WIA Image Processing Help

[hyarion]

I've struggled with the limited csharp examples and documentation for WIA for a while now, but I finally have it scanning from an ADF scanner (I will be posting finished code soon as a reference for others wanting to code WIA).

What I'm now stuck with is using the Image Processing. I feel like I am so close yet it's just out of my grasp.

Here is the code I've been currently trying:

 WIA.ImageProcess IP = new ImageProcessClass();
                
                foreach (FilterInfo F in IP.FilterInfos)
                {
                	
                	if (F.Name == "Convert")
                	{
                		IP.Filters.Add(F.FilterID,0);
                		
                		foreach (Property Prp in IP.Filters[1].Properties)
                		{
                			
                			if (Prp.Name == "Compression")
                			{
                				//set jpeg compression for image
                				
                				IP.Filters[1].Properties[Prp] = 50;
                			}
                		}
                		
                		
                	}
                }

Unfortunately the line IP.Filters[1].Properties[Prp] = 50; fails with errors:

Argument '1': cannot convert from 'WIA.Property' to 'ref object' (CS1503)
The best overloaded method match for 'WIA.IProperties.this[ref object]' has some invalid arguments (CS1502)

Obviously I'm not doing it the right way for the properties but the examples on the net are all for VB and I can't seem to convert them to C# (I'm also fairly new to C#)

This is the VB example for creating a filter:

Dim Img 'As ImageFile
Dim IP 'As ImageProcess

Set Img = CreateObject("WIA.ImageFile")
Set IP = CreateObject("WIA.ImageProcess")

Img.LoadFile "C:\WINDOWS\Web\Wallpaper\Bliss.bmp"

IP.Filters.Add IP.FilterInfos("Convert").FilterID
IP.Filters(1).Properties("FormatID").Value = wiaFormatJPEG
IP.Filters(1).Properties("Quality").Value = 5

Set Img = IP.Apply(Img)

Img.SaveFile "C:\WINDOWS\Web\Wallpaper\BlissCompressed.jpg"

Is anyone able to shed some light on how I can set the properties for the ImageFilter?

[Tischnoetentoet]

IP.Filters[1].Properties[Prp] = 50 is completely wrong.

OR you should loop through the properties using a for-loop so you are able to use:

IP.Filters[1].Properties[i] = 50

OR you should use the reference to the property (and I assume you also need a .Value or something like that):

Prp.Value = 50

[hyarion]

Thank you, yes I know my test was completely wrong. The problem is I cannot work out what value to insert for IP.Filters[1].Properties[] as it does not accept an int or long or anything like that. It is looking for an object. If I type the first [ bracket SharpDevelop shows the following message indicating what it's looking for:

WIA.Property WIA.IProperties.this[ref object Index]

It does not accept a number value and I was assuming it might accept a "WIA.Property" object... unfortunately it doesn't or not in the way I'm trying.

Any other suggestions?

[Tischnoetentoet]

Since it uses an object, you can put anything in it.

Check the original documentation what value to set for each object.

For example, you can set a property like this (from the example code you gave):

WIA.ImageProcess IP = new ImageProcessClass();

foreach (FilterInfo F in IP.FilterInfos)
{
    if (F.Name == "Convert")
    {
        IP.Filters.Add(F.FilterID,0);
                		
        foreach (Property Prp in IP.Filters[1].Properties)
        {
            // Switch properties
            switch (prp.Name.ToLower())
            {
                case "compression":
                    //set jpeg compression for image				
                    Prp.Value = 50;
                    break;
            }                	
        }
    }
}

[hyarion]

Thank you for helping, and yes I did try that. This is what frustrated me the most. The example does not match the practice.

Prp does not have a ".Value" property. I also cannot put anything in the place for "object". A string gives me an error, and int gives me an error, so does everything else I tried.

I've tried my best with searching and given up. It seems that it may be that with WIA Automation 2.0 one cannot set values, only read them, although I cannot confirm this in any documentation. I know that this is the case with the WIA Scripting Model 1.0.

I have decided to make my own image processing functions to do what I need instead.

[Tischnoetentoet]

If it was a read-only field, the compiler would tell you, so this isn't a read-only field.

The compiler cannot cast a string to an object, you have to do this yourself.

Prp.Value = (object)50;