/// <summary>
/// Initializes a new instance of the FastBitmapLocker struct with an initial fast bitmap object.
/// The fast bitmap object passed will be unlocked after calling Dispose() on this struct
/// </summary>
/// <param name="fastBitmap">A fast bitmap to attach to this locker which will be released after a call to Dispose</param>
public FastBitmapLocker(FastBitmap fastBitmap)
{
_fastBitmap = fastBitmap;
}
/// <summary>
/// Copies a region of the source bitmap into this fast bitmap
/// </summary>
/// <param name="source">The source image to copy</param>
/// <param name="srcRect">The region on the source bitmap that will be copied over</param>
/// <param name="destRect">The region on this fast bitmap that will be changed</param>
/// <exception cref="ArgumentException">The provided source bitmap is the same bitmap locked in this FastBitmap</exception>
public void CopyRegion(Bitmap source, Rectangle srcRect, Rectangle destRect)
{
// Throw exception when trying to copy same bitmap over
if (source == _bitmap)
{
throw new ArgumentException("Copying regions across the same bitmap is not supported", "source");
}
Rectangle srcBitmapRect = new Rectangle(0, 0, source.Width, source.Height);
Rectangle destBitmapRect = new Rectangle(0, 0, _width, _height);
// Check if the rectangle configuration doesn't generate invalid states or does not affect the target image
if (srcRect.Width <= 0 || srcRect.Height <= 0 || destRect.Width <= 0 || destRect.Height <= 0 ||
!srcBitmapRect.IntersectsWith(srcRect) || !destRect.IntersectsWith(destBitmapRect))
{
return;
}
// Find the areas of the first and second bitmaps that are going to be affected
srcBitmapRect = Rectangle.Intersect(srcRect, srcBitmapRect);
// Clip the source rectangle on top of the destination rectangle in a way that clips out the regions of the original bitmap
// that will not be drawn on the destination bitmap for being out of bounds
srcBitmapRect = Rectangle.Intersect(srcBitmapRect, new Rectangle(srcRect.X, srcRect.Y, destRect.Width, destRect.Height));
destBitmapRect = Rectangle.Intersect(destRect, destBitmapRect);
// Clipt the source bitmap region yet again here
srcBitmapRect = Rectangle.Intersect(srcBitmapRect, new Rectangle(-destRect.X + srcRect.X, -destRect.Y + srcRect.Y, _width, _height));
// Calculate the rectangle containing the maximum possible area that is supposed to be affected by the copy region operation
int copyWidth = Math.Min(srcBitmapRect.Width, destBitmapRect.Width);
int copyHeight = Math.Min(srcBitmapRect.Height, destBitmapRect.Height);
if (copyWidth == 0 || copyHeight == 0)
{
return;
}
int srcStartX = srcBitmapRect.Left;
int srcStartY = srcBitmapRect.Top;
int destStartX = destBitmapRect.Left;
int destStartY = destBitmapRect.Top;
using (FastBitmap fastSource = source.FastLock())
{
ulong strideWidth = (ulong)copyWidth * BytesPerPixel;
for (int y = 0; y < copyHeight; y++)
{
int destX = destStartX;
int destY = destStartY + y;
int srcX = srcStartX;
int srcY = srcStartY + y;
long offsetSrc = (srcX + srcY * fastSource._strideWidth);
long offsetDest = (destX + destY * _strideWidth);
memcpy(_scan0 + offsetDest, fastSource._scan0 + offsetSrc, strideWidth);
}
}
}
