C / C++ / MFC

About Graphics::RotateTransform()????

7-Sep-08 23:26

Dhiraj kumar Saini wrote:
Thanx u

You're welcome.
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Dhiraj kumar Saini wrote:
u r genius

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Dhiraj kumar Saini wrote:
It solved my problem

I'm glad it helped.
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TooShy2Talk7-Sep-08 21:32

TooShy2Talk

7-Sep-08 21:32

Hi,

Is it possible to use RotateTransform() after Graphics::DrawImage()?

Ex.

Graphics g(hMemDC);

for(){
for(){
.....
g.DrawImage();
}
}

g.RotateTransform();

Based from MSDN example RotateTransform is before DrawImage() function but I have tried the above code (6 months ago) and it works.
But now this code doesn't work anymore.
Image doesn't rotating anymore.

My code is for stitching tiles of an image to make it whole. When I place RotateTransform() before DrawImage() it produces black dash lines in between tiles.

It's been a solution to place RotateTrasform after DrawImage but now I can't make it work.

What seems to be the problem?
Do I have to add some more code?

Hope somebody can help me. Thanks.

CPallini7-Sep-08 21:37

7-Sep-08 21:37

Well, I guess DrawImage should follow RotateTransform and not the opposite. If you got undesidered lines, probably there's something wrong in your parameters.
Smile | :)

TooShy2Talk7-Sep-08 21:57

TooShy2Talk

7-Sep-08 21:57

Thanks for the reply.

Placing DrawImage after RotateTransform somewhat rotate my image tiles before stitching them. What I wanted is to stitch all first then rotate.

Is there any other way to do this.

SandipG 7-Sep-08 22:00

SandipG

7-Sep-08 22:00

Why dont you create a stitched bitmap first and then draw this bitmap on device context.
i mean
Graphics gr(bmpTemp)
.... Stitching code.

Graphics gr(hDC)
RatateTransform()...
DrawImage(bmpTemp)..

Does it make sense??

Regards,
Sandip.

TooShy2Talk7-Sep-08 22:45

TooShy2Talk

7-Sep-08 22:45

Thanks for the reply.

I look at MSDN and I haven't found a constructor for bitmap.

Is there any?

Initializing class from it's name - Standard C++

SandipG 7-Sep-08 22:51

SandipG

7-Sep-08 22:51

check this
http://msdn.microsoft.com/en-us/library/ms535632(VS.85).aspx

N a v a n e e t h7-Sep-08 21:05

Re: Initializing class from it's name - Standard C++

7-Sep-08 21:05

I am working on a phonetic converter program. There are converter classes like "aConverter","bConverter" etc which contains rules for converting english letters to equivalant text in other language.

In some cases fonts may have different formats. So I need to create different converters for it and plug with the application. I plan to supply all the converter details in a file and load the converter on runtime. So if I have specified "aConverter" in a file, how can I initialize it's instance? Each converter implements "IConverter" interface.

In C# I can use Activator.CreateInstance and cast to IConverter type. I am looking for a method to do this in standard C++ not MFC/C++ CLI. Or is there anyother changes which I can make in the existing design so that new converters can be plugged in?

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CPallini7-Sep-08 21:33

Re: Initializing class from it's name - Standard C++

7-Sep-08 21:33

Please elaborate: What exactly do you need that you can't find in standard C++ (possibly persistence?)?

N a v a n e e t h7-Sep-08 23:25

Re: Initializing class from it's name - Standard C++

7-Sep-08 23:25

CPallini wrote:
What exactly do you need that you can't find in standard C++ (possibly persistence?)?

I didn't get you. I am looking for some reflection kind of stuff.

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CPallini7-Sep-08 23:33

Re: Initializing class from it's name - Standard C++

7-Sep-08 23:33

Well, probably I had to use serialization instead of persistence, I meant saving/loading an object to/from a file. Is that what you need? On the other hand, as you probably know, reflection is a .NET feature not supported by standard C++.
Smile | :)

N a v a n e e t h7-Sep-08 23:40

Re: Initializing class from it's name - Standard C++

7-Sep-08 23:40

Thank you very much for your help.

CPallini wrote:
I meant saving/loading an object to/from a file. Is that what you need?

NO. I just need to plug new converters to the application. All the converters implement IConverter interface.

CPallini wrote:
reflection is a .NET feature not supported by standard C++.

I know. I used the term "reflection" here for better understanding. I need to compile this code in multiple platforms, that's why I am sticking with standard C++.

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CPallini7-Sep-08 23:51

Re: Initializing class from it's name - Standard C++

7-Sep-08 23:51

Not sure I got you, anyway have a look at creational design patterns [^].
Smile | :)

N a v a n e e t h8-Sep-08 0:14

Re: Initializing class from it's name - Standard C++

8-Sep-08 0:14

CPallini wrote:
Not sure I got you

I might have not explained clearly Frown | :(

Let me try my luck once more Smile | :)

I need some thing simlar to Builder[^] pattern. In that link PizzaBuilder is an abstract class providing methods to override. Many builder classes are derived from it and overrides the functionality. If you look at the main function (C#) you will find

PizzaBuilder hawaiianPizzaBuilder = new HawaiianPizzaBuilder();
PizzaBuilder spicyPizzaBuilder = new SpicyPizzaBuilder();

In this case we knows HawaiianPizzaBuilder or SpicyPizzaBuilder is the one to instantiate.

But in my case, I know only the class is derived from PizzaBuilder and it's name, say CustomPizzaBuilder. In that case, how do I instantiate it?

This can be easily done using reflection in managed code. As reflection is not supported in standard C++, is there a workaround for this? Or how does the Builder pattern is implemented in C++ when we have only the subclass name available?

I hope I made it clear.

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CPallini8-Sep-08 0:35

Re: Initializing class from it's name - Standard C++

8-Sep-08 0:35

OK. I think you may exploit the Prototype pattern:
(1)
Every new converter, say kConverter, should provide a clone method like

class kConverter : public IConverter
{
  //...
public:
  IConverter * clone()
  {
    return new kConverter();
  }
  //..
};

(2) Every new converter should add himself to a global map<string, IConverter>

Does the above make sense?
Smile | :)

N a v a n e e t h8-Sep-08 0:48

Re: Initializing class from it's name - Standard C++

8-Sep-08 0:48

CPallini wrote:
Does the above make sense?

Perfect! It did. This is going to work. Many thanks.

I think the clone() method is not needed as I will add new converters to map<string, IConverter>.

Thanks for taking time to help me. A well deserved 5

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CPallini8-Sep-08 0:56

Avoid includei in header files

8-Sep-08 0:56

N a v a n e e t h wrote:
I think the clone() method is not needed as I will add new converters to map<string,>.

Yes, that makes perfect sense.

N a v a n e e t h wrote:
Thanks for taking time to help me

You're welcome.
Smile | :)

reza matinnejad7-Sep-08 20:11

reza matinnejad

7-Sep-08 20:11

Hi,
I prefer not to include any header files in other header files as long as it is possible.
But I have problem when I want to use an Enumeration type in a header file, which is defined in another header file.
I mean we can introduce classes and structs at the start of a header file, but it is not the case about Enumeration Data Types:

struct st1; //correct
Class C1; //correct
Enum e1; //Incorrect

toxcct7-Sep-08 21:09

toxcct

7-Sep-08 21:09

is this a design question ?

or just trying to inform somebody here ?
if so, I strongly unadvise to do so. that is just not suitable for most advanced designs, and it's just the way C/C++ is designed and intended to work...

so, to make it short, go with #includes withing headers, it's not bad to do so !

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reza matinnejad7-Sep-08 21:15

reza matinnejad

7-Sep-08 21:15

I am not sure, but I think it is a good idea to do such a thing.
Actually I avoid making circular includes in this way.

toxcct7-Sep-08 21:21

toxcct

7-Sep-08 21:21

reza matinnejad wrote:
I avoid making circular includes in this way

this CANNOT happen, as long as you designed your headers correctly.

there is a multiple includes exclusion system which tells for the header which it's defined in not to include it more than once...

If you're using Visual Studio only, the following is good and prefered for performances. This is MS specific:

<font color="green">//Beginning of the header file</font>
<font color="blue">#pragma once</font>
 
<font color="green">//...remaining of your file...</font>

if your sources are portable on pultiple plateforms, then use the standard construction which works on any compiler (Visual C++ included):

<font color="green">//Beginning of the header file</font>
<font color="blue">#ifndef</font> __YOUR_HEADER_FILE_H_INCLUDED__
<font color="blue">#define</font> __YOUR_HEADER_FILE_H_INCLUDED__
 
<font color="green">//...remaining of your file...</font>
 
<font color="blue">#endif</font> <font color="green">//At the very end of the file</font>

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reza matinnejad7-Sep-08 21:28

reza matinnejad

7-Sep-08 21:28

Thank you