Comments on: Plotting a Sine Wave with the iPhone SDK http://trailsinthesand.com/plotting-a-sine-wave-with-the-iphone-sdk/ Mon, 22 Mar 2010 14:08:14 +0000 http://wordpress.org/?v=2.7.1 hourly 1 By: Leo http://trailsinthesand.com/plotting-a-sine-wave-with-the-iphone-sdk/comment-page-1/#comment-120 Leo Fri, 18 Apr 2008 22:40:03 +0000 http://trailsinthesand.com/plotting-a-sine-wave-with-the-iphone-sdk/#comment-120 We forgot to add ink to our pen... I added this line and it works as advertised! CGContextSetRGBStrokeColor(ctx, 1.0, 0.0, 1.0, 1.0); We forgot to add ink to our pen… I added this line and it works as advertised!

CGContextSetRGBStrokeColor(ctx, 1.0, 0.0, 1.0, 1.0);

]]> By: Leo http://trailsinthesand.com/plotting-a-sine-wave-with-the-iphone-sdk/comment-page-1/#comment-119 Leo Fri, 18 Apr 2008 22:29:10 +0000 http://trailsinthesand.com/plotting-a-sine-wave-with-the-iphone-sdk/#comment-119 I have this exact code in my test app: #define PI 3.14159 - (void)drawRect:(CGRect)rect { CGContextRef ctx = UIGraphicsGetCurrentContext(); CGContextClearRect(ctx, rect); CGContextBeginPath(ctx); int x; for(int y=rect.origin.y; y < rect.size.height; y++) { x = ((rect.size.width/4) * sin(((y*4) % 360) * PI/180)) + rect.size.width/2; if(y == 0) { CGContextMoveToPoint(ctx, x, y); } else { CGContextAddLineToPoint(ctx, x, y); } } CGContextStrokePath(ctx); } and nothing happens! Either I forgot something - or you did.... I have this exact code in my test app:

#define PI 3.14159
- (void)drawRect:(CGRect)rect
{
CGContextRef ctx = UIGraphicsGetCurrentContext();
CGContextClearRect(ctx, rect);
CGContextBeginPath(ctx);

int x;
for(int y=rect.origin.y; y < rect.size.height; y++)
{
x = ((rect.size.width/4) * sin(((y*4) % 360) * PI/180)) + rect.size.width/2;

if(y == 0)
{
CGContextMoveToPoint(ctx, x, y);
}
else
{
CGContextAddLineToPoint(ctx, x, y);
}
}
CGContextStrokePath(ctx);
}

and nothing happens! Either I forgot something - or you did….

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