WPF Canvas - Single Pixel Grid

Question

I have a custom WPF Canvas, upon which I would like to show a grid. I do so by overriding the OnRender method on Canvas, and using the DrawingContext drawing functions. IsGridVisible, GridWidth, GridHeight are the number of pixels between each grid line horizontally and vertically respectively.

I also use a ScaleTransform on the Canvas.LayoutTransform property to zoom the Canvas items and as one expects, the grid line thicknesses are multiplied by the ScaleTransform scaling factors as shown in the below image. Is there any way to draw single pixel lines, irrespective of the current Canvas RenderTransform?

 protected override void OnRender(System.Windows.Media.DrawingContext dc) { base.OnRender(dc); if (IsGridVisible) { // Draw GridLines Pen pen = new Pen(new SolidColorBrush(GridColour), 1); pen.DashStyle = DashStyles.Dash; for (double x = 0; x < this.ActualWidth; x += this.GridWidth) { dc.DrawLine(pen, new Point(x, 0), new Point(x, this.ActualHeight)); } for (double y = 0; y < this.ActualHeight; y += this.GridHeight) { dc.DrawLine(pen, new Point(0, y), new Point(this.ActualWidth, y)); } } }

alt text http://www.freeimagehosting.net/uploads/f05ad1f602.png

Thanks for the above code. I have been searching for this type of examples from past 2 days. I have implement a custom canvas and drawing the grids as shown. The problem is that it is very slow. When I maximize or resize the window, the performance is really very slow. It hang a bit. Is there any solution to that? — Vinod Maurya
– Vinod Maurya, Commented Oct 18, 2010 at 10:02

LiamV · Accepted Answer · 2010-07-17 09:19:50Z

1

As the comments to the original post state. The Pen thickness should be set to 1.0/zoom.

answered Jul 17, 2010 at 9:19

LiamV

1,1081 gold badge14 silver badges21 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

WPF Canvas - Single Pixel Grid

1 Answer 1

Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Linked

Related