Re: Converting to WMF - C# Discussion Boards

21-Oct-09 5:31

I am having a little trouble converting files to WMF.
This code actually does change the extension, but I am having trouble believing it creates a true WMF.

Bitmap b = new Bitmap(@"Test.tif");
b.Save(@"Result.wmf", ImageFormat.Wmf);

I know there is probably a lot more to it, and I really don't know where to get started.

Richard MacCutchan21-Oct-09 5:39

Richard MacCutchan

21-Oct-09 5:39

mypicturefaded wrote:
I am having trouble believing it creates a true WMF.

According to the documentation for Bitmap.Save() you are doing this correctly. What is it that makes you think it is not working?

mypicturefaded21-Oct-09 5:45

21-Oct-09 5:45

Well, these WMF are stored in a database, and when needed they are called from some code and displayed. If I use a batch converter that I downloaded, convert the file, and store it in the database, the program displays the image correctly, but if I use my converter, nothing happens.

That makes me believe something is wrong with my converter.

mypicturefaded21-Oct-09 5:52

21-Oct-09 5:52

Oh...From MSDN

"If no encoder exists for the file format of the image, the Portable Network Graphics (PNG) encoder is used. When you use the Save method to save a graphic image as a Windows Metafile Format (WMF) or Enhanced Metafile Format (EMF) file, the resulting file is saved as a Portable Network Graphics (PNG) file. This behavior occurs because the GDI+ component of the .NET Framework does not have an encoder that you can use to save files as .wmf or .emf files.

Saving the image to the same file it was constructed from is not allowed and throws an exception."

Richard MacCutchan21-Oct-09 5:53

Richard MacCutchan

21-Oct-09 5:53

mypicturefaded wrote:
but if I use my converter, nothing happens.

Well I think you need to track through the code with the debugger in order to find which part of your converter is not working, and why. There is nothing here that would give any clue to what is wrong.

mypicturefaded21-Oct-09 9:01

21-Oct-09 9:01

I have also tried this, it doesn't work, it seems to be a little closer though.
Read my post right above your last one, it states .Net doesn't have an encoder for saving as .wmf so it just makes it a .png file.

Here is my new code:

int width, height;
string filename = "testresult.wmf";

try
{
    Bitmap Sig = new Bitmap("test.bmp");

    width = Sig.Width;
    height = Sig.Height;

    Graphics sigGraphics = Graphics.FromImage(new Bitmap(width, height));
    IntPtr SigHDC = sigGraphics.GetHdc();

    Rectangle Bounds = new Rectangle(0, 0, width, height);

    Metafile sigMetaFile = new Metafile(filename, SigHDC, Bounds, MetafileFrameUnit.Pixel);
    sigGraphics.ReleaseHdc(SigHDC);

    sigGraphics = Graphics.FromImage(sigMetaFile);
    sigGraphics.PageUnit = GraphicsUnit.Pixel;
    sigGraphics.Clear(Color.White);
    sigGraphics.DrawImage(Sig, Bounds);

    sigGraphics.Save();

    sigGraphics.Dispose();
    sigMetaFile.Dispose();

    Image SigN = Image.FromFile("testresult.wmf");
    MessageBox.Show(SigN.RawFormat.Guid.Equals(ImageFormat.Wmf.Guid).ToString());

}

catch (Exception Meta)
{
    MessageBox.Show(Meta.ToString());
}

The last two lines of the try statement check to see if it is truly a .WMF. On my other files, it returns true. When I run them through this though, it returns false.

Richard MacCutchan21-Oct-09 11:10

Richard MacCutchan

21-Oct-09 11:10

mypicturefaded wrote:
When I run them through this though, it returns false.

I'm afraid I'm as stumped as you on this. If the framework cannot save in wmf format then the only option would seem to be to find some external agent that will do it for you.

What is the best way to call methods in a commom class?

Luc Pattyn21-Oct-09 11:22

Luc Pattyn

21-Oct-09 11:22

While WMF can deal with bitmaps, it is "generally used to store line-art, illustrations and content created in drawing or presentation applications" (Wikipedia). Now how would you convert an arbitrary bitmap (i.e. an image, not a drawing) to that, other than saying it is all one bitmap. But then why use WMF in the first place?

FYI: the inverse is also true; if you have a WMF drawing, you can't load it into a Bitmap; you can get Image.FromFile() to work on it, however you can't cast it to a Bitmap.

Smile | :)

Luc Pattyn

I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages

Local announcement (Antwerp region): Lange Wapper? 59.24% waren verstandig genoeg om NEEN te stemmen; bye bye viaduct.

CBenac21-Oct-09 5:04

CBenac

21-Oct-09 5:04

I want to create an UtilLib class to contain commonly used methods (business logic, etc...) that are called from different modules inside the application.

So far, I know of 2 ways of doing it and would like to find out which one is better, or the advantages of each one.

1. Create an instance of the class (Inside the method that calls it) then call the desired method. I know the instance will be disposed once the calling method ends, or goes out of scope and the GC quicks in.

2. Make the class and all the methods static and call the method directly.
(Less code to write)

NOTE: The UtilLib will contain mostly simple methods. nothing too complex.

Re: What is the best way to call methods in a commom class?

Luc Pattyn21-Oct-09 5:07

Luc Pattyn

21-Oct-09 5:07

IMO as long as such methods don't have a state that needs to persist from one invocation to the next, go for statics. And when state is required, they belong in an object (a real object, not an instance of a MethodCollection class).

Smile | :)

Luc Pattyn

I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages

Local announcement (Antwerp region): Lange Wapper? 59.24% waren verstandig genoeg om NEEN te stemmen; bye bye viaduct.

Re: What is the best way to call methods in a commom class?

CBenac21-Oct-09 13:36

CBenac

21-Oct-09 13:36

Thanks for the reply. It appears that the thread went totaly out of the subject.
I'll try to explain in another way: Using a classic example, let's say there is a Calculator class with 4 methods that perform the basic 4 aritmetic operations, and these 4 methods are called several times from several different classes spread throught several modules in the application (Thread is not an issue here,please)

The question is: What approach is better?

1. Always create an instance of the class inside every methods that uses it then wait for the GC to dispose of it.

2. Create 4 static methods inside the Calculator class and access then directly.

3. Is there any other way?

Re: What is the best way to call methods in a commom class?

Luc Pattyn21-Oct-09 13:43

Luc Pattyn

21-Oct-09 13:43

CBenac wrote:
It appears that the thread went totaly out of the subject.

I don't feel responsible for that, and I think I already answered your question.

Now if you want a calculator (real ones have state), then create a Calculator class as I said before. Make it static, a singleton, or a normal class, that's up to you. The really reusable one is the normal one.

Smile | :)

Luc Pattyn

I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages

Local announcement (Antwerp region): Lange Wapper? 59.24% waren verstandig genoeg om NEEN te stemmen; bye bye viaduct.

Re: What is the best way to call methods in a commom class?

CBenac22-Oct-09 2:49

CBenac

22-Oct-09 2:49

Luc,

Yes, you already answered the question. Thanks. I'm going with static.
I only used the calculator class as an example, I'm not the type to reinvent the wheel.

Re: What is the best way to call methods in a commom class?

dan!sh 21-Oct-09 5:32

Re: What is the best way to call methods in a commom class?

21-Oct-09 5:32

How about inheriting from it? Just a thought.

It's not necessary to be so stupid, either, but people manage it. - Christian Graus, 2009 AD

Not Active21-Oct-09 5:48

Re: What is the best way to call methods in a commom class?

21-Oct-09 5:48

And what will this do for them?

only two letters away from being an asset

dan!sh 21-Oct-09 5:55

Re: What is the best way to call methods in a commom class?

21-Oct-09 5:55

May be I misunderstood the thing. If the OP has a class say BaseClass which contains common methods that will be used throughout the application AND if there is a feasibility of using inheritance(since we do not have multiple inheritance) then maybe he can inherit the base class. That way, he would be able to access the common methods without creating objects for the base class. Does that sounds OK or has flaws in it?

It's not necessary to be so stupid, either, but people manage it. - Christian Graus, 2009 AD

Not Active21-Oct-09 6:28

Re: What is the best way to call methods in a commom class?

21-Oct-09 6:28

and if there is a need later to add more methods to support additional functionality every derived class will need to be updated, regardless of whether they need the functionality or not. Do you see any flaws here?

Remember the "is a" relationship with inheritance. I can't think how that would apply to the OP's situation. If you want to use String.Format in your class do you derive from String?

only two letters away from being an asset

dan!sh 21-Oct-09 7:26

Re: What is the best way to call methods in a commom class?

21-Oct-09 7:26

Mark Nischalke wrote:
if there is a need later to add more methods to support additional functionality every derived class will need to be updated, regardless of whether they need the functionality or not.

Not sure about this thing. If I inherit from a class, and later sometime I change the base class, how would that affect child classes which do not need the newly added methods?

I just created a sample solution. There, class X (not an abstract class) had a protected method Test1. I inherited that in class Y. I had called Test1 in the constructor of Y. Then, I added another method in class X. I ran the application again. Worked fine. Are we at the same page?

It's not necessary to be so stupid, either, but people manage it. - Christian Graus, 2009 AD

Not Active21-Oct-09 7:49

Re: What is the best way to call methods in a commom class?

21-Oct-09 7:49

Sorry, yes I was think abstract classes or methods. However; I still don't view it as applicable or a good design for this situation.

only two letters away from being an asset

dan!sh 21-Oct-09 7:59

Re: What is the best way to call methods in a commom class?

21-Oct-09 7:59

Mark Nischalke wrote:
I still don't view it as applicable or a good design for this situation.

Can you please elaborate? I seem to be blinded by this approach. Cannot see any problems with this.

It's not necessary to be so stupid, either, but people manage it. - Christian Graus, 2009 AD

Not Active21-Oct-09 8:28