25-Canvas Grid

 In this post, we will add the grid to the Schematic Canvas. The grid functionality is setup in MainForm.

• Add the grid gap attribute to MainForm

        // The grid spacing.
        public const int grid_gap = 10;

• Add the DrawBackgoundGrid() helper function to MainForm

        // Draw the background grid as a Bitmap
        private void DrawBackgroundGrid()
        {
            Bitmap bm = new Bitmap(
                schematicCanvas.ClientSize.Width,
                schematicCanvas.ClientSize.Height);
            for (int x = 0; x < schematicCanvas.ClientSize.Width; x += grid_gap)
            {
                for (int y = 0; y < schematicCanvas.ClientSize.Height; y += grid_gap)
                {
                    bm.SetPixel(x, y, Color.DarkGray);
                }
            }
 
            schematicCanvas.BackgroundImage = bm;
        }

• Add the Resize() event handler and call the DrawBackgroudGrid() function

        private void schematicCanvas_Resize(object sender, EventArgs e)
        {
            DrawBackgroundGrid();
        }

Run the program to test that the grid is drawn on the window on startup and after the window is resized. The source code for this post is on GitHub.