问题
I am getting an image from the CameraCaptureTask, and I would like to be able to make the image much smaller before saving. The width and height are automatically set to the highest resolution, which is much more than what I need. I have been trying to get the image, change the dimensions, and then attempt to save, although I am getting errors.
ORIGINAL
MainPage.xaml.cs
private void cameraTask_Completed(object sender, PhotoResult e)
{
if (e.TaskResult == TaskResult.OK)
{
BitmapImage bmi = new BitmapImage();
bmi.SetSource(e.ChosenPhoto);
//MessageBox.Show(bmi.PixelWidth.ToString() + "x" + bmi.PixelHeight.ToString());
var gcd = GCD(bmi.PixelWidth, bmi.PixelHeight);
var result = string.Format("{0}:{1}", bmi.PixelWidth / gcd, bmi.PixelHeight / gcd);
WriteableBitmap wb;
Stream stream;
switch (result)
{
case "3:4":
wb = new WriteableBitmap(480,640);
break;
case "4:3":
wb = new WriteableBitmap(640,480);
break;
case "9:16":
wb = new WriteableBitmap(448, 800);
break;
case "16:9":
wb = new WriteableBitmap(800, 448);
break;
default:
wb = null;
return;
}
//Set the wb to the original stream?
wb.SetSource(e.ChosenPhoto);
//Convert the wb to a stream for saving
stream = new MemoryStream(wb.ToByteArray());
//Need to replace the following line with the new image stream for saving?
//var capturedPicture = new CapturedPicture(e.OriginalFileName, e.ChosenPhoto);
var capturedPicture = new CapturedPicture(e.OriginalFileName, stream);
}
}
public int GCD(int a, int b)
{
while (a != 0 && b != 0)
{
if (a > b)
a %= b;
else
b %= a;
}
if (a == 0)
return b;
else
return a;
}
EDIT: new implementation
private void cameraTask_Completed(object sender, PhotoResult e)
{
if (e.TaskResult == TaskResult.OK)
{
BitmapImage bmi = new BitmapImage();
bmi.SetSource(e.ChosenPhoto);
var gcd = GCD(bmi.PixelWidth, bmi.PixelHeight);
var result = string.Format("{0}:{1}", bmi.PixelWidth / gcd, bmi.PixelHeight / gcd);
WriteableBitmap wb = new WriteableBitmap(bmi);
Stream stream = new MemoryStream();
switch (result)
{
case "3:4":
wb.SaveJpeg(stream, 480, 640, 0, 100);
break;
case "4:3":
wb.SaveJpeg(stream, 640, 480, 0, 100);
break;
case "9:16":
wb.SaveJpeg(stream, 448, 800, 0, 100);
break;
case "16:9":
wb.SaveJpeg(stream, 800, 448, 0, 100);
break;
default:
wb = null;
return;
}
stream.Seek(0, SeekOrigin.Begin);
//var capturedPicture = new CapturedPicture(e.OriginalFileName, e.ChosenPhoto);
var capturedPicture = new CapturedPicture(e.OriginalFileName, stream);
回答1:
use the overloaded Bitmap constructor to create a re-sized image, the only thing you were missing was a cast back to the Image data type:
public static Image resizeImage(Image imgToResize, Size size)
{
return (Image)(new Bitmap(imgToResize, size));
}
yourImage = resizeImage(yourImage, new Size(50,50));
来源:https://stackoverflow.com/questions/18951955/how-to-change-size-of-image