Re: Problem with painting a form - C# Discussion Boards

Re: Differences between strings

10-Mar-07 5:57

You'd have to write something to do this. A starting point may be to sort both strings alphabetically, and then compare them, to work out if you only have an error of letter order. Then you can walk them character by character, to work out a list of letters that were added, and that were missing, if the wrong letters were also used.

Christian Graus - Microsoft MVP - C++
Metal Musings - Rex and my new metal blog
"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )

Phillip M. Hoff10-Mar-07 16:43

Phillip M. Hoff

10-Mar-07 16:43

There are a number of algorithms that have been developed to determine the similarity between strings (either spelling-wise or pronunciation-wise). A quick Google search brought up this[^], which should give you a good starting point.

-Phil

move image through a path [modified]

waleed9910-Mar-07 5:33

waleed99

10-Mar-07 5:33

I want to move Image through a Path on form
I mean from many points in form until reach destianation
from A , B ,c , d
Like a Flash ,
please Help me.

-- modified at 11:39 Saturday 10th March, 2007

Re: move image through a path

Christian Graus10-Mar-07 5:43

Re: move image through a path

10-Mar-07 5:43

You need to either use a picturebox ( this is for girls ), or draw the image yourself. You need to set a timer, and handle your paint event. Your timer needs to call Invalidate() to force a paint message, and your paint event needs to draw the image in the right location.

Actually, if you use a picturebox, your timer event can set it's location without having to Invalidate(), but that solution doesn't scale well if you have a lot of images.

waleed9910-Mar-07 21:13

waleed99

10-Mar-07 21:13

Thank You very much !
Keep in touch

Problem with painting a form

-raada-10-Mar-07 5:06

-raada-

10-Mar-07 5:06

Hi,

I'm fighting with performance problems in application which displays data from sound card on the fly.

How can I suppress repaintig a form everytime I move other window over the form or scroll it?

Can I control painting the form only programmaticaly, makes the form holds its state when other window covers it and simply ignore such an events?

Christian Graus10-Mar-07 5:15

10-Mar-07 5:15

-raada- wrote:
How can I suppress repaintig a form everytime I move other window over the form or scroll it?

You can't.

-raada- wrote:
Can I control painting the form only programmaticaly, makes the form holds its state when other window covers it and simply ignore such an events?

What you are asking is, you want the form to not refresh itself when it is obscured. If the form is covered, it won't paint itself. It will paint itself when it is uncovered again, or it will be blank.

You can set the AllPaintInWMPaint ( something like that ) control flag, and override the Paint event to control exactly what gets painted. You could set flags within the program which cause this event to do nothing, but, of course, your program will then be ugly.

How do you know that the paint event is your performance problem ? What are you painting ?

-raada-10-Mar-07 7:49

-raada-

10-Mar-07 7:49

I know it because when the painting module is not attached the problem doesn't exist. (Module works with already preprocessed data and doesn't do much other thing then just paint them.)

Each sample is represented by array of double values which represents intensity of given frequency in that sample - when it's bigger than a threshold I paint a line at proper place (x axis is time y frequency)

When I repaint the whole signal when new sample was processed - it was unbearable.
Painting is executed in separate thread and I couldn't achieved satisfying results by just set time interval for repainting the signal.
So now I paint just individual samples by calling InvalidateRectangle method and whole signal when Paint event is fired not programmaticaly. But still not satisfyed.

I was asking just to be sure if I have to optimalize painting algorythm or I'm missing something else.

Christian Graus10-Mar-07 8:10

10-Mar-07 8:10

It does sound like your actual painting code needs optimising. Not drawing parts of it, is not optimisation.

Luc Pattyn10-Mar-07 15:15

Luc Pattyn

10-Mar-07 15:15

Hi,

how much data is there to paint ? More samples than pixels in a row ?? If so, reduce the paint work
by either skipping or taking an average value.

It might help to show some code (and some typical values).

Smile | :)

Luc Pattyn

[My Articles]

-raada-12-Mar-07 12:03

-raada-

12-Mar-07 12:03

Hi Luc,

well ... I supppose that the most used setting will lead to 160 or 80 Hz frequency when 256 long array of transformed double values has to be processed by painting algorythm.

here is sample code

private void DrawDFTSample(double[] sample, Graphics g)
{
	Range yRange = description.YRange;
	double colorIndex = 0;
	double colorIndexStep = description.Colors.Length / sample.Length;
	double fi;	//frequency intensity

	int yGraphBeginning = Height;	// subtract value to display from this

	double yDisplay;
	int xDisplay = currentRectangle.X + currentRectangle.Width / 2;

	Pen p = new Pen(Color.Red);
	p.Width = (currentRectangle.Width > 1) ? currentRectangle.Width - 1 : 1;

	double threshold = 0;
			
	yDisplay = yGraphBeginning;

	for(int i=0; i<sample.Length; i++)
	{
		fi = sample[i];
		if(fi >= threshold)
		{
			p.Color = description.Colors[(int)colorIndex];
			yDisplay -= yPixStep;
			g.DrawLine(p, xDisplay-1, (int)yDisplay, xDisplay+1, (int)yDisplay);
		}
		colorIndex += colorIndexStep;
	}

	counter++;
	currentRectangle.X = (int)((double)counter * xPixStep);
}

Now I will try to optimize it by storing already computed values into array of points so I will be able to just draw them without reprocessing signal values when need to repaint whole signal occur.

Hope it will help me Smile | :)

Luc Pattyn12-Mar-07 12:37

Luc Pattyn

12-Mar-07 12:37

Hi,

at first glance your code is OK except maybe for p.Color=...
I am not sure but this seems potentially the most expensive line in the for loop.

May I suggest you first retry with only one pen that does not change at all;
if perfo then is all right (or at least much better), make an array of pens
corresponding to description.Colors[] unless that array is really big.

Furthermore I am confused by the line
colorIndexStep = description.Colors.Length / sample.Length;
since it suggests there are more colors than samples (and with 256 samples, that would
be a lot of colors...)

And what is the "160 or 80 Hz frequency" you mentioned ?
is this the rate at which you hope to get the display updated ?? I dont think
Windows can do this at all (see my timers article !).

Best regards.

Luc Pattyn

[My Articles]

Error

shamsteady10-Mar-07 4:43

shamsteady

10-Mar-07 4:43

There are error to compile this code because panel3.left and panel3.top are not defined in the class. How to overcome this?

protected override void OnMouseMove(MouseEventArgs e)
{
base.OnMouseMove (e);

if (isDragging3 == true)
{

panel3.Left = e.X + panel3.Left - x3;
panel3.Top = e.Y + panel3.Top - y3;

}
}

Christian Graus10-Mar-07 4:48

10-Mar-07 4:48

What is panel3, if it's a control of any type, then it would have those properties.

shamsteady10-Mar-07 5:00

shamsteady

10-Mar-07 5:00

Actually it has that control but it need to be declared. But when i made it into class, but in class it can't be done.

Christian Graus10-Mar-07 5:16

10-Mar-07 5:16

OK, so the control does not exist ? You didn't say that. In the properties window of the designer, make sure the GenerateMember property is true.

And, choose a better name for it.

M-Hall10-Mar-07 6:48

M-Hall

10-Mar-07 6:48

The problem is that you have abstracted the class from the control, and you have control specific code: you should use
protect override void OnmouseMouseMove(System.Object sender,
System.Windows.Forms.MouseEventArgs e) then you should be able to access the left and top property's through the sender object

shamsteady10-Mar-07 7:01

shamsteady

10-Mar-07 7:01

How to access the left and top property's through the sender object? Can you give example. i am new to c# and need guide..

Christian Graus10-Mar-07 7:27

Do you know any API that can get the name of DVD movie? [modified]

10-Mar-07 7:27

Sounds to me like you need to learn some C# before you try to write whatever it is you are trying to write.

If you handle an event for a control, within your main class, then you have two incoming variables, like this

protected void OnPaneResize(object sender, EventArgs ea)
{
}

You can then do this:

protected void OnPaneResize(object sender, EventArgs ea)
{
Control c = sender as Control;

if (c != null)
{
c.Left = 5; // or whatever
}
}

Khoramdin10-Mar-07 4:30

Khoramdin

10-Mar-07 4:30

Hello,

I am using C# and DirectShow making a Windows Application to play DVD. I would like to be able to display the name of the DVD movie which is playing in the application.

I was wondering if you know of any API that I can use to get this information.

Thank you very much and have a great day.

Khoramdin

-- modified at 10:35 Saturday 10th March, 2007

Re: Do you know any API that can get the name of DVD movie?

Christian Graus10-Mar-07 5:17

Re: Do you know any API that can get the name of DVD movie?

10-Mar-07 5:17

You should be able to get the name of hte disc, the name that Windows displays. There is no movie name apart from the disc name encoded onto the disc, so no API can get it.

Khoramdin11-Mar-07 9:31

Khoramdin

11-Mar-07 9:31

Hello Christian,

Thanx for the reply. Since your last message I have done some research and have come to conclusion that base on your advise I should use "System.Management namespace" to get required information.

Could you be kind enough to let me know if this is the correct way to get this done?

Thank you so much for your help.

Khoramdin

Need help creating thumbnails

Mark F.10-Mar-07 4:15

Mark F.

10-Mar-07 4:15

I have the following code that creates a thumbnail for a given image and saves the new image to disk. It works but the images cannot be displayed by MSIE, and it appears that they are a different format than jpeg. Here's the code:

private void MakeThumbImage(string sSrcFilename, string sDestFilename)
{
    Image orgImg = Image.FromFile(sSrcFilename);

    int iHeight = orgImg.Height;
    int iWidth = orgImg.Width;
    int iNewHeight = iHeight;
    int iNewWidth = iWidth;

    if (orgImg.Width >= 96)
    {
        iNewWidth = 96;
    }
    else
    {
        iNewWidth = orgImg.Width;
    }

    double ratio = (double)iWidth / iNewWidth;
    iNewHeight = (iHeight / (int)ratio);

    Image.GetThumbnailImageAbort myCallback = new Image.GetThumbnailImageAbort(ThumbnailCallback);
    Image thumb = orgImg.GetThumbnailImage(iNewWidth, iNewHeight, myCallback, IntPtr.Zero);

    if (thumb != null)
    {
        thumb.Save(sDestFilename);
    }

    orgImg.Dispose();
    thumb.Dispose();
}

private bool ThumbnailCallback()
{
    return false;
}

I need to create a thumb for whatever file type it is (e.g., gif, png, jpg).

Thanks,
Mark

Re: Need help creating thumbnails

Christian Graus10-Mar-07 5:17