iOS自己使用的一些小方法

label的高度确定 计算label所占的宽度

CGRect temp = [text boundingRectWithSize:CGSizeMake(MAXFLOAT, 21) options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName: [UIFont systemFontOfSize:15.0]} context:nil];

NSLog(@"宽度 : %f",temp.size.width);

图片按比例缩放

UIImageView *imgView = [[UIImageView alloc] init];

imgView.image = [UIImage imageNamed:@"流程图1.png"];

CGFloat scale = imgView.image.size.width / (SCREENW / 2);

CGFloat imgViewHeight = imgView.image.size.height / scale;

imgView.frame = CGRectMake(0, 0, SCREENW / 2, imgViewHeight);

imgView.image = [UIImage imageWithCGImage:imgView.image.CGImage scale:scale orientation:UIImageOrientationUp];

通过颜色制作图片 我是用在导航栏上了

///  通过颜色制作图片

- (UIImage *)imageWithFrame:(CGRect)frame color:(UIColor *)color alphe:(CGFloat)alphe {

frame = CGRectMake(0, 0, frame.size.width, frame.size.height);

UIColor *redColor = color;

UIGraphicsBeginImageContext(frame.size);

CGContextRef context = UIGraphicsGetCurrentContext();

CGContextSetAlpha(context, alphe);

CGContextSetFillColorWithColor(context, [redColor CGColor]);

CGContextFillRect(context, frame);

UIImage *theImage = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

return theImage;

}

按钮的图片和文字位置的调整 图片在上 文字在下

-(void)initWithButton:(UIButton*)btn

{

btn.contentHorizontalAlignment = UIControlContentHorizontalAlignmentCenter;//使图片和文字水平居中显示

[btn setTitleEdgeInsets:UIEdgeInsetsMake(btn.imageView.height + 10,-btn.imageView.width, 0.0,0.0)];

[btn setImageEdgeInsets:UIEdgeInsetsMake(-btn.titleLabel.height - 10, 0.0,0.0, -btn.titleLabel.bounds.size.width)];

}