以编程方式将图像600x600调整为100x100

Question

我的图像高度为600，宽度也是600现在我想以100x100的形式在UIImageView中以编程方式显示该图像。我尝试但是图像不像原始图像我添加图像的屏幕截图首先是100x100，第二个是200x200。第二个很好。但是第一个不像原始图像。知道我做什么请

in.h中

@interface ViewController : UIViewController
{
    IBOutlet UIImageView *imageView1;
    IBOutlet UIImageView *imageView2;
}
@end

In.m

- (void)viewDidLoad
{
    [super viewDidLoad];
    imageView1.frame=CGRectMake(100, 50, 100, 100);
    imageView2.frame=CGRectMake(50, 200, 200, 200);
    imageView1.image = [UIImage imageNamed:@"Untitled-7.png"];
    imageView2.image = [UIImage imageNamed:@"Untitled-7.png"];
}

Answer 1

请尝试此

UIImage *originalImage = [UIImage imageNamed:@"5.png"];
        CGSize destinationSize = CGSizeMake(100, 100);
        UIGraphicsBeginImageContext(destinationSize);
        [originalImage drawInRect:CGRectMake(0,0,destinationSize.width,destinationSize.height)];
        UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();
        UIImageView *newImageView = [[UIImageView alloc] initWithFrame:CGRectMake(20, 20, 100, 100)];
        newImageView.image = newImage;
        [self.view addSubview:newImageView];

Answer 2

尝试imageView1.contentMode = UIViewContentModeScaleAspectFit;

Answer 3

使用此方法：

- (UIImage*)imageWithImage:(UIImage*)image
              scaledToSize:(CGSize)newSize;
{
    UIGraphicsBeginImageContext( newSize );
    [image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
    UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return newImage;
}

调用方法：

CGSize newSize = CGSizeMake(100.0,100.0);
[self imageWithImage:image scaledToSize:newSize];

Answer 4

设置内容模式

imageView2.contentMode = UIViewContentModeScaleAspectFit;

Answer 5

在swift 3中

func createImage(withImage image: UIImage, forSize size: CGSize) -> UIImage? {
    UIGraphicsBeginImageContext(size)
    image.draw(in: CGRect(x: 0, y: 0, width: size.width, height: size.height))
    if let newImage: UIImage = UIGraphicsGetImageFromCurrentImageContext() {
        UIGraphicsEndImageContext()
        return newImage;
    }
    return nil
}

Answer 6

点击此链接以编程方式调整图片大小

http://developer.appcelerator.com/question/121517/how-to-scale-image-proportionally http://iphonedevsdk.com/forum/iphone-sdk-development/95666-resize-uiimageview-proportionally.html

Answer 7

从Swift 4.2开始，

使用此选项，您将获得正确宽高比的非模糊调整大小图像-

class func resizeImage(image: UIImage, targetSize: CGSize) -> UIImage {
    let size = image.size

    let widthRatio  = targetSize.width  / size.width
    let heightRatio = targetSize.height / size.height

    // Figure out what our orientation is, and use that to form the rectangle
    var newSize: CGSize
    if(widthRatio > heightRatio) {
        newSize = CGSize(width: size.width * heightRatio, height: size.height * heightRatio)
    } else {
        newSize = CGSize(width: size.width * widthRatio,  height: size.height * widthRatio)
    }

    // This is the rect that we've calculated out and this is what is actually used below
    let rect = CGRect(x: 0, y: 0, width: newSize.width, height: newSize.height)

    //resizing the rect using the ImageContext
    UIGraphicsBeginImageContextWithOptions(newSize, false, 0)
    image.draw(in: rect)
    let newImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()

    return newImage!
}

根据开发人员文档，以下方法使用指定的选项创建基于位图的图形上下文-

func UIGraphicsBeginImageContextWithOptions（_ size：CGSize，_ opaque：Bool，_ scale：CGFloat）

参数-

大小： 新位图上下文的大小（以磅为单位）。这表示由UIGraphicsGetImageFromCurrentImageContext（）函数返回的图像的大小。

不透明： 一个布尔型标志，指示位图是否不透明。

规模： 应用于位图的比例因子。如果您将值指定为0.0，则比例因子将设置为设备主屏幕的比例因子。

参考资料-https://developer.apple.com/documentation/uikit/1623912-uigraphicsbeginimagecontextwitho

Answer 8

使用图像初始化imageView，然后调整其大小

imageView1 = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"Untitled-7.png"]];
imageView2 = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"Untitled-7.png"]];
[imageView1 setFrame:CGRectMake(100, 50, 100, 100)];
[imageView2 setFrame:CGRectMake(50, 200, 200, 200)];

尝试一下，让我知道它是否有效！

Answer 9

试试这个： -

- (void)viewDidLoad
{
    [super viewDidLoad];
    imageView1.frame=CGRectMake(100, 50, 100, 100);
    imageView2.frame=CGRectMake(50, 200, 200, 200);
    imageView1.contentMode = UIViewContentModeScaleAspectFit;
    imageView2.contentMode = UIViewContentModeScaleAspectFit;
    imageView1.image = [UIImage imageNamed:@"Untitled-7.png"];
    imageView2.image = [UIImage imageNamed:@"Untitled-7.png"];
}

享受。

Answer 10

尝试更改此内容：

imageView1.image = [UIImage imageNamed:@"Untitled-7.png"];

对此：

imageView1.image = [[UIImage imageNamed:@"Untitled-7.png"] resizableImageWithCapInsets:UIEdgeInsetsZero
                                                                          resizingMode:UIImageResizingModeStretch];

Answer 11

我喜欢在UIImage上使用类别，方法如下：

// Returns a rescaled copy of the image, taking into account its orientation
// The image will be scaled disproportionately if necessary to fit the bounds specified by the parameter
- (UIImage *)resizedImage:(CGSize)newSize interpolationQuality:(CGInterpolationQuality)quality {
    CGRect newRect = CGRectIntegral(CGRectMake(0, 0, newSize.width * self.scale, newSize.height * self.scale));

    UIImage *newImage;
    UIGraphicsBeginImageContextWithOptions(newRect.size, NO, 0.0);
    newImage = [UIImage imageWithCGImage:[self CGImage] scale:0.0 orientation:self.imageOrientation];
    [newImage drawInRect:newRect];
    newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return newImage;
}

请参阅此updated repo和此blog post。

这适用于调整PDF图像的大小，特别是如果你需要在UIBarButtonItem中添加一个。

Answer 12

嘿，如果您已经在使用Alamofire图像库，那么您可以使用以下代码：

UIImage(named:"image").af_imageScaled(to: CGSize(width: 100, height: 100))