naming background panel image

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Hi.
I have opened an image in the background panel. I would like to get colour of pixel and that Hue-Saturation-Brightness values. I have a code which accomplishes thsi in another part of my program but I am not sure what to call my image when it is opened in background panel. I get error messages saying the name 'myImage' does not exist in the current context.
thanks

C#

private void button1_Click(object sender, EventArgs e)
{
    openFileDialog1.Filter = "JPEG IMAGES|*.jpg";
    openFileDialog1.InitialDirectory = "C:\\Users\\jason\\Documents\\IProject\\code\\imageAlign\\imageAlign\\bin\\Debug";
    openFileDialog1.Title = "Open Image";
    if (openFileDialog1.ShowDialog() == System.Windows.Forms.DialogResult.OK)
   {
        panel1.BackgroundImage = Image.FromFile(openFileDialog1.FileName);
        panel1.Invalidate();
   }
    // Array for keeping the sums of each row of pixels
    float[] resultArray = new float[myImage.Height];

    // Populate the array with data from each row of pixels, using the brightness value
    for (int i = 0; i < myImage.Height; i++)
    {
        float value = 0;
        for (int j = 0; j < myImage.Width; j++)
        {
            value += myImage.GetPixel(j, i).GetBrightness();//get colour of pixel and that Hue-Saturation-Brightness values
        }
        resultArray[i] = value;
    }
}

Posted 24-Feb-13 6:32am

defunktlemon

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Comments

Thomas Daniels 24-Feb-13 12:39pm

Where is <small>myImage</small> declared?

defunktlemon 24-Feb-13 12:58pm

it's not - I don't know what to declare it as. A bitmap - but the image is drawn on background so does that make it a Bitmap, I thought not - I thought if background panel image it was just held in memory.

defunktlemon 24-Feb-13 13:07pm

I decalred it as Bitmap myImage;
All errors left except one - 'use of unasigned local variable myImage'

or should it be - Bitmap myImage = panel1.BackgroundImage(Image.FromFile);

GrooverFromHolland 24-Feb-13 13:37pm

You are almost there.
MyImage = Image.FromFile(openFileDialog1.FileName);
panel1.BackgroundImage = MyImage;

defunktlemon 24-Feb-13 13:48pm

yes - that has gotten rid of the red. thank you Groover - I have one more error and then I think I can fly :)
for (int j = 0; j < myImage.Width; j++)
{
value += myImage.GetPixel(j, i).GetBrightness();//get colour of pixel and that Hue-Saturation-Brightness values
}
On the GetPixel i'm asked if i'm missing a using directive or an assembly reference - isn't this normally if a namespace is missing?

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OriginalGriff · Accepted Answer · 2013-02-25T01:37:00

Add a declaration:

C#

Image myImage = panel1.BackgroundImage;

And put it after your if condition (or expand the if to encompass the remaining code - you only want to execute it if the user presses "OK" after all. I would also recommend that your OpenFileDialog is constructed in the method, and you use a Bitmap as the generic Image does not have a GetPixel method.

C#

OpenFileDialog openFileDialog1 = new OpenFileDialog();
openFileDialog1.Filter = "JPEG IMAGES|*.jpg";
openFileDialog1.InitialDirectory = "C:\\Users\\jason\\Documents\\IProject\\code\\imageAlign\\imageAlign\\bin\\Debug";
openFileDialog1.Title = "Open Image";
if (openFileDialog1.ShowDialog() == System.Windows.Forms.DialogResult.OK)
    {
    Bitmap myImage = (Bitmap)Image.FromFile(openFileDialog1.FileName);
    panel1.BackgroundImage = myImage;
    panel1.Invalidate();
    // Array for keeping the sums of each row of pixels
    float[] resultArray = new float[myImage.Height];

    // Populate the array with data from each row of pixels, using the brightness value
    for (int i = 0; i < myImage.Height; i++)
        {
        float value = 0;
        for (int j = 0; j < myImage.Width; j++)
            {
            value += myImage.GetPixel(j, i).GetBrightness();//get colour of pixel and that Hue-Saturation-Brightness values
            }
        resultArray[i] = value;
        }
    }

defunktlemon · Accepted Answer · 2013-02-25T01:29:00

Solution 1

I have managed to find a solution myself :)

The myImage image needed to be cast in Bitmap form

Solution:

C#

Bitmap myImage;
myImage = (Bitmap)Image.FromFile(openFileDialog1.Filename);
panel1.BackgroundImage = myImage;

Thanks all
And thanks me too :)

Posted 25-Feb-13 1:29am