Hi NG,
is there a way to copy a buffer pointed to by a IntPtr directly into a two
dimensional byte-array?
I tried this, what obviously doesn't work:
byte[,] image = new byte[numLine,lineLength];
IntPtr p = <hardwareDeviceClass>.GetBufPtr();
Marshal.Copy(p,image,0,numLine*lineLength);
thanks for help
Rainer 4 11906
Hi Rainer,
is there a way to copy a buffer pointed to by a IntPtr directly into a
two dimensional byte-array?
I tried this, what obviously doesn't work:
byte[,] image = new byte[numLine,lineLength];
IntPtr p = <hardwareDeviceClass>.GetBufPtr();
Marshal.Copy(p,image,0,numLine*lineLength);
How about copying to a single-dimensional array first?
byte[] imageData = new byte[numLines * lineLength];
Marshal.Copy(p, imageData, 0, numLines * lineLength);
byte[,] image = new byte[numLines, lineLength];
for (int i = 0; i < numLines; i++)
for (int j = 0; j < lineLength; j++)
image[i, j] = imageData[(i * lineLength) + j];
Or, you could read each byte separately but that would be slower:
byte[,] image = new byte[numLines * lineLength];
for (int i = 0; i < numLines; i++)
for (int j = 0; i < lineLength; j++)
image[i, j] = Marshal.ReadByte(p, (i * lineLength) + j);
Best Regards,
Dustin Campbell
Developer Express Inc.
Hi Dustin,
thanks for your comments.
"Dustin Campbell" <du*****@no-spam-pleasedevexpress.comschrieb im
Newsbeitrag news:c1**************************@news.microsoft.c om...
How about copying to a single-dimensional array first?
This is what I am doing right now ...
//=========
byte[] tmpImage = new byte[numLine*lineLength];
List<byte[]imageLines = new List<byte[]>();
Marshal.Copy(frameGrabber.GetBufPtr(deviceId), tmpImage, 0,
numLine*lineLength);
for(int i = 0; i< numLine; i++)
{
byte[] line = new byte[lineLength];
Buffer.BlockCopy(tmpImage, i * lineLength, line, 0, lineLength);
imageLines.Add(line);
}
//=========
But the application ist quit time critical, and I wanted to do the Copy(s)
as fast as posible.
Right now (current hardware with current code) it takes me 3 mSek which is
quite acceptable, but faster would be better....
Rainer
Hi Dustin,
>
thanks for your comments.
"Dustin Campbell" <du*****@no-spam-pleasedevexpress.comschrieb im
Newsbeitrag news:c1**************************@news.microsoft.c om...
>How about copying to a single-dimensional array first?
This is what I am doing right now ...
//=========
byte[] tmpImage = new byte[numLine*lineLength];
List<byte[]imageLines = new List<byte[]>();
Marshal.Copy(frameGrabber.GetBufPtr(deviceId), tmpImage, 0,
numLine*lineLength);
for(int i = 0; i< numLine; i++)
{
byte[] line = new byte[lineLength];
Buffer.BlockCopy(tmpImage, i * lineLength, line, 0, lineLength);
imageLines.Add(line);
}
//=========
But the application ist quit time critical, and I wanted to do the
Copy(s)
as fast as posible.
Right now (current hardware with current code) it takes me 3 mSek
which is
quite acceptable, but faster would be better....
Since you know the number of lines in advance, you might use a jagged array
instead of a List<byte[]like so:
byte[] tmpImage = new byte[numLine*lineLength];
byte[][] imageLines = new byte[numLine][];
Marshal.Copy(frameGrabber.GetBufPtr(deviceId), tmpImage, 0, numLine*lineLength);
for (int i = 0; i < numLine; i++)
{
imageLines[i] = new byte[lineLength];
Buffer.BlockCopy(tmpImage, i * lineLength, imageLines[i], 0, lineLength);
}
Best Regards,
Dustin Campbell
Developer Express Inc.
Hi Dustin,
"Dustin Campbell" <du*****@no-spam-pleasedevexpress.comschrieb im
Newsbeitrag news:c1**************************@news.microsoft.c om...
Since you know the number of lines in advance, you might use a jagged
array
Thanks for this hint. Jagged arrays did not cross my way up today and they
sound like what I need.
instead of a List<byte[]like so:
byte[] tmpImage = new byte[numLine*lineLength];
byte[][] imageLines = new byte[numLine][];
Marshal.Copy(frameGrabber.GetBufPtr(deviceId), tmpImage, 0,
numLine*lineLength);
for (int i = 0; i < numLine; i++)
{
imageLines[i] = new byte[lineLength];
Buffer.BlockCopy(tmpImage, i * lineLength, imageLines[i], 0, lineLength);
}
This is how I will do it.
Regards
Rainer This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics
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