UIButton 设置字体，图片大小和位置

屏幕快照 2019-08-15 下午6.30.39.png
屏幕快照 2019-08-16 上午9.01.49.png 屏幕快照 2019-08-15 下午6.30.51.png

    _cusServer.contentEdgeInsets=UIEdgeInsetsMake(-9,0, 9, 0);//上左下右
[_cusServer setImageEdgeInsets:UIEdgeInsetsMake(0, -7, 0, 0)];//上左下右

1.图片大小和位置

UIButton *button = [[UIButton alloc]initWithFrame:CGRectMake(15, 345, SCREEN_Width-30, 50)];
[button setImage:[UIImage imageNamed:@"scan"] forState:UIControlStateNormal];
        soundBtn.titleLabel.font = [UIFont systemFontOfSize: 14.0];

[button setTitle:@"扫码添加" forState:UIControlStateNormal];
[button setTitleColor:mainColor forState:UIControlStateNormal];
//关键是下面两行代码
[button setImageEdgeInsets:UIEdgeInsetsMake(15, 0, 15, 0)];//上左下右
button.imageView.contentMode = UIViewContentModeScaleAspectFit;
[self.view addSubview:button];
    [button addTarget:self action:@selector(closeOnClick:) forControlEvents:UIControlEventTouchUpInside];

设置UIButton 的 contentMode 可以让图片等比例缩放，设置 ImageEdgeInsets 可以缩小图片，必须两个同时设置才能起效果，让一张在button里面过大的图片等比例缩小到你想要的大小.
2.1设置文字位置

    _btn.titleEdgeInsets = UIEdgeInsetsMake(0,0, 22, 0); // 设置文字的位置 上左下右

2.2字体的大小

[btn setFont: [UIFont systemFontSize: 14.0]];  

3. 让按钮内部的所有内容左对齐

        button.contentHorizontalAlignment = UIControlContentHorizontalAlignmentLeft;

4.让按钮的内容往左边偏移10

        button.contentEdgeInsets = UIEdgeInsetsMake(0, -10, 0, 0);//上左下右

5.圆角

            _getVerificationCodeBtn.layer.masksToBounds = YES;

button.layer.cornerRadius = 2.0;//2.0是圆角的弧度，根据需求自己更改