C / C++ / MFC

6-Apr-04 7:36

Sorry bro, no one can help u with this.

This is a digital world. U cant do an optical ZOOM to a digital bitmap, lolz

^{Remember... testing & debugging are always part of programming ...so exterminate those stinking bugs}

Re: bitmap

John R. Shaw6-Apr-04 16:48

John R. Shaw

6-Apr-04 16:48

What you have is a pixalation problem, unless the displayed size is not a multiple of the bitmap size. When you wish to show a bitmap at a size larger than the original, it should be a multiple of the original bitmap. That way the individual pixels are enlarge and not blured. Example: if you have a 12x12 bitmap then the enlarged version should be 24x24, 36x36, ect...

If you are enlarging to some size that is not a multiple of the original then in will blur and there is nothing that can be done.

Look in the Bitmap & Pallete section of code project for more info..

INTP

Rassul Yunussov6-Apr-04 0:07

Rassul Yunussov

6-Apr-04 0:07

How to delete menu from my application and create and insert another menu. I would like to have two menu resources ( For example IDR_MENU1, IDR_MENU2), and I want to "step" between them dinamically, without exiting the programm. Actually i've already posted similar question about "multilanguage problems", and the menu is the last problem i have Smile | :)

Empty19816-Apr-04 0:36

Empty1981

6-Apr-04 0:36

your menu is a popup menu or a mainfram menu

Antony M Kancidrowski6-Apr-04 1:22

Antony M Kancidrowski

6-Apr-04 1:22

CMainFrame header

CMenu m_menu;

HMENU SetNewMenu(UINT nMenu);

CMainFrame body

HMENU CMainFrame::SetNewMenu(UINT nMenu)
{
    // Load the menu from the resources
    m_menu.LoadMenu(nMenu);
    m_menu.LoadToolbar(nMenu);  // if you will need a toolbar also

    return (m_menu.Detach());
}

Code that sets menu

CMenu* pMenu = AfxGetMainWnd()->GetMenu();

if (pMenu)
	pMenu->DestroyMenu();
	
CMainFrame* pFrame = reinterpret_cast<CMainFrame*>(m_pMainWnd)->SetNewMenu(IDR_MENU1);
ASSERT(pFrame != NULL);

HMENU hMenu = pFrame->NewMenu();
CMenu* pNewMenu = CMenu::FromHandle( hMenu );
ASSERT(pNewMenu != NULL);

AfxGetMainWnd()->SetMenu(pNewMenu);

Ant.

Rassul Yunussov6-Apr-04 22:30

Rassul Yunussov

6-Apr-04 22:30

Thanks, that helped me so much.
Actually i used it in Pocket PC, but using the different way.
I used there CCeCommandBar, and just did this:

AfxSetResourceHandle(hInst);
CMainFrame* pMainFrame = (CMainFrame*)AfxGetApp()->m_pMainWnd;
pMainFrame->m_wndMenuBar.ResetCommandBar();
pMainFrame->m_wndMenuBar.InsertMenuBar(IDR_MAINFRAME);
pMainFrame->m_wndMenuBar.LoadToolBar(IDR_TOOLBAR1);

Thanks again.

avenger_sb25//read, write data files

Antony M Kancidrowski7-Apr-04 2:12

Antony M Kancidrowski

7-Apr-04 2:12

I'm glad it helped as I have just noticed that I did not format the code correctly for HTML and therefore some of it is missing. D'Oh! | :doh:

I'll modify it just for the records!

Ant.

dairiseky5-Apr-04 23:53

5-Apr-04 23:53

Hi.
Everything is nice about what u said to me for reading and writing to files. Except one or two things. Frown | :(

Well first of all it cannot convert from objectA to char*.
That's why I didn't use this method before, because I couldn't handle this stuff.
Anyway why do u have to use binary files?

outfile.write ((char*)objectA, sizeof(objectA)); //this line writes the complete 
objectA(field by field) into the file test.txt. 
Remember, the file contents are now binary. 
So u may see many strange character when you open test.txt in a notepad.

THX

Steve S6-Apr-04 1:21

Steve S

6-Apr-04 1:21

Ah. You've been told how to without any understanding of what's happening, which makes it difficult to fix this minor problem.

The line

outfile.write( (char*) objectA, sizeof(objectA));

should probably read

outfile.write( (char*)&objectA, sizeof(objectA));

as you need to specify the address.

Essentially, it's writing everything from memory to do with objectA's storage out to disk. This is not necessarily a good thing.
If objectA contains any pointers, or has other objects embedded within it, you may well be able to read objectA back some time later, but then not be able to use it.

Serialising an object is something that the object itself should know how to do, since it is possibly the only entity aware of all it's members. A blind write (and read) of the space occupied does not take into account the fact that the object may refer to other things, such as a char* member. In that case, the address in the char* member would be written out, and not the string it's pointing to¹. When the object is later read back, the same address is assigned. Now if the memory map has changed significantly, it's possible that the address is not only not pointing to the right data, but it may in fact be pointing to unallocated or deallocated memory, which will cause an exception in your app.

Steve S
¹Yes, I know it's not a proper string, it's only an illustration, so calm down... Smile | :)

avenger_sb256-Apr-04 11:15

6-Apr-04 11:15

Thanx steve for pointing out my error D'Oh! | :doh:

, i wrote that reply in a hurry.
I'll make no such mistakes in future.;)

^{Remember... testing & debugging are always part of programming ...so exterminate those stinking bugs}

David Crow6-Apr-04 2:11

David Crow

6-Apr-04 2:11

dairiseky wrote:
Anyway why do u have to use binary files?

See if these help:

http://www.felgall.com/cplus4.htm

http://www.techtv.com/screensavers/answerstips/story/0,24330,3373133,00.html

http://forums.devshed.com/archive/t-105787

"The pointy end goes in the other man." - Antonio Banderas (Zorro, 1998)

Re: why binary?

dairiseky6-Apr-04 2:32

6-Apr-04 2:32

ok got y. thx again.

Though u didn't say to me what u meant by the lenght of a line. Does space and zero count in this lenght? i'm talking about the seekg().
Is this seekg() givin' me the possibility to read only a certain length of the file?

THX

Re: why binary?

David Crow6-Apr-04 3:27

David Crow

6-Apr-04 3:27

dairiseky wrote:
Is this seekg() givin' me the possibility to read only a certain length of the file?

I'm not exactly sure what you are asking here, but seekg() can be used to get a file's length.

file.seekg(0, ios::end); // seek to the end
long filesize = file.tellg();

"The pointy end goes in the other man." - Antonio Banderas (Zorro, 1998)

avenger_sb256-Apr-04 11:12

6-Apr-04 11:12

Sorry! my mistake. Thanks a lot to Steve for clearing the doubts.
You need not even include the (char*) part in read and write functions.

Only outfile.write (&objectA, sizeof(objectA)); should also work.

Keep in ur mind the things told by Steve about Pointers.
Avoid including pointers in classes that you have to write to the disk. But as far as simple data types and arrays are concerned, it would do just fine.

I hope that you know by now "why binary?"
Sorry again for the mistake on my part. thx steve

^{Remember... testing & debugging are always part of programming ...so exterminate those stinking bugs}

dairiseky6-Apr-04 23:48

6-Apr-04 23:48

yep is ok about binary. Yet there is still a problem. The objectA must be a const char*, that is not.
U said to me :

class A
{
public:
	double x;
	double y;
	double speed;
	double z;
};

As u can see here if I want to write the x, y, z. I could do as:

main(int argc, char *argv[])
{
	A objectA;

    fstream File;
	File.open ("test.txt", ios::binary);

	File.seekp(0);

	objectA.x=25.314;//xcoord
    objectA.y=-478.215;//ycoord
    objectA.z=34821.01;//zcoord

Up to here nothing wierd.
But then when I want to write into file I will use:

File.write(&objectA.x, sizeof(objectA.x));

And the error will be:

'class ostream &__thiscall ostream::write(const char *,int)' : cannot convert parameter 1 from 'double *' to 'const char *'

And even if I will write simply :

File.write(&objectA, sizeof(objectA));

There will still be the same error:

'class ostream &__thiscall ostream::write(const char *,int)' : cannot convert parameter 1 from 'class A *' to 'const char *'

I might have get things wrong... D'Oh! | :doh:

THX

Anonymous7-Apr-04 3:27

Anonymous

7-Apr-04 3:27

Ooops! a small mistake on my part again. I was actually mixing the read function of C with read member of C++.

In C++, the prototype for write is:
istream& read(signed char*, int);
So whatever we write, we have to cast its pointer to (char*)

So if we have to write some object AAA to the file, we will use the following syntax:

ofstream outfile("test.txt", ios::binary);
outfile.write((char *) &AAA, sizeof(AAA));

Now let me tell you a few things:
Dont try to retrieve data from a file using read where you have manually entered data. What i mean is, if you have created a file from notepad and have manually typed in the data, you cannot retrieve those data using istream::read()

So the point is:- retrieve only those data from the file using istream::read that have been written to it using ostream::write.

The following code is tested on my system and will help you in understanding all this better. After running the program, open the "123.txt" file in c:\ drive to view how data has been written in binary.

#include <iostream.h>
#include <fstream.h>
int main()
{
class A
{
public:
double x;
double y;
double z;
};

A objectA,objectB;

objectA.x=123.345;
objectA.y=345.003;
objectA.z=456.2;
cout<<"Following data will be written to 123.txt"<<endl;
cout<<"A.x="<<objectA.x<<endl;
cout<<"A.y="<<objectA.y<<endl;
cout<<"A.z="<<objectA.z<<endl;

ofstream outfile("c:\\123.txt",ios::binary);//creare ofstream object
outfile.write((char*)&objectA,sizeof(objectA));//write object
outfile.close(); //close the stream-NEVER FORGET TO DO THIS
cout<<"object A has been written to the file"<<endl<<endl;
cout<<"reading data from 123.txt"<<endl;
ifstream infile("c:\\123.txt",ios::binary); //create stream
infile.read((char*)&objectB,sizeof(objectB)); //read object from stream
outfile.close(); //close stream
cout<<"B.x="<<objectB.x<<endl;
cout<<"B.y="<<objectB.y<<endl;
cout<<"B.z="<<objectB.z<<endl;

return 0;
}

Avoid that seek stuff. Dead | X|

Suppose you have performed 5 writes to a file(i.e. you have written 5 objects one after the other) and you want to read the 3rd object later, then use the following technique.

ifstream infile("test.txt", ios::binary);<br />
A objectA;<br />
for(i=0;i<3;i++)<br />
{<br />
infile.read((char *) &objectA, sizeof(objectA));<br />
}<br />
infile.close();

After the for loop, objectA will contain the data from the 3rd record;
Ask if u have any problems.

avenger_sb257-Apr-04 3:35

7-Apr-04 3:35

ofstream outfile("test.txt", ios::binary);
outfile.write((char *) &AAA, sizeof(AAA));

#include <iostream.h>
#include <fstream.h>
int main()
{
class A
{
public:
double x;
double y;
double z;
};

A objectA,objectB;

objectA.x=123.345;
objectA.y=345.003;
objectA.z=456.2;
cout<<"Following data will be written to 123.txt"<<endl;
cout<<"A.x="<<objectA.x<<endl;
cout<<"A.y="<<objectA.y<<endl;
cout<<"A.z="<<objectA.z<<endl;

ofstream outfile("c:\\123.txt",ios::binary);//creare ofstream object
outfile.write((char*)&objectA,sizeof(objectA));//write object
outfile.close(); //close the stream-NEVER FORGET TO DO THIS
cout<<"object A has been written to the file"<<endl<<endl;
cout<<"reading data from 123.txt"<<endl;
ifstream infile("c:\\123.txt",ios::binary); //create stream
infile.read((char*)&objectB,sizeof(objectB)); //read object from stream
outfile.close(); //close stream
cout<<"B.x="<<objectB.x<<endl;
cout<<"B.y="<<objectB.y<<endl;
cout<<"B.z="<<objectB.z<<endl;

return 0;
}

Avoid that seek stuff. Dead | X|

Suppose you have performed 5 writes to a file(i.e. you have written 5 objects one after the other) and you want to read the 3rd object later, then use the following technique.

ifstream infile("test.txt", ios::binary);<br />
A objectA;<br />
for(i=0;i<3;i++)<br />
{<br />
infile.read((char *) &objectA, sizeof(objectA));<br />
}<br />
infile.close();

After the for loop, objectA will contain the data from the 3rd record;
Ask if u have any problems.

...Avenger

Remember... testing & debugging are always part of programming ...so exterminate those stinking bugs

dairiseky7-Apr-04 5:32