中心点からの角度
2011/10/22
ios
objective-c
角度
以前書いた記事から
プログラマメモ2: 中心点からの角度
今度は、objective-cで作成してみました。
#import "MyView.h"
@implementation MyView
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
// Initialization code
}
return self;
}
/*
タッチイベント:touchesBegan
*/
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
[self setNeedsDisplay];
}
/*
タッチイベント:touchesBegan
*/
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
[self setNeedsDisplay];
}
/*
タッチイベント:touchesMoved
*/
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
// CGPoint
touchPoint = [[touches anyObject] locationInView:self];
[self setNeedsDisplay];
}
- (void)drawRect:(CGRect)rect
{
CGContextRef context = UIGraphicsGetCurrentContext();
float cx = self.bounds.size.width/2;
float cy = self.bounds.size.height/2;
// 文字色
CGContextSetRGBFillColor(context, 0, 0, 0, .2);
// 線色
CGContextSetRGBStrokeColor(context, 0, 0, 0, .2);
double degree;
{ // 初期値(中心値からの角度をもとめる)
int mx = touchPoint.x - cx;
int my = touchPoint.y - cy;
if (mx == 0 && my == 0) {
degree = 0;
} else {
degree = atan2(my, mx) * (180 / M_PI);
}
}
{ // line
CGContextMoveToPoint(context, cx, cy);
CGContextAddLineToPoint(context, touchPoint.x,touchPoint.y);
CGContextStrokePath(context);
}
{ // string
NSString *str1 = [NSString stringWithFormat:@"x=%.0f, y=%.0f", touchPoint.x, touchPoint.y];
NSString *str2 = [NSString stringWithFormat:@"degree:%.0f", degree];
NSString *str3 = [NSString stringWithFormat:@"角度(0~360):%.0f", degree < 0 ? (180 + degree) + 180:degree];
UIFont *font = [UIFont fontWithName:@"Helvetica-Bold" size:20];
[str1 drawAtPoint:CGPointMake(touchPoint.x, touchPoint.y) withFont:font];
[str2 drawAtPoint:CGPointMake(touchPoint.x, touchPoint.y+20) withFont:font];
[str3 drawAtPoint:CGPointMake(touchPoint.x, touchPoint.y+40) withFont:font];
}
}
@end
