How can I do

When I move the rectangle, the color of the area in the rectangle will be changed.
I just do like this:
combine the two bitmaps, one has color, one is grayscale.But I want the processing smooth，real time

Hello,

Before I can recommended any changes, I need to know a few things.

1.  What version of the toolkit are you using?
2.  What language are you programming in?
3.  What features of the toolkit are you using to implement the above functionality?  (what ImageProcessing objects, Annotations, etc.)

1. Ver12.1
2. MFC
3. LBitmapRgn

Since you're using LBitmapRgn, it seems that the drawing of the region would be handled by you.  Correct?  If not, could you create a small demo (not your whole app) that shows the behavior and attach it to your reply?

LBitmapRgn Region1(&bmp2, L_RGN_SETNOT);
Region1.SetRgnRect(&Rect);

LBitmap bmpRgn;//
Region1.CreateMaskFromBitmapRgn(&bmpRgn);
bmpRgn.ColorRes(24, CRF_BYTEORDERBGR);
bmpRgn.Combine(&bmp2, 1024, 768);
bmpRgn.GrayScale(8);
bmpRgn.ColorRes(24, CRF_BYTEORDERBGR);
LBitmap bmpColor;
bmpColor.CopyRect(bmp2, Rect);
//
bmpColor.ColorRes(24, CRF_BYTEORDERBGR);
Region1.Free();
if (bmp2.HasRgn())
{
LBitmapRgn rgn(&bmp2);
rgn.Free();
}
if (bmpColor.HasRgn())
{
LBitmapRgn rgn(&bmpColor);
rgn.Free();
}
bmpRgn.Combine(&bmpColor,
(Rect.right - Rect.left), (Rect.bottom - Rect.top),
Rect.left, Rect.top, 0, 0, CB_OP_OR);
//
m_picEdit.Copy(bmpRgn);
bmpColor.Free();
bmpRgn.Free();

<BLOCKQUOTE><table width="85%"><tr><td class="txt4"><img src="/SupportPortal/cs/Themes/default/images/icon-quote.gif">&nbsp;<strong>hxboxy wrote:</strong></td></tr><tr><td class="quoteTable"><table width="100%"><tr><td width="100%" valign="top" class="txt4">LBitmapRgn Region1(&bmp2, L_RGN_SETNOT);
Region1.SetRgnRect(&Rect);

LBitmap bmpRgn;//
Region1.CreateMaskFromBitmapRgn(&bmpRgn);
bmpRgn.ColorRes(24, CRF_BYTEORDERBGR);
bmpRgn.Combine(&bmp2, 1024, 768);
bmpRgn.GrayScale(8);
bmpRgn.ColorRes(24, CRF_BYTEORDERBGR);
LBitmap bmpColor;
bmpColor.CopyRect(bmp2, Rect);
//
bmpColor.ColorRes(24, CRF_BYTEORDERBGR);
Region1.Free();
if (bmp2.HasRgn())
{
LBitmapRgn rgn(&bmp2);
rgn.Free();
}
if (bmpColor.HasRgn())
{
LBitmapRgn rgn(&bmpColor);
rgn.Free();
}
bmpRgn.Combine(&bmpColor,
(Rect.Width()), (Rect.Height()),
Rect.left, Rect.top, 0, 0, CB_OP_OR);
//
m_picEdit.Copy(bmpRgn);
bmpColor.Free();
bmpRgn.Free();</td></tr></table></td></tr></table></BLOCKQUOTE>

How are you moving the rectangle?  On a mouse move event?

Yes！
But I think there must be a better way……

Yeah, I agree.  There maybe a way to do it through Win32 API calls, like painting directly on the DC (device context).   I'm trying a few things right now to see how it works out.

How about that， two bitmap, part of one transparency

I came up with this: instead of using regions, you combine the image on the fly.  Combining image is very fast.  You load the image in LBitmapWindow.  You load the image in 2 other LBitmap objects, so you will have 3 instances of the image in memory.  One of the LBitmap objects will be the original that will never be modified.  The LBimtapWindow will house the grayscale version and the second LBitmap object will house the color image.

We'll define those as:

LBitmapWindow mainGrayscale
LBitmap orginalCopy
LBimtap colorCopy

To draw the rectangle the very first time you do: mainGrayscale->Combine(colorCopy, [check help file for these params], CB_OP_ADD | CP_DST_0)

When the user moves the rectangle you take the previous rectangle value and you gray out that previously colored area, then you color in the new area, like so:

mainGrayscale->Combine(originalCopy, [old rect], CB_OP_ADD | CP_DST_0)
mainGrayscale->Combine(colorCopy, [new rect], CB_OP_ADD | CP_DST_0)

This is close to perfect, but you will notice a minor flicker.

I will update your other post with this same information.

Thanks for the quick response.
That's exaclty what I was looking for. I'll try this approach.