Converting Large images to low size in IOS

Question

I am working on an app which has to load images taken from camera which is generally around 5-6MB , into tableview. I am loading the image asynchronously and caching it but i want to know that is there any way through which i can change this large size images to lower size?

Answer 1

try this simple way ... i found from this post What's the easiest way to resize/optimize an image size with the iPhone SDK?

+ (UIImage*)imageWithImage:(UIImage*)image 
           scaledToSize:(CGSize)newSize;
{
   UIGraphicsBeginImageContext( newSize );
   [image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
   UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
   UIGraphicsEndImageContext();

   return newImage;
}

Answer 2

Here i put logic of both Crop and resize image, use it as per your requirement.

For Get Cropped Image:

UIImage *croppedImg = nil;
CGRect cropRect = CGRectMake(AS YOu Need); // set frame as you need
croppedImg = [self croppIngimageByImageName:self.imageView.image toRect:cropRect];

The following method that return UIImage (as You want size of image)

- (UIImage *)croppIngimageByImageName:(UIImage *)imageToCrop toRect:(CGRect)rect
    {
        //CGRect CropRect = CGRectMake(rect.origin.x, rect.origin.y, rect.size.width, rect.size.height+15);

        CGImageRef imageRef = CGImageCreateWithImageInRect([imageToCrop CGImage], rect);
        UIImage *cropped = [UIImage imageWithCGImage:imageRef];
        CGImageRelease(imageRef);

        return cropped;
    }

Here you get Croped Image that return by above method;

OR RESIZING

And also use following method with specific hight and width of image for Resizing:

+ (UIImage*)resizeImage:(UIImage*)image withWidth:(CGFloat)width withHeight:(CGFloat)height
{
    CGSize newSize = CGSizeMake(width, height);
    CGFloat widthRatio = newSize.width/image.size.width;
    CGFloat heightRatio = newSize.height/image.size.height;

    if(widthRatio > heightRatio)
    {
        newSize=CGSizeMake(image.size.width*heightRatio,image.size.height*heightRatio);
    }
    else
    {
        newSize=CGSizeMake(image.size.width*widthRatio,image.size.height*widthRatio);
    }


    UIGraphicsBeginImageContextWithOptions(newSize, NO, 0.0);
    [image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
    UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return newImage;
}

This method return NewImage, with specific size that you want.