我正在以“宽高比”模式将图像加载到图像视图。我需要知道图像缩放到的尺寸。请帮忙。
Answers:
请参阅@ Paul-de-Lange的答案,而不是此答案
我在具有此功能的易于访问的变量中找不到任何内容,因此这是蛮力方式:
- (CGSize) aspectScaledImageSizeForImageView:(UIImageView *)iv image:(UIImage *)im {
float x,y;
float a,b;
x = iv.frame.size.width;
y = iv.frame.size.height;
a = im.size.width;
b = im.size.height;
if ( x == a && y == b ) { // image fits exactly, no scaling required
// return iv.frame.size;
}
else if ( x > a && y > b ) { // image fits completely within the imageview frame
if ( x-a > y-b ) { // image height is limiting factor, scale by height
a = y/b * a;
b = y;
} else {
b = x/a * b; // image width is limiting factor, scale by width
a = x;
}
}
else if ( x < a && y < b ) { // image is wider and taller than image view
if ( a - x > b - y ) { // height is limiting factor, scale by height
a = y/b * a;
b = y;
} else { // width is limiting factor, scale by width
b = x/a * b;
a = x;
}
}
else if ( x < a && y > b ) { // image is wider than view, scale by width
b = x/a * b;
a = x;
}
else if ( x > a && y < b ) { // image is taller than view, scale by height
a = y/b * a;
b = y;
}
else if ( x == a ) {
a = y/b * a;
b = y;
} else if ( y == b ) {
b = x/a * b;
a = x;
}
return CGSizeMake(a,b);
}
为什么不使用OS函数AVMakeRectWithAspectRatioInsideRect?
[imageView setFrame:AVMakeRectWithAspectRatioInsideRect(image.size, imageView.frame)]
)
AVMakeRectWithAspectRatioInsideRect()
在单独的答案中发布了两个替代实用程序函数。
我想在AVMakeRectWithAspectRatioInsideRect()
不包含AVFoundation框架的情况下使用。
因此,我实现了以下两个实用程序功能:
CGSize CGSizeAspectFit(CGSize aspectRatio, CGSize boundingSize)
{
float mW = boundingSize.width / aspectRatio.width;
float mH = boundingSize.height / aspectRatio.height;
if( mH < mW )
boundingSize.width = boundingSize.height / aspectRatio.height * aspectRatio.width;
else if( mW < mH )
boundingSize.height = boundingSize.width / aspectRatio.width * aspectRatio.height;
return boundingSize;
}
CGSize CGSizeAspectFill(CGSize aspectRatio, CGSize minimumSize)
{
float mW = minimumSize.width / aspectRatio.width;
float mH = minimumSize.height / aspectRatio.height;
if( mH > mW )
minimumSize.width = minimumSize.height / aspectRatio.height * aspectRatio.width;
else if( mW > mH )
minimumSize.height = minimumSize.width / aspectRatio.width * aspectRatio.height;
return minimumSize;
}
编辑:下面通过删除重复的分区进行了优化。
CGSize CGSizeAspectFit(const CGSize aspectRatio, const CGSize boundingSize)
{
CGSize aspectFitSize = CGSizeMake(boundingSize.width, boundingSize.height);
float mW = boundingSize.width / aspectRatio.width;
float mH = boundingSize.height / aspectRatio.height;
if( mH < mW )
aspectFitSize.width = mH * aspectRatio.width;
else if( mW < mH )
aspectFitSize.height = mW * aspectRatio.height;
return aspectFitSize;
}
CGSize CGSizeAspectFill(const CGSize aspectRatio, const CGSize minimumSize)
{
CGSize aspectFillSize = CGSizeMake(minimumSize.width, minimumSize.height);
float mW = minimumSize.width / aspectRatio.width;
float mH = minimumSize.height / aspectRatio.height;
if( mH > mW )
aspectFillSize.width = mH * aspectRatio.width;
else if( mW > mH )
aspectFillSize.height = mW * aspectRatio.height;
return aspectFillSize;
}
编辑结束
这采用给定的大小(第一个参数)并保持其长宽比。然后,它将在不违反宽高比的情况下尽可能地填充给定的边界(第二个参数)。
用这个来回答原始问题:
// Using aspect fit, scale the image (size) to the image view's size.
CGSize sizeBeingScaledTo = CGSizeAspectFit(theImage.size, theImageView.frame.size);
请注意,图像如何确定纵横比,而图像视图则确定要填充的尺寸。
反馈非常欢迎。
CGFloats
如果您喜欢这种东西,可以调整为使用。
这个简单的函数将在调整宽高比之后计算图像的大小:
迅捷5.1
extension UIImageView {
var imageSizeAfterAspectFit: CGSize {
var newWidth: CGFloat
var newHeight: CGFloat
guard let image = image else { return frame.size }
if image.size.height >= image.size.width {
newHeight = frame.size.height
newWidth = ((image.size.width / (image.size.height)) * newHeight)
if CGFloat(newWidth) > (frame.size.width) {
let diff = (frame.size.width) - newWidth
newHeight = newHeight + CGFloat(diff) / newHeight * newHeight
newWidth = frame.size.width
}
} else {
newWidth = frame.size.width
newHeight = (image.size.height / image.size.width) * newWidth
if newHeight > frame.size.height {
let diff = Float((frame.size.height) - newHeight)
newWidth = newWidth + CGFloat(diff) / newWidth * newWidth
newHeight = frame.size.height
}
}
return .init(width: newWidth, height: newHeight)
}
}
目标C:
-(CGSize)imageSizeAfterAspectFit:(UIImageView*)imgview{
float newwidth;
float newheight;
UIImage *image=imgview.image;
if (image.size.height>=image.size.width){
newheight=imgview.frame.size.height;
newwidth=(image.size.width/image.size.height)*newheight;
if(newwidth>imgview.frame.size.width){
float diff=imgview.frame.size.width-newwidth;
newheight=newheight+diff/newheight*newheight;
newwidth=imgview.frame.size.width;
}
}
else{
newwidth=imgview.frame.size.width;
newheight=(image.size.height/image.size.width)*newwidth;
if(newheight>imgview.frame.size.height){
float diff=imgview.frame.size.height-newheight;
newwidth=newwidth+diff/newwidth*newwidth;
newheight=imgview.frame.size.height;
}
}
NSLog(@"image after aspect fit: width=%f height=%f",newwidth,newheight);
//adapt UIImageView size to image size
//imgview.frame=CGRectMake(imgview.frame.origin.x+(imgview.frame.size.width-newwidth)/2,imgview.frame.origin.y+(imgview.frame.size.height-newheight)/2,newwidth,newheight);
return CGSizeMake(newwidth, newheight);
}
Swift 3人类可读版本
extension UIImageView {
/// Find the size of the image, once the parent imageView has been given a contentMode of .scaleAspectFit
/// Querying the image.size returns the non-scaled size. This helper property is needed for accurate results.
var aspectFitSize: CGSize {
guard let image = image else { return CGSize.zero }
var aspectFitSize = CGSize(width: frame.size.width, height: frame.size.height)
let newWidth: CGFloat = frame.size.width / image.size.width
let newHeight: CGFloat = frame.size.height / image.size.height
if newHeight < newWidth {
aspectFitSize.width = newHeight * image.size.width
} else if newWidth < newHeight {
aspectFitSize.height = newWidth * image.size.height
}
return aspectFitSize
}
/// Find the size of the image, once the parent imageView has been given a contentMode of .scaleAspectFill
/// Querying the image.size returns the non-scaled, vastly too large size. This helper property is needed for accurate results.
var aspectFillSize: CGSize {
guard let image = image else { return CGSize.zero }
var aspectFillSize = CGSize(width: frame.size.width, height: frame.size.height)
let newWidth: CGFloat = frame.size.width / image.size.width
let newHeight: CGFloat = frame.size.height / image.size.height
if newHeight > newWidth {
aspectFillSize.width = newHeight * image.size.width
} else if newWidth > newHeight {
aspectFillSize.height = newWidth * image.size.height
}
return aspectFillSize
}
}
我还想在应用纵横比之后计算高度,以便能够计算表格视图单元格的高度。所以,我通过一点数学就达到了
ratio = width / height
和高度将成为
height = width / ratio
所以代码片段是
UIImage *img = [UIImage imageNamed:@"anImage"];
float aspectRatio = img.size.width/img.size.height;
float requiredHeight = self.view.bounds.size.width / aspectRatio;
UITableViewCell
课堂上使用它,因此requiredHeight
变为float requiredHeight = self.bounds.size.width / aspectRatio;
。
对于Swift使用下面的代码
func imageSizeAspectFit(imgview: UIImageView) -> CGSize {
var newwidth: CGFloat
var newheight: CGFloat
let image: UIImage = imgFeed.image!
if image.size.height >= image.size.width {
newheight = imgview.frame.size.height;
newwidth = (image.size.width / image.size.height) * newheight
if newwidth > imgview.frame.size.width {
let diff: CGFloat = imgview.frame.size.width - newwidth
newheight = newheight + diff / newheight * newheight
newwidth = imgview.frame.size.width
}
}
else {
newwidth = imgview.frame.size.width
newheight = (image.size.height / image.size.width) * newwidth
if newheight > imgview.frame.size.height {
let diff: CGFloat = imgview.frame.size.height - newheight
newwidth = newwidth + diff / newwidth * newwidth
newheight = imgview.frame.size.height
}
}
print(newwidth, newheight)
//adapt UIImageView size to image size
return CGSizeMake(newwidth, newheight)
}
和通话功能
imgFeed.sd_setImageWithURL(NSURL(string:"Your image URL")))
self.imageSizeAfterAspectFit(imgFeed)
+(UIImage *)CreateAResizeImage:(UIImage *)Img ThumbSize:(CGSize)ThumbSize
{
float actualHeight = Img.size.height;
float actualWidth = Img.size.width;
if(actualWidth==actualHeight)
{
actualWidth = ThumbSize.width;
actualHeight = ThumbSize.height;
}
float imgRatio = actualWidth/actualHeight;
float maxRatio = ThumbSize.width/ThumbSize.height; //320.0/480.0;
if(imgRatio!=maxRatio)
{
if(imgRatio < maxRatio)
{
imgRatio = ThumbSize.height / actualHeight; //480.0 / actualHeight;
actualWidth = imgRatio * actualWidth;
actualHeight = ThumbSize.height; //480.0;
}
else
{
imgRatio = ThumbSize.width / actualWidth; //320.0 / actualWidth;
actualHeight = imgRatio * actualHeight;
actualWidth = ThumbSize.width; //320.0;
}
}
else
{
actualWidth = ThumbSize.width;
actualHeight = ThumbSize.height;
}
CGRect rect = CGRectMake(0, 0, (int)actualWidth, (int)actualHeight);
UIGraphicsBeginImageContext(rect.size);
[Img drawInRect:rect];
UIImage *NewImg = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return NewImg;
}
Swift 4:.aspectFit
图像
框架为-
import AVFoundation
let x: CGRect = AVMakeRect(aspectRatio: myImage.size, insideRect: sampleImageView.frame)
这一行可以完成这项工作
CGSize sizeInView = AVMakeRectWithAspectRatioInsideRect(imgViewFake.image.size, imgViewFake.bounds).size;
公认的答案非常复杂,并且在某些情况下失败。我认为此解决方案更加优雅:
- (CGSize) sizeOfImage:(UIImage*)image inAspectFitImageView:(UIImageView*)imageView
{
UKAssert(imageView.contentMode == UIViewContentModeScaleAspectFit, @"Image View must use contentMode = UIViewContentModeScaleAspectFit");
CGFloat imageViewWidth = imageView.bounds.size.width;
CGFloat imageViewHeight = imageView.bounds.size.height;
CGFloat imageWidth = image.size.width;
CGFloat imageHeight = image.size.height;
CGFloat scaleFactor = MIN(imageViewWidth / imageWidth, imageViewHeight / imageHeight);
return CGSizeMake(image.size.width*scaleFactor, image.size.height*scaleFactor);
}
这是我针对相同问题的解决方案:https : //github.com/alexgarbarev/UIImageView-ImageFrame
优点:
这是我的无AVFoundation解决方案。
首先,这是CGSize扩展,用于计算适合其他尺寸的尺寸:
extension CGSize
{
func sizeThatFitsSize(_ aSize: CGSize) -> CGSize
{
let width = min(self.width * aSize.height / self.height, aSize.width)
return CGSize(width: width, height: self.height * width / self.width)
}
}
因此,OP问题的解决方案归结为:
let resultSize = image.size.sizeThatFitsSize(imageView.bounds.size)
另外,这是在另一个rect中安装一个rect的另一个扩展(它利用了上面的CGSize扩展):
extension CGRect
{
func rectThatFitsRect(_ aRect:CGRect) -> CGRect
{
let sizeThatFits = self.size.sizeThatFitsSize(aRect.size)
let xPos = (aRect.size.width - sizeThatFits.width) / 2
let yPos = (aRect.size.height - sizeThatFits.height) / 2
let ret = CGRect(x: xPos, y: yPos, width: sizeThatFits.width, height: sizeThatFits.height)
return ret
}
}
我在Swift中使用以下内容:
private func CGSizeAspectFit(aspectRatio:CGSize,boundingSize:CGSize) -> CGSize
{
var aspectFitSize = boundingSize
let mW = boundingSize.width / aspectRatio.width
let mH = boundingSize.height / aspectRatio.height
if( mH < mW )
{
aspectFitSize.width = mH * aspectRatio.width
}
else if( mW < mH )
{
aspectFitSize.height = mW * aspectRatio.height
}
return aspectFitSize
}
private func CGSizeAspectFill(aspectRatio:CGSize,minimumSize:CGSize) -> CGSize
{
var aspectFillSize = minimumSize
let mW = minimumSize.width / aspectRatio.width
let mH = minimumSize.height / aspectRatio.height
if( mH > mW )
{
aspectFillSize.width = mH * aspectRatio.width
}
else if( mW > mH )
{
aspectFillSize.height = mW * aspectRatio.height
}
return aspectFillSize
}
我正在这样使用它:
let aspectSize = contentMode == .ScaleAspectFill ? CGSizeAspectFill(oldSize,minimumSize: newSize) : CGSizeAspectFit(oldSize, boundingSize: newSize)
let newRect = CGRect( x: (newSize.width - aspectSize.width)/2, y: (newSize.height - aspectSize.height)/2, width: aspectSize.width, height: aspectSize.height)
CGContextSetFillColorWithColor(context,IOSXColor.whiteColor().CGColor)
CGContextFillRect(context, CGRect(origin: CGPointZero,size: newSize))
CGContextDrawImage(context, newRect, cgImage)
如果仅知道imageview的宽度,并且图像的高度是动态的,则需要根据给定的宽度缩放图像的高度,以删除图像上方和下方的空白。从此处使用以下方法根据屏幕的标准宽度缩放图像的高度。
-(UIImage*)imageWithImage: (UIImage*) sourceImage scaledToWidth: (float) i_width
{
float oldWidth = sourceImage.size.width;
float scaleFactor = i_width / oldWidth;
float newHeight = sourceImage.size.height * scaleFactor;
float newWidth = oldWidth * scaleFactor;
UIGraphicsBeginImageContext(CGSizeMake(newWidth, newHeight));
[sourceImage drawInRect:CGRectMake(0, 0, newWidth, newHeight)];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}
并从您的cellForRowAtIndexPath:方法中调用它,如下所示:
UIImage *img = [dictImages objectForKey:yourImageKey]; // loaded the image
cell.imgView.image = [self imageWithImage:img scaledToWidth:self.view.frame.size.width];
Swift 4版本
extension CGSize {
enum AspectMode {
case fit
case fill
}
enum Orientation {
case portrait
case landscape
}
func aspectCorrectSizeToFit(targetSize: CGSize, aspectMode: AspectMode = .fill) -> CGSize {
switch aspectMode {
case .fill: return aspectFill(targetSize: targetSize)
case .fit: return aspectFit(targetSize: targetSize)
}
}
var orientation: Orientation {
if height >= width { return .portrait }
else { return .landscape }
}
func aspectFit(targetSize: CGSize) -> CGSize {
let wRatio = targetSize.width / width
let hRatio = targetSize.height / height
let scale = min(wRatio, hRatio)
return applying(CGAffineTransform(scaleX: scale, y: scale))
}
func aspectFill(targetSize: CGSize) -> CGSize {
let wRatio = targetSize.width / width
let hRatio = targetSize.height / height
let scale = max(wRatio, hRatio)
return applying(CGAffineTransform(scaleX: scale, y: scale))
}
}
上述方法从不给出所需的值,因为宽高比保持相同的宽高比,我们只需要简单的数学即可计算出值
检测宽高比
CGFloat imageViewAspectRatio = backgroundImageView.bounds.size.width / backgroundImageView.bounds.size.height;
CGFloat imageAspectRatio = backgroundImageView.image.size.width / backgroundImageView.image.size.height;
CGFloat mulFactor = imageViewAspectRatio/imageAspectRatio;
获取新值
CGFloat newImageWidth = mulFactor * backgroundImageView.bounds.size.width;
CGFloat newImageHeight = mulFactor * backgroundImageView.bounds.size.height;
if ( a - x > b - y ) {
对if ( a - x > b - y && (y/b * a) < x) {
解决它。他们的其他陈述也应检查。