how to rotate the Circle in DrawRect?
- by senthilmuthu
HI,
i want to draw a circle in DrawRect through context like pie chart(took from tutorial) thorugh UITouch? i have given the code as follows,how can i rotate ? any help please?
define PI 3.14159265358979323846
define snapshot_start 360
define snapshot_finish 360
static inline float radians(double degrees) { return degrees * PI / 180; }
- (void)drawRect:(CGRect)rect
{
// Drawing code
CGRect parentViewBounds = self.bounds;
CGFloat x = CGRectGetWidth(parentViewBounds)/2;
CGFloat y = CGRectGetHeight(parentViewBounds)*0.55;
// Get the graphics context and clear it
CGContextRef ctx = UIGraphicsGetCurrentContext();
CGContextClearRect(ctx, rect);
// define stroke color
CGContextSetRGBStrokeColor(ctx, 1, 1, 1, 1.0);
// define line width
CGContextSetLineWidth(ctx, 4.0);
// need some values to draw pie charts
double snapshotCapacity =20;
double rawCapacity = 100;
double systemCapacity = 1;
int offset = 5;
double pie1_start = 315.0;
double pie1_finish = snapshotCapacity *360.0/rawCapacity;
double system_finish = systemCapacity*360.0/rawCapacity;
CGContextSetFillColor(ctx, CGColorGetComponents( [[UIColor greenColor] CGColor]));
CGContextMoveToPoint(ctx, x+2*offset, y);
CGContextAddArc(ctx, x+2*offset, y, 100, radians(snapshot_start), radians(snapshot_start+snapshot_finish), 0);
CGContextClosePath(ctx);
CGContextFillPath(ctx);
// system capacity
CGContextSetFillColor(ctx, CGColorGetComponents( [[UIColor colorWithRed:15 green:165/255 blue:0 alpha:1 ] CGColor]));
CGContextMoveToPoint(ctx, x+offset,y);
CGContextAddArc(ctx, x+offset, y, 100, radians(snapshot_start+snapshot_finish+offset), radians(snapshot_start+snapshot_finish+system_finish), 0);
CGContextClosePath(ctx);
CGContextFillPath(ctx);
/* data capacity */
CGContextSetFillColor(ctx, CGColorGetComponents( [[UIColor colorWithRed:99/255 green:184/255 blue:255/255 alpha:1 ] CGColor]));
CGContextMoveToPoint(ctx, x, y);
CGContextAddArc(ctx, x, y, 100, radians(snapshot_start+snapshot_finish+system_finish+offset), radians(snapshot_start), 0);
CGContextClosePath(ctx);
CGContextFillPath(ctx);
}
