an-image-on-a-mkoverlayview Calculate colorspace for the specified image CGColorSpaceRef imageColorSpace CGImageGetColorSpace imageReference Allocate and clear memory for the data of the image unsigned char imageData unsigned char malloc height width 4 memset imageData..
Save Youtube video to iPhone in the app http://stackoverflow.com/questions/5087249/save-youtube-video-to-iphone-in-the-app or a temp named file in your Documents directory . Set up your progress bar and whatever else you need to do. Allocate and start an NSURLConnection to fetch the file from the URL. Do not use sendSynchronousRequest returningResponse error of..
how to display test IAd banner in the simulator http://stackoverflow.com/questions/5947552/how-to-display-test-iad-banner-in-the-simulator view to that particular ViewController.Assume I have taken @property weak nonatomic IBOutlet UIView contentView Step 2 Allocate it in ViewDidLoad method void viewDidLoad _bannerView ADBannerView alloc init _bannerView.delegate self super viewDidLoad..
iPhone FFT with Accelerate framework vDSP http://stackoverflow.com/questions/6358764/iphone-fft-with-accelerate-framework-vdsp return result FFT code below log2n N n 1 log2n stride 1 nOver2 n 2 printf 1D real FFT of length log2 d d n n n log2n Allocate memory for the input operands and check its availability use the vector version to get 16 byte alignment. A.realp float..
Undo drawing in Paint Application http://stackoverflow.com/questions/6689600/undo-drawing-in-paint-application from Points to Pixels CGFloat scale 1.0 self.contentScaleFactor start.x scale start.y scale end.x scale end.y scale Allocate vertex array buffer if eraseBuffer NULL eraseBuffer malloc eraseMax 2 sizeof GLfloat Add points to the buffer so there are..
How to check if iPhone supports CDMA or GSM http://stackoverflow.com/questions/7596079/how-to-check-if-iphone-supports-cdma-or-gsm size of the data returned so we can allocate appropriate amount of space sysctlbyname hw.machine NULL size NULL 0 Allocate the space to store name char name malloc size Get the platform name sysctlbyname hw.machine name size NULL 0 Place name..
OpenGL ES 2.0 / MonoTouch: Texture is colorized red http://stackoverflow.com/questions/7986153/opengl-es-2-0-monotouch-texture-is-colorized-red bitmapBytesPerRow pixelsHigh Note implicit colorSpace.Dispose using var colorSpace CGColorSpace.CreateDeviceRGB Allocate the bitmap and create context var bitmapData Marshal.AllocHGlobal bitmapByteCount if bitmapData IntPtr.Zero throw new Exception..
Make Background of UIView a Gradient Without Sub Classing http://stackoverflow.com/questions/844710/make-background-of-uiview-a-gradient-without-sub-classing You can use UIColor colorWithPatternImage to produce a patterned background. Example bring your own CGGradient Allocate color space CGColorSpaceRef colorSpace CGColorSpaceCreateDeviceRGB Allocate bitmap context CGContextRef bitmapContext CGBitmapContextCreate.. Example bring your own CGGradient Allocate color space CGColorSpaceRef colorSpace CGColorSpaceCreateDeviceRGB Allocate bitmap context CGContextRef bitmapContext CGBitmapContextCreate NULL 320 480 8 4 320 colorSpace kCGImageAlphaNoneSkipFirst..
Save OpenGL Drawn item as a Image http://stackoverflow.com/questions/9660723/save-opengl-drawn-item-as-a-image from Points to Pixels CGFloat scale self.contentScaleFactor start.x scale start.y scale end.x scale end.y scale Allocate vertex array buffer if vertexBuffer NULL vertexBuffer malloc vertexMax 2 sizeof GLfloat Add points to the buffer so there.. the dimensions and takes appropriate action if they are not a power of 2. Make sure the image exists if brushImage Allocate memory needed for the bitmap context brushData GLubyte calloc width height 4 sizeof GLubyte Use the bitmatp creation function..
Record the drawing as a m4v video file - OpenGL http://stackoverflow.com/questions/9661259/record-the-drawing-as-a-m4v-video-file-opengl from Points to Pixels CGFloat scale self.contentScaleFactor start.x scale start.y scale end.x scale end.y scale Allocate vertex array buffer if vertexBuffer NULL vertexBuffer malloc vertexMax 2 sizeof GLfloat Add points to the buffer so there.. the dimensions and takes appropriate action if they are not a power of 2. Make sure the image exists if brushImage Allocate memory needed for the bitmap context brushData GLubyte calloc width height 4 sizeof GLubyte Use the bitmatp creation function..
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