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POReduce Core-Graphics memory consumption on iphone
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copied!<p>I am writing a program which redraws a graph every so often. Unfortunately it seems that for some reason core graphics does not seem to release the previous graphic so I run into memory problems fast. How can I force it to release memory at the end of each draw?</p> <p>Not that this is not a memory leak as the memory does get released when I leave close that view. I have tried moving the NSTimer to several places in the code to no avail.</p> <p>Here is the code below with the files going from most important to (potentially) irrelevant.</p> <p>First is the core file+header which draws the graphic (in this case a sine wave) every so often.</p> <p>GraphicsView.h</p> <pre><code>#import <UIKit/UIKit.h> #import "Model.h" @interface GraphicsView : UIView { Model * model; } @end </code></pre> <p>GraphicsView.m</p> <pre><code>#import "GraphicsView.h" @implementation GraphicsView - (id)initWithFrame:(CGRect)frame { if (self = [super initWithFrame:frame]) { model=[Model sharedModel]; [NSTimer scheduledTimerWithTimeInterval:.010 target:self selector:@selector(setNeedsDisplay) userInfo:nil repeats:YES]; } return self; } - (void)drawRect:(CGRect)rect { int now=[model n]; CGContextRef context = UIGraphicsGetCurrentContext(); CGContextClearRect(context, CGRectMake(0, 0, rect.size.width, rect.size.height)); CGContextSetStrokeColorWithColor(context, [UIColor redColor].CGColor); CGContextMoveToPoint(context, 0.0, 0.0); double xc_old=0; double yc_old=100; for (int i=0;i<now;i++) { double xc=(double)i/(double)now*200; double yc=100-100*sin((double)i/6); CGContextMoveToPoint(context, xc_old, yc_old); CGContextAddLineToPoint(context, xc, yc); CGContextStrokePath(context); xc_old=xc; yc_old=yc; } } - (void)dealloc { [super dealloc]; } @end </code></pre> <p>The view controller header:</p> <pre><code>#import <UIKit/UIKit.h> #import "GraphicsView.h" @interface SbarLeakAppDelegate : NSObject <UIApplicationDelegate> { UIWindow *window; Model *model; GraphicsView * gv; NSTimer * timer; } @end </code></pre> <p>The view controller itself.</p> <pre><code>#import "SbarLeakAppDelegate.h" @implementation SbarLeakAppDelegate - (void)applicationDidFinishLaunching:(UIApplication *)application { model=[Model sharedModel]; CGRect appRect; CGRect frame = CGRectInset(appRect, 0.0f, 0.0f); appRect.origin=CGPointMake(0.0, 40.0); appRect.size = CGSizeMake(200.0f, 200.0f); frame = CGRectInset(appRect, 0.0f, 0.0f); gv=[[GraphicsView alloc] initWithFrame:appRect]; [gv setFrame:frame]; [window addSubview:gv]; [gv release]; [window makeKeyAndVisible]; } -(void) viewDidAppear:(id)sender { //timer=[NSTimer scheduledTimerWithTimeInterval:.250 target:gv selector:@selector(setNeedsDisplay) userInfo:nil repeats:YES]; } - (void)dealloc { [window release]; [super dealloc]; } @end </code></pre> <p>This code is only included for completeness but (should not) affect the question. The data source header file (just a simple integer)</p> <pre><code>#import <UIKit/UIKit.h> @interface Model : NSObject { int n; } @property int n; +(Model *) sharedModel; -(void) inc; @end </code></pre> <p>The data source, Model.m:</p> <pre><code>#import "Model.h" @implementation Model static Model * sharedModel = nil; + (Model *) sharedModel { if (sharedModel == nil) sharedModel = [[self alloc] init]; return sharedModel; } @synthesize n; -(id) init { self=[super init]; [NSTimer scheduledTimerWithTimeInterval:.05 target:self selector:@selector(inc) userInfo:nil repeats:YES]; return self; } -(void) inc { n++; } @end </code></pre>

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