Ribbon button image with partial transparent pixels

[jholdawayUKBGN]

Hello,

I have seen all the examples of adding a button to the ribbon in Inventor.  I have to set the image using a the picture converter to get a stdole.IPictureDisp.  It works just fine except if my image has partially transparent pixels, the graphic is not correct.

Addin.InventorApplication.CommandManager.ControlDefinitions.AddButtonDefinition("my button",
				"myId",
				CommandTypesEnum.kQueryOnlyCmdType,
				Addin.ID,
				"tooltip",
				"tooltip,
				null,
				PictureDispConverter.ToIPictureDisp(Properties.Resources.ManMotion_32),
				ButtonDisplayEnum.kAlwaysDisplayText)


	public sealed class PictureDispConverter
    {
        [DllImport("OleAut32.dll",
            EntryPoint = "OleCreatePictureIndirect",
            ExactSpelling = true,
            PreserveSig = false)]
        private static extern stdole.IPictureDisp
            OleCreatePictureIndirect(
                [MarshalAs(UnmanagedType.AsAny)] object picdesc,
                ref Guid iid,
                [MarshalAs(UnmanagedType.Bool)] bool fOwn);

        static Guid iPictureDispGuid = typeof(stdole.IPictureDisp).GUID;

        private static class PICTDESC
        {
            //Picture Types
            public const short PICTYPE_UNINITIALIZED = -1;
            public const short PICTYPE_NONE = 0;
            public const short PICTYPE_BITMAP = 1;
            public const short PICTYPE_METAFILE = 2;
            public const short PICTYPE_ICON = 3;
            public const short PICTYPE_ENHMETAFILE = 4;

            [StructLayout(LayoutKind.Sequential)]
            public class Icon
            {
                internal int cbSizeOfStruct = Marshal.SizeOf(typeof(PICTDESC.Icon));
                internal int picType = PICTDESC.PICTYPE_ICON;
                internal IntPtr hicon = IntPtr.Zero;
                internal int unused1;
                internal int unused2;

                internal Icon(System.Drawing.Icon icon)
                {
                    this.hicon = icon.ToBitmap().GetHicon();
                }
            }

            [StructLayout(LayoutKind.Sequential)]
            public class Bitmap
            {
                internal int cbSizeOfStruct = Marshal.SizeOf(typeof(PICTDESC.Bitmap));
                internal int picType = PICTDESC.PICTYPE_BITMAP;
                internal IntPtr hbitmap = IntPtr.Zero;
                internal IntPtr hpal = IntPtr.Zero;
                internal int unused;

                internal Bitmap(System.Drawing.Bitmap bitmap)
                {
                    this.hbitmap = bitmap.GetHbitmap();
                }
            }
        }

        public static stdole.IPictureDisp ToIPictureDisp(System.Drawing.Icon icon)
        {
            PICTDESC.Icon pictIcon = new PICTDESC.Icon(icon);

            return OleCreatePictureIndirect(pictIcon, ref iPictureDispGuid, true);
        }

        public static stdole.IPictureDisp ToIPictureDisp(System.Drawing.Bitmap bmp)
        {
            PICTDESC.Bitmap pictBmp = new PICTDESC.Bitmap(bmp);

            return OleCreatePictureIndirect(pictBmp, ref iPictureDispGuid, true);
        }
    }

I have attached the sample png to see what I'm doing wrong.  Any help would be appreciated!. 

[jholdawayUKBGN · Accepted solution]

Here is the fix after playing around.  It seems you need to use an actual .ico file, and that PictureDispConverter needs to be updated with the following for the icon.

[StructLayout(LayoutKind.Sequential)]
            public class Icon
            {
                internal int cbSizeOfStruct = Marshal.SizeOf(typeof(PICTDESC.Icon));
                internal int picType = PICTDESC.PICTYPE_ICON;
                internal IntPtr hicon = IntPtr.Zero;
                internal int unused1;
                internal int unused2;

                internal Icon(System.Drawing.Icon icon)
                {
                    this.hicon = icon.Handle;
                }
            }

[MjDeck]

Thanks @jholdawayUKBGN . That makes a big difference.

One note: it looks like the handle returned directly from the icon might not always be valid. This seems to depend on how the icon was created. I recommend replacing the line:

  this.hicon = icon.Handle;

 with this:

  System.Drawing.Icon newIcon = icon.Clone() as System.Drawing.Icon;
  this.hicon = newIcon.Handle;