How to Reduce Size of Image in windows phone

问题

I am trying to port my app in windows phone . i have to upload an image on server So it is in small Size For uploading i have done this thing in Widows Successfully but problem is when i failed in it .. here is my code for windows App

public void CompressImage(int i, int j)
        {
            bmp1.SetPixel(j, i, Color.FromArgb(bmp.GetPixel(j, i).R, bmp.GetPixel(j, i).G, bmp.GetPixel(j, i).B));   
        }



        private void bLoadImage_Click(object sender, EventArgs e)
        {
            OpenFileDialog file = new OpenFileDialog();
            if (file.ShowDialog() == DialogResult.OK)
            {
                pictureBox1.Image = new Bitmap(file.FileName);
            }
        }


        private void bCompression_Click(object sender, EventArgs e)
        {
            bmp = new Bitmap(pictureBox1.Image);
            bmp1 = new Bitmap(bmp.Width, bmp.Height);
            for (int i = 1; i < bmp.Height; i++)
                for (int j = 1; j < bmp.Width; j++)
                {
                    CompressImage(i, j);
                }
            pictureBox2.Image = bmp1;
            bmp1.Save("Picture.jpeg", System.Drawing.Imaging.ImageFormat.Jpeg);
        }

After Searching on google i found out that windows Phone does not support Bitmap .. any idea how i can do the same thing in windows phone or any other alternative for doing this

回答1:

You should use WriteablBitmap to reduce size of image. WriteablBitmap has number of methods for images in windows phone Here is more about writeablebitmapex.

回答2:

Try to load your original image to WriteableBitmap object, then you can use SaveJpeg() extension method from System.Windows.Media.Imaging namespace, to save new image with reduced size. For example :

.......
WriteableBitmap wb = new WriteableBitmap(bitmapImageObject);
wb.SaveJpeg(stream, 120, 160, 0, 100);
.......

回答3:

When you are taking picture you can choose the resolution with which the picture will be taken. This can be done by

PhotoCamera cam;

After camera initizalition.

Following code when image is capturing (in the method that captures the image)

IEnumerable<Size> resList = cam.AvailableResolutions;

Size res;
if (resList.Count() > 0)
{
    res = resList.ElementAt<Size>(0);
    cam.Resolution = res;

 }

This sample chooses the first resolution

回答4:

You can try this. It worked for me. It reduced my 9.70MB file into 270KB.

WriteableBitmap cameraCapturedImage = PictureDecoder.DecodeJpeg(e.ChosenPhoto, 1024, 1024);

using (IsolatedStorageFileStream myFileStream = myStore.CreateFile(fileName))
{
  System.Windows.Media.Imaging.Extensions.SaveJpeg(cameraCapturedImage, myFileStream, cameraCapturedImage.PixelWidth, cameraCapturedImage.PixelHeight, 0, 85);
  myFileStream.Close();
}

N.B: fileName is the name of file to save size reduced image.

来源：https://stackoverflow.com/questions/22163959/how-to-reduce-size-of-image-in-windows-phone

标签

windows-phone-8

bitmap

writeablebitmap