图片裁剪，左右超出了等距裁剪图片左右部分 上下超出了就等距裁剪图片上下部分
+ (UIImage *)handleImage:(UIImage *)originalImage withSize:(CGSize)size
{
CGSize originalsize = [originalImage size];
NSLog(@"改变前图片的宽度为%f,图片的高度为%f",originalsize.width,originalsize.height);
//原图长宽均小于标准长宽的，不作处理返回原图
if (originalsize.width
{
return originalImage;
}//原图长宽均大于标准长宽的，按比例缩小至最大适应值
else if(originalsize.width>size.width && originalsize.height>size.height)
{
CGFloat rate = 1.0;
CGFloat widthRate = originalsize.width/size.width;
CGFloat heightRate = originalsize.height/size.height;
rate = widthRate>heightRate?heightRate:widthRate;
CGImageRef imageRef = nil;
if (heightRate>widthRate)
{
imageRef = CGImageCreateWithImageInRect([originalImage CGImage], CGRectMake(0, originalsize.height/2-size.height*rate/2, originalsize.width, size.height*rate));//获取图片整体部分
}
else
{
imageRef = CGImageCreateWithImageInRect([originalImage CGImage], CGRectMake(originalsize.width/2-size.width*rate/2, 0, size.width*rate, originalsize.height));//获取图片整体部分
}
UIGraphicsBeginImageContext(size);//指定要绘画图片的大小
CGContextRef con = UIGraphicsGetCurrentContext();
CGContextTranslateCTM(con, 0.0, size.height);
CGContextScaleCTM(con, 1.0, -1.0);
CGContextDrawImage(con, CGRectMake(0, 0, size.width, size.height), imageRef);
UIImage *standardImage = UIGraphicsGetImageFromCurrentImageContext();
NSLog(@"改变后图片的宽度为%f,图片的高度为%f",[standardImage size].width,[standardImage size].height);
UIGraphicsEndImageContext();
CGImageRelease(imageRef);
return standardImage;
}
//原图长宽有一项大于标准长宽的，对大于标准的那一项进行裁剪，另一项保持不变
else if(originalsize.height>size.height || originalsize.width>size.width)
{
CGImageRef imageRef = nil;
if(originalsize.height>size.height)
{
imageRef = CGImageCreateWithImageInRect([originalImage CGImage], CGRectMake(0, originalsize.height/2-size.height/2, originalsize.width, size.height));//获取图片整体部分
}
else if (originalsize.width>size.width)
{
imageRef = CGImageCreateWithImageInRect([originalImage CGImage], CGRectMake(originalsize.width/2-size.width/2, 0, size.width, originalsize.height));//获取图片整体部分
}
UIGraphicsBeginImageContext(size);//指定要绘画图片的大小
CGContextRef con = UIGraphicsGetCurrentContext();
CGContextTranslateCTM(con, 0.0, size.height);
CGContextScaleCTM(con, 1.0, -1.0);
CGContextDrawImage(con, CGRectMake(0, 0, size.width, size.height), imageRef);
UIImage *standardImage = UIGraphicsGetImageFromCurrentImageContext();
NSLog(@"改变后图片的宽度为%f,图片的高度为%f",[standardImage size].width,[standardImage size].height);
UIGraphicsEndImageContext();
CGImageRelease(imageRef);
return standardImage;
}
//原图为标准长宽的，不做处理
else
{
return originalImage;
}
}