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wpfwpf-controlsantialiasingimagebrush

Is it possible to turn off antialiasing when using ImageBrush tiling?

Is it possible to turn off anti-aliasing in WPF when using an ImageBrush?

Given the following code:

var handleImage = new BitmapImage(new Uri($"pack://application:,,,/Resources/myimage.png"));
var imageBrush = new ImageBrush(handleImage);
imageBrush.AlignmentY = AlignmentY.Top;
imageBrush.AlignmentX = AlignmentX.Left;
imageBrush.Stretch = Stretch.Uniform;
imageBrush.Viewport = new Rect(0, 0, _handleImage.Width, _handleImage.Height);
imageBrush.ViewportUnits = BrushMappingMode.Absolute;
imageBrush.TileMode = TileMode.Tile;
drawingContext.DrawRectangle(imageBrush, null, new Rect(0, 0, width, height));

Gives me something like: WPF Output

But I'm expecting: Expected Output

WPF's default antialiasing makes it look terrible. I've tried UseLayoutRounding=true, SnapsToDevicePixels=true, RenderOptions.SetBitmapScalingMode(this, BitmapScalingMode.HighQuality), RenderOptions.SetBitmapScalingMode(this, BitmapScalingMode.NearestNeighbor) RenderOptions.SetEdgeMode(this, EdgeMode.Unspecified); on the window. The only one that changes any visual difference is BitmapScalingMode.NearestNeighbor however it still looks odd and the tiling overlaps itself.

EDIT: Download full working sample: WpfImageBrushExample.zip

Solution

  • The problem here was that the BitmapImage width and height were different fractional numbers - in this case it was 5.333 x 6x666 instead of the expected 4 x 5 pixels. If I use _handleImage.PixelWidth and _handleImage.PixelHeight the problem is fixed and I don't get weird aliasing under any of those rendering options set.

    var handleImage = new BitmapImage(new Uri($"pack://application:,,,/Resources/myimage.png"));
var imageBrush = new ImageBrush(handleImage);
imageBrush.AlignmentY = AlignmentY.Top;
imageBrush.AlignmentX = AlignmentX.Left;
imageBrush.Stretch = Stretch.Uniform;
imageBrush.Viewport = new Rect(0, 0, _handleImage.PixelWidth, _handleImage.PixelHeight);
imageBrush.ViewportUnits = BrushMappingMode.Absolute;
imageBrush.TileMode = TileMode.Tile;
drawingContext.DrawRectangle(imageBrush, null, new Rect(0, 0, width, height));

    Produces: Expected