Re: Loading a string from a binary file - C / C++ / MFC Discussion Boards

Re: Breakpoint problem----howto use it in a loop

James R. Twine28-Dec-01 7:09

28-Dec-01 7:09

> How can I step into the 10000th execuation?

   Conditional Breakpoints.

   Open the Breakpoints dialog (Edit-Breakpoints or Alt+F9 in DevStudio 6.0), specify the location (or select a previously marked Breakpoint, which is easier), and then click on Condition... to specify a condition for the Breakpoint.

   Peace!

-=- James.

Re: Breakpoint problem----howto use it in a loop

Todd Smith28-Dec-01 13:34

Todd Smith

28-Dec-01 13:34

Your condition should be something like

i == 10000

Todd Smith

Re: Breakpoint problem----howto use it in a loop

Nemanja Trifunovic28-Dec-01 7:15

Nemanja Trifunovic

28-Dec-01 7:15

if (i == 10000)
  __asm int 3;

It is faster than conditional breakpoints.

I vote pro drink Beer | [beer]

GetDeviceCaps problems...

Braulio Dez28-Dec-01 6:05

Braulio Dez

28-Dec-01 6:05

Hi,

I´m trying to get the size of the paper when printing ( I just want to fit a metafile in the size of the paper), to get the size of the paper I tried this:

CSize himetricPrinter(pDC->GetDeviceCaps(HORZSIZE)*100, pDC->GetDeviceCaps(VERTSIZE)*100);

pDC->HIMETRICtoDP(&PaperSize); // Printer DC

The that value I use it to play the metafile.

And then I got wrong values ( For the Y axis). Can anybody help me ?, Thanks, Bye !
Braulio

Loading a string from a binary file

James Bird28-Dec-01 5:34

James Bird

28-Dec-01 5:34

I am having troubles loading a string from a binary file. My original problem was that it the string had wierd characters on the end when I was using this code (I am not using MFC):

HANDLE hFile = CreateFile(szFN, GENERIC_READ, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);

DWORD read = 0x00000000;
TCHAR szTest[9];
ReadFile(hFile, &szTest, 9, &read, NULL);

I realised that if I let 'szTest[9] = NULL', there would be no wierd characters at the end and it worked. However, when I do something like,

if (szTest == "BLABLABLA")
{
MessageBox(NULL, "It Worked", "", MB_OK); // Lets me know that it worked!
};

even though "BLABLABLA" is correct it doesn't recognise it. Is it because there is a NULL character now on the end (szTest[9])?

Any help would be greatly appreciated,

James Bird - birdjames@bigfoot.com

Re: Loading a string from a binary file

Nemanja Trifunovic28-Dec-01 5:44

Nemanja Trifunovic

28-Dec-01 5:44

ReadFile reads binary data. If you don't put \0 in your file, it won't read it. You have two solutions:

1. When you write to the file, write a \0 at the and of your string, and when you read the string, read \0 with it.

2. Read the text, and then add the \0 at the end:

<br />
HANDLE hFile = CreateFile(szFN, GENERIC_READ, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);<br />
<br />
DWORD read = 0x00000000;<br />
TCHAR szTest[10];<br />
ReadFile(hFile, &szTest, 9, &read, NULL);<br />
szTest[9] = '\0';<br />

And use strcmp for comparing two strings.

I vote pro drink Beer | [beer]

Re: Loading a string from a binary file

Daniel Lohmann28-Dec-01 5:53

Daniel Lohmann

28-Dec-01 5:53

No, your problem is a different one. It't the difference between "equal" and "same" you are falling over. The Statement

if (szTest == "BLABLABLA")

compares two character pointer if they are equal. Or in other words: The statement returns true, iff both string references refer to the same object (same address in memory). However, what you want to know is if the two strings are equal, which means that boths string buffers contain the same value. For this you need the strcmp() CRT call:

if( strcmp( szTest, "BLABLABLA" ) == 0 )

Daniel

--

Daniel Lohmann

http://www.losoft.de

Re: Loading a string from a binary file

James R. Twine28-Dec-01 7:06

James R. Twine

28-Dec-01 7:06

   You problem is two-fold.

   The first problem was already mentioned: your use of "==" will compare two pointers, not test for equality between two strings.

   The second problem (garbage characters) stems from the fact that C-Style character strings are normally terminated with a NUL (not NULL) character.  That NUL character tells whatever routine is manipulating the string where the end of the string is.  You will see garbage characters after your read in your 9 characters because whatever is displaying the string is going to keep showing characters until it finds the terminating NUL.

   While you do not need to write out the terminating NUL character when you write the string to a file (text or binary), you need to have that NUL there after you read it in (you can manually place it in the buffer) in order to have it treated as a C-Style string.  That is basically what you did when you had

szTest[9] = NULL

in your code.

(BTW: Your code writes the NULL/NUL off the end of the allocated array. Character arrays that are going to contain C-Style strings should always 1 be character larger than the maximum length of the string.)

Peace!

-=- James.

Trying to get the size of A3...

Braulio Dez28-Dec-01 4:35

Braulio Dez

28-Dec-01 4:35

Hi,

I have a metafile, and I want to print it at full size of the page ( full size in A4, and A3 as well), what I thought is in the playMetafile method give the width and the height of the paper, but... it doesn´t work for me, I have tried:

CSize himetricPrinter(pDC->GetDeviceCaps(HORZSIZE)*100, pDC->GetDeviceCaps(VERTSIZE)*100);
CSize sizePrinterDP(HimetricPrinter.cx, HimetricPrinter.cy);
pDC->HIMETRICtoDP(&sizePrinterDP);

::PlayEnhMetaFile(hPrinterDC, hEnhMetaFile,
CRect(0, 0, (sizePrinterDP.cx), (sizePrinterDP.cy)));

Where is the error ?, Thanks Bye !
Braulio

Rotating shapes

bhat_adarsh28-Dec-01 4:24

bhat_adarsh

28-Dec-01 4:24

Dear friends,
There is an MFC Sample called DRAWCLI provided in MSDN which is a drawing application with Visual Editing
container support. Basically you can draw rectangles, circles and polygons and these shapes are represented
as separate objects which can be moved, resized, filled with color etc. (CDrawObj is the base class
and individual classes have been derived from CDrawObj for each kind of shape)
Now I want to add a feature of rotating these objects. I do not want any fancy rotation using the mouse (like in Microsoft Word). The user will
simply enter the degrees to be rotated in a dialog and the object has to rotate after that.
I have tried this by changing the World transformation (using the SetWorldTransform function) specifying
appropriate XFORM values just before drawing the object ( say a rectangle) and set the transformation
back to normal after the rectangle is drawn and I am able to rotate the rectangle by the required degrees
although a part of the rectangle is hidden.
What I am unable to do is other operations like selecting, moving etc after rotating the rectangle since
the coordinates defining the rectangle (a CRect object) still are the same even after rotation. All
operations like invalidating, detecting mouse clicks (hit-testing) on the rectangle are based on its CRect object
which stores its position.
How can I update or store the coordinates of this rotated rectangle.
OR
If I am going in a totally wrong direction please tell me a better way to accomplish this

Re: Rotating shapes

567890123430-Dec-01 1:08

5678901234

30-Dec-01 1:08

First I will try to solve the simple problem ("am able to rotate the rectangle by the required degrees
although a part of the rectangle is hidden"). I think every object should be rotated around it's top-left vertex. In this case I use two functions which prepare DC state to draw the object:

// Set device context to new state:
// every object drawn after call to this function will be rotated
// to nAngle degrees around (x, y) point.
// Rotation direction: positive - clockwise
//
void CWorldTransform2View::SetRotation(CDC* pDC,
int x,
int y,
int nAngle) // degrees
{
double dAngle = nAngle * PI_X_2 / 360.0; // PI_X_2 is pi*2

XFORM xForm;

xForm.eM11 = (FLOAT) cos(dAngle);
xForm.eM12 = (FLOAT) sin(dAngle);
xForm.eM21 = (FLOAT) (-sin(dAngle));
xForm.eM22 = (FLOAT) cos(dAngle);
xForm.eDx = (FLOAT) 0.0;
xForm.eDy = (FLOAT) 0.0;

int x1, y1;
x1 = (int) ( (x * cos(dAngle)) - (y * sin(dAngle)) );
y1 = (int) ( (x * sin(dAngle)) + (y * cos(dAngle)) );

GetViewportOrgEx(pDC->m_hDC, &m_PointOrigin);
SetViewportOrgEx(pDC->m_hDC, -x1 + x, -y1 + y, NULL);

m_nGraphicsMode = GetGraphicsMode(pDC->m_hDC);
SetGraphicsMode(pDC->m_hDC, GM_ADVANCED);

GetWorldTransform(pDC->m_hDC, &m_xForm);
SetWorldTransform(pDC->m_hDC, &xForm);

}

// Restore device context to the state is was before call to SetRotation
void CWorldTransform2View::RestoreDC(CDC* pDC)
{
SetWorldTransform(pDC->m_hDC, &m_xForm);

SetGraphicsMode(pDC->m_hDC, m_nGraphicsMode);

SetViewportOrgEx(pDC->m_hDC, m_PointOrigin.x, m_PointOrigin.y, NULL);
}

I hope this will help you to draw (if you have such problem).

To solve the second problem you need derive new class from drawing object you need to rotate (for example, CDrawRect) and add to it member m_nRotationAngle. After this rewrite all class functions using this angle. For example, function CDrawRect::GetHandle returns point. In your class you should rotate this point around rectangle's top-left vertex (some math...) and after this return it. Function Draw should draw the object with rotation angle (this is the problem you always solved, I beleive). Function MoveHandleTo should first rotate point (parameter) to -m_nRotationAngle degrees and after this work as usual (at least, such it seems to me now...). Function Intersects should work with region rather than rectangle etc.

So, you have some work for a couple of days or more, good luck.

Migrating from Win9x to Linux - PLEASE HELP!

Sergei Yevseyev28-Dec-01 4:16

Sergei Yevseyev

28-Dec-01 4:16

Who knows, how to perform a migration from VC6 code to GNU C++ (from Slackware Linux 7.10 distribution) with minimum rewriting. Any ideas? My application is not a console one
Frown | :(

. and uses:
1. MFC Cdialog
2. Subclassed dialog amd buttons from BCGControlBar and other libs
3. DAO
Thanks!

Re: Migrating from Win9x to Linux - PLEASE HELP!

Matt Newman28-Dec-01 4:31

Matt Newman

28-Dec-01 4:31

Sergei Yevseyev wrote:
MFC Cdialog

You are going to need a MFC alternative for Linux. I don't know of any though

Sergei Yevseyev wrote:
Subclassed dialog amd buttons from BCGControlBar and other libs

Doesn't sound promising. Contact the makers and see if there is a Linux port. Although if they are subclassed from MFC it doesn't sound promising.

Sergei Yevseyev wrote:
DAO

I don't know anything about this but I would think there is a Linux alternative.

I would suggest you start over in terms of GUI.

- Suspicious | :suss:

Matt Newman Suspicious | :suss:

-Sonork ID: 100.11179:BestSnowman

Re: Migrating from Win9x to Linux - PLEASE HELP!

Nemanja Trifunovic28-Dec-01 5:25

Nemanja Trifunovic

28-Dec-01 5:25

Well, I'm afraid you are in trouble. There is no MFC for Linux, and you'll have to rewrite your applications. I suggest you use some OS-independent library like wxWindows.

Anyway, why would you port your GUI application to Linux? Less then 5% of PC users run Linux on their desktop computers?

I vote pro drink Beer | [beer]

Re: Migrating from Win9x to Linux - PLEASE HELP!

Fazlul Kabir28-Dec-01 5:30

Fazlul Kabir

28-Dec-01 5:30

try MainSoft's WinMain. It has a MFC to UNIX port library. Unfortunately it's a bit expensive.

// Fazlul

Get RadVC today! Play RAD in VC++
http://www.capitolsoft.com

Re: Migrating from Win9x to Linux - PLEASE HELP!

Ravi Bhavnani28-Dec-01 5:31

Ravi Bhavnani

28-Dec-01 5:31

Sergei, we use Tcl/TK to build cross platform GUIs. All the non-GUI code is built as libraries (DLL/so) that are linked into Tcl.

/ravi

"There is always one more bug..."
ravib@ravib.com
http://www.ravib.com

Re: Migrating from Win9x to Linux - PLEASE HELP!

Tomasso7-Jan-02 7:10

Tomasso

7-Jan-02 7:10

What about wxWindows (http://www.wxwindows.org/)?

It works on both Windows, Linux, MacOS, and several others, I'm sure.

I've toyed around with it, and it works nicely.

"If ye love wealth better than liberty, the tranquility of servitude better than the animating contest of freedom, go home from us in peace. We ask not your counsels or your arms. Crouch down and lick the hands which feed you. May your chains set lightly upon you, and may posterity forget that ye were our countrymen."

--Samuel Adams

access CRecordSet from another class

jafrazee28-Dec-01 2:43

jafrazee

28-Dec-01 2:43

I have created an interface to a recordset within a dialog. i have now created another dialog for reporting. How can i access the recordset from that dialog. i have tried including the header, and defining the recordset external. i think i am just missing a step. thank you for any help on this.

Re: access CRecordSet from another class

Carlos Antollini28-Dec-01 3:05

Carlos Antollini

28-Dec-01 3:05

You need to open the recordset from a extarnal class to your dialogs, for example in the app class.... In this way the recordset can be open from any dialog and readed from any dialog....

Best Regards....

Carlos Antollini.
Sonork ID 100.10529 cantollini

Re: access CRecordSet from another class

jafrazee28-Dec-01 3:46

jafrazee

28-Dec-01 3:46

i used the wizard to create my app. it placed the following in my view to init the recordset.

m_pSet = &GetDocument()->m_tDSMSet;
CRecordView::OnInitialUpdate();

in my view header i have

class CTDSMSet;
.....
CTDSMSet* m_pSet;

i have been able to move the class declaration to my app header but nothing else with out errors. do you know if there is any documentation on moveing everything to the app class from a view class? or am i just looking to hard at this configuration maybe?

Re: access CRecordSet from another class

Carlos Antollini28-Dec-01 5:07

Carlos Antollini

28-Dec-01 5:07

Always I prefer no use CRecordView, I prefer to declare de Database class and recordset in a public class for all classes in my application.... You need to see how can get access to the view from any dialog or other classes....
Try to get access to the View using AfxGetMainWnd();

Best Regards....
Green Alien | [Alien]

Happy new year!!!

Carlos Antollini.
Sonork ID 100.10529 cantollini

how can i DRAW in CVIEW:OnInitialUpdate() function?

AnonymousBabe@usa.net28-Dec-01 2:08

AnonymousBabe@usa.net

28-Dec-01 2:08

the MSDN said you can not DRAW in OnUpdate() function, which is called by OnInitialUpdate by default

one is the other who absorbs the thoughts of others

Re: how can i DRAW in CVIEW:OnInitialUpdate() function?

AnonymousBabe@usa.net28-Dec-01 6:07

AnonymousBabe@usa.net

28-Dec-01 6:07

who knows the answer , please tell me
thanks

one is the other who absorbs the thoughts of others

Re: how can i DRAW in CVIEW:OnInitialUpdate() function?

Shog⁹28-Dec-01 8:58

Shog⁹

28-Dec-01 8:58

You can draw, provided you can get a DC;

// ...
CClientDC dc(this);
// draw stuff
// ...

However, there's a good chance that the window is not visible yet, so drawing into it will not be very useful. A better idea is to use the class as it was intended; initialize any data necessary for drawing in OnInitialUpdate(), updated it in OnUpdate(), and draw it in OnDraw(). OnDraw() will be called when the window is shown and first needs to be updated, so if you place your drawing code there, the view will act as desired.

i ain't happy, i'm feeling glad; i got sunshine in a bag; i'm useless, but not for long; the future is coming on...

gorillaz, clint eastwood

Re: how can i DRAW in CVIEW:OnInitialUpdate() function?

AnonymousBabe@usa.net28-Dec-01 14:23

AnonymousBabe@usa.net

28-Dec-01 14:23

i set a breakpoint in first line of the OnDraw
but can not trace into the code

one is the other who absorbs the thoughts of others

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