Iphone UIImage:调整大小,然后裁剪
几天来,我一直在向这张脸猛击,尽管我一直觉得自己就在启示的边缘,但我根本无法实现我的目标 在我设计的概念阶段之前,我认为从iPhone的摄像头或库中抓取图像,将其缩小到指定的高度,使用相当于UIImageView的Aspect Fill选项(完全以代码形式)的功能是一件小事,然后裁剪出任何不符合通过的CGRect的内容 从相机或图书馆中获取原始图像是件小事。我对其他两个步骤被证明是多么困难感到震惊Iphone UIImage:调整大小,然后裁剪,iphone,ios,image-processing,core-graphics,Iphone,Ios,Image Processing,Core Graphics,几天来,我一直在向这张脸猛击,尽管我一直觉得自己就在启示的边缘,但我根本无法实现我的目标 在我设计的概念阶段之前,我认为从iPhone的摄像头或库中抓取图像,将其缩小到指定的高度,使用相当于UIImageView的Aspect Fill选项(完全以代码形式)的功能是一件小事,然后裁剪出任何不符合通过的CGRect的内容 从相机或图书馆中获取原始图像是件小事。我对其他两个步骤被证明是多么困难感到震惊 所附图片显示了我正在努力实现的目标。请有人握住我的手好吗?到目前为止,我发现的每一个代码示例似乎都
所附图片显示了我正在努力实现的目标。请有人握住我的手好吗?到目前为止,我发现的每一个代码示例似乎都会将图像粉碎、颠倒、看起来像垃圾、画出边界,或者根本无法正常工作。一篇较旧的文章包含了一种调整图像大小的方法的代码。有关部分如下:
+ (UIImage*)imageWithImage:(UIImage*)image
scaledToSize:(CGSize)newSize;
{
UIGraphicsBeginImageContext( newSize );
[image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}
至于裁剪,我相信如果你改变方法,使用与上下文不同的缩放尺寸,你的结果图像应该被裁剪到上下文的边界。我需要同样的东西——在我的例子中,选择适合缩放的尺寸,然后裁剪每一端,使其适合宽度。(我在横向工作,所以可能没有注意到纵向模式的任何缺陷。)这是我的代码——它是UIImage分类的一部分。我的代码中的目标大小始终设置为设备的全屏大小
@implementation UIImage (Extras)
#pragma mark -
#pragma mark Scale and crop image
- (UIImage*)imageByScalingAndCroppingForSize:(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) == NO)
{
CGFloat widthFactor = targetWidth / width;
CGFloat heightFactor = targetHeight / height;
if (widthFactor > heightFactor)
{
scaleFactor = widthFactor; // scale to fit height
}
else
{
scaleFactor = heightFactor; // scale to fit width
}
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;
}
}
}
UIGraphicsBeginImageContext(targetSize); // this will crop
CGRect thumbnailRect = CGRectZero;
thumbnailRect.origin = thumbnailPoint;
thumbnailRect.size.width = scaledWidth;
thumbnailRect.size.height = scaledHeight;
[sourceImage drawInRect:thumbnailRect];
newImage = UIGraphicsGetImageFromCurrentImageContext();
if(newImage == nil)
{
NSLog(@"could not scale image");
}
//pop the context to get back to the default
UIGraphicsEndImageContext();
return newImage;
}
@实现UIImage(附加)
#布拉格标记-
#pragma标记比例和裁剪图像
-(UIImage*)图像按缩放和裁剪大小:(CGSize)目标大小
{
UIImage*sourceImage=self;
UIImage*newImage=nil;
CGSize imageSize=sourceImage.size;
CGFloat width=imageSize.width;
CGFloat height=图像大小.height;
CGFloat targetWidth=targetSize.width;
CGFloat targetHeight=targetSize.height;
CGFloat scaleFactor=0.0;
CGFloat scaledWidth=targetWidth;
CGFloat缩放高度=目标高度;
CGPoint thumbnailPoint=CGPointMake(0.0,0.0);
if(CGSizeEqualToSize(imageSize,targetSize)==否)
{
CGFloat宽度系数=目标宽度/宽度;
CGFloat高度系数=目标高度/高度;
如果(宽度因子>高度因子)
{
scaleFactor=widthFactor;//缩放以适应高度
}
其他的
{
scaleFactor=heightFactor;//缩放以适应宽度
}
scaledWidth=宽度*缩放因子;
缩放高度=高度*缩放因子;
//将图像居中
如果(宽度因子>高度因子)
{
thumbnailPoint.y=(targetLight-缩放高度)*0.5;
}
其他的
{
if(宽度系数<高度系数)
{
thumbnailPoint.x=(targetWidth-缩放宽度)*0.5;
}
}
}
UIGraphicsBeginImageContext(targetSize);//这将裁剪
CGRect thumbnailRect=CGRectZero;
thumbnailRect.origin=thumbnailPoint;
thumbnailRect.size.width=缩放宽度;
thumbnailRect.size.height=缩放高度;
[sourceImage drawInRect:thumbnailRect];
newImage=UIGraphicsGetImageFromCurrentImageContext();
if(newImage==nil)
{
NSLog(@“无法缩放图像”);
}
//弹出上下文以返回默认值
UIGraphicsSendImageContext();
返回新图像;
}
有一段很棒的代码与图像的大小调整以及其他一些操作有关。我在尝试调整图像大小时遇到了这个问题。。。
我提议这样做。她不是个美人吗 给你。这个很完美;-)
编辑:请参阅下面的注释-“不适用于某些图像,失败原因:CGContextSetInterpolationQuality:无效上下文0x0错误”
我修改了Brad Larson的密码。它将以给定的矩形填充图像
-(UIImage*) scaleAndCropToSize:(CGSize)newSize;
{
float ratio = self.size.width / self.size.height;
UIGraphicsBeginImageContext(newSize);
if (ratio > 1) {
CGFloat newWidth = ratio * newSize.width;
CGFloat newHeight = newSize.height;
CGFloat leftMargin = (newWidth - newHeight) / 2;
[self drawInRect:CGRectMake(-leftMargin, 0, newWidth, newHeight)];
}
else {
CGFloat newWidth = newSize.width;
CGFloat newHeight = newSize.height / ratio;
CGFloat topMargin = (newHeight - newWidth) / 2;
[self drawInRect:CGRectMake(0, -topMargin, newSize.width, newSize.height/ratio)];
}
UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}
下面的简单代码适合我
[imageView setContentMode:UIViewContentModeScaleAspectFill];
[imageView setClipsToBounds:YES];
然后,您可以通过此按钮对图像进行屏幕截图
float zoomScale = 1.0 / [scrollView zoomScale];
CGRect rect;
rect.origin.x = [scrollView contentOffset].x * zoomScale;
rect.origin.y = [scrollView contentOffset].y * zoomScale;
rect.size.width = [scrollView bounds].size.width * zoomScale;
rect.size.height = [scrollView bounds].size.height * zoomScale;
CGImageRef cr = CGImageCreateWithImageInRect([[imageView image] CGImage], rect);
UIImage *cropped = [UIImage imageWithCGImage:cr];
CGImageRelease(cr);
is的Xamarin.iOS版本
下面
公共静态UIImage ScaleAndRopimage(UIImage sourceImage,SizeF targetSize)
{
var imageSize=sourceImage.Size;
UIImage newImage=null;
var-width=imageSize.width;
var高度=图像大小。高度;
var targetWidth=targetSize.Width;
var targetHeight=targetSize.高度;
var scaleFactor=0.0f;
var scaledWidth=targetWidth;
var scaledHeight=目标高度;
var thumbnailPoint=PointF.Empty;
如果(imageSize!=targetSize)
{
var widthFactor=目标宽度/宽度;
var高度系数=目标高度/高度;
如果(宽度因子>高度因子)
{
scaleFactor=widthFactor;//缩放以适应高度
}
其他的
{
scaleFactor=heightFactor;//缩放以适应宽度
}
scaledWidth=宽度*缩放因子;
缩放高度=高度*缩放因子;
//将图像居中
如果(宽度因子>高度因子)
{
thumbnailPoint.Y=(targetLight-缩放高度)*0.5f;
}
其他的
{
if(宽度系数<高度系数)
{
thumbnailPoint.X=(targetWidth-缩放宽度)*0.5f;
}
}
}
UIGraphics.BeginImageContextWithOptions(targetSize,false,0.0f);
var thumbnailRect=新矩形F(thumbnailPoint,new SizeF(scaledWidth,scaledHeight));
sourceImage.Draw(thumbnailRect);
newImage=UIGraphics.GetImageFromCurrentImageContext();
if(newImage==null)
{
Console.WriteLine(“无法缩放图像”);
[imageView setContentMode:UIViewContentModeScaleAspectFill];
[imageView setClipsToBounds:YES];
scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0.0,0.0,ScreenWidth,ScreenHeigth)];
[scrollView setBackgroundColor:[UIColor blackColor]];
[scrollView setDelegate:self];
[scrollView setShowsHorizontalScrollIndicator:NO];
[scrollView setShowsVerticalScrollIndicator:NO];
[scrollView setMaximumZoomScale:2.0];
image=[image scaleToSize:CGSizeMake(ScreenWidth, ScreenHeigth)];
imageView = [[UIImageView alloc] initWithImage:image];
UIImageView* imageViewBk = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"background.png"]];
[self.view addSubview:imageViewBk];
CGRect rect;
rect.origin.x=0;
rect.origin.y=0;
rect.size.width = image.size.width;
rect.size.height = image.size.height;
[imageView setFrame:rect];
[scrollView setContentSize:[imageView frame].size];
[scrollView setMinimumZoomScale:[scrollView frame].size.width / [imageView frame].size.width];
[scrollView setZoomScale:[scrollView minimumZoomScale]];
[scrollView addSubview:imageView];
[[self view] addSubview:scrollView];
float zoomScale = 1.0 / [scrollView zoomScale];
CGRect rect;
rect.origin.x = [scrollView contentOffset].x * zoomScale;
rect.origin.y = [scrollView contentOffset].y * zoomScale;
rect.size.width = [scrollView bounds].size.width * zoomScale;
rect.size.height = [scrollView bounds].size.height * zoomScale;
CGImageRef cr = CGImageCreateWithImageInRect([[imageView image] CGImage], rect);
UIImage *cropped = [UIImage imageWithCGImage:cr];
CGImageRelease(cr);
public static UIImage ScaleAndCropImage(UIImage sourceImage, SizeF targetSize)
{
var imageSize = sourceImage.Size;
UIImage newImage = null;
var width = imageSize.Width;
var height = imageSize.Height;
var targetWidth = targetSize.Width;
var targetHeight = targetSize.Height;
var scaleFactor = 0.0f;
var scaledWidth = targetWidth;
var scaledHeight = targetHeight;
var thumbnailPoint = PointF.Empty;
if (imageSize != targetSize)
{
var widthFactor = targetWidth / width;
var heightFactor = targetHeight / height;
if (widthFactor > heightFactor)
{
scaleFactor = widthFactor;// scale to fit height
}
else
{
scaleFactor = heightFactor;// scale to fit width
}
scaledWidth = width * scaleFactor;
scaledHeight = height * scaleFactor;
// center the image
if (widthFactor > heightFactor)
{
thumbnailPoint.Y = (targetHeight - scaledHeight) * 0.5f;
}
else
{
if (widthFactor < heightFactor)
{
thumbnailPoint.X = (targetWidth - scaledWidth) * 0.5f;
}
}
}
UIGraphics.BeginImageContextWithOptions(targetSize, false, 0.0f);
var thumbnailRect = new RectangleF(thumbnailPoint, new SizeF(scaledWidth, scaledHeight));
sourceImage.Draw(thumbnailRect);
newImage = UIGraphics.GetImageFromCurrentImageContext();
if (newImage == null)
{
Console.WriteLine("could not scale image");
}
//pop the context to get back to the default
UIGraphics.EndImageContext();
return newImage;
}
- (UIImage*)imageScale:(CGFloat)scaleFactor cropForSize:(CGSize)targetSize
{
targetSize = !targetSize.width?self.size:targetSize;
UIGraphicsBeginImageContext(targetSize); // this will crop
CGRect thumbnailRect = CGRectZero;
thumbnailRect.size.width = targetSize.width*scaleFactor;
thumbnailRect.size.height = targetSize.height*scaleFactor;
CGFloat xOffset = (targetSize.width- thumbnailRect.size.width)/2;
CGFloat yOffset = (targetSize.height- thumbnailRect.size.height)/2;
thumbnailRect.origin = CGPointMake(xOffset,yOffset);
[self drawInRect:thumbnailRect];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
if(newImage == nil)
{
NSLog(@"could not scale image");
}
UIGraphicsEndImageContext();
return newImage;
}
[yourImage imageScale:2.0f cropForSize:CGSizeZero];
static func imageWithImage(image:UIImage, newSize:CGSize) ->UIImage {
UIGraphicsBeginImageContextWithOptions(newSize, true, UIScreen.mainScreen().scale);
image.drawInRect(CGRectMake(0, 0, newSize.width, newSize.height))
let newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage
}
import AVFoundation
import ImageIO
class Image {
class func crop(image:UIImage, crop source:CGRect, aspect:CGSize, outputExtent:CGSize) -> UIImage {
let sourceRect = AVMakeRectWithAspectRatioInsideRect(aspect, source)
let targetRect = AVMakeRectWithAspectRatioInsideRect(aspect, CGRect(origin: CGPointZero, size: outputExtent))
let opaque = true, deviceScale:CGFloat = 0.0 // use scale of device's main screen
UIGraphicsBeginImageContextWithOptions(targetRect.size, opaque, deviceScale)
let scale = max(
targetRect.size.width / sourceRect.size.width,
targetRect.size.height / sourceRect.size.height)
let drawRect = CGRect(origin: -sourceRect.origin * scale, size: image.size * scale)
image.drawInRect(drawRect)
let scaledImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return scaledImage
}
}
func resizedCroppedImage(image: UIImage, newSize:CGSize) -> UIImage {
var ratio: CGFloat = 0
var delta: CGFloat = 0
var offset = CGPointZero
if image.size.width > image.size.height {
ratio = newSize.width / image.size.width
delta = (ratio * image.size.width) - (ratio * image.size.height)
offset = CGPointMake(delta / 2, 0)
} else {
ratio = newSize.width / image.size.height
delta = (ratio * image.size.height) - (ratio * image.size.width)
offset = CGPointMake(0, delta / 2)
}
let clipRect = CGRectMake(-offset.x, -offset.y, (ratio * image.size.width) + delta, (ratio * image.size.height) + delta)
UIGraphicsBeginImageContextWithOptions(newSize, true, 0.0)
UIRectClip(clipRect)
image.drawInRect(clipRect)
let newImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return newImage
}
public func resizeImage(image: UIImage, size: CGSize) -> UIImage? {
var returnImage: UIImage?
var scaleFactor: CGFloat = 1.0
var scaledWidth = size.width
var scaledHeight = size.height
var thumbnailPoint = CGPointMake(0, 0)
if !CGSizeEqualToSize(image.size, size) {
let widthFactor = size.width / image.size.width
let heightFactor = size.height / image.size.height
if widthFactor > heightFactor {
scaleFactor = widthFactor
} else {
scaleFactor = heightFactor
}
scaledWidth = image.size.width * scaleFactor
scaledHeight = image.size.height * scaleFactor
if widthFactor > heightFactor {
thumbnailPoint.y = (size.height - scaledHeight) * 0.5
} else if widthFactor < heightFactor {
thumbnailPoint.x = (size.width - scaledWidth) * 0.5
}
}
UIGraphicsBeginImageContextWithOptions(size, true, 0)
var thumbnailRect = CGRectZero
thumbnailRect.origin = thumbnailPoint
thumbnailRect.size.width = scaledWidth
thumbnailRect.size.height = scaledHeight
image.drawInRect(thumbnailRect)
returnImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return returnImage
}
extension UIImage {
static func resizedCroppedImage(image: UIImage, newSize:CGSize) -> UIImage? {
var ratio: CGFloat = 0
var delta: CGFloat = 0
var offset = CGPoint.zero
if image.size.width > image.size.height {
ratio = newSize.width / image.size.width
delta = (ratio * image.size.width) - (ratio * image.size.height)
offset = CGPoint(x: delta / 2, y: 0)
} else {
ratio = newSize.width / image.size.height
delta = (ratio * image.size.height) - (ratio * image.size.width)
offset = CGPoint(x: 0, y: delta / 2)
}
let clipRect = CGRect(x: -offset.x, y: -offset.y, width: (ratio * image.size.width) + delta, height: (ratio * image.size.height) + delta)
UIGraphicsBeginImageContextWithOptions(newSize, true, 0.0)
UIRectClip(clipRect)
image.draw(in: clipRect)
let newImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return newImage
}
}
static func resizedCroppedImage(image: UIImage, newSize:CGSize) -> UIImage? {
// This function returns a newImage, based on image
// - image is scaled uniformaly to fit into a rect of size newSize
// - if the newSize rect is of a different aspect ratio from the source image
// the new image is cropped to be in the center of the source image
// (the excess source image is removed)
var ratio: CGFloat = 0
var delta: CGFloat = 0
var drawRect = CGRect()
if newSize.width > newSize.height {
ratio = newSize.width / image.size.width
delta = (ratio * image.size.height) - newSize.height
drawRect = CGRect(x: 0, y: -delta / 2, width: newSize.width, height: newSize.height + delta)
} else {
ratio = newSize.height / image.size.height
delta = (ratio * image.size.width) - newSize.width
drawRect = CGRect(x: -delta / 2, y: 0, width: newSize.width + delta, height: newSize.height)
}
UIGraphicsBeginImageContextWithOptions(newSize, true, 0.0)
image.draw(in: drawRect)
let newImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return newImage
}