防止UIImage为UIButton调整大小

Question

我有一个没有文字的UIButton,有2个我想使用的图像(一个用于正常状态,另一个用于选择状态).图像小于按钮大小.

如何确保在绘制按钮时不缩放任何图像？设置imageView属性仅在正常状态下正确更改比例,而不是为选定状态更改比例.

    UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];

    [button setImage:imageNormal forState:UIControlStateNormal];
    [button setImage:imageSelected forState:UIControlStateSelected];

    // this shows the correct scale in normal mode but not when button is tapped
    button.imageView.contentScaleFactor = 1.0;
    button.imageView.contentMode = UIViewContentModeCenter;

Answer 1

假设你有图像的高度和宽度,你可以这样做:

int topBottom = (button.frame.size.height - imageHeight) / 2;
int leftRight = (button.frame.size.width - imageWidth) / 2;

button.imageEdgeInsets = UIEdgeInsetsMake(topBottom,leftRight,topBottom,leftRight);

然后您不需要设置contentMode/scalefactor.