一.目的:
有时候我们获得到的图片我们不是我们想要的方向,需要对图片进行旋转.比如:图片旋转90度180度等.
二.实现过程.
1.获取到该UIImage.
2.开启上下文.
3.上下文的具体操作.
4. 将上下文转化为想要的UIImage
三.UIImage 的 Category
UIImage+ImageRotate.h
#import <UIKit/UIKit.h>@interface UIImage (ImageRotate)- (UIImage *)imageRotateWithIndegree:(CGFloat)indegree;@end
UIImage+ImageRotate.m
#import "UIImage+ImageRotate.h"
#import <QuartzCore/QuartzCore.h>
#import <Accelerate/Accelerate.h>@implementation UIImage (ImageRotate)#pragma mark - 图片旋转// 1 image --> Context 2. context 3. context --> image- (UIImage *)imageRotateWithIndegree:(CGFloat)indegree { // 1. image --> context
size_t width = (size_t)(self.size.width * self.scale);
size_t height = (size_t)(self.size.height * self.scale); size_t bytesPerRow = width * ; // 每行图片字节数
CGImageAlphaInfo alphaInfo = kCGImageAlphaPremultipliedFirst; // alpha // 配置上下文
// CGColorRef bmContext = CGBitmapContextCreate(<#void * _Nullable data#>, <#size_t width#>, <#size_t height#>, <#size_t bitsPerComponent#>, <#size_t bytesPerRow#>, <#CGColorSpaceRef _Nullable space#>, <#uint32_t bitmapInfo#>)
CGContextRef bmContext = CGBitmapContextCreate(NULL, width, height, , bytesPerRow, CGColorSpaceCreateDeviceRGB(), kCGBitmapByteOrderDefault | alphaInfo); if (!bmContext) {
return nil;
} CGContextDrawImage(bmContext, CGRectMake(, , width, height), self.CGImage); // 2. 旋转
UInt8 * data = (UInt8 *)CGBitmapContextGetData(bmContext); // 需要引入 #import <Accelerate/Accelerate.h> 解释这个类干什么用的
vImage_Buffer src = {data,height,width,bytesPerRow};
vImage_Buffer dest = {data,height,width,bytesPerRow};
Pixel_8888 bgColor = {,,,};
vImageRotate_ARGB8888(&src, &dest, NULL, indegree, bgColor, kvImageBackgroundColorFill); // 3. context --> UIImage
CGImageRef rotateImageRef = CGBitmapContextCreateImage(bmContext);
UIImage * rotateImage = [UIImage imageWithCGImage:rotateImageRef scale:self.scale orientation:self.imageOrientation]; CGContextRelease(bmContext);
CGImageRelease(rotateImageRef); return rotateImage;
}@end
四.使用
UIImage * image = [image imageRotateWithIndegree:M_PI / 2];
github地址: https://github.com/mancongiOS/UIImage.git
