亲测：两种方式都有效
第一种方式：缩略成固定的尺寸大小
- (UIImage *)thumbnailWithImageWithoutScale:(UIImage *)image size:(CGSize)asize
{
UIImage *newimage;
if (nil == image) {
newimage = nil;
} else {
UIGraphicsBeginImageContext(asize);
[image drawInRect:CGRectMake(, , asize.width, asize.height)];
newimage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
}
return newimage;
}
第二种方式：保持原来图片的宽高比
- (UIImage *)thumbnailWithImageWithoutScale:(UIImage *)image size:(CGSize)asize
{
UIImage *newimage;
if (nil == image) {
newimage = nil;
}
else{
CGSize oldsize = image.size;
CGRect rect;
if (asize.width/asize.height > oldsize.width/oldsize.height) {
rect.size.width = asize.height*oldsize.width/oldsize.height;
rect.size.height = asize.height;
rect.origin.x = (asize.width - rect.size.width)/;
rect.origin.y = ;
}
else{
rect.size.width = asize.width;
rect.size.height = asize.width*oldsize.height/oldsize.width;
rect.origin.x = ;
rect.origin.y = (asize.height - rect.size.height)/;
}
UIGraphicsBeginImageContext(asize);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetFillColorWithColor(context, [[UIColor clearColor] CGColor]);
UIRectFill(CGRectMake(, , asize.width, asize.height));//clear background
[image drawInRect:rect];
newimage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
}
return newimage;
}