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I am using a NSRulerView in MacOS in order to display line numbers next to a NSTextView.
Both views share the same font and the same font size, however while in NSTextView string rendering is automatically managed, in the NSRulerView I need to compute correct line number (and this part works fine) and then render the string inside a drawHashMarksAndLabelsInRect.
My issue is that I am unable to correctly align text between the two views. For some font it works fine while for other fonts there are visible differences.
The code I am actually using is:
#define BTF_RULER_WIDTH 40.0f
#define BTF_RULER_PADDING 5.0f
static inline void drawLineNumber(NSUInteger lineNumber, CGFloat y, NSDictionary *attributes, CGFloat ruleThickness) {
NSString *string = [[NSNumber numberWithUnsignedInteger:lineNumber] stringValue];
NSAttributedString *attString = [[NSAttributedString alloc] initWithString:string attributes:attributes];
NSUInteger x = ruleThickness - BTF_RULER_PADDING - attString.size.width;
[attString drawAtPoint:NSMakePoint(x, y)];
}
static inline NSUInteger countNewLines(NSString *s, NSUInteger location, NSUInteger length) {
CFStringInlineBuffer inlineBuffer;
CFStringInitInlineBuffer((__bridge CFStringRef)s, &inlineBuffer, CFRangeMake(location, length));
NSUInteger counter = 0;
for (CFIndex i=0; i < length; ++i) {
UniChar c = CFStringGetCharacterFromInlineBuffer(&inlineBuffer, i);
if (c == (UniChar)'\n') ++counter;
}
return counter;
}
#implementation BTFRulerView
- (instancetype)initWithBTFTextView:(BTFTextView *)textView {
self = [super initWithScrollView:textView.enclosingScrollView orientation:NSVerticalRuler];
if (self) {
self.clientView = textView;
// default settings
self.ruleThickness = BTF_RULER_WIDTH;
self.textColor = [NSColor grayColor];
}
return self;
}
- (void)drawHashMarksAndLabelsInRect:(NSRect)rect {
// do not use drawBackgroundInRect for background color otherwise a 1px right border with a different color appears
if (_backgroundColor) {
[_backgroundColor set];
[NSBezierPath fillRect:rect];
}
BTFTextView *textView = (BTFTextView *)self.clientView;
if (!textView) return;
NSLayoutManager *layoutManager = textView.layoutManager;
if (!layoutManager) return;
NSString *textString = textView.string;
if ((!textString) || (textString.length == 0)) return;
CGFloat insetHeight = textView.textContainerInset.height;
CGPoint relativePoint = [self convertPoint:NSZeroPoint fromView:textView];
NSDictionary *lineNumberAttributes = #{NSFontAttributeName: textView.font, NSForegroundColorAttributeName: _textColor};
NSRange visibleGlyphRange = [layoutManager glyphRangeForBoundingRect:textView.visibleRect inTextContainer:textView.textContainer];
NSUInteger firstVisibleGlyphCharacterIndex = [layoutManager characterIndexForGlyphAtIndex:visibleGlyphRange.location];
// line number for the first visible line
NSUInteger lineNumber = countNewLines(textString, 0, firstVisibleGlyphCharacterIndex)+1;
NSUInteger glyphIndexForStringLine = visibleGlyphRange.location;
// go through each line in the string
while (glyphIndexForStringLine < NSMaxRange(visibleGlyphRange)) {
// range of current line in the string
NSRange characterRangeForStringLine = [textString lineRangeForRange:NSMakeRange([layoutManager characterIndexForGlyphAtIndex:glyphIndexForStringLine], 0)];
NSRange glyphRangeForStringLine = [layoutManager glyphRangeForCharacterRange: characterRangeForStringLine actualCharacterRange:nil];
NSUInteger glyphIndexForGlyphLine = glyphIndexForStringLine;
NSUInteger glyphLineCount = 0;
while (glyphIndexForGlyphLine < NSMaxRange(glyphRangeForStringLine)) {
// check if the current line in the string spread across several lines of glyphs
NSRange effectiveRange = NSMakeRange(0, 0);
// range of current "line of glyphs". If a line is wrapped then it will have more than one "line of glyphs"
NSRect lineRect = [layoutManager lineFragmentRectForGlyphAtIndex:glyphIndexForGlyphLine effectiveRange:&effectiveRange withoutAdditionalLayout:YES];
// compute Y for line number
CGFloat y = NSMinY(lineRect) + relativePoint.y + insetHeight;
// draw line number only if string does not spread across several lines
if (glyphLineCount == 0) {
drawLineNumber(lineNumber, y, lineNumberAttributes, self.ruleThickness);
}
// move to next glyph line
++glyphLineCount;
glyphIndexForGlyphLine = NSMaxRange(effectiveRange);
}
glyphIndexForStringLine = NSMaxRange(glyphRangeForStringLine);
++lineNumber;
}
// draw line number for the extra line at the end of the text
if (layoutManager.extraLineFragmentTextContainer) {
CGFloat y = NSMinY(layoutManager.extraLineFragmentRect) + relativePoint.y + insetHeight;
drawLineNumber(lineNumber, y, lineNumberAttributes, self.ruleThickness);
}
}
I think that the issue is the y computation then passed to the drawLineNumber function. Any idea about how to correctly compute it?
I found a solution and I think it could be quite useful to others:
#define BTF_RULER_WIDTH 40.0f
#define BTF_RULER_PADDING 5.0f
static inline void drawLineNumberInRect(NSUInteger lineNumber, NSRect lineRect, NSDictionary *attributes, CGFloat ruleThickness) {
NSString *string = [[NSNumber numberWithUnsignedInteger:lineNumber] stringValue];
NSAttributedString *attString = [[NSAttributedString alloc] initWithString:string attributes:attributes];
NSUInteger x = ruleThickness - BTF_RULER_PADDING - attString.size.width;
// Offetting the drawing keeping into account the ascender (because we draw it without NSStringDrawingUsesLineFragmentOrigin)
NSFont *font = attributes[NSFontAttributeName];
lineRect.origin.x = x;
lineRect.origin.y += font.ascender;
[attString drawWithRect:lineRect options:0 context:nil];
}
static inline NSUInteger countNewLines(NSString *s, NSUInteger location, NSUInteger length) {
CFStringInlineBuffer inlineBuffer;
CFStringInitInlineBuffer((__bridge CFStringRef)s, &inlineBuffer, CFRangeMake(location, length));
NSUInteger counter = 0;
for (CFIndex i=0; i < length; ++i) {
UniChar c = CFStringGetCharacterFromInlineBuffer(&inlineBuffer, i);
if (c == (UniChar)'\n') ++counter;
}
return counter;
}
#implementation BTFRulerView
- (instancetype)initWithBTFTextView:(BTFTextView *)textView {
self = [super initWithScrollView:textView.enclosingScrollView orientation:NSVerticalRuler];
if (self) {
self.clientView = textView;
// default settings
self.ruleThickness = BTF_RULER_WIDTH;
self.textColor = [NSColor grayColor];
}
return self;
}
- (void)drawHashMarksAndLabelsInRect:(NSRect)rect {
// do not use drawBackgroundInRect for background color otherwise a 1px right border with a different color appears
if (_backgroundColor) {
[_backgroundColor set];
[NSBezierPath fillRect:rect];
}
BTFTextView *textView = (BTFTextView *)self.clientView;
if (!textView) return;
NSLayoutManager *layoutManager = textView.layoutManager;
if (!layoutManager) return;
NSString *textString = textView.string;
if ((!textString) || (textString.length == 0)) return;
CGFloat insetHeight = textView.textContainerInset.height;
CGPoint relativePoint = [self convertPoint:NSZeroPoint fromView:textView];
// Gettign text attributes from the textview
NSMutableDictionary *lineNumberAttributes = [[textView.textStorage attributesAtIndex:0 effectiveRange:NULL] mutableCopy];
lineNumberAttributes[NSForegroundColorAttributeName] = self.textColor;
NSRange visibleGlyphRange = [layoutManager glyphRangeForBoundingRect:textView.visibleRect inTextContainer:textView.textContainer];
NSUInteger firstVisibleGlyphCharacterIndex = [layoutManager characterIndexForGlyphAtIndex:visibleGlyphRange.location];
// line number for the first visible line
NSUInteger lineNumber = countNewLines(textString, 0, firstVisibleGlyphCharacterIndex)+1;
NSUInteger glyphIndexForStringLine = visibleGlyphRange.location;
// go through each line in the string
while (glyphIndexForStringLine < NSMaxRange(visibleGlyphRange)) {
// range of current line in the string
NSRange characterRangeForStringLine = [textString lineRangeForRange:NSMakeRange([layoutManager characterIndexForGlyphAtIndex:glyphIndexForStringLine], 0)];
NSRange glyphRangeForStringLine = [layoutManager glyphRangeForCharacterRange: characterRangeForStringLine actualCharacterRange:nil];
NSUInteger glyphIndexForGlyphLine = glyphIndexForStringLine;
NSUInteger glyphLineCount = 0;
while (glyphIndexForGlyphLine < NSMaxRange(glyphRangeForStringLine)) {
// check if the current line in the string spread across several lines of glyphs
NSRange effectiveRange = NSMakeRange(0, 0);
// range of current "line of glyphs". If a line is wrapped then it will have more than one "line of glyphs"
NSRect lineRect = [layoutManager lineFragmentRectForGlyphAtIndex:glyphIndexForGlyphLine effectiveRange:&effectiveRange withoutAdditionalLayout:YES];
// compute Y for line number
CGFloat y = ceil(NSMinY(lineRect) + relativePoint.y + insetHeight);
lineRect.origin.y = y;
// draw line number only if string does not spread across several lines
if (glyphLineCount == 0) {
drawLineNumberInRect(lineNumber, lineRect, lineNumberAttributes, self.ruleThickness);
}
// move to next glyph line
++glyphLineCount;
glyphIndexForGlyphLine = NSMaxRange(effectiveRange);
}
glyphIndexForStringLine = NSMaxRange(glyphRangeForStringLine);
++lineNumber;
}
// draw line number for the extra line at the end of the text
if (layoutManager.extraLineFragmentTextContainer) {
NSRect lineRect = layoutManager.extraLineFragmentRect;
CGFloat y = ceil(NSMinY(lineRect) + relativePoint.y + insetHeight);
lineRect.origin.y = y;
drawLineNumberInRect(lineNumber, lineRect, lineNumberAttributes, self.ruleThickness);
}
}
I use drawWithRect instead of drawAtPoint and I use the attributes directly from the connected textView.
I'm trying to compile an Apple sample : KMLViewer, but Xcode show this error:
variable 'lat' may be uninitializated when used here
The code is this:
// Convert a KML coordinate list string to a C array of CLLocationCoordinate2Ds
// KML coordinate lists are longitude,latitude[,altitude] tuples specified by whitespace.
static void strToCoords(NSString *str, CLLocationCoordinate2D **coordsOut, NSUInteger *coordsLenOut)
{
NSUInteger read = 0, space = 10;
CLLocationCoordinate2D *coords = malloc(sizeof(CLLocationCoordinate2D) * space);
NSArray *tuples = [str componentsSeparatedByCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
for (NSString *tuple in tuples) {
if (read == space) {
space *= 2;
coords = realloc(coords, sizeof(CLLocationCoordinate2D) * space);
}
double lat, lon;
NSScanner *scanner = [[NSScanner alloc] initWithString:tuple];
[scanner setCharactersToBeSkipped:[NSCharacterSet characterSetWithCharactersInString:#","]];
BOOL success = [scanner scanDouble:&lon];
if (success)
success = [scanner scanDouble:&lat];
if (success) {
CLLocationCoordinate2D c = CLLocationCoordinate2DMake(lat, lon);
if (CLLocationCoordinate2DIsValid(c))
coords[read++] = c;
}
}
*coordsOut = coords;
*coordsLenOut = read;
}
The Xcode "solution" add 0.0 to double lat,lon (double lat = 0.0, lat), but does not work.
Any suggestion?
You need to have a default value for your variables as you only set them if certain conditions are met, but you use them regardless. This could lead to the variable not being set but you trying to use them. XCode is suggesting you default your variables to some value.
I.E:
double lat = 0.0;
double lon = 0.0;
I need to substring to the 2nd comma in an NSString.
Input:
NSString *input = #"title, price, Camry, $19798, active";
Desired Output:
NSString *output = #"title, price";
Thanks!
UPDATE:
I have the following but the problem is it needs to skip the last comma:
NSString *output = [input rangeOfString:#"," options:NSBackwardsSearch];
Try this:
- (NSString *)substringOfString:(NSString *)base untilNthOccurrence:(NSInteger)n ofString:(NSString *)delim
{
NSScanner *scanner = [NSScanner scannerWithString:base];
NSInteger i;
for (i = 0; i < n; i++)
{
[scanner scanUpToString:delim intoString:NULL];
[scanner scanString:delim intoString:NULL];
}
return [base substringToIndex:scanner.scanLocation - delim.length];
}
this code should do what you need:
NSString *input = #"title, price, Camry, $19798, active";
NSArray *array = [input componentsSeparatedByString:#","];
NSArray *subArray = [array subarrayWithRange:NSMakeRange(0, 2)];
NSString *output = [subArray componentsJoinedByString:#","];
NSLog(output);
You could split -> splice -> join that string like this in objc:
NSString *input = #"title, price, Camry, $19798, active";
// split by ", "
NSArray *elements = [input componentsSeparatedByString: #", "];
// grab the subarray
NSArray *subelements = [elements subarrayWithRange: NSMakeRange(0, 2)];
// concat by ", " again
NSString *output = [subelements componentsJoinedByString:#", "];
You can try something like this:
NSArray *items = [list componentsSeparatedByString:#", "];
NSString result = #"";
result = [result stringByAppendingString:[items objectAtIndex:0]];
result = [result stringByAppendingString:#", "];
result = [result stringByAppendingString:[items objectAtIndex:1]];
You have to check you have at least two items if you want avoid an exception.
There's really nothing wrong with simply writing the code to do what you want. Eg:
int commaCount = 0;
int i;
for (i = 0; i < input.count; i++) {
if ([input characterAtIndex:i] == (unichar) ',') {
commaCount++;
if (commaCount == 2) break;
}
}
NSString output = nil;
if (commaCount == 2) {
output = [input substringToIndex:i];
}
You could create an NSString category to handle finding nth occurrences of any string. This is example is for ARC.
//NSString+MyExtension.h
#interface NSString(MyExtension)
-(NSString*)substringToNthOccurrence:(NSUInteger)nth
ofString:(NSString*)string;
-(NSString*)substringToNthOccurrence:(NSUInteger)nth
ofString:(NSString*)string
options:(NSStringCompareOptions)options;
#end
#implementation NSString(MyExtension)
-(NSString*)substringToNthOccurrence:(NSUInteger)nth
ofString:(NSString*)string
{
return [self substringToNthOccurrence:nth ofString:string options:0];
}
-(NSString*)substringToNthOccurrence:(NSUInteger)nth
ofString:(NSString*)string
options:(NSStringCompareOptions)options
{
NSUInteger location = 0,
strlength = [string length],
mylength = [self length];
NSRange range = NSMakeRange(location, mylength);
while(nth--)
{
location = [self rangeOfString:string
options:options
range:range].location;
if(location == NSNotFound || (location + strlength) > mylength)
{
return [self copy]; //nth occurrence not found
}
if(nth == 0) strlength = 0; //This prevents the last occurence from being included
range = NSMakeRange(location + strlength, mylength - strlength - location);
}
return [self substringToIndex:location];
}
#end
//main.m
#import "NSString+MyExtension.h"
int main(int argc, char *argv[])
{
#autoreleasepool {
NSString *output = [#"title, price, Camry, $19798, active" substringToNthOccurrence:2 ofString:#","];
NSLog(#"%#", output);
}
}
*I'll leave it as an exercise for someone to implement the mutable versions.
I'm looking for how to draw the sound amplitude.
I found http://supermegaultragroovy.com/2009/10/06/drawing-waveforms/ but i have some problems. How get a list of floating-point values representing the audio?
Thank all.
I found this example here: Drawing waveform with AVAssetReader , changed it and developed a new class based on.
This class returns UIImageView.
//.h file
#import <UIKit/UIKit.h>
#interface WaveformImageVew : UIImageView{
}
-(id)initWithUrl:(NSURL*)url;
- (NSData *) renderPNGAudioPictogramLogForAssett:(AVURLAsset *)songAsset;
#end
//.m file
#import "WaveformImageVew.h"
#define absX(x) (x<0?0-x:x)
#define minMaxX(x,mn,mx) (x<=mn?mn:(x>=mx?mx:x))
#define noiseFloor (-50.0)
#define decibel(amplitude) (20.0 * log10(absX(amplitude)/32767.0))
#define imgExt #"png"
#define imageToData(x) UIImagePNGRepresentation(x)
#implementation WaveformImageVew
-(id)initWithUrl:(NSURL*)url{
if(self = [super init]){
AVURLAsset * urlA = [AVURLAsset URLAssetWithURL:url options:nil];
[self setImage:[UIImage imageWithData:[self renderPNGAudioPictogramLogForAssett:urlA]]];
}
return self;
}
-(UIImage *) audioImageLogGraph:(Float32 *) samples
normalizeMax:(Float32) normalizeMax
sampleCount:(NSInteger) sampleCount
channelCount:(NSInteger) channelCount
imageHeight:(float) imageHeight {
CGSize imageSize = CGSizeMake(sampleCount, imageHeight);
UIGraphicsBeginImageContext(imageSize);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetFillColorWithColor(context, [UIColor blackColor].CGColor);
CGContextSetAlpha(context,1.0);
CGRect rect;
rect.size = imageSize;
rect.origin.x = 0;
rect.origin.y = 0;
CGColorRef leftcolor = [[UIColor whiteColor] CGColor];
CGColorRef rightcolor = [[UIColor redColor] CGColor];
CGContextFillRect(context, rect);
CGContextSetLineWidth(context, 1.0);
float halfGraphHeight = (imageHeight / 2) / (float) channelCount ;
float centerLeft = halfGraphHeight;
float centerRight = (halfGraphHeight*3) ;
float sampleAdjustmentFactor = (imageHeight/ (float) channelCount) / (normalizeMax - noiseFloor) / 2;
for (NSInteger intSample = 0 ; intSample < sampleCount ; intSample ++ ) {
Float32 left = *samples++;
float pixels = (left - noiseFloor) * sampleAdjustmentFactor;
CGContextMoveToPoint(context, intSample, centerLeft-pixels);
CGContextAddLineToPoint(context, intSample, centerLeft+pixels);
CGContextSetStrokeColorWithColor(context, leftcolor);
CGContextStrokePath(context);
if (channelCount==2) {
Float32 right = *samples++;
float pixels = (right - noiseFloor) * sampleAdjustmentFactor;
CGContextMoveToPoint(context, intSample, centerRight - pixels);
CGContextAddLineToPoint(context, intSample, centerRight + pixels);
CGContextSetStrokeColorWithColor(context, rightcolor);
CGContextStrokePath(context);
}
}
// Create new image
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
// Tidy up
UIGraphicsEndImageContext();
return newImage;
}
- (NSData *) renderPNGAudioPictogramLogForAssett:(AVURLAsset *)songAsset {
NSError * error = nil;
AVAssetReader * reader = [[AVAssetReader alloc] initWithAsset:songAsset error:&error];
AVAssetTrack * songTrack = [songAsset.tracks objectAtIndex:0];
NSDictionary* outputSettingsDict = [[NSDictionary alloc] initWithObjectsAndKeys:
[NSNumber numberWithInt:kAudioFormatLinearPCM],AVFormatIDKey,
// [NSNumber numberWithInt:44100.0],AVSampleRateKey, /*Not Supported*/
// [NSNumber numberWithInt: 2],AVNumberOfChannelsKey, /*Not Supported*/
[NSNumber numberWithInt:16],AVLinearPCMBitDepthKey,
[NSNumber numberWithBool:NO],AVLinearPCMIsBigEndianKey,
[NSNumber numberWithBool:NO],AVLinearPCMIsFloatKey,
[NSNumber numberWithBool:NO],AVLinearPCMIsNonInterleaved,
nil];
AVAssetReaderTrackOutput* output = [[AVAssetReaderTrackOutput alloc] initWithTrack:songTrack outputSettings:outputSettingsDict];
[reader addOutput:output];
[output release];
UInt32 sampleRate,channelCount;
NSArray* formatDesc = songTrack.formatDescriptions;
for(unsigned int i = 0; i < [formatDesc count]; ++i) {
CMAudioFormatDescriptionRef item = (CMAudioFormatDescriptionRef)[formatDesc objectAtIndex:i];
const AudioStreamBasicDescription* fmtDesc = CMAudioFormatDescriptionGetStreamBasicDescription (item);
if(fmtDesc ) {
sampleRate = fmtDesc->mSampleRate;
channelCount = fmtDesc->mChannelsPerFrame;
// NSLog(#"channels:%u, bytes/packet: %u, sampleRate %f",fmtDesc->mChannelsPerFrame, fmtDesc->mBytesPerPacket,fmtDesc->mSampleRate);
}
}
UInt32 bytesPerSample = 2 * channelCount;
Float32 normalizeMax = noiseFloor;
NSLog(#"normalizeMax = %f",normalizeMax);
NSMutableData * fullSongData = [[NSMutableData alloc] init];
[reader startReading];
UInt64 totalBytes = 0;
Float64 totalLeft = 0;
Float64 totalRight = 0;
Float32 sampleTally = 0;
NSInteger samplesPerPixel = sampleRate / 50;
while (reader.status == AVAssetReaderStatusReading){
AVAssetReaderTrackOutput * trackOutput = (AVAssetReaderTrackOutput *)[reader.outputs objectAtIndex:0];
CMSampleBufferRef sampleBufferRef = [trackOutput copyNextSampleBuffer];
if (sampleBufferRef){
CMBlockBufferRef blockBufferRef = CMSampleBufferGetDataBuffer(sampleBufferRef);
size_t length = CMBlockBufferGetDataLength(blockBufferRef);
totalBytes += length;
NSAutoreleasePool *wader = [[NSAutoreleasePool alloc] init];
NSMutableData * data = [NSMutableData dataWithLength:length];
CMBlockBufferCopyDataBytes(blockBufferRef, 0, length, data.mutableBytes);
SInt16 * samples = (SInt16 *) data.mutableBytes;
int sampleCount = length / bytesPerSample;
for (int i = 0; i < sampleCount ; i ++) {
Float32 left = (Float32) *samples++;
left = decibel(left);
left = minMaxX(left,noiseFloor,0);
totalLeft += left;
Float32 right;
if (channelCount==2) {
right = (Float32) *samples++;
right = decibel(right);
right = minMaxX(right,noiseFloor,0);
totalRight += right;
}
sampleTally++;
if (sampleTally > samplesPerPixel) {
left = totalLeft / sampleTally;
if (left > normalizeMax) {
normalizeMax = left;
}
// NSLog(#"left average = %f, normalizeMax = %f",left,normalizeMax);
[fullSongData appendBytes:&left length:sizeof(left)];
if (channelCount==2) {
right = totalRight / sampleTally;
if (right > normalizeMax) {
normalizeMax = right;
}
[fullSongData appendBytes:&right length:sizeof(right)];
}
totalLeft = 0;
totalRight = 0;
sampleTally = 0;
}
}
[wader drain];
CMSampleBufferInvalidate(sampleBufferRef);
CFRelease(sampleBufferRef);
}
}
NSData * finalData = nil;
if (reader.status == AVAssetReaderStatusFailed || reader.status == AVAssetReaderStatusUnknown){
// Something went wrong. Handle it.
}
if (reader.status == AVAssetReaderStatusCompleted){
// You're done. It worked.
NSLog(#"rendering output graphics using normalizeMax %f",normalizeMax);
UIImage *test = [self audioImageLogGraph:(Float32 *) fullSongData.bytes
normalizeMax:normalizeMax
sampleCount:fullSongData.length / (sizeof(Float32) * 2)
channelCount:2
imageHeight:100];
finalData = imageToData(test);
}
[fullSongData release];
[reader release];
return finalData;
}
#end
Been reading your question and created a control for this. Looks like this:
Code here:
https://github.com/fulldecent/FDWaveformView
Discussion here:
https://www.cocoacontrols.com/controls/fdwaveformview
UPDATE 2015-01-29: This project is going strong and making consistent releases. Thanks for SO for all the exposure!
I can give you reference of the one that I have implemented in my application. It was apple's example. Here is the example of AurioTouch which analyzes 3 types of sound audio. Apple has still not provided to analyse directly the audio waves... so this example also uses the Mic to analyse the sound...
Amongst 3 I have used only Oscilloscope for analysing the amplitude effect. I have to change that code drastically to match my requirement, so best of luck if you are going to use...
You can also see one more example using such amplitude : SpeakHere of Apple
This is the code I have used to convert my audio data (audio file ) into floating point representation and saved into an array.
-(void) PrintFloatDataFromAudioFile {
NSString * name = #"Filename"; //YOUR FILE NAME
NSString * source = [[NSBundle mainBundle] pathForResource:name ofType:#"m4a"]; // SPECIFY YOUR FILE FORMAT
const char *cString = [source cStringUsingEncoding:NSASCIIStringEncoding];
CFStringRef str = CFStringCreateWithCString(
NULL,
cString,
kCFStringEncodingMacRoman
);
CFURLRef inputFileURL = CFURLCreateWithFileSystemPath(
kCFAllocatorDefault,
str,
kCFURLPOSIXPathStyle,
false
);
ExtAudioFileRef fileRef;
ExtAudioFileOpenURL(inputFileURL, &fileRef);
AudioStreamBasicDescription audioFormat;
audioFormat.mSampleRate = 44100; // GIVE YOUR SAMPLING RATE
audioFormat.mFormatID = kAudioFormatLinearPCM;
audioFormat.mFormatFlags = kLinearPCMFormatFlagIsFloat;
audioFormat.mBitsPerChannel = sizeof(Float32) * 8;
audioFormat.mChannelsPerFrame = 1; // Mono
audioFormat.mBytesPerFrame = audioFormat.mChannelsPerFrame * sizeof(Float32); // == sizeof(Float32)
audioFormat.mFramesPerPacket = 1;
audioFormat.mBytesPerPacket = audioFormat.mFramesPerPacket * audioFormat.mBytesPerFrame; // = sizeof(Float32)
// 3) Apply audio format to the Extended Audio File
ExtAudioFileSetProperty(
fileRef,
kExtAudioFileProperty_ClientDataFormat,
sizeof (AudioStreamBasicDescription), //= audioFormat
&audioFormat);
int numSamples = 1024; //How many samples to read in at a time
UInt32 sizePerPacket = audioFormat.mBytesPerPacket; // = sizeof(Float32) = 32bytes
UInt32 packetsPerBuffer = numSamples;
UInt32 outputBufferSize = packetsPerBuffer * sizePerPacket;
// So the lvalue of outputBuffer is the memory location where we have reserved space
UInt8 *outputBuffer = (UInt8 *)malloc(sizeof(UInt8 *) * outputBufferSize);
AudioBufferList convertedData ;//= malloc(sizeof(convertedData));
convertedData.mNumberBuffers = 1; // Set this to 1 for mono
convertedData.mBuffers[0].mNumberChannels = audioFormat.mChannelsPerFrame; //also = 1
convertedData.mBuffers[0].mDataByteSize = outputBufferSize;
convertedData.mBuffers[0].mData = outputBuffer; //
UInt32 frameCount = numSamples;
float *samplesAsCArray;
int j =0;
double floatDataArray[882000] ; // SPECIFY YOUR DATA LIMIT MINE WAS 882000 , SHOULD BE EQUAL TO OR MORE THAN DATA LIMIT
while (frameCount > 0) {
ExtAudioFileRead(
fileRef,
&frameCount,
&convertedData
);
if (frameCount > 0) {
AudioBuffer audioBuffer = convertedData.mBuffers[0];
samplesAsCArray = (float *)audioBuffer.mData; // CAST YOUR mData INTO FLOAT
for (int i =0; i<1024 /*numSamples */; i++) { //YOU CAN PUT numSamples INTEAD OF 1024
floatDataArray[j] = (double)samplesAsCArray[i] ; //PUT YOUR DATA INTO FLOAT ARRAY
printf("\n%f",floatDataArray[j]); //PRINT YOUR ARRAY'S DATA IN FLOAT FORM RANGING -1 TO +1
j++;
}
}
}}
this is my answer, thx all geek
obj-c
here is code:
-(void) listenerData:(NSNotification *) notify
{
int resnum=112222;
unsigned int bitsum=0;
for(int i=0;i<4;i++)
{
bitsum+=(resnum>>(i*8))&0xff;
}
bitsum=bitsum&0xff;
NSString * check=[NSString stringWithFormat:#"%x %x",resnum,bitsum];
check=nil;
self.drawData=notify.object;``
[self setNeedsDisplay];
}
-(void)drawRect:(CGRect)rect
{
NSArray *data=self.drawData;
NSData *tdata=[data objectAtIndex:0];
double *srcdata=(double*)tdata.bytes;
int datacount=tdata.length/sizeof(double);
tdata=[data objectAtIndex:1];
double *coveddata=(double*)tdata.bytes;
CGContextRef context=UIGraphicsGetCurrentContext();
CGRect bounds=self.bounds;
CGContextClearRect(context, bounds);
CGFloat midpos=bounds.size.height/2;
CGContextBeginPath(context);
const double scale=1.0/100;
CGFloat step=bounds.size.width/(datacount-1);
CGContextMoveToPoint(context, 0, midpos);
CGFloat xpos=0;
for(int i=0;i<datacount;i++)
{
CGContextAddLineToPoint(context, xpos, midpos-srcdata[i]*scale);
xpos+=step;
}
CGContextAddLineToPoint(context, bounds.size.width, midpos);
CGContextClosePath(context);
CGContextSetRGBFillColor(context, 1.0, 0.0, 0.0, 1.0);
CGContextFillPath(context);
CGContextBeginPath(context);
const double scale2=1.0/100;
CGContextMoveToPoint(context, 0, midpos);
xpos=0;
for(int i=0;i<datacount;i++)
{
CGContextAddLineToPoint(context, xpos, midpos+coveddata[i]*scale2);
xpos+=step;
}
CGContextAddLineToPoint(context, bounds.size.width, midpos);
CGContextClosePath(context);
CGContextSetRGBFillColor(context, 1.0, 0.0, 1.0, 1.0);
CGContextFillPath(context);
}
I have been googling so much on how to do this, but how would I reverse a NSString? Ex:hi would become: ih
I am looking for the easiest way to do this.
Thanks!
#Vince I made this method:
- (IBAction)doneKeyboard {
// first retrieve the text of textField1
NSString *myString = field1.text;
NSMutableString *reversedString = [NSMutableString string];
NSUInteger charIndex = 0;
while(myString && charIndex < [myString length]) {
NSRange subStrRange = NSMakeRange(charIndex, 1);
[reversedString appendString:[myString substringWithRange:subStrRange]];
charIndex++;
}
// reversedString is reversed, or empty if myString was nil
field2.text = reversedString;
}
I hooked up that method to textfield1's didendonexit. When I click the done button, it doesn't reverse the text, the UILabel just shows the UITextField's text that I entered. What is wrong?
Block version.
NSString *myString = #"abcdefghijklmnopqrstuvwxyz";
NSMutableString *reversedString = [NSMutableString stringWithCapacity:[myString length]];
[myString enumerateSubstringsInRange:NSMakeRange(0,[myString length])
options:(NSStringEnumerationReverse | NSStringEnumerationByComposedCharacterSequences)
usingBlock:^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop) {
[reversedString appendString:substring];
}];
// reversedString is now zyxwvutsrqponmlkjihgfedcba
Write a simple loop to do that:
// myString is "hi"
NSMutableString *reversedString = [NSMutableString string];
NSInteger charIndex = [myString length];
while (charIndex > 0) {
charIndex--;
NSRange subStrRange = NSMakeRange(charIndex, 1);
[reversedString appendString:[myString substringWithRange:subStrRange]];
}
NSLog(#"%#", reversedString); // outputs "ih"
In your case:
// first retrieve the text of textField1
NSString *myString = textField1.text;
NSMutableString *reversedString = [NSMutableString string];
NSInteger charIndex = [myString length];
while (myString && charIndex > 0) {
charIndex--;
NSRange subStrRange = NSMakeRange(charIndex, 1);
[reversedString appendString:[myString substringWithRange:subStrRange]];
}
// reversedString is reversed, or empty if myString was nil
textField2.text = reversedString;
jano’s answer is correct. Unfortunately, it creates a lot of unnecessary temporary objects. Here is a much faster (more complicated) implementation that basically does the same thing, but uses memcpy and unichar buffers to keep memory allocations to a minimum.
- (NSString *)reversedString
{
NSUInteger length = [self length];
if (length < 2) {
return self;
}
unichar *characters = calloc(length, sizeof(unichar));
unichar *reversedCharacters = calloc(length, sizeof(unichar));
if (!characters || !reversedCharacters) {
free(characters);
free(reversedCharacters);
return nil;
}
[self getCharacters:characters range:NSMakeRange(0, length)];
NSUInteger i = length - 1;
NSUInteger copiedCharacterCount = 0;
// Starting from the end of self, copy each composed character sequence into reversedCharacters
while (copiedCharacterCount < length) {
NSRange characterRange = [self rangeOfComposedCharacterSequenceAtIndex:i];
memcpy(reversedCharacters + copiedCharacterCount, characters + characterRange.location, characterRange.length * sizeof(unichar));
i = characterRange.location - 1;
copiedCharacterCount += characterRange.length;
}
free(characters);
NSString *reversedString = [[NSString alloc] initWithCharactersNoCopy:reversedCharacters length:length freeWhenDone:YES];
if (!reversedString) {
free(reversedCharacters);
}
return reversedString;
}
I tested this on 100,000 random multi-byte Unicode strings with lengths between 1 and 128. This version is about 4–5x faster than jano’s.
Enumerate substrings: 2.890528
MemCopy: 0.671090
Enumerate substrings: 2.840411
MemCopy: 0.662882
Test code is at https://gist.github.com/prachigauriar/9739805.
Update: I tried this again by simply converting to a UTF-32 buffer and reversing that.
- (NSString *)qlc_reversedStringWithUTF32Buffer
{
NSUInteger length = [self length];
if (length < 2) {
return self;
}
NSStringEncoding encoding = NSHostByteOrder() == NS_BigEndian ? NSUTF32BigEndianStringEncoding : NSUTF32LittleEndianStringEncoding;
NSUInteger utf32ByteCount = [self lengthOfBytesUsingEncoding:encoding];
uint32_t *characters = malloc(utf32ByteCount);
if (!characters) {
return nil;
}
[self getBytes:characters maxLength:utf32ByteCount usedLength:NULL encoding:encoding options:0 range:NSMakeRange(0, length) remainingRange:NULL];
NSUInteger utf32Length = utf32ByteCount / sizeof(uint32_t);
NSUInteger halfwayPoint = utf32Length / 2;
for (NSUInteger i = 0; i < halfwayPoint; ++i) {
uint32_t character = characters[utf32Length - i - 1];
characters[utf32Length - i - 1] = characters[i];
characters[i] = character;
}
return [[NSString alloc] initWithBytesNoCopy:characters length:utf32ByteCount encoding:encoding freeWhenDone:YES];
}
This is about 3–4x times faster than the memcpy version. The aforementioned gist has been updated with the latest version of the code.
Enumerate substrings: 2.168705
MemCopy: 0.488320
UTF-32: 0.150822
Enumerate substrings: 2.169655
MemCopy: 0.481786
UTF-32: 0.147534
Enumerate substrings: 2.248812
MemCopy: 0.505995
UTF-32: 0.154531
I thought I'd throw another version out there in case anyone's interested.. personally, I like the cleaner approach using NSMutableString but if performance is the highest priority this one is faster:
- (NSString *)reverseString:(NSString *)input {
NSUInteger len = [input length];
unichar *buffer = malloc(len * sizeof(unichar));
if (buffer == nil) return nil; // error!
[input getCharacters:buffer];
// reverse string; only need to loop through first half
for (NSUInteger stPos=0, endPos=len-1; stPos < len/2; stPos++, endPos--) {
unichar temp = buffer[stPos];
buffer[stPos] = buffer[endPos];
buffer[endPos] = temp;
}
return [[NSString alloc] initWithCharactersNoCopy:buffer length:len freeWhenDone:YES];
}
I also wrote a quick test as well to compare this with the more traditional NSMutableString method (which I also included below):
// test reversing a really large string
NSMutableString *string = [NSMutableString new];
for (int i = 0; i < 10000000; i++) {
int digit = i % 10;
[string appendFormat:#"%d", digit];
}
NSTimeInterval startTime = [[NSDate date] timeIntervalSince1970];
NSString *reverse = [self reverseString:string];
NSTimeInterval elapsedTime = [[NSDate date] timeIntervalSince1970] - startTime;
NSLog(#"reversed in %f secs", elapsedTime);
Results were:
using NSMutableString method (below) - "reversed in 3.720631 secs"
using unichar *buffer method (above) - "reversed in 0.032604 secs"
Just for reference, here's the NSMutableString method used for this comparison:
- (NSString *)reverseString:(NSString *)input {
NSUInteger len = [input length];
NSMutableString *result = [[NSMutableString alloc] initWithCapacity:len];
for (int i = len - 1; i >= 0; i--) {
[result appendFormat:#"%c", [input characterAtIndex:i]];
}
return result;
}
Use method with any objects: NSString,NSNumber,etc..:
NSLog(#"%#",[self reverseObject:#12345]);
NSLog(#"%#",[self reverseObject:#"Hello World"]);
Method:
-(NSString*)reverseObject:(id)string{
string = [NSString stringWithFormat:#"%#",string];
NSMutableString *endString = [NSMutableString new];
while ([string length]!=[endString length]) {
NSRange range = NSMakeRange([string length]-[endString length]-1, 1);
[endString appendString: [string substringWithRange:range]];
}
return endString;}
Log:
2014-04-16 11:20:25.312 TEST[23733:60b] 54321
2014-04-16 11:20:25.313 TEST[23733:60b] dlroW olleH
Swift 2.0:
1) let str = "Hello, world!"
let reversed = String(str.characters.reverse())
print(reversed)
In Short:
String("This is a test string.".characters.reverse())
2)
let string = "This is a test string."
let characters = string.characters
let reversedCharacters = characters.reverse()
let reversedString = String(reversedCharacters)
The short way :
String("This is a test string.".characters.reverse())
OR
let string = "This is a test string."
let array = Array(string)
let reversedArray = array.reverse()
let reversedString = String(reversedArray)
The short way :
String(Array("This is a test string.").reverse())
Tested on Play Ground:
import Cocoa
//Assigning a value to a String variable
var str = "Hello, playground"
//Create empty character Array.
var strArray:Character[] = Character[]()
//Loop through each character in the String
for character in str {
//Insert the character in the Array variable.
strArray.append(character)
}
//Create a empty string
var reversedStr:String = ""
//Read the array from backwards to get the characters
for var index = strArray.count - 1; index >= 0;--index {
//Concatenate character to String.
reversedStr += strArray[index]
}
The shorter version:
var str = “Hello, playground”
var reverseStr = “”
for character in str {
reverseStr = character + reverseStr
}
Would it be faster if you only iterated over half the string swapping the characters at each end? So for a 5 character string, you swap characters 1 + 5, then 2 + 4 and 3 doesn't need swapped with anything.
NSMutableString *reversed = [original mutableCopyWithZone:NULL];
NSUInteger i, length;
length = [reversed length];
for (i = 0; i < length / 2; i++) {
// Store the first character as we're going to replace with the character at the end
// in the example, it would store 'h'
unichar startChar = [reversed characterAtIndex:i];
// Only make the end range once
NSRange endRange = NSMakeRange(length - i, 1);
// Replace the first character ('h') with the last character ('i')
// so reversed now contains "ii"
[reversed replaceCharactersInRange:NSMakeRange(i, 1)
withString:[reversed subStringWithRange:endRange];
// Replace the last character ('i') with the stored first character ('h)
// so reversed now contains "ih"
[reversed replaceCharactersInRange:endRange
withString:[NSString stringWithFormat:#"%c", startChar]];
}
edit ----
Having done some tests, the answer is No, its about 6 times slower than the version that loops over everything. The thing that slows us down is creating the temporary NSStrings for the replaceCharactersInRange:withString method. Here is a method that creates only one NSString by manipulating the character data directly and seems a lot faster in simple tests.
NSUInteger length = [string length];
unichar *data = malloc(sizeof (unichar) * length);
int i;
for (i = 0; i < length / 2; i++) {
unichar startChar = [string characterAtIndex:i];
unichar endChar = [string characterAtIndex:(length - 1) - i];
data[i] = endChar;
data[(length - 1) - i] = startChar;
}
NSString *reversed = [NSString stringWithCharacters:data length:length];
free(data);
Reverse the string using recursion:
#implementation NSString (Reversed)
+ (NSString *)reversedStringFromString:(NSString *)string
{
NSUInteger count = [string length];
if (count <= 1) { // Base Case
return string;
} else {
NSString *lastLetter = [string substringWithRange:NSMakeRange(count - 1, 1)];
NSString *butLastLetter = [string substringToIndex:count - 1];
return [lastLetter stringByAppendingString:[self reversedStringFromString:butLastLetter]];
}
}
#end
Google is your friend:
-(NSString *) reverseString
{
NSMutableString *reversedStr;
int len = [self length];
// Auto released string
reversedStr = [NSMutableString stringWithCapacity:len];
// Probably woefully inefficient...
while (len > 0)
[reversedStr appendString:
[NSString stringWithFormat:#"%C", [self characterAtIndex:--len]]];
return reversedStr;
}
None of the answers seem to consider multibyte characters so here is my sample code. It assumes you only ever pass in a string longer than one character.
- (void)testReverseString:(NSString *)string
{
NSMutableString *rString = [NSMutableString new];
NSInteger extractChar = [string length] - 1;
while (extractChar >= 0)
{
NSRange oneCharPos = [string rangeOfComposedCharacterSequenceAtIndex:extractChar];
for (NSUInteger add = 0; add < oneCharPos.length; ++ add)
{
unichar oneChar = [string characterAtIndex:oneCharPos.location + add];
[rString appendFormat:#"%C", oneChar];
}
extractChar -= oneCharPos.length;
}
NSLog(#"%# becomes %#", string, encryptedString );
}
NSString into char utf32 (always 32 bits (unsigned int))
Reverse
char utf32 into NSString
+ (NSString *)reverseString3:(NSString *)str {
unsigned int *cstr, buf, len = [str length], i;
cstr = (unsigned int *)[str cStringUsingEncoding:NSUTF32LittleEndianStringEncoding];
for (i=0;i < len/2;i++) buf = cstr[i], cstr[i] = cstr[len -i-1], cstr[len-i-1] = buf;
return [[NSString alloc] initWithBytesNoCopy:cstr length:len*4 encoding:NSUTF32LittleEndianStringEncoding freeWhenDone:NO];
}
Example : Apple_is ---> si_elppA
NSMutableString *result = [NSMutableString stringWithString:#""];
for (long i = self.length - 1; i >= 0; i--) {
[result appendFormat:#"%c", [self characterAtIndex:i]];
}
return (NSString *)result;
Here is a collection of categories in Objective-C that will reverse both NSStrings and NSAttributedStrings (while preserving character attributes): TextFlipKit
For example:
NSString *example = #"Example Text";
NSString *reversed = example.tfk_reversed;
NSLog(#"Reversed: %#", reversed);
//prints 'Reversed: txeT elpmaxE'
Swift:
let string = "reverse"
let reversedStringCollection = string.characters.reversed()
for character in reversedStringCollection {
reversedString.append(character)
print(reversedString)
}
We can also achieve the reverse string as follows.
NSString *originalString = #"Hello";
NSString *reverseString;
for (NSUInteger index = originalString.length; index > 0; index--) {
char character = [originalString characterAtIndex:index];
reverseString = [reverseString stringByAppendingString:[NSString stringWithFormat:#"%c", character]];
}
or
NSString *originalString = #"Hello";
NSString *reverseString;
for (NSUInteger index = originalString.length; index > 0; index--) {
char *character = [originalString characterAtIndex:index];
reverseString = [reverseString stringByAppendingString:[NSString stringWithFormat:#"%s", character]];
}
Add a category to NSString so you can call reverse on any NSString in the future like this:
#import "NSString+Reverse.h"
#implementation NSString (Reverse)
-(NSString*)reverse {
char* cstring = (char*)[self UTF8String];
int length = [self length]-1;
int i=0;
while (i<=length) {
unichar tmp = cstring[i];
cstring[i] = cstring[length];
cstring[length] = tmp;
i++;
length--;
}
return [NSString stringWithCString:cstring encoding:NSUTF8StringEncoding];
}
#end
str=#"india is my countery";
array1=[[NSMutableArray alloc] init];
for(int i =0 ;i<[str length]; i++) {
NSString *singleCharacter = [NSString stringWithFormat:#"%c", [str characterAtIndex:i]];
[array1 addObject:singleCharacter];
}
NSMutableString* theString = [NSMutableString string];
for (int i=[array1 count]-1; i>=0;i--){
[theString appendFormat:#"%#",[array1 objectAtIndex:i]];
}
I have written a category ove that one :D
//NSString+Reversed.h
#import
//
// NSString+Reversed.h
// HTMLPageFormatter
// Created by beit46 on 21.06.13.
//
#interface NSString (Reversed)
- (NSString *)reversedString;
#end
//NSString+Reversed.m
//
// NSString+Reversed.m
// HTMLPageFormatter
// Created by beit46 on 21.06.13.
#import "NSString+Reversed.h"
#implementation NSString (Reversed)
- (NSString *)reversedString {
NSMutableString *reversedString = [NSMutableString stringWithCapacity:[self length]];
[self enumerateSubstringsInRange:NSMakeRange(0,[self length])
options:(NSStringEnumerationReverse | NSStringEnumerationByComposedCharacterSequences)
usingBlock:^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop) {
[reversedString appendString:substring];
}];
return [reversedString copy];
}
#end
I have two simple solutions for that purpose:
+(NSString*)reverseString:(NSString *)str
{
NSMutableString* reversed = [NSMutableString stringWithCapacity:str.length];
for (int i = (int)str.length-1; i >= 0; i--){
[reversed appendFormat:#"%c", [str characterAtIndex:i]];
}
return reversed;
}
+(NSString*)reverseString2:(NSString *)str
{
char* cstr = (char*)[str UTF8String];
int len = (int)str.length;
for (int i = 0; i < len/2; i++) {
char buf = cstr[i];
cstr[i] = cstr[len-i-1];
cstr[len-i-1] = buf;
}
return [[NSString alloc] initWithBytes:cstr length:len encoding:NSUTF8StringEncoding];
}
Now, lets test it!
NSString* str = #"Objective-C is a general-purpose, object-oriented programming language that adds Smalltalk-style messaging to the C programming language";
NSLog(#"REV 1: %#", [Util reverseString:str]);
start = [NSDate date];
for (int i = 0 ; i < 1000; ++i)
[Util reverseString:str];
end = [NSDate date];
NSLog(#"Time per 1000 repeats: %f", [end timeIntervalSinceDate:start]);
NSLog(#"REV 2: %#", [Util reverseString2:str]);
start = [NSDate date];
for (int i = 0 ; i < 1000; ++i)
[Util reverseString2:str];
end = [NSDate date];
NSLog(#"Time per 1000 repeats: %f", [end timeIntervalSinceDate:start]);
Results:
ConsoleTestProject[68292:303] REV 1: egaugnal gnimmargorp C eht ot gnigassem elyts-klatllamS sdda taht egaugnal gnimmargorp detneiro-tcejbo ,esoprup-lareneg a si C-evitcejbO
ConsoleTestProject[68292:303] Time per 1000 repeats: 0.063880
ConsoleTestProject[68292:303] REV 2: egaugnal gnimmargorp C eht ot gnigassem elyts-klatllamS sdda taht egaugnal gnimmargorp detneiro-tcejbo ,esoprup-lareneg a si C-evitcejbO
ConsoleTestProject[68292:303] Time per 1000 repeats: 0.002038
And more chars result was:
ConsoleTestProject[68322:303] chars: 1982
ConsoleTestProject[68322:303] Time 1 per 1000 repeats: 1.014893
ConsoleTestProject[68322:303] Time 2 per 1000 repeats: 0.024928
The same text with above functions:
ConsoleTestProject[68366:303] Time 1 per 1000 repeats: 0.873574
ConsoleTestProject[68366:303] Time 2 per 1000 repeats: 0.019300
ConsoleTestProject[68366:303] Time 3 per 1000 repeats: 0.342735 <-Vladimir Gritsenko
ConsoleTestProject[68366:303] Time 4 per 1000 repeats: 0.584012 <- Jano
So, choose performance!