Notes of a Developer » iPad

Create movie from array of images

Vladimir Boychentsov — Mon, 30 Jan 2012 21:22:59 +0000

Create movie from images seq.

First part of method, initialize

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- (void) writeImagesAsMovie:(NSArray *)array toPath:(NSString*)path {

NSString *documents = [NSSearchPathForDirectoriesInDomains (NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex: 0];
documents = [documents stringByAppendingPathComponent:currentWorkspace];

//NSLog(path);
NSString *filename = [documents stringByAppendingPathComponent:[array objectAtIndex:0]];
UIImage *first = [UIImage imageWithContentsOfFile:filename];

CGSize frameSize = first.size;

NSError *error = nil;
AVAssetWriter *videoWriter = [[AVAssetWriter alloc] initWithURL:
[NSURL fileURLWithPath:path] fileType:AVFileTypeQuickTimeMovie
error:&error];

if(error) {
NSLog(@"error creating AssetWriter: %@",[error description]);
}
NSDictionary *videoSettings = [NSDictionary dictionaryWithObjectsAndKeys:
AVVideoCodecH264, AVVideoCodecKey,
[NSNumber numberWithInt:frameSize.width], AVVideoWidthKey,
[NSNumber numberWithInt:frameSize.height], AVVideoHeightKey,
nil];

AVAssetWriterInput* writerInput = [[AVAssetWriterInput
assetWriterInputWithMediaType:AVMediaTypeVideo
outputSettings:videoSettings] retain];

NSMutableDictionary *attributes = [[NSMutableDictionary alloc] init];
[attributes setObject:[NSNumber numberWithUnsignedInt:kCVPixelFormatType_32ARGB] forKey:(NSString*)kCVPixelBufferPixelFormatTypeKey];
[attributes setObject:[NSNumber numberWithUnsignedInt:frameSize.width] forKey:(NSString*)kCVPixelBufferWidthKey];
[attributes setObject:[NSNumber numberWithUnsignedInt:frameSize.height] forKey:(NSString*)kCVPixelBufferHeightKey];

AVAssetWriterInputPixelBufferAdaptor *adaptor = [AVAssetWriterInputPixelBufferAdaptor
assetWriterInputPixelBufferAdaptorWithAssetWriterInput:writerInput
sourcePixelBufferAttributes:attributes];

[videoWriter addInput:writerInput];

// fixes all errors
writerInput.expectsMediaDataInRealTime = YES;

//Start a session:
BOOL start = [videoWriter startWriting];
NSLog(@"Session started? %d", start);
[videoWriter startSessionAtSourceTime:kCMTimeZero];

Second part, writing

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CVPixelBufferRef buffer = NULL;
buffer = [self pixelBufferFromCGImage:[first CGImage]];
BOOL result = [adaptor appendPixelBuffer:buffer withPresentationTime:kCMTimeZero];

if (result == NO) //failes on 3GS, but works on iphone 4
NSLog(@"failed to append buffer");

if(buffer)
CVBufferRelease(buffer);

[NSThread sleepForTimeInterval:0.05];

int reverseSort = NO;
NSArray *newArray = [array sortedArrayUsingFunction:sort context:&reverseSort];

delta = 1.0/[newArray count];

int fps = (int)fpsSlider.value;

int i = 0;
for (NSString *filename in newArray)
{
if (adaptor.assetWriterInput.readyForMoreMediaData)
{

i++;
NSLog(@"inside for loop %d %@ ",i, filename);
CMTime frameTime = CMTimeMake(1, fps);
CMTime lastTime=CMTimeMake(i, fps);
CMTime presentTime=CMTimeAdd(lastTime, frameTime);

NSString *filePath = [documents stringByAppendingPathComponent:filename];

UIImage *imgFrame = [UIImage imageWithContentsOfFile:filePath] ;
buffer = [self pixelBufferFromCGImage:[imgFrame CGImage]];
BOOL result = [adaptor appendPixelBuffer:buffer withPresentationTime:presentTime];

if (result == NO) //failes on 3GS, but works on iphone 4
{
NSLog(@"failed to append buffer");
NSLog(@"The error is %@", [videoWriter error]);
}
if(buffer)
CVBufferRelease(buffer);
[NSThread sleepForTimeInterval:0.05];
}
else
{
NSLog(@"error");
i--;
}
[NSThread sleepForTimeInterval:0.02];
}

//Finish the session:
[writerInput markAsFinished];
[videoWriter finishWriting];
CVPixelBufferPoolRelease(adaptor.pixelBufferPool);
[videoWriter release];
[writerInput release];
}

Convert UIImage to CVPixelBufferRef

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- (CVPixelBufferRef) pixelBufferFromCGImage: (CGImageRef) image
{
NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithBool:YES], kCVPixelBufferCGImageCompatibilityKey,
[NSNumber numberWithBool:YES], kCVPixelBufferCGBitmapContextCompatibilityKey,
nil];
CVPixelBufferRef pxbuffer = NULL;

CVPixelBufferCreate(kCFAllocatorDefault, CGImageGetWidth(image),
CGImageGetHeight(image), kCVPixelFormatType_32ARGB, (CFDictionaryRef) options,
&pxbuffer);

CVPixelBufferLockBaseAddress(pxbuffer, 0);
void *pxdata = CVPixelBufferGetBaseAddress(pxbuffer);

CGColorSpaceRef rgbColorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef context = CGBitmapContextCreate(pxdata, CGImageGetWidth(image),
CGImageGetHeight(image), 8, 4*CGImageGetWidth(image), rgbColorSpace,
kCGImageAlphaNoneSkipFirst);

CGContextConcatCTM(context, CGAffineTransformMakeRotation(0));

CGAffineTransform flipVertical = CGAffineTransformMake(
1, 0, 0, -1, 0, CGImageGetHeight(image)
);
CGContextConcatCTM(context, flipVertical);

CGAffineTransform flipHorizontal = CGAffineTransformMake(
-1.0, 0.0, 0.0, 1.0, CGImageGetWidth(image), 0.0
);

CGContextConcatCTM(context, flipHorizontal);

CGContextDrawImage(context, CGRectMake(0, 0, CGImageGetWidth(image),
CGImageGetHeight(image)), image);
CGColorSpaceRelease(rgbColorSpace);
CGContextRelease(context);

CVPixelBufferUnlockBaseAddress(pxbuffer, 0);

return pxbuffer;
}

ScrollView with scroll’s indicators, which are shown all the time.

Vladimir Boychentsov — Thu, 22 Dec 2011 09:53:13 +0000

My simple solution by writing category for UIImageView, because scroller is imageview.

How to use :)
Just setup tag for your scrollview and you will get one with scroll indicators, which are shown all the time.

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#define noDisableVerticalScrollTag 836913
#define noDisableHorizontalScrollTag 836914

@implementation UIImageView (ForScrollView)

- (void) setAlpha:(float)alpha {

if (self.superview.tag == noDisableVerticalScrollTag) {
if (alpha == 0 && self.autoresizingMask == UIViewAutoresizingFlexibleLeftMargin) {
if (self.frame.size.width < 10 && self.frame.size.height > self.frame.size.width) {
UIScrollView *sc = (UIScrollView*)self.superview;
if (sc.frame.size.height < sc.contentSize.height) {
return;
}
}
}
}

if (self.superview.tag == noDisableHorizontalScrollTag) {
if (alpha == 0 && self.autoresizingMask == UIViewAutoresizingFlexibleTopMargin) {
if (self.frame.size.height < 10 && self.frame.size.height < self.frame.size.width) {
UIScrollView *sc = (UIScrollView*)self.superview;
if (sc.frame.size.width < sc.contentSize.width) {
return;
}
}
}
}

[super setAlpha:alpha];
}
@end

If you want both scroll it’s easy to change code.

AVPlayer – looping video without “hiccup”/delays

Vladimir Boychentsov — Sat, 17 Dec 2011 10:35:35 +0000

I tried create loop by AVQueuePlayer, this method has delays between end and start play.

for looping AVQueuePlayer i use this code:

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[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(playerItemDidReachEnd:)
name:AVPlayerItemDidPlayToEndTimeNotification
object:self.mPlayerItem];

[self player].actionAtItemEnd = AVPlayerActionAtItemEndNone;

and playerItemDidReachEnd

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- (void)playerItemDidReachEnd:(NSNotification *)notification
{
AVPlayerItem *p = [notification object];
[p seekToTime:kCMTimeZero];
}

Another solution without hiccups/delays based on AVMutableComposition!

Easily solution, I use one AVURLAsset for inserting to composition. No memory leaks and warnings, because used just one object.

Solution:

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- (AVAsset*) makeAssetComposition {

int numOfCopies = 25;

AVMutableComposition *composition = [[[AVMutableComposition alloc] init] autorelease];
AVURLAsset* sourceAsset = [AVURLAsset URLAssetWithURL:mURL options:nil];

// calculate time
CMTimeRange editRange = CMTimeRangeMake(CMTimeMake(0, 600), CMTimeMake(sourceAsset.duration.value, sourceAsset.duration.timescale));

NSError *editError;

// and add into your composition
BOOL result = [composition insertTimeRange:editRange ofAsset:sourceAsset atTime:composition.duration error:&editError];

if (result) {
for (int i = 0; i < numOfCopies; i++) {
[composition insertTimeRange:editRange ofAsset:sourceAsset atTime:composition.duration error:&editError];
}
}

return composition;
}

Play composition:

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AVAsset *composition = [self makeAssetComposition];

// create an AVPlayer with your composition
AVPlayer* mp = [AVPlayer playerWithPlayerItem:[AVPlayerItem playerItemWithAsset:composition]];

// Add the player to your UserInterface
// Create a PlayerLayer:
AVPlayerLayer *playerLayer = [AVPlayerLayer playerLayerWithPlayer:mp];

// integrate it to your view. Here you can customize your player (Fullscreen, or a small preview)
[[self window].layer insertSublayer:playerLayer atIndex:0];
playerLayer.frame = [self window].layer.bounds;
playerLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;
//And finally play your video:

[mp play];

Any questions to comments please.

AudioSession AudioRouteChange

Vladimir Boychentsov — Sat, 17 Dec 2011 09:56:46 +0000

if you will use or used AVPlayer or you want just know about changes, you can check AudioRouteChange.

Simple solution:

Add framework AudioToolbox and add import to file

#import

Insert into init method or any other

1	AudioSessionAddPropertyListener (kAudioSessionProperty_AudioRouteChange, callbackHeadphone_func, self);

Listener callback

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void callbackHeadphone_func ( void *inClientData, AudioSessionPropertyID inID, UInt32 inDataSize, const void *inData ) {
if ( inID == kAudioSessionProperty_AudioRouteChange ) {
[mainViewController performSelector:@selector(isHeadsetPluggedIn)];
}
}

- (void) isHeadsetPluggedIn {

UInt32 routeSize = sizeof (CFStringRef); CFStringRef route;

AudioSessionGetProperty (kAudioSessionProperty_AudioRoute, &routeSize, &route);
/* Known values of route:
"Headset"
"Headphone"
"Speaker"
"SpeakerAndMicrophone"
"HeadphonesAndMicrophone"
"HeadsetInOut"
"ReceiverAndMicrophone"
"Lineout" */

NSString* routeStr = (NSString*)route;
DLog(@"%@",routeStr);
}

Sorting by block

Vladimir Boychentsov — Sat, 22 Oct 2011 19:17:30 +0000

Sorting by block

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NSArray *stringsArray = [NSArray arrayWithObjects:
@"string 1",
@"String 21",
@"string 12",
@"String 11",
@"String 02", nil];

static NSStringCompareOptions comparisonOptions = NSCaseInsensitiveSearch | NSNumericSearch |
NSWidthInsensitiveSearch | NSForcedOrderingSearch;
NSLocale *currentLocale = [NSLocale currentLocale];

NSComparator finderSortBlock = ^(id string1, id string2) {

NSRange string1Range = NSMakeRange(0, [string1 length]);
return [string1 compare:string2 options:comparisonOptions range:string1Range locale:currentLocale];
};

NSArray *finderSortArray = [stringsArray sortedArrayUsingComparator:finderSortBlock];
NSLog(@"finderSortArray: %@", finderSortArray);

Result:
/*
Output:
finderSortArray: (
“string 1″,
“String 02″,
“String 11″,
“string 12″,
“String 21″
)
*/

Getting Font Metrics

Vladimir Boychentsov — Sat, 22 Oct 2011 19:11:16 +0000

Doc about font metric

Getting Font Metrics

Tweeting – example of Apple

Vladimir Boychentsov — Wed, 05 Oct 2011 11:51:43 +0000

Tweeting

Assistive Touch в iOS 5 beta 3

Vladimir Boychentsov — Tue, 12 Jul 2011 08:20:17 +0000

В новой бета-версии прошивки iOS 5, которую Apple выпустили сегодня, они активировали новую функцию под названием «Assistive Touch». Это было и в прошлых бетах, но активировать их можно только сейчас. Новая функция призвана принести немного больше возможностей для тех, кто испытывает проблемы с использованием традиционных жестов.

Assistive Touch активируется при нажатии на заранее указанный угол.

Далее скриншоты и видео

How to include ttf fonts to iOS app

Vladimir Boychentsov — Thu, 14 Apr 2011 11:42:06 +0000

Up till now there hasn’t been an easy way to add custom fonts to your iPhone applications. As of iOS 4 it has become very easy to do. Here is what you need to do in order to add custom fonts:

Add your custom font files into your project using XCode as a resource
Add a key to your info.plist file called UIAppFonts.
Make this key an array
For each font you have, enter the full name of your font file (including the extension) as items to the UIAppFonts array
Save info.plist
Now in your application you can simply call [UIFont fontWithName:@"CustomFontName" size:12] to get the custom font to use with your UILabels and UITextViews, etc…

It’s that simple!

Adding SVN revision to Xcode project

Vladimir Boychentsov — Wed, 23 Feb 2011 12:43:01 +0000

Просмотр ревизии в самом приложении предотвращает путаницу и всякие проблемы с отслеживанием текущей версии.

Чтоб отслеживать версию репозитория нам нужно добавить слдеющий код bash скрипта.

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REVISION=`svnversion -nc | /usr/bin/sed -e 's/^[^:]*://;s/[A-Za-z]//'`
APPVERSION=`/usr/libexec/PlistBuddy -c "Print CFBundleVersion" "${TARGET_BUILD_DIR}"/${INFOPLIST_PATH}`

xported="xported"

if [ $APPVERSION != $xported ]; then
/usr/libexec/PlistBuddy -c "Delete :CFBundleDisplayVersion" "${TARGET_BUILD_DIR}"/${INFOPLIST_PATH}
/usr/libexec/PlistBuddy -c "Add :CFBundleDisplayVersion string" "${TARGET_BUILD_DIR}"/${INFOPLIST_PATH}
/usr/libexec/PlistBuddy -c "Set :CFBundleDisplayVersion $APPVERSION.$REVISION" "${TARGET_BUILD_DIR}"/${INFOPLIST_PATH}
fi

Чтоб добавить скрипт, необходимо выполнить следующие действия:
1. Зажать Ctrl+клик на фаил проекта в дереве проекта
2. Add->New Build Phase -> New Run Script Build Phase
3. Откроется окно в которое нужно вставить скрипт.

В самом проекте, пример на сплеш скрине, создаем лейбл и читаем версию программы к примеру как-то так.

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NSString *version = @"Version ";
if ([[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleDisplayVersion"] != nil) {
version = [version stringByAppendingString:[[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleDisplayVersion"]];
} else {
version = @"";
}

Существует и второй вариант, более простой. (На самом деле можно придумать еще много разных способов.) Добавляем следующий bash скрипт в проект и добавляем фаил revision.h.

1 2	REV=`svnversion -n` echo "#define kRevisionNumber @\"$REV\"" > ${PROJECT_DIR}/revision.h

Желательно фаил вставить в один какой-то дальний хидер, чтоб при компилировании не пересобирался весь проект.

Для этого варианта можно написать что-то типа этого:

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NSString *version = @"Version ";
if ([[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleVersion"] != nil) {
version = [version stringByAppendingString:[[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleVersion"]];
version = [version stringByAppendingString:@"."];
version = [version stringByAppendingString:kRevisionNumber];
} else {
version = @"";
}