Pass "transparent" image between pages

Question

How can I pass images between pages with transparent background, png format? Now I passed image but background is black.

Here is my code:

First page:

WriteableBitmap wb = new WriteableBitmap(logoQrCodeImage, null);
Byte[] array = ConvertImage.ConvertToBytes(wb);
if (!IsolatedStorageSettings.ApplicationSettings.Contains("State"))
{
    IsolatedStorageSettings.ApplicationSettings["State"] = array;
    IsolatedStorageSettings.ApplicationSettings.Save();
}

Second page:

Byte[] array = IsolatedStorageSettings.ApplicationSettings["State"] as Byte[];
MemoryStream stream = new MemoryStream(array);
WriteableBitmap wb = new WriteableBitmap(50, 50);
//wb.LoadJpeg(stream);

var encoder = new PngEncoder();
ExtendedImage myImage;
myImage = wb.ToImage();
encoder.Encode(myImage, stream);

icon.Source = myImage.ToBitmap();
IsolatedStorageSettings.ApplicationSettings.Remove("State");
IsolatedStorageSettings.ApplicationSettings.Save();

score 0 · Answer 1 · answered Nov 25 '13 at 13:13

0

You seem to encode/decode the image as JPEG, which does not handles transparency.

Try saving it as-is (Bitmap) or PNG.

answered Nov 25 '13 at 13:13

Olivier Payen

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But how Can I save this image as PNG ? Any clue ? – user2962457 Nov 25 '13 at 14:17
You need to use third-party libraries, like ImageTools (http://imagetools.codeplex.com/). – Olivier Payen Nov 25 '13 at 15:29
Ok, I'm going to try. But I don't know how pass this image between pages, because it should be in bytes. – user2962457 Nov 25 '13 at 17:07
What is the method name which I can use to save image to PNG format ? – user2962457 Nov 25 '13 at 17:29
You shouldn't have edited your question as you are basically asking a new question here. I see 2 problems with your new code: you don't encode the image in the first page (what does your ConvertToBytes method does?) and you don't decode it in the second. – Olivier Payen Nov 26 '13 at 13:16

Pass "transparent" image between pages

1 Answers1