C# Discussion Boards - CodeProject

Image Brightness and Contrast change together

19-Jul-09 14:49

I assume you're teaching yourself for fun, because if you were in a class, you'd talk to your teacher, and if you were being paid for this, that would be immoral and borderline criminal.

This is a complex task for a 'very beginner'. Instead, buy a C# book and learn some basics first.

Christian Graus

Driven to the arms of OSX by Vista.

Read my blog to find out how I've worked around bugs in Microsoft tools and frameworks.

lexx_zone19-Jul-09 9:32

lexx_zone

19-Jul-09 9:32

Guys, I need help. Sorry for my English now,my brain just refused to work. I have an Image in PictureBox and have some filters to its process: contrast and brightness. Two trackbars controls filters changing values. When trackBar1_ValueChanged or trackBar2_ValueChanged events raises, function ApplyFilter() starts to work in different thread. When I using the brightness trackbar it changes the brightness of basic image. When I using the contrast trackbar it changes the contrast of image, But I don't know how to change the brightness and contrast together and show it in pictureBox component. For example I want to increase a brightness of an image. After that I want to increase a contrast but not of basic image, and what has turned out at brightness increase. After that I want to decrease a brightness to its basic level or lower. I don't know How to explain it clearly... If anybody have Vista you can see the same example in Vista PhotoGallery fix component. There are a lot of filters which you can apply to your image and change it back as you need. Here is a logic of my code...

Bitmap previewimage = null;
int brightness_value = 0;
int contrast_value = 0;

public PicPreviewForm(string filename) 
{
	previewimage = new Bitmap(Image.FromFile(filename));
	pictureBox1.Image = previewimage;
}
public void ApplyFilter()
{
      Bitmap bit;
      bit = new Bitmap(previewimage);
	
if(brightness had been changed)
{
	BrightnessFilter(bit, brightness_value);
}
If(contrast had been changed)
{
	ContrastFilter(bit, contrast_value);            
}
PictureBox.Image = bit;               
                
        
}

I could apply all filters every time when I changing some trackbar but it really decrease program performance..

Re: Image Brightness and Contrast change together

Christian Graus19-Jul-09 14:07

Create a program play video file on Pocket PC?

19-Jul-09 14:07

All you need to do, is start with the image already in the picture box, then apply your filter to that. How are you doing the brightness and contrast ? If you're using a matrix, you can combine the two matrices and do the operations together in one pass. That would also make a lot of sense, speed wise

Christian Graus

Driven to the arms of OSX by Vista.

Read my blog to find out how I've worked around bugs in Microsoft tools and frameworks.

phamminh0519-Jul-09 7:43

phamminh05

19-Jul-09 7:43

I have just begun to program in C# and I created this program by 2 ways:
1. Used wmp.dll at C:\WINDOWS\system32 in Windows XP but my program run on Pocket PC only play audio file, not video file.
2. I tried use Microsoft.DirectX.AudioVideoPlayback but it only run in Window project, not run in Smart Device project.

Have any solution as there is a like library wmp.dll or Microsoft.DirectX.AudioVideoPlayback in Windows Mobile?
Everybody, help me?
Thanks.

Re: Create a program play video file on Pocket PC?

Nishant_Mishra19-Jul-09 19:45

Nishant_Mishra

19-Jul-09 19:45

Please send me your code on my email mishra.nishant4@gmail.com i must need to see it before commenting.

WHy C#net doesnot support Mul.inheritance?

Ali_10019-Jul-09 6:52

Ali_100

19-Jul-09 6:52

Why C#.net does not support multiple inheritance?why it can support by interface?why not by class?

PIEBALDconsult19-Jul-09 7:05

19-Jul-09 7:05

Because the designers decided they'd cripple the language in the interests of making it "safer". Dead | X|

Implementing an interface is unrelated to inheritence.

Uri Lavi19-Jul-09 8:15

Uri Lavi

19-Jul-09 8:15

C# and Java languages don't support multiple inheritance because of the diamond problem[^].

Here is the short summary:

The diamond problem is an ambiguity that arises when two classes B and C inherit from A, and class D inherits from both B and C. If a method in D calls a method defined in A (and does not override the method), and B and C have overridden that method differently, then from which class does it inherit: B, or C?

Uri

Christian Graus19-Jul-09 14:10

19-Jul-09 14:10

This is a stupid example, given by people too stupid to understand the value of multiple inheritance. It seems the C# team is in general too stupid to understand complex solutions, I asked them for default parameter values years ago, and they got very confused trying to work out how that would work, or why you'd use it.

The example is valid, but it assumes the programmer is a moron. A good language assumes it will be used well, not protects itself from being used poorly

Christian Graus

Driven to the arms of OSX by Vista.

Read my blog to find out how I've worked around bugs in Microsoft tools and frameworks.

PIEBALDconsult19-Jul-09 14:45

19-Jul-09 14:45

Hear hear! I think that's what I said. Big Grin | :-D

Christian Graus wrote:
default parameter values

Aren't those in C# 4.0 ?

Christian Graus19-Jul-09 14:53

19-Jul-09 14:53

Yes, you did.

PIEBALDconsult wrote:
Aren't those in C# 4.0 ?

Yes, it's taken them three iterations to realise the people crying for it were right. And, they explicitly told me that if they have a choice between making the language powerful, or making it easy and safe, they choose the latter.

Christian Graus

Driven to the arms of OSX by Vista.

Read my blog to find out how I've worked around bugs in Microsoft tools and frameworks.

S. Senthil Kumar19-Jul-09 17:41

S. Senthil Kumar

19-Jul-09 17:41

Christian Graus wrote:
It seems the C# team is in general too stupid to understand complex solutions

Wow, that's quite an accusation. How many programming languages have you written, Christian?

I'd think the main issue here is not language, but the CLR. If C# supports multiple inheritance, there must be some way to express it in metadata and IL, which means the CLR must support it. I'm guessing here that that would mean only a language which is aware of multiple inheritance would be able to deal with that type. Also, the way C++ implements MI might not be compatible with the CLR requirements (reflection etc..), so there are problems even for a language that already supports MI.

In general, I'd say language changes that only affect code generation (lambdas, automatic properties) are much more simpler than those that change the type system (generics etc..).

Christian Graus wrote:
I asked them for default parameter values years ago, and they got very confused trying to work out

Unlike C++ which requires recompilation whenever a module changes, .NET supports binding against different versions of a module (assembly). Which means that embedding the default values at the caller will break versioning. I don't see how that assumes the programmer is a moron.

Regards
Senthil
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PIEBALDconsult19-Jul-09 14:54

19-Jul-09 14:54

That's no reason. Pointers are much more dangerous yet they're still available in C#.

Why not allow multiple inheritence in an unsafe context? Big Grin | :-D

N a v a n e e t h19-Jul-09 16:53

N a v a n e e t h

19-Jul-09 16:53

Chris Brumme from the CLR team explain here[^] the reason.

Navaneeth

How to use google | Ask smart questions

PIEBALDconsult19-Jul-09 17:48