- 1 year ago
How to downscale the pixel values in UWP App (C#)?
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To downscale the pixel values in a UWP app using C#, you can use the Win2D library, which is a powerful 2D graphics library for UWP. With Win2D, you can easily manipulate images, including downscaling the pixel values. Here's a step-by-step guide on how to do it:
Install the Win2D NuGet package in your UWP project.
- Open your UWP project in Visual Studio.
- Right-click on your project in the Solution Explorer.
- Select "Manage NuGet Packages..."
- Search for "Win2D.uwp" and click on "Install" to install the package.
Add the necessary using directives at the top of your code-behind file.
csharpusing Microsoft.Graphics.Canvas;
using Microsoft.Graphics.Canvas.UI.Xaml;
using Windows.Storage;
using Windows.Storage.Streams;
- Create a CanvasBitmap to load the original image.
csharpprivate CanvasBitmap originalBitmap;
private async Task LoadImageAsync()
{
// Replace "imageFilePath" with the path to your image file.
StorageFile imageFile = await StorageFile.GetFileFromPathAsync("imageFilePath");
IRandomAccessStream stream = await imageFile.OpenReadAsync();
originalBitmap = await CanvasBitmap.LoadAsync(CanvasDevice.GetSharedDevice(), stream);
}
- Create a function to downscale the image.
csharpprivate CanvasBitmap downscaledBitmap;
private void DownscaleImage(double scaleFactor)
{
int newWidth = (int)(originalBitmap.Size.Width * scaleFactor);
int newHeight = (int)(originalBitmap.Size.Height * scaleFactor);
using (CanvasRenderTarget renderTarget = new CanvasRenderTarget(CanvasDevice.GetSharedDevice(), newWidth, newHeight, originalBitmap.Dpi))
using (CanvasDrawingSession ds = renderTarget.CreateDrawingSession())
{
ds.DrawImage(originalBitmap, 0, 0, newWidth, newHeight);
downscaledBitmap = CanvasBitmap.CreateFromBytes(CanvasDevice.GetSharedDevice(), renderTarget.GetPixelBytes(), newWidth, newHeight, originalBitmap.Format);
}
}
- Finally, use the
CanvasControl
to draw the downscaled image on the screen.
csharpprivate void canvas_Draw(CanvasControl sender, CanvasDrawEventArgs args)
{
if (downscaledBitmap != null)
{
args.DrawingSession.DrawImage(downscaledBitmap);
}
}
- Optionally, call the
LoadImageAsync
andDownscaleImage
functions in theOnNavigatedTo
method of your page to load and downscale the image when the page is navigated to.
That's it! Now you have downscaled the pixel values of the image using Win2D in your UWP app. Remember that the downscaling process will reduce the image's resolution, so choose an appropriate scaleFactor
value based on your requirements.