PlotBitmap rises CPU

[Inomed1]

I use the PlotBitpmap function and I considered the hints I read in this forum:

- disabling the  ATTR_REFRESH_GRAPH before calling PlotBitmap

- setting the width and height to 0.0  like PlotBitmap(handle, PANEL_GRAPH, x, y, 0.0, 0.0, NULL);

- discarding the Bitmap after plotting

With small bitmaps everthing works fine. But I want to plot a semi transparent bitmap created with NewBitmapEx() which height is about 870px. With some graphic cards (like the ATI Radeon 9250) the Plotbitmap function causes a percent rise of the CPU about 40% an my application hangs up.With other graphic cards I have no problems too.

  

What may cause this problem?

Thanks in advance

[ralfn]

Hello Inomed1,

which version of CVI do you use?

Maybe the problem comes from the graphicscard-driver. So please download the newest driver and test it again. 

If this doesn't solve the problem please send a small example.

Thank you.

With best regards,

Ralf N.

Application Engineering

Germany 

[Inomed1]

Hello Ralf N.

thanks for your reply.

- I use the LabWindows CVI 8.5.1 

- I installed the newest driver of my graphic card, but I have the same problem, too.

Here is my example code:

static void PlotAlphaBitmap (int windowHandle, int *plotHandle, double x, double y, int width, int height, int colorDepth)
{
	int			size;
	int			bmpId;
	int			bitmap;
	unsigned char		*pixels;
	unsigned char		*mask;
	unsigned char		*alpha; 
	
	SetCtrlAttribute (windowHandle, PANEL_GRAPH, ATTR_REFRESH_GRAPH, 0); 
	
	if (*plotHandle > 0)
	{
		SetCtrlBitmap(windowHandle, PANEL_GRAPH, *plotHandle, 0);  
		DeleteGraphPlot(windowHandle, PANEL_GRAPH, *plotHandle, VAL_DELAYED_DRAW);
		*plotHandle = -1;
	}

	size = sizeof(unsigned char) * width * height * colorDepth; 
	
	pixels = (unsigned char*) malloc(size);
	mask = (unsigned char*) malloc(size);
	alpha = (unsigned char*) malloc(size);
	
	memset(pixels, 0xff, size);
	memset(mask, 0xff, size);
	memset(alpha, 0x40, size);

	bitmap = NewBitmapEx(-1, colorDepth, width, height, NULL, pixels, mask, alpha, &bmpId);  
	*plotHandle = PlotBitmap(windowHandle, PANEL_GRAPH, x, y, 0.0, 0.0, NULL);  
	
	if (bitmap >= 0 && *plotHandle > 0)
		SetCtrlBitmap(windowHandle, PANEL_GRAPH, *plotHandle, bmpId);   
	
	SetCtrlAttribute (windowHandle, PANEL_GRAPH, ATTR_REFRESH_GRAPH, 1); 
	
	DiscardBitmap(bmpId);
	free(pixels);
	free(mask);
	free(alpha);
}

 With best regards

[ralfn]

Hello Inomed1,

thanks for the reply.

At first glance it's not a obvious problem... 

So it would be the best if you send me a simplified CVI-project (with all necessary files) so that we can reproduce the issue here. 

Does it hang the first time when you call the PlotAlphaBitmap()-function or after serveral calls? 

With which graphic-cards did you test the project?

Till the next time.

With best regards

Ralf N.

Applications Engineering