A Class like TreeNode - C# Discussion Boards

Re: Bitmap to Pointer ?

Jared Parsons10-Dec-05 18:54

Jared Parsons

10-Dec-05 18:54

Try the following code

public void CallExternalMethod(Bitmap map)<br />
		{<br />
			System.IO.MemoryStream stream = new System.IO.MemoryStream();<br />
			map.Save(stream, System.Drawing.Imaging.ImageFormat.Bmp);<br />
			byte[] rawBytes = stream.GetBuffer();<br />
<br />
			unsafe <br />
			{<br />
				fixed (byte* rawPointer = rawBytes)<br />
				{<br />
					function1(rawPointer, classificator);<br />
				}<br />
			}<br />
		}<br />

Jared Parsons
jaredp@beanseed.org
http://spaces.msn.com/members/jaredp/

Re: Bitmap to Pointer ?

ger_creal11-Dec-05 2:22

ger_creal

11-Dec-05 2:22

It runs

thx a lot. Roll eyes | :rolleyes:

Re: Bitmap to Pointer ?

Ista11-Dec-05 14:28

Ista

11-Dec-05 14:28

If you have a library use PInvoke and give the DLLImport attribute.

To get a pointer use IntPtr.

You might do that instead having to all the unsafe declarations

I'm not an expert yet, but I play one at work. Yeah and here too.

-- modified at 20:29 Sunday 11th December, 2005

Re: Bitmap to Pointer ?

Jared Parsons12-Dec-05 4:56

Jared Parsons

12-Dec-05 4:56

I typically prefer IntPtr's to unsafe code myself but the poster wanted a real *. For the curious though, here is the example with "safe" code.

<br />
[DllImport]<br />
public static extern bool function1<br />
[MarashalAs(UnmanagedType.LPArray)]byte[] data,<br />
int classificator);<br />

That's not 100% correct though because I don't know the return type and I'm not sure what type classificator is.

Note: By "safe" I mean the opposite of unsafe. I'm not implying this code is secure Smile | :)

Jared Parsons
jaredp@beanseed.org
http://spaces.msn.com/members/jaredp/

Need Help

cmrotruck10-Dec-05 9:48

cmrotruck

10-Dec-05 9:48

I was wondering if you can help me. I am trying to get a number pad to show up in a text box. EX. if you click on button 1 then the number 1 will show up in the text box. I have already created the form

Re: Need Help

Colin Angus Mackay10-Dec-05 13:35

Colin Angus Mackay

10-Dec-05 13:35

In the button event for each of the buttons set (or append) the relevant number to the Text property of the TextBox.

My: Blog | Photos

"Man who stand on hill with mouth open will wait long time for roast duck to drop in." -- Confucious

Re: Need Help

Ista11-Dec-05 11:29

Ista

11-Dec-05 11:29

private void Button1(object ....

myText.Text += "1";

I'm not an expert yet, but I play one at work. Yeah and here too.

A Class like TreeNode

Bahadir Cambel10-Dec-05 9:31

Bahadir Cambel

10-Dec-05 9:31

How could I design a class like TreeNode, I have tried but I am getting a Object Reference Exception

public class classA<br />
{<br />
public classA(){}<br />
public void INeed()<br />
{<br />
classB b = new classB();<br />
b.Add(string something);<br />
}<br />
}<br />
public class classB<br />
{<br />
private string att1;<br />
private int index ;<br />
private classB[] container;<br />
public classB()<br />
{<br />
container = new classB[100];index = 0 ;<br />
}<br />
public void Add(string addNew)<br />
{<br />
container[index].att1 = addNew;//causes error<br />
index++;<br />
}<br />
}

If I do so , am getting a Object reference not set to an instance of an object error
in the line that I try to add something to the container.
Could you explain why ?
And how could I deal with the issue ?

-- modified at 15:24 Saturday 10th December, 2005

Re: A Class like TreeNode

Sean Michael Murphy10-Dec-05 10:05

Sean Michael Murphy

10-Dec-05 10:05

Bahadir Cambel wrote:
If I do so , am getting a Object reference not set to an instance of an object error
in the line that I try to add something to the container.
Could you explain why ?

Bahadir Cambel wrote:
C#
container = new classB[100];</code></blockquote>

That <code>new</code> just allocates the space for the array elements.  It doesn't instantiate the 100 objects; you have to do that yourself.
<pre>public void Add(string addNew) {
   container[index] = new classB(); // my addition.
   container[index].att1 = addNew;//causes error
   index++;
}
If you don't actually want exactly 100 elements (did you just pick an arbitrarily large number...?) you should use a dynamically sized container, like an ArrayList, rather than an array. Just my 2 cents...

Share and enjoy.
Sean

Re: A Class like TreeNode

Bahadir Cambel10-Dec-05 10:20

Bahadir Cambel

10-Dec-05 10:20

Yes it was a arbitrarily large number.

Thanks for you replay , it solved my problem.

Bado

Re: A Class like TreeNode

Ista11-Dec-05 14:31

Ista

11-Dec-05 14:31

why not just use the add method to add your object.

Try extending the IList Interface. It will help you

class MyClass : IList

I'm not an expert yet, but I play one at work. Yeah and here too.

How to make a report in c#

ngt10-Dec-05 5:35

ngt

10-Dec-05 5:35

I'm quiet new in c#, Now I'm try to develop a HR management program and this application need to have a report to show and print out to user, and there are more than one type of report that available for my user to choose, all the user have to do is just choose which report he/she like, So I want to know is there any easy tool to do a report? I try to use crystal report but I have to make a file name .rpt but in my case I need many report ,so do i have to make many .rpt file? or is there any other way to implement this? And can i use sql command with each report? if yes how? Please give me some suggestion . Thanks... I use VS.Net 2003 And SQL Server 2000 .

Re: How to make a report in c#

Ista11-Dec-05 11:30

Ista

11-Dec-05 11:30

do crystal reports or something.

You can use the printing namespace but would take forever

I'm not an expert yet, but I play one at work. Yeah and here too.

For image processing experts

haytham_mohammad10-Dec-05 3:06

haytham_mohammad

10-Dec-05 3:06

I would like to know why we write this formula to change from color to Grayscale picture
The formula is p[0] = p[1] = p[2] = (byte)(.299 * red + .587 * green + .114 * blue);
thanks in advance

haitham

Re: For image processing experts

rob tillaart10-Dec-05 5:08

rob tillaart

10-Dec-05 5:08

The different colors have a different brightness, red and blue are perceived darker as darker colors. I assume it has to do with the fact that red and blue are on the ends of the visible spectrum while green is in the middle.

regards,
rob tillaart

Re: For image processing experts

haytham_mohammad10-Dec-05 6:33

haytham_mohammad

10-Dec-05 6:33

i know that this code convert the perceived bytes of the RGB to be within the domain 0-->255 and the rgb saved as 24byte per pixel i.e 3 * 8 bytes in other words red take byte blue takes byte etc so my question why we multiply the red color by the number (.299) specifically and of course the remaining numbers
thanks for ur attention.

haitham

Re: For image processing experts

Stanciu Vlad10-Dec-05 8:09

Stanciu Vlad

10-Dec-05 8:09

Converting a image to a grayscale has no standard. Mostly on the internet you will find this forumla givven by the NTSC standard

GS = 0.3*R + 0.59*G + 0.11*B

These scaling values (0.3, 0.59, 0.11) can variate. Their main purpose is to sum up to a property (luminance) of the givven color. The final color is from the grayscale because you set all the 3 bytes to the same value.

Try using other scaling values in your ConvertToGrayscale procedure and observe the diferrences.- of course that the standard values haven't been found through experimentation, a good image processing skil is required and if I m not mistaking phisics is needed too in order to get to a such result.

protected internal static readonly ... and I wish the list could continue ...

Re: For image processing experts

rob tillaart11-Dec-05 1:20

rob tillaart

11-Dec-05 1:20

http://www.pjb.com.au/comp/colours.html#item_rgb2gray[^]

states it comes from the NTSC video standard.

"The above invocation causes the r g b colour to be converted to its equivalent gray value, which is then left on the stack. The conversion follows the NTSC video standard, which determines how a colour television signal is rendered on a black and white television: gray = .3 * red + .59 * green + .11 * blue"

http://www.netnam.vn/unescocourse/computervision/12.htm[^]
has some more background about different color spaces.

regards rob

Re: For image processing experts

Ista11-Dec-05 14:33

Ista

11-Dec-05 14:33

You know they provide an imaging namespacing to do this math so as specifications change your code will not.

And the Color object can convert values for you

I'm not an expert yet, but I play one at work. Yeah and here too.

Re: For image processing experts

haytham_mohammad12-Dec-05 3:18

haytham_mohammad

12-Dec-05 3:18

DO u mean that the color object consists a method to convert the picture from color to grayscale or any specific format?
i didnt try it yet but i think that it will be slower than we handle this ourselves
thanks for ur help

haitham

Re: For image processing experts

Ista12-Dec-05 3:22

Ista

12-Dec-05 3:22

no,but there is an imaging namespace that would be more effecient, unless you do the processing in C++

I'm not an expert yet, but I play one at work. Yeah and here too.

Re: For image processing experts

haytham_mohammad12-Dec-05 18:42

haytham_mohammad

12-Dec-05 18:42

how can i know the capabilities of the imaging name space
and i want to know also if there is any book talk about the image processing in c# or handle the image processing methods of matlab in c#
thanks in advance

haitham

Re: For image processing experts

Ista13-Dec-05 2:28

Ista

13-Dec-05 2:28

a link to using matlab http://www.codeproject.com/dotnet/matlabeng.asp[^] in c#

Just create an image and use the System.Drawing.Imaging namespace.

Use your Object Browser to view the objects you can use.

Nick

I'm not an expert yet, but I play one at work. Yeah and here too.

request:source code

sachappi10-Dec-05 2:30

sachappi

10-Dec-05 2:30

hello everybody..can someone help me in finding the source code in c# for my major project..my topic is "IMPLEMENTATION OF VIRTUAL PRIVATE NETWORK USING LOGICAL TUNNELING"..actually i found a software on net similar to my project..the name is AccessPoint SSL VPN software..but i am not able to download the toolkit version 1.1 from freedownloadscentre..can someone please help me out..thanx in advance..God bless u all..
spider

hi guys i am spiderman

Re: request:source code

Colin Angus Mackay10-Dec-05 7:22

Colin Angus Mackay

10-Dec-05 7:22

I would have thought that VPN software would more commonly be found lower down than C#. I would have said that implementations would most likely be written in C or C++ and be written as a driver rather than in a high level C# application.

My: Blog | Photos

"Man who stand on hill with mouth open will wait long time for roast duck to drop in." -- Confucious

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.