将 UIButton 中的图像缩放为 AspectFit？

Question

我想将图像添加到 UIButton，并且还想缩放图像以适合 UIButton（使图像变小）。请告诉我该怎么做。

这是我尝试过的，但它不起作用：

• 将图像添加到按钮并使用

  setContentMode

  :

[self.itemImageButton setImage:stretchImage forState:UIControlStateNormal];
[self.itemImageButton setContentMode:UIViewContentModeScaleAspectFit];

• 制作“拉伸图像”：

UIImage *stretchImage = [updatedItem.thumbnail stretchableImageWithLeftCapWidth:0 topCapHeight:0];

Answer 1

我也有同样的问题。只需设置 UIButton 内的 ImageView 的 ContentMode 即可。

[[self.itemImageButton imageView] setContentMode: UIViewContentModeScaleAspectFit];
[self.itemImageButton setImage:[UIImage imageNamed:stretchImage] forState:UIControlStateNormal];

Answer 2

这里的答案都不适合我，我用以下代码解决了问题：

button.contentMode = UIViewContentModeScaleToFill;
button.contentHorizontalAlignment = UIControlContentHorizontalAlignmentFill;
button.contentVerticalAlignment = UIControlContentVerticalAlignmentFill;

您也可以在 Interface Builder 中执行此操作。

Answer 3

以编程方式在 aspect fit 模式下设置 UIButton imageView 的最简单方法：

斯威夫特

button.contentHorizontalAlignment = .fill
button.contentVerticalAlignment = .fill
button.imageView?.contentMode = .scaleAspectFit

Objective-C

button.contentHorizontalAlignment = UIControlContentHorizontalAlignmentFill;
button.contentVerticalAlignment = UIControlContentVerticalAlignmentFill;
button.imageView.contentMode = UIViewContentModeScaleAspectFit;

---

注意： 您可以将 .scaleAspectFit (UIViewContentModeScaleAspectFit) 更改为 .scaleAspectFill (UIViewContentModeScaleAspectFill) 以设置 aspect fill 模式

Answer 4

如果您确实想缩放图像，请执行此操作，但应在使用之前调整其大小。在运行时调整它的大小只会损失 CPU 周期。

这是我用来缩放图像的类别：

UIImage+Extra.h

@interface UIImage (Extras)
- (UIImage *)imageByScalingProportionallyToSize:(CGSize)targetSize;
@end;

UIImage+Extra.m

@implementation UIImage (Extras)

- (UIImage *)imageByScalingProportionallyToSize:(CGSize)targetSize {

UIImage *sourceImage = self;
UIImage *newImage = nil;

CGSize imageSize = sourceImage.size;
CGFloat width = imageSize.width;
CGFloat height = imageSize.height;

CGFloat targetWidth = targetSize.width;
CGFloat targetHeight = targetSize.height;

CGFloat scaleFactor = 0.0;
CGFloat scaledWidth = targetWidth;
CGFloat scaledHeight = targetHeight;

CGPoint thumbnailPoint = CGPointMake(0.0,0.0);

if (!CGSizeEqualToSize(imageSize, targetSize)) {

        CGFloat widthFactor = targetWidth / width;
        CGFloat heightFactor = targetHeight / height;

        if (widthFactor < heightFactor) 
                scaleFactor = widthFactor;
        else
                scaleFactor = heightFactor;

        scaledWidth  = width * scaleFactor;
        scaledHeight = height * scaleFactor;

        // center the image

        if (widthFactor < heightFactor) {
                thumbnailPoint.y = (targetHeight - scaledHeight) * 0.5; 
        } else if (widthFactor > heightFactor) {
                thumbnailPoint.x = (targetWidth - scaledWidth) * 0.5;
        }
}


// this is actually the interesting part:

UIGraphicsBeginImageContextWithOptions(targetSize, NO, 0);

CGRect thumbnailRect = CGRectZero;
thumbnailRect.origin = thumbnailPoint;
thumbnailRect.size.width  = scaledWidth;
thumbnailRect.size.height = scaledHeight;

[sourceImage drawInRect:thumbnailRect];

newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

if(newImage == nil) NSLog(@"could not scale image");


return newImage ;
}

@end

您可以根据需要使用它的尺寸。喜欢：

[self.itemImageButton setImage:[stretchImage imageByScalingProportionallyToSize:CGSizeMake(20,20)]];

Answer 5

我遇到了图像大小未按比例调整大小的问题，因此我修复它的方法是使用边缘插入。

fooButton.contentEdgeInsets = UIEdgeInsetsMake(10, 15, 10, 15);

Answer 6

现在可以通过 IB 的 UIButton 属性来完成此操作。关键是要把你的图片设置为背景，否则不起作用。

Answer 7

扩展戴夫的答案，您可以使用运行时属性在IB中设置按钮的

contentMode

，无需任何代码：

imageView
• 表示

  1

  ,
UIViewContentModeScaleAspectFit
• 的意思是

  2

  。

Answer 8

2 - 设置像图像一样的对齐方式

3 - 设置内容模式如图像

Answer 9

UIViewContentModeScaleAspectFill

Answer 10

yourButton.contentMode = UIViewContentModeScaleAspectFit;
yourButton.imageEdgeInsets = UIEdgeInsetsMake(10, 10, 10, 10);

并使图像宽高比适合。

UIButton

Answer 11

-(void)makeImageAspectFitForButton:(UIButton*)button{
    button.imageView.contentMode=UIViewContentModeScaleAspectFit;
    button.contentHorizontalAlignment=UIControlContentHorizontalAlignmentFill;
    button.contentVerticalAlignment=UIControlContentVerticalAlignmentFill;
}

Answer 12

自动布局

。我降低了

 myButton2.contentMode = .scaleAspectFit
 myButton2.contentHorizontalAlignment = .fill
 myButton2.contentVerticalAlignment = .fill

的内容压缩阻力优先级，并通过

Interface Builder

设置图像（不是背景图像）。之后，我添加了几个定义按钮大小的约束（在我的例子中相当复杂），它的工作就像一个魅力。

Answer 13

UIButton

配置为

Style

，将

Default

配置为

State Config

Answer 14

Answer 15

Default

Answer 16

- (CGRect)backgroundRectForBounds:(CGRect)bounds
{
    // you'll need the original size of the image, you 
    // can save it from setBackgroundImage:forControlState
    return CGRectFitToFillRect(__original_image_frame_size__, bounds);
}

// Utility function, can be saved elsewhere
CGRect CGRectFitToFillRect( CGRect inRect, CGRect maxRect )
{
    CGFloat origRes = inRect.size.width / inRect.size.height;
    CGFloat newRes = maxRect.size.width / maxRect.size.height;

    CGRect retRect = maxRect;

    if (newRes < origRes)
    {
        retRect.size.width = inRect.size.width * maxRect.size.height / inRect.size.height;
        retRect.origin.x = roundf((maxRect.size.width - retRect.size.width) / 2);
    }
    else
    {
        retRect.size.height = inRect.size.height * maxRect.size.width / inRect.size.width;
        retRect.origin.y = roundf((maxRect.size.height - retRect.size.height) / 2);
    }

    return retRect;
}

Answer 17

您只需为三个事件设置UIButton imageview的内容模式即可。 -

    myButton.VerticalAlignment = UIControlContentVerticalAlignment.Fill;
    myButton.HorizontalAlignment = UIControlContentHorizontalAlignment.Fill;
    myButton.ImageView.ContentMode = UIViewContentMode.ScaleAspectFit;

我们有三个事件 bcoz 的代码，同时突出显示或选择，如果按钮大小为正方形并且图像大小为矩形，那么它将在突出显示或选择时显示方形图像。

我相信它会对你有用。