Creating a GraphicsInterface.ImageBGRA32

By Balaji Ramamoorthy

Here is a sample code to demonstrate the creation of an instance of “ImageBGRA32” class from a bitmap and to use it in a “WorldDraw” method. The code to copy the raw bytes between two arrays is not optimized and I think there are more efficient way to do it. But I hope this sample code helps you get started.

Circle c = (Circle)drawable;
Bitmap bitmap = new Bitmap(@"c:WorkTest.bmp");
 
BitmapData raw = bitmap.LockBits
    (
        new Rectangle(0, 0, (int)bitmap.Width, (int)bitmap.Height), 
        ImageLockMode.ReadOnly, 
        bitmap.PixelFormat
    );
 
int size = raw.Height * raw.Stride;
byte[] rawImageRGB24 = new Byte[size];
System.Runtime.InteropServices.Marshal.Copy(
        raw.Scan0, rawImageRGB24, 0, size);
 
byte[] rawImageBGRA32 = new Byte[bitmap.Width * bitmap.Height * 4];
int rgbIndex = 0;
int rgbaIndex = 0;
for (int row = 0; row < bitmap.Height; row++)
{
    for (int col = 0; col < bitmap.Width; col++)
    {
        rgbIndex = col * 3 + row * raw.Stride;
        rgbaIndex = col * 4 + row * bitmap.Width * 4;
 
        rawImageBGRA32[rgbaIndex] 
                    = rawImageRGB24[rgbIndex];         // Blue
 
        rawImageBGRA32[rgbaIndex + 1] 
                    = rawImageRGB24[rgbIndex + 1];    // Green
 
        rawImageBGRA32[rgbaIndex + 2] 
                    = rawImageRGB24[rgbIndex + 2];    // Red
 
        rawImageBGRA32[rgbaIndex + 3] 
                    = 255;                            // Alpha
    }
}
if (raw != null)
{
    bitmap.UnlockBits(raw);
}
 
IntPtr unmanagedPointer 
                = Marshal.AllocHGlobal(rawImageBGRA32.Length);
 
Marshal.Copy(
             rawImageBGRA32, 
             0, 
             unmanagedPointer, 
             rawImageBGRA32.Length); 
 
ImageBGRA32 imgBGRA32 
    = new ImageBGRA32
                    (
                        (uint)bitmap.Width, 
                        (uint)bitmap.Height, 
                        unmanagedPointer
                    );
 
bool result 
        = wd.Geometry.Image
                (
                    imgBGRA32, 
                    c.Center, 
                    Vector3d.XAxis * (bitmap.Width / bitmap.Height), 
                    Vector3d.YAxis
                );
Marshal.FreeHGlobal(unmanagedPointer);
return result;