#import "UIImage+More.h"
@implementation UIImage (More)
// 来自相机或相册的相片大小处理
// 1. 等比绽放图片 照相出来时 1936.000000 2592.000000
+ (UIImage *)getScaleImage:(UIImage *)image toSize:(CGSize)size
{
//压缩图片
int iWidth = image.size.width;
int iHeight = image.size.height;
if (iWidth > size.width) // 自定义大小，想要弄多大，就弄多大
{
iWidth = size.width;
iHeight = image.size.height*iWidth/image.size.width;
if (iHeight > size.height)
{
iHeight = size.height;
iWidth = image.size.width*iHeight/image.size.height;
}
}
//主要在这里
UIGraphicsBeginImageContext(CGSizeMake(iWidth, iHeight)); // 创建一个context
// 绘制改变大小的图片
[image drawInRect:CGRectMake(0, 0, iWidth, iHeight)];
// 从当前context中创建一个改变大小后的图片
UIImage* scaledImage = UIGraphicsGetImageFromCurrentImageContext();
// 使当前的context出堆栈
UIGraphicsEndImageContext();
// 返回新的改变大小后的图片
return scaledImage;
}
// 2. 截取图中某部分小图
+ (UIImage *)getSubImageFromImage:(UIImage *)oldImage withRect:(CGRect)rect
{
CGImageRef imageRef = oldImage.CGImage;
CGImageRef subImageRef = CGImageCreateWithImageInRect(imageRef, rect);
CGSize size = CGSizeMake(rect.size.width, rect.size.height);
// 创建一个新图像上下文
UIGraphicsBeginImageContext(size);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextDrawImage(context, rect, subImageRef);
UIImage* smallImage = [UIImage imageWithCGImage:subImageRef];
UIGraphicsEndImageContext();
return smallImage;
}
// 3. 固定某张图片方向 向上
+ (UIImage *)fixOrientationForImage:(UIImage *)image
{
// No-op if the orientation is already correct
if (image.imageOrientation == UIImageOrientationUp) return image;
// We need to calculate the proper transformation to make the image upright.
// We do it in 2 steps: Rotate if Left/Right/Down, and then flip if Mirrored.
CGAffineTransform transform = CGAffineTransformIdentity;
// if(self.imageOrientation == UIImageOrientationDown)
switch (image.imageOrientation) {
case UIImageOrientationDown:
case UIImageOrientationDownMirrored:
transform = CGAffineTransformTranslate(transform, image.size.width, image.size.height);
transform = CGAffineTransformRotate(transform, M_PI);
break;
case UIImageOrientationLeft:
case UIImageOrientationLeftMirrored:
transform = CGAffineTransformTranslate(transform, image.size.width, 0);
transform = CGAffineTransformRotate(transform, M_PI_2);
break;
case UIImageOrientationRight:
case UIImageOrientationRightMirrored:
transform = CGAffineTransformTranslate(transform, 0, image.size.height);
transform = CGAffineTransformRotate(transform, -M_PI_2);
break;
default:
break;
}
switch (image.imageOrientation) {
case UIImageOrientationUpMirrored:
case UIImageOrientationDownMirrored:
transform = CGAffineTransformTranslate(transform, image.size.width, 0);
transform = CGAffineTransformScale(transform, -1, 1);
break;
case UIImageOrientationLeftMirrored:
case UIImageOrientationRightMirrored:
transform = CGAffineTransformTranslate(transform, image.size.height, 0);
transform = CGAffineTransformScale(transform, -1, 1);
break;
default:
break;
}
// Now we draw the underlying CGImage into a new context, applying the transform
// calculated above.
CGContextRef ctx = CGBitmapContextCreate(NULL, image.size.width, image.size.height,
CGImageGetBitsPerComponent(image.CGImage), 0,
CGImageGetColorSpace(image.CGImage),
CGImageGetBitmapInfo(image.CGImage));
CGContextConcatCTM(ctx, transform);
switch (image.imageOrientation) {
case UIImageOrientationLeft:
case UIImageOrientationLeftMirrored:
case UIImageOrientationRight:
case UIImageOrientationRightMirrored:
// Grr...
CGContextDrawImage(ctx, CGRectMake(0,0,image.size.height,image.size.width), image.CGImage);
break;
default:
CGContextDrawImage(ctx, CGRectMake(0,0,image.size.width,image.size.height), image.CGImage);
break;
}
// And now we just create a new UIImage from the drawing context
CGImageRef cgimg = CGBitmapContextCreateImage(ctx);
UIImage *img = [UIImage imageWithCGImage:cgimg];
CGContextRelease(ctx);
CGImageRelease(cgimg);
return img;
}
// 4. 获取自适应大小的图片
+ (UIImage *)getResizableImage:(NSString *)name
{
UIImage *image = [UIImage imageNamed:name];
image = [image resizableImageWithCapInsets:UIEdgeInsetsMake(5, 5, 5, 5) resizingMode:UIImageResizingModeStretch];
return image;
}
@end
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