Contrast solutions for drawing text and lines onto an image - C# Discussion Boards

3-Jul-07 9:53

since your saying "chunk of data" i would prefer using datasets because..if your using datareaders each time u connect to the database whenever u execute a query..but datasets you can work in disconnected mode..

aneef

Problem with 2 forms

mcaos3-Jul-07 6:09

mcaos

3-Jul-07 6:09

Hi!
I have 2 forms:
Form1 and Form2, how I can write the text of a textbox in Form1 in another textbox in form2?
Thank
Bye.

Luc Pattyn3-Jul-07 6:30

3-Jul-07 6:30

There are a lot of ways to do this. The easiest ones are:

- If form B is created by form A, and A has the initiative (e.g. because there is an
event firing in A), let A do the work using a property of B.

- if the initiative is reverse (the slave form B decides when), then the easiest is by
giving it a public event, so the master form A can wire a delegate to it and
un its update method whenever required.

Hope this helps.

Smile | :)

Luc Pattyn

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mcaos4-Jul-07 0:16

mcaos

4-Jul-07 0:16

Luc Pattyn wrote:
- If form B is created by form A, and A has the initiative (e.g. because there is an
event firing in A), let A do the work using a property of B.

Thaks, but how i can do that? Confused | :confused:

Any example??

By Windows M

Luc Pattyn4-Jul-07 0:29

4-Jul-07 0:29

How does form A change form B's size ? by setting a new value to its Size property.
SImilar for any other property you can imagine (and hence add to a class):

in FormTypeA class:

FormTypeB formB=new FormTypeB();
formB.Show();

...

private void myTextBoxA_TextChanged(object sender, EventArgs e) {
    formB.Size=new Size(500, 600);
    formB.TextBoxText=myTextBoxA.Text;
}

In FormTypeB class:

public string TextBoxText {
    set {
        myTextBoxB.Text=value;
    }
}

May I suggest you work your way through a general C# book...

Smile | :)

Luc Pattyn

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Contrast solutions for drawing text and lines onto an image

thrakazog3-Jul-07 7:37

thrakazog

3-Jul-07 7:37

Bind the same datasource to both textboxes. That way a change in one will show up immediately in the other.

Jon Hulatt3-Jul-07 5:07

Jon Hulatt

3-Jul-07 5:07

Hi All,

The project i'm working on at the moment needs to draw information on top of a photo. The content of the photo varies massively - the colour and brightness vary a lot.

Can anyone think of a way of colouring the lines and text so that they are visible whatever the background image? and even if a line starts in a bright area and proceeds into a dark area?

My only idea is to use a "negative" approach, but i'm not sure how that can be implemented (easily) in GDI+

Any ideas greatfully received.

Thanks

Jon

using System.Beer;

Re: Contrast solutions for drawing text and lines onto an image

Dario Solera3-Jul-07 7:16

Dario Solera

3-Jul-07 7:16

You could probably draw two texts/lines varying the pen width and color, so that each element actually has a small visible outline. For the text, you have to add it to a Path object and use the DrawPath method.
Here you can find some help: http://www.bobpowell.net/faqmain.htm[^]

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Re: Contrast solutions for drawing text and lines onto an image

Luc Pattyn3-Jul-07 7:31

Suppress "CAPS Lock is ON" warning in Windows XP

3-Jul-07 7:31

Hi,

I know of no general solution. Here are some ideas though:

- for lines, one could draw two parallel lines in different colors
- for text, use a heavy font (either bold or black) and make it sufficiently large
- or for text, draw text twice, same font, same size, slightly offset (x+2, y+2)
using different colors
- smart color selection: built a histogram on your image (pick 100 pixels, convert them
to hue value, and now choose a color with the opposite hue = add 180 degrees, full
saturation, full brightness (unless histogram shows image is bright, then use black).
- on a display, use blinking (500 msec on/off)
- on a display, let the added info be drawn differently (other color, wider, ...)
while the user holds down CTRL key

Hope this helps

Smile | :)

Luc Pattyn

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Subrahmanyam K3-Jul-07 4:52

Subrahmanyam K

3-Jul-07 4:52

Hi,

How can the default OS warning message "CAPS Lock is ON" can be suppressed on Windows XP for a password field in C# (.Net FW 2.0).

Note: Windows XP automatically shows the warning message when the CAPS Lock key is turned on for a password field.

Thanks in advance.

Subrahmanyam K

Re: Suppress "CAPS Lock is ON" warning in Windows XP

Dario Solera3-Jul-07 7:08

Dario Solera

3-Jul-07 7:08

You cannot do that in C#. Maybe with some interop, but I don't know.

Reading a Bitmap in Unsafe vs InteropServices.Marshall

PhilDanger3-Jul-07 4:40

PhilDanger

3-Jul-07 4:40

Hi,

I've got the following code which reads from an image that has information encoded in as pixels. My job is to scan through the image, and set the value of an array to true if a pixel is black, and false if it is any other color. I have the following bit of unsafe code that performs it:

            BitmapData bmpdata = AOIImg.LockBits(new Rectangle(0, 0, WIDTH, HEIGHT), ImageLockMode.ReadOnly, AOIImg.PixelFormat);
            IntPtr scan0 = bmpdata.Scan0;
            int stride = bmpdata.Stride;
            int imgOffs;
            try
            {
                //loop through the image and set the main AOI mask
                unsafe
                {
                    byte* imgPtr;
                    for (int y = 0; y < HEIGHT; ++y)
                    {
                        imgOffs = y * stride;
                        imgPtr = &((byte*)scan0)[imgOffs];
                        for (int x = 0; x < WIDTH; ++x)
                        {
                            //checks the blue, green, and red values of the pixel to see if it's black
                            if (imgPtr[0] == 0 && imgPtr[1] == 0 && imgPtr[2] == 0)
                            { //pixel is black -- exclude from aoi mask
                                AOIMask[y * WIDTH + x] = true;
                            }
                            else //no feature
                            {
                                AOIMask[y * WIDTH + x] = false;
                            }
                            imgPtr += 3; //advance ptr by 3 bytes (one pixel)
                        }

                    }
                }
            }
            finally 
            {
                AOIImg.UnlockBits(bmpdata);
#if DEBUG
                //TODO -- remove
                AOIImg.Save(@"C:\temp.png", ImageFormat.Png);
#endif
                AOIImg.Dispose();
            }

However, I was wondering if I could turn this into managed code using InteropsServices.Marshall to copy the pixel data to an array and read through it in a safe context. I was wondering if anyone had any warnings about using this method, such as the stride not being correctly accounted for in the marshalled array (I'm not sure if I have to do this manually or not at all!).

Thanks in advance,

Phil

Re: Reading a Bitmap in Unsafe vs InteropServices.Marshall

Jon Hulatt3-Jul-07 5:31

Jon Hulatt

3-Jul-07 5:31

You'll have to account for stride manually, but there is nothing to this.

The Marshal.Copy() method just copy blocks of data.

If Stride and (Width * BytesPerPixel) are not equal, then the data at the end of each image row is padded with zeros.

This doesn't matter. Make sure you allocate a byte [] array of size = height * stride, and use marshal.copy to fill it.

Use nested loops to avoid any stride difference:-

for (y=0; y<height; y++)
{
  for (x=0; x < width; x++)
  {
      int offset = (y * stride) + (x * BytesPerPixel);
      if (pixels[offset] == black)
           // a black pixel
  } 

}

using System.Beer;

Re: Reading a Bitmap in Unsafe vs InteropServices.Marshall

PhilDanger3-Jul-07 5:53

PhilDanger

3-Jul-07 5:53

Thanks,

This will be double the memory usage of the unsafe version, correct?

-Phil

Re: Reading a Bitmap in Unsafe vs InteropServices.Marshall

Luc Pattyn3-Jul-07 6:35

Reading a remote mp3 file for file size and length

3-Jul-07 6:35

Sure, twice the memory, and a lot slower if you dont use a pointer...

Smile | :)

Luc Pattyn

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mfmaneef3-Jul-07 4:25

Re: Reading a remote mp3 file for file size and length

3-Jul-07 4:25

im coding an mp3 database which will read the URL of an MP3 given by the user and will tell the file size and the length of the mp3. i was trying with FilInfo but it doesnt support URIs.. so i tried System.Net.Webrequest and i couldnt achive what i wanted..please give me a hint how to do it..a little code sample or just the idea would be a great help for me..

P.S: by the way is it possible to get all file details within a remote folder

aneef

Judah Gabriel Himango3-Jul-07 5:20

Re: Reading a remote mp3 file for file size and length

3-Jul-07 5:20

What problems did you run into with WebRequest? I would have thought that would work.

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mfmaneef3-Jul-07 5:31

Re: Reading a remote mp3 file for file size and length

3-Jul-07 5:31

actually i dont know much about webrequest..i just tried it and it was taking alot of time to respond.can you show me a sample code how to use that?

aneef

Judah Gabriel Himango3-Jul-07 5:47

Using WebRequest and WebResponse[^]

3-Jul-07 5:47

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Re: Reading a remote mp3 file for file size and length

mfmaneef3-Jul-07 6:28

Re: Reading a remote mp3 file for file size and length

3-Jul-07 6:28

it seems web request has methods to download the file..bt isnt there anyway to get the file details without downloading..something like this download accelerators does..they show the file size n details before they download a perticular file.

aneef

Judah Gabriel Himango3-Jul-07 9:05

Compilation Error with Resource strings

3-Jul-07 9:05

I'm not sure...have you looked at the header or any of the other data exposed through WebRequest or WebResponse? I see ContentLength in WebResponse, that may give you the file size. File details are probably contained within the first few bytes of the WebResponse stream.

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jayart3-Jul-07 3:46

jayart

3-Jul-07 3:46

<br />
class MyClass<br />
{<br />
    private const string MY_NAME = Resources.MyResourceName;<br />
}<br />

This gives a compilation error.
The property or indexer 'App.Properties.Resources.MyResourceName' cannot be used in this context because it lacks the get accessor.

How can I solve this?

Re: Compilation Error with Resource strings

Judah Gabriel Himango3-Jul-07 4:33