Puts the generation logic in a seperate file. Adds stereo

SpectogramPrototype.xcodeproj/project.pbxproj

@@ -29,6 +29,7 @@
 		426665BC1869EF4B005D62AC /* CoreAudio.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 426665BB1869EF4B005D62AC /* CoreAudio.framework */; };
 		426665C11869F194005D62AC /* AudioToolbox.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 426665C01869F194005D62AC /* AudioToolbox.framework */; };
 		426665C51869F50B005D62AC /* MediaPlayer.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 426665C41869F50B005D62AC /* MediaPlayer.framework */; };
+		42ABF54B187035F900B20D82 /* Spectographer.m in Sources */ = {isa = PBXBuildFile; fileRef = 42ABF54A187035F900B20D82 /* Spectographer.m */; };
 		42E12A91186F122400866CB3 /* testMusic.mp3 in Resources */ = {isa = PBXBuildFile; fileRef = 42E12A90186F122400866CB3 /* testMusic.mp3 */; };
 		42E12A94186F1F4C00866CB3 /* AudioFile.m in Sources */ = {isa = PBXBuildFile; fileRef = 42E12A93186F1F4C00866CB3 /* AudioFile.m */; };
 /* End PBXBuildFile section */
@@ -73,6 +74,8 @@
 		426665BB1869EF4B005D62AC /* CoreAudio.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = CoreAudio.framework; path = System/Library/Frameworks/CoreAudio.framework; sourceTree = SDKROOT; };
 		426665C01869F194005D62AC /* AudioToolbox.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = AudioToolbox.framework; path = System/Library/Frameworks/AudioToolbox.framework; sourceTree = SDKROOT; };
 		426665C41869F50B005D62AC /* MediaPlayer.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = MediaPlayer.framework; path = System/Library/Frameworks/MediaPlayer.framework; sourceTree = SDKROOT; };
+		42ABF549187035F900B20D82 /* Spectographer.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = Spectographer.h; sourceTree = "<group>"; };
+		42ABF54A187035F900B20D82 /* Spectographer.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = Spectographer.m; sourceTree = "<group>"; };
 		42E12A90186F122400866CB3 /* testMusic.mp3 */ = {isa = PBXFileReference; lastKnownFileType = audio.mp3; path = testMusic.mp3; sourceTree = "<group>"; };
 		42E12A92186F1F4C00866CB3 /* AudioFile.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = AudioFile.h; sourceTree = "<group>"; };
 		42E12A93186F1F4C00866CB3 /* AudioFile.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = AudioFile.m; sourceTree = "<group>"; };
@@ -150,6 +153,8 @@
 				424F84BD18661F8000687D3B /* Main_iPad.storyboard */,
 				424F84C018661F8000687D3B /* ViewController.h */,
 				424F84C118661F8000687D3B /* ViewController.m */,
+				42ABF549187035F900B20D82 /* Spectographer.h */,
+				42ABF54A187035F900B20D82 /* Spectographer.m */,
 				42E12A92186F1F4C00866CB3 /* AudioFile.h */,
 				42E12A93186F1F4C00866CB3 /* AudioFile.m */,
 				426665B31869A7CC005D62AC /* RuledScrollView.h */,
@@ -293,6 +298,7 @@
 			buildActionMask = 2147483647;
 			files = (
 				42E12A94186F1F4C00866CB3 /* AudioFile.m in Sources */,
+				42ABF54B187035F900B20D82 /* Spectographer.m in Sources */,
 				426665B81869CEFE005D62AC /* FFTTest.m in Sources */,
 				424F84C218661F8000687D3B /* ViewController.m in Sources */,
 				424F84B918661F8000687D3B /* AppDelegate.m in Sources */,

SpectogramPrototype/AudioFile.h

@@ -16,6 +16,6 @@
 + (AudioFile*) audioFileFromURL:(NSURL*) url;
 
 // Reads nSamples of data (left channel), return actual number of samples read
-- (unsigned int) fillArray:(float*)array withNumberOfSamples:(unsigned int)nSamples;
+- (unsigned int) fillLeft:(float*)left andRight:(float*)right withNumberOfSamples:(unsigned int)nSamples;
 
 @end

SpectogramPrototype/AudioFile.m

@@ -62,7 +62,7 @@
 #pragma mark
 #pragma mark Usage
 
-- (unsigned int)fillArray:(float *)array withNumberOfSamples:(unsigned int)nSamples{
+- (unsigned int)fillLeft:(float *)left andRight:(float *)right withNumberOfSamples:(unsigned int)nSamples {
 	AudioBufferList bufferList;
 	bufferList.mNumberBuffers = 1;
 	bufferList.mBuffers[0].mNumberChannels = 2;
@@ -74,15 +74,16 @@
 	assert(err == 0);
 	
 	short * buffer = bufferList.mBuffers[0].mData;
-	float * end = array + nSamples;
+	float * leftEnd = left + nSamples;
 	for(unsigned int i = 0; i < nFrames; ++i){
-		*array++ = *buffer++ / 32768.0;
+		*left++ = *buffer++ / 32768.0;
-		// skip right channel
+		*right++ = *buffer++ / 32768.0;
-		buffer++;
 	}
 	
-	while(array != end){
+	// assume left and right are of the same size
-		*array++ = 0.0;
+	while(left != leftEnd){
+		*left++ = 0.0;
+		*right++ = 0.0;
 	}
 	
 	free(bufferList.mBuffers[0].mData);

SpectogramPrototype/Spectographer.h

@@ -0,0 +1,16 @@
+//
+//  Spectographer.h
+//  SpectogramPrototype
+//
+//  Created by Joshua Moerman on 29/12/13.
+//  Copyright (c) 2013 Joshua Moerman. All rights reserved.
+//
+
+#import <Foundation/Foundation.h>
+
+@interface Spectographer : NSObject
+
+- (void)openAudioFile:(NSURL*)url;
+- (CGImageRef)generate;
+
+@end

SpectogramPrototype/Spectographer.m

@@ -0,0 +1,78 @@
+//
+//  Spectographer.m
+//  SpectogramPrototype
+//
+//  Created by Joshua Moerman on 29/12/13.
+//  Copyright (c) 2013 Joshua Moerman. All rights reserved.
+//
+
+#import "Spectographer.h"
+#import "FFTTest.h"
+#import "AudioFile.h"
+
+UInt8 clamp_to_uint8(float x){
+	if(x >= 1.0) return 255;
+	if(x <= 0.0) return 0;
+	return 255.0 * x;
+}
+
+@interface Spectographer (){
+	FFTTest * FFTHandler;
+	AudioFile * audioFile;
+	float * left;
+	float * right;
+}
+
+@end
+
+@implementation Spectographer
+
+- (id)init{
+	if(self = [super init]){
+		FFTHandler = [[FFTTest alloc] init];
+		left = calloc(FFTHandler.acceptedSize, sizeof(float));
+		right = calloc(FFTHandler.acceptedSize, sizeof(float));
+	}
+	return self;
+}
+
+- (void)openAudioFile:(NSURL *)url{
+	audioFile = [AudioFile audioFileFromURL: url];
+	assert(audioFile);
+}
+
+- (CGImageRef)generate{
+	unsigned int size = FFTHandler.acceptedSize;
+	unsigned int width = size/4;
+	unsigned int height = size/8;
+	
+	char * rgba = calloc(width*height*4, sizeof(char));
+	
+	for(unsigned int x = 0; x < width; ++x){
+		[audioFile fillLeft:left andRight:right withNumberOfSamples:size];
+		[FFTHandler inPlaceFFT:left forSize:size];
+		[FFTHandler inPlaceFFT:right forSize:size];
+		for(unsigned int y = 0; y < height; ++y){
+			unsigned int yy = height - y - 1;
+			rgba[4*width*yy + 4*x + 0] = clamp_to_uint8(100.0 * left[y]);
+			rgba[4*width*yy + 4*x + 1] = clamp_to_uint8(100.0 * right[y]);
+			rgba[4*width*yy + 4*x + 2] = clamp_to_uint8(10.0 * (left[y] + right[y]));
+			rgba[4*width*yy + 4*x + 3] = 0;
+		}
+	}
+	
+	CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
+	assert(colorSpace);
+	CGContextRef bitmapContext = CGBitmapContextCreate(rgba, width, height, 8, 4*width, colorSpace, (CGBitmapInfo)kCGImageAlphaNoneSkipLast);
+	assert(bitmapContext);
+	CGImageRef cgImage = CGBitmapContextCreateImage(bitmapContext);
+	assert(cgImage);
+	
+	CGContextRelease(bitmapContext);
+	CGColorSpaceRelease(colorSpace);
+	free(rgba);
+	
+	return cgImage;
+}
+
+@end

SpectogramPrototype/ViewController.m

@@ -11,8 +11,7 @@
 
 #import "ViewController.h"
 #import "RuledScrollView.h"
-#import "FFTTest.h"
+#import "Spectographer.h"
-#import "AudioFile.h"
 
 typedef enum {
 	iPad,
@@ -38,16 +37,9 @@ device get_device(){
 	return device;
 }
 
-UInt8 clamp_to_uint8(float x){
-	if(x >= 1.0) return 255;
-	if(x <= 0.0) return 0;
-	return 255.0 * x;
-}
-
 @interface ViewController () <MPMediaPickerControllerDelegate> {
+	Spectographer * spectographer;
 	UIPopoverController * pop;
-	FFTTest * fft_handler;
-	float * data;
 }
 - (void) openAudioFile:(NSURL*)filePath;
 @property (nonatomic, strong) UILabel* header;
@@ -73,51 +65,22 @@ UInt8 clamp_to_uint8(float x){
 }
 
 - (void)openAudioFile:(NSURL *)filePath{
-	AudioFile * audioFile = [AudioFile audioFileFromURL:filePath];
+	if(!spectographer)
-	
+		spectographer = [[Spectographer alloc] init];
-	if(!fft_handler)
-		fft_handler = [[FFTTest alloc] init];
-	
-	unsigned int size = fft_handler.acceptedSize;
-	unsigned int width = size/4;
-	unsigned int height = size/8;
 	
-	if(!data)
+	[spectographer openAudioFile:filePath];
-		data = calloc(size, sizeof(float));
+	CGImageRef image = [spectographer generate];
-	
-	char * rgba = calloc(width*height*4, sizeof(char));
-	
-	for(unsigned int x = 0; x < width; ++x){
-		[audioFile fillArray:data withNumberOfSamples:size];
-		[fft_handler inPlaceFFT:data forSize:size];
-		for(unsigned int y = 0; y < height; ++y){
-			unsigned int yy = height - y - 1;
-			rgba[4*width*yy + 4*x + 0] = clamp_to_uint8(100.0 * data[y]);
-			rgba[4*width*yy + 4*x + 1] = clamp_to_uint8(50.0 * data[y]);
-			rgba[4*width*yy + 4*x + 2] = clamp_to_uint8(10.0 * data[y]);
-			rgba[4*width*yy + 4*x + 3] = 0;
-		}
-	}
 	
-	CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
+	UIImage * newUIImage = [UIImage imageWithCGImage:image];
-	assert(colorSpace);
-	CGContextRef bitmapContext = CGBitmapContextCreate(rgba, width, height, 8, 4*width, colorSpace, (CGBitmapInfo)kCGImageAlphaNoneSkipLast);
-	assert(bitmapContext);
-	CGImageRef cgImage = CGBitmapContextCreateImage(bitmapContext);
-	assert(cgImage);
-	UIImage * newUIImage = [UIImage imageWithCGImage:cgImage];
 	assert(newUIImage);
 	
-	CGColorSpaceRelease(colorSpace);
+	CGImageRelease(image);
-	CGContextRelease(bitmapContext);
-	CGImageRelease(cgImage);
-	free(rgba);
 	
 	UIImageView * view = [[UIImageView alloc] initWithImage:newUIImage];
-	view.frame = CGRectMake(0, 0, width, height);
 	
 	[contentView removeFromSuperview];
 	contentView = view;
+	scrollView.zoomScale = 1.0;
 	
 	[scrollView.content addSubview:contentView];
 	contentView.autoresizingMask = UIViewAutoresizingNone;