Re: Sine Wave using GDI+ - C# Discussion Boards

4-Jun-08 2:55

Hi..

I Need to Draw a sine wave on the form based on the X and Y values. I have stored those values in List variable..

How can i draw a continuous sine wave using GDI+ using C#

Guffa4-Jun-08 3:00

Guffa

4-Jun-08 3:00

In the Graphics class you have the DrawLine, DrawLines, DrawBezier and DrawBeziers methods. Use whatever fits the kind of data you have in the list.

To draw graphics on a form, use the Paint event of the form or of a control on the form. A graphics object that you should use for the drawing is send in the event arguments to the event handler.

Despite everything, the person most likely to be fooling you next is yourself.

vinay_K4-Jun-08 3:10

4-Jun-08 3:10

But How can i get a continuous sine wave using Drawline, etc..

I have 100 samples from ADC, now i need to draw a waveform in winForm. Can u suggest me some link where can i get the complete information abt thid..??

leppie4-Jun-08 3:14

leppie

4-Jun-08 3:14

DrawLines takes a Point[], what is the problem?

xacc.ide - now with TabsToSpaces support
IronScheme - 1.0 alpha 4a out now (29 May 2008)

vinay_K4-Jun-08 3:36

4-Jun-08 3:36

When i increase the HZoomFactor (zoom in). the waveform that is displaying is not looks like Sine wave.. What can i do for that..?

Can i Get any Examples on GDI+.

leppie4-Jun-08 3:42

leppie

4-Jun-08 3:42

Use DrawCurve rather then.

Actually I have no idea what you mean by that. What does it look like if it does not look like a Sine wave?

xacc.ide - now with TabsToSpaces support
IronScheme - 1.0 alpha 4a out now (29 May 2008)

Alan Balkany4-Jun-08 4:06

Alan Balkany

4-Jun-08 4:06

When you zoom in you need to redraw your sine wave in OnPaint ().

Because pixels on the screen are discrete, any "curve" you draw is only an approximation at a given level. Zooming in gives you more pixels per measurement unit, magnifying the approximation errors from the previous curve, so it needs to be redrawn.

Guffa4-Jun-08 3:28

Guffa

4-Jun-08 3:28

There is no method that can draw a sine wave. You have to divide the wave into lines or curves, and draw them individually. The DrawLines method takes an array of Point values, so that you can draw several attached lines in one call.

Despite everything, the person most likely to be fooling you next is yourself.

vinay_K4-Jun-08 3:44

4-Jun-08 3:44

Yes i tried and i got the solution for my problem, initially i was trying with Drawline so im not able to draw properly, using Drawlines it is coming properly..

Thank you.
Guffa

Performance issue when using DLL Import to call C++ function from C#

Russell Jones4-Jun-08 5:53

Russell Jones

4-Jun-08 5:53

if the problem is that you require smoothing between points you could use something like a bezier curve to draw your sine wave

GalitM4-Jun-08 1:45

GalitM

4-Jun-08 1:45

Hi,

We are using a C++ dll from our C# code.
The C++ code reads data from a serial communication port, and fills up a buffer with the data read.
We are sometimes experiencing a big delay (around 5 seconds) when the C++ function returns.
The C# code looks something like this:

class Program
{

[DllImport("SerialCommunication.dll", EntryPoint = "SerialCommRead", SetLastError = true)]
protected static extern unsafe SERIAL_COM_STATUS SerialCommRead(uint handle,
[MarshalAs(UnmanagedType.LPArray)] byte[] buffer,
uint length, [MarshalAs(UnmanagedType.LPArray)] uint[] bytesRead);

protected void Read()
{
StreamWriter logWriter = new new StreamWriter("test.log", true);
SERIAL_COM_STATUS status = SerialCommRead(m_PortHandle, m_ReadBuffer,(uint)m_ReadBuffer.Length, bytesRead);
DateTime t = DateTime.Now;
logWriter.Write(t.Day.ToString() + "/" + t.Month.ToString() + "/" + t.Year.ToString() + " " +
t.Hour.ToString() + ":" + t.Minute.ToString() + ":" + t.Second.ToString() + "." +
t.Millisecond.ToString() + " ");
logWriter.WriteLine("After SerialCommRead(), status: " + status.ToString() + " bytesRead: " +
bytesRead[0].ToString());
logWriter.Flush();
}
}

The C++ code:

__declspec(dllexport) SERIAL_COM_STATUS SerialCommRead(HANDLE handle, unsigned char *buffer,
unsigned int length, unsigned int *bytesRead)
{
COMSTAT ComStat;
DWORD errorFlags, err;
*bytesRead = 0;
OVERLAPPED overlappedRead;
memset(&overlappedRead, 0, sizeof(OVERLAPPED));
overlappedRead.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
if (!overlappedRead.hEvent) {
err = GetLastError();
return(SER_COM_CREATE_EVENT_ERROR);
}
if (!ClearCommError(handle, &errorFlags, &ComStat)) {
err = GetLastError();
CloseHandle(overlappedRead.hEvent);
return(SER_COM_READ_ERROR);
}
if (!ComStat.cbInQue) {
CloseHandle(overlappedRead.hEvent);
return(SER_COM_OK); // There is nothing in queue to read
}
DWORD numOfBytesRead = 0;
if (!ReadFile(handle, (LPVOID)buffer, (DWORD)length, &numOfBytesRead, &overlappedRead)) {
err = GetLastError();
if (ERROR_IO_PENDING == err) {
DWORD res = WaitForSingleObject(overlappedRead.hEvent, SER_COM_OVERLAP_READ_TIMEOUT);
switch (res) {
case WAIT_OBJECT_0:
if (!GetOverlappedResult(handle, &overlappedRead, &numOfBytesRead, TRUE)) {
err = GetLastError();
CloseHandle(overlappedRead.hEvent);
return(SER_COM_GET_OVERLAP_ERROR);
}
break;
case WAIT_TIMEOUT:
*bytesRead = (unsigned int)numOfBytesRead;
CloseHandle(overlappedRead.hEvent);
return(SER_COM_TIMEOUT_ERROR);
case WAIT_FAILED:
err = GetLastError();
*bytesRead = (unsigned int)numOfBytesRead;
CloseHandle(overlappedRead.hEvent);
return(SER_COM_WAIT_ERROR);
default:
*bytesRead = (unsigned int)numOfBytesRead;
CloseHandle(overlappedRead.hEvent);
return(SER_COM_ERROR);
}
} else {
CloseHandle(overlappedRead.hEvent);
return(SER_COM_READ_ERROR);
}
}
CloseHandle(overlappedRead.hEvent);
*bytesRead = (unsigned int)numOfBytesRead;
PrintToFile("SerialCommRead(): going to return");
return(SER_COM_OK);
}

void PrintToFile(char *str)
{
struct _timeb timebuffer;
_ftime( &timebuffer );
char timeline[26];
ctime_s( timeline, 26, & ( timebuffer.time ) );
static FILE *fHandle = NULL;
if (NULL == fHandle)
{
// First time, open th file
fHandle = fopen(“test2.log”, "wt");
}
if (fHandle) {
fprintf(fHandle, "%.19s.%hu ", timeline, timebuffer.millitm);
fprintf(fHandle, "%s\n", str);
fflush(fHandle);
}
}

In file “test2.log” the printout of “SerialCommRead(): going to return” appears with a timestamp that is sometimes 5 seconds earlier than the printout to “test.log” from the C# code.
Looks like it takes the C++ function 5 seconds to return…

Any ideas?

Thanks,

Galit.

Re: Performance issue when using DLL Import to call C++ function from C#

Harvey Saayman4-Jun-08 4:56

Harvey Saayman

4-Jun-08 4:56

ive got an idea...

PUT YOUR CODE IN [pre] and [code] TAGS!!!

no one wants to read unindented code. especially if its as much code as you posted

Harvey Saayman - South Africa
Junior Developer
.Net, C#, SQL
think BIG and kick ASS

you.suck = (you.passion != Programming)

Help with Excel Formula

MumbleB4-Jun-08 1:43

4-Jun-08 1:43

Hi Guys. I have an application that writes a bunch of records to Excel. At the end of writing the data I need to sum a column. However, I don't know how many records there will be in the file so I can't set the range to sum in the code. I tried this by setting it something like the below but for some reason it doubles the Total that is summed.

I need to know how to get the last range and set that in the formula dynamically.

objRange = objSheet.get_Range("E1", System.Reflection.Missing.Value);
objRange.Formula = "=SUM(J4:J50000)";
objRange.FormulaHidden = true;
objRange.Calculate();
objRange.Font.Bold = true;
objRange.Font.ColorIndex = "5";

From the above I am selecting cel E1 and in this cell I have the formula to sum the totals of the data in Column J. As I don't know what the last line of data is going to be I set the final cell to calculate as J50000.

Can somebody please help me with this??

Cheers

Excellence is doing ordinary things extraordinarily well.

Jimmanuel4-Jun-08 2:48

4-Jun-08 2:48

int lastUsedColumn = worksheet.Cells.SpecialCells(XlCellType.xlCellTypeLastCell, Type.Missing).Column;
int lastUsedRow = worksheet.Cells.SpecialCells(XlCellType.xlCellTypeLastCell, Type.Missing).Row;

should tell you the last used row and column

MumbleB4-Jun-08 2:58

4-Jun-08 2:58

Thanks mate. Then how do I use that in the formula. Sorry for asking.

Excellence is doing ordinary things extraordinarily well.

Jimmanuel4-Jun-08 3:08

4-Jun-08 3:08

instead of summing from J4 to J5000 sum from J4 to J[last used row]. then you won't be including any extra rows in your sum

MumbleB4-Jun-08 3:15

4-Jun-08 3:15

Brilliant. I'll give that a shot.

Excellence is doing ordinary things extraordinarily well.

MumbleB4-Jun-08 3:24

4-Jun-08 3:24

Hi Jimmanuel. I have used the below and I get an error when it does the calculation. Am I doing this right?

int lastUsedRow = objSheet.Cells.SpecialCells(Excel.XlCellType.xlCellTypeLastCell,
    Type.Missing).Row;

And this is where I add it into the formula.

objRange = objSheet.get_Range("E1", System.Reflection.Missing.Value);
objRange.Formula = "=SUM(J4:J[lastUsedRow])"; //Added in here
objRange.FormulaHidden = true;
objRange.Calculate();
objRange.Font.Bold = true;
objRange.Font.ColorIndex = "5";

Excellence is doing ordinary things extraordinarily well.

Jimmanuel4-Jun-08 3:31

4-Jun-08 3:31

objRange.Formula = string.Format("=SUM(J4:J{0})", lastUsedRow);

it might also be a good idea to do some error checking to make sure that lastUsedRow is valid. I don't know what would happen if you tried summing from J4 to J0 for instance . . .

MumbleB4-Jun-08 3:36

4-Jun-08 3:36

Thanks a million mate. It works 1000% now.

Excellence is doing ordinary things extraordinarily well.

Jimmanuel4-Jun-08 3:41