如何缩小iPhone 7中相机拍摄的照片的大小

Question

I am working on xamarin ios. I have to implement camera functionality in iphone app. I have implemted the code. But the problem is that when I try to upload the picture with webservices, it doesn't upload due to size of the image.

So I tried to scale the size of picture but in that case the image is looking strethced. I want that image should be uploaded with same size, may be with worst quality but height and width should be original.

Here is the code I implemented:

Camera.TakePicture(this, (obj) =>
            {
                var photo = obj.ValueForKey(new NSString("UIImagePickerControllerOriginalImage")) as UIImage;
                var image = photo.Scale(new CGSize(1280, 720));
                Byte[] myByteArray;
                using (NSData imageData = image.AsJPEG(0.0f))
                {

                    myByteArray = new Byte[imageData.Length];
                    System.Runtime.InteropServices.Marshal.Copy(imageData.Bytes, myByteArray, 0, Convert.ToInt32(imageData.Length));
                }

            }); 

Answer 1

Dont perform the scale operation

var image = photo.Scale(new CGSize(1280, 720));

if you DONT want to change the size. If you do want to resize and also keep the aspect ratio, this code sniped should do it

// Resize the image to be contained within a maximum width and height, keeping aspect ratio
        public UIImage MaxResizeImage (UIImage sourceImage, float maxWidth, float maxHeight)
        {
            var sourceSize = sourceImage.Size;
            var maxResizeFactor = Math.Max (maxWidth / sourceSize.Width, maxHeight / sourceSize.Height);
            if (maxResizeFactor > 1) return sourceImage;
            var width = maxResizeFactor * sourceSize.Width;
            var height = maxResizeFactor * sourceSize.Height;
            UIGraphics.BeginImageContext (new SizeF ((float)width, (float)height));
            sourceImage.Draw (new RectangleF (0, 0, (float)width, (float)height));
            var resultImage = UIGraphics.GetImageFromCurrentImageContext ();
            UIGraphics.EndImageContext ();
            return resultImage;
        }

How to use on your code

Camera.TakePicture(this, (obj) =>
            {
                var photo = obj.ValueForKey(new NSString("UIImagePickerControllerOriginalImage")) as UIImage;
                var image = MaxResizeImage (photo,1280, 720);
                Byte[] myByteArray;
                using (NSData imageData = image.AsJPEG(0.0f))
                {

                    myByteArray = new Byte[imageData.Length];
                    System.Runtime.InteropServices.Marshal.Copy(imageData.Bytes, myByteArray, 0, Convert.ToInt32(imageData.Length));
                }

            });