TODO features:

- Custom cursor showing painting size
- Alt-Scroll to change painting size

McBitFont/McCursor.cs

@@ -0,0 +1,105 @@
+using System;
+using System.Collections.Generic;
+using System.Drawing;
+using System.Drawing.Drawing2D;
+using System.Drawing.Imaging;
+using System.Linq;
+using System.Runtime.InteropServices;
+using System.Text;
+using System.Threading.Tasks;
+using System.Windows.Forms;
+
+namespace McBitFont {
+    internal class McCursor {
+
+        public struct IconInfo {
+            public bool fIcon;
+            public int xHotspot;
+            public int yHotspot;
+            public IntPtr hbmMask;
+            public IntPtr hbmColor;
+        }
+        [DllImport("user32.dll")]
+        [return: MarshalAs(UnmanagedType.Bool)]
+        public static extern bool GetIconInfo(IntPtr hIcon, ref IconInfo pIconInfo);
+        [DllImport("user32.dll")]
+        public static extern IntPtr CreateIconIndirect(ref IconInfo icon);
+
+        /// <summary>
+        /// Create a cursor from a bitmap without resizing and with the specified
+        /// hot spot
+        /// </summary>
+        public static Cursor CreateCursorNoResize(Bitmap bmp, int xHotSpot, int yHotSpot) {
+            IntPtr ptr = bmp.GetHicon();
+            IconInfo tmp = new IconInfo();
+            GetIconInfo(ptr, ref tmp);
+            tmp.xHotspot = xHotSpot;
+            tmp.yHotspot = yHotSpot;
+            tmp.fIcon = false;
+            ptr = CreateIconIndirect(ref tmp);
+            return new Cursor(ptr);
+        }
+
+
+        /// <summary>
+        /// Create a 32x32 cursor from a bitmap, with the hot spot in the middle
+        /// </summary>
+        public static Cursor CreateCursor(Bitmap bmp) {
+            int xHotSpot = 16;
+            int yHotSpot = 16;
+
+            IntPtr ptr = ((Bitmap)ResizeImage(bmp, 32, 32)).GetHicon();
+            IconInfo tmp = new IconInfo();
+            GetIconInfo(ptr, ref tmp);
+            tmp.xHotspot = xHotSpot;
+            tmp.yHotspot = yHotSpot;
+            tmp.fIcon = false;
+            ptr = CreateIconIndirect(ref tmp);
+            return new Cursor(ptr);
+        }
+
+
+        /// <summary>
+        /// Resize the image to the specified width and height.
+        /// </summary>
+        /// <param name="image">The image to resize.</param>
+        /// <param name="width">The width to resize to.</param>
+        /// <param name="height">The height to resize to.</param>
+        /// <returns>The resized image.</returns>
+        public static Bitmap ResizeImage(Image image, int width, int height) {
+            var destRect = new Rectangle(0, 0, width, height);
+            var destImage = new Bitmap(width, height);
+
+            destImage.SetResolution(image.HorizontalResolution, image.VerticalResolution);
+
+            using (var graphics = Graphics.FromImage(destImage)) {
+                graphics.CompositingMode = CompositingMode.SourceCopy;
+                graphics.CompositingQuality = CompositingQuality.HighQuality;
+                graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
+                graphics.SmoothingMode = SmoothingMode.HighQuality;
+                graphics.PixelOffsetMode = PixelOffsetMode.HighQuality;
+
+                using (var wrapMode = new ImageAttributes()) {
+                    wrapMode.SetWrapMode(WrapMode.TileFlipXY);
+                    graphics.DrawImage(image, destRect, 0, 0, image.Width, image.Height, GraphicsUnit.Pixel, wrapMode);
+                }
+            }
+
+            return destImage;
+        }
+
+        public static Cursor GetCursor(int penSize, int cellSize, int gap) {
+            int size = (cellSize + gap) * penSize;
+
+            Bitmap bmp = new(size, size);
+            Pen pb = new(Color.Black, 1);
+            SolidBrush bw = new(Color.FromArgb(160, Color.White));
+            using (Graphics g = Graphics.FromImage(bmp)) {
+                g.DrawRectangle(pb, 0, 0, size-1, size-1);
+                g.FillRectangle(bw, 1, 1, size - 2, size - 2);
+            }
+            return CreateCursorNoResize(bmp, cellSize / 2, cellSize / 2);
+        }
+
+    }
+}