How to make a control transparent in a dialog - C / C++ / MFC Discussion Boards

Re: type safe issue

Rajkumar R12-Feb-08 1:45

Rajkumar R

12-Feb-08 1:45

I just meant search the web. Language type safety is what i meant. Smile | :)

Re: type safe issue

George_George12-Feb-08 1:52

George_George

12-Feb-08 1:52

Thanks Rajkumar,

What is your preferred definition of type safe (from the discussion, you are so knowledgeable and I think you have your or your preferred definition of type safe)? The search gives me a couple of various definitions of type safe. Smile | :)

regards,
George

Re: type safe issue

Rajkumar R12-Feb-08 2:58

Rajkumar R

12-Feb-08 2:58

Hi George,
May be this is helpful most definitions involve the use of a type system to prevent certain erroneous or undesirable program behavior (called type errors)[^]

Re: type safe issue

George_George12-Feb-08 3:09

George_George

12-Feb-08 3:09

Thanks Rajkumar,

I will read through it. Smile | :)

regards,
George

Re: type safe issue

George_George12-Feb-08 1:20

George_George

12-Feb-08 1:20

Thanks Matthew,

Which rule do you refer in the link from MSDN? Implementing IUnknown?

regards,
George

Re: type safe issue

Matthew Faithfull12-Feb-08 2:18

Matthew Faithfull

12-Feb-08 2:18

It's Rule number 1.[^]

"Rule #1: Must Implement IUnknown"

Hence the only certain thing about the pointer returned from CoCreateInstance, no matter how you wrap it up, it that it's an IUnknown pointer. Any assumption on top of that is at your own risk. Smile | :)

Nothing is exactly what it seems but everything with seems can be unpicked.

Re: type safe issue

George_George12-Feb-08 2:23

George_George

12-Feb-08 2:23

Thanks Matthew!

I think both you and Rajkumar are correct. Smile | :)

regards,
George

How to make a control transparent in a dialog

swarup10-Feb-08 22:03

swarup

10-Feb-08 22:03

hi guys

can i make a control say listctrl transparent,
say i have a list control in my dialog, i want to make the list control transparent so that the background of dialog will be visible through list control

Thanks
Swarup

Re: How to make a control transparent in a dialog

Hamid_RT10-Feb-08 22:13

Hamid_RT

10-Feb-08 22:13

swarup wrote:
How to make a control transparent in a dialog

See http://www.codeproject.com/KB/buttons/cbuttonst.aspx[^] of course its for buttons.

Text Draw problem with Print Preview

Anik3310-Feb-08 21:33

Anik33

10-Feb-08 21:33

I am using Visual Studio 6.0. Print preview changes text width on different zoom view. Let me describe in details.(Tested in an SDI application) I want to draw a text "Sample text1 Sample text1 Sample text1" whose font size is 10 and face is Arial.Just below this text I want to draw another text "Sample text2 Sample text2" whose font size is 15 and face is Comic Sans MS. Both are aligned LEFT or RIGHT.It draws fine. Now when I want to see the print preview it shows different text width than what was drawn previously. Now after zoom in again the view changes. In a word I dont get actual print preview. Can you help me plz?

Re: Text Draw problem with Print Preview

Hamid_RT10-Feb-08 22:05

Hamid_RT

10-Feb-08 22:05

Does this[^] helpful?

Re: Text Draw problem with Print Preview

Anik3310-Feb-08 23:04

Anik33

10-Feb-08 23:04

Not Solved Yet. Just Create an SDI Application and insert the following codes in OnDraw()

<br />
        CRect rcPos = CRect(10,10,500,40);<br />
	CFont font; LOGFONT lf;<br />
	ZeroMemory(&lf,sizeof(lf));<br />
	lf.lfHeight = 25;       lstrcpy(lf.lfFaceName,"Arial");<br />
	lf.lfWeight = FW_BOLD;	lf.lfCharSet = DEFAULT_CHARSET;<br />
	font.CreateFontIndirect(&lf);<br />
	pDC->SelectObject(&font);<br />
	CString str = "Sample Text1 Sample Text1 Sample Text1";	<br />
	pDC->DrawText(str, &rcPos, DT_LEFT|DT_VCENTER|DT_SINGLELINE);<br />
	font.DeleteObject();<br />
	rcPos.top	 += 30;<br />
	rcPos.bottom += 30;<br />
	<br />
	lf.lfHeight = 30;		 lstrcpy(lf.lfFaceName,"Comic Sans MS");<br />
	font.CreateFontIndirect(&lf);<br />
	pDC->SelectObject(&font);<br />
	str = "Sample Text2 Sample Text2";<br />
	pDC->DrawText(str, &rcPos, DT_LEFT|DT_VCENTER|DT_SINGLELINE);<br />
	font.DeleteObject();<br />

and insert following code to OnPrepareDC()

<br />
    pDC->SetMapMode(MM_ANISOTROPIC);<br />
CSize sizeDoc = CSize(1000,1000);<br />
pDC->SetWindowExt(sizeDoc);<br />
CDC dcScreen;<br />
dcScreen.CreateCompatibleDC(0);<br />
int nLogPixelX = dcScreen.GetDeviceCaps(LOGPIXELSX);<br />
int nLogPixelY = dcScreen.GetDeviceCaps(LOGPIXELSY);<br />
int nDevPixelX = pDC->GetDeviceCaps(LOGPIXELSX);<br />
int nDevPixelY = pDC->GetDeviceCaps(LOGPIXELSY);<br />
if (nLogPixelX != nDevPixelX || nLogPixelY != nDevPixelY)<br />
{<br />
    sizeDoc.cx = (sizeDoc.cx * nDevPixelX) / nLogPixelX;<br />
    sizeDoc.cy = (sizeDoc.cy * nDevPixelY) / nLogPixelY;<br />
}<br />
pDC->SetViewportExt(sizeDoc);<br />

Now run the exe. and see print preview.

Re: Text Draw problem with Print Preview

Roger Allen15-Feb-08 1:10

Roger Allen

15-Feb-08 1:10

Its not an issue with your code, its an issue with the way print preview is implemented itself. As the screen metrics (resolution/ dpi etc) may/are not an exact match to the target print device, especially when zooming in on the content, print preview has to do an estimation when converting from the requested font size of the target DC to the screen dpi/zoom metric DC used to display the preview.

This causes the generated font size to vary slightly at various zoom levels. To see this when you select a font into a CPreviewDC you should see that is does a lot of extra work converting the font from the outputDC to the previewDC format, its at thispoint that the scaling issues occur.

If you vote me down, my score will only get lower

Dynamically define arrays

CodingLover10-Feb-08 21:29

CodingLover

10-Feb-08 21:29

Hi all,

I can declare an array dynamically as follows.

int *array_T = new int[1024];

In multi-dimensional arrays why I can't do this.

int *array_T = new int[1024][2];

I appreciate your help all the time...
Eranga Smile | :)

Re: Dynamically define arrays

Cedric Moonen10-Feb-08 21:35

Cedric Moonen

10-Feb-08 21:35

You need to allocate each element of your array:

int** array_T = new int* [1024];
for(int i=0;i<1024;i++)
array_T[i] = new int[2];

Cédric Moonen
Software developer

Charting control [v1.2]

Re: Dynamically define arrays

CodingLover10-Feb-08 21:57

CodingLover

10-Feb-08 21:57

Thanks for the quick replay. I'll check it... Smile | :)

I appreciate your help all the time...
Eranga Smile | :)

Re: Dynamically define arrays

Rajkumar R11-Feb-08 0:31

Rajkumar R

11-Feb-08 0:31

Eranga Thennakoon wrote:
In multi-dimensional arrays why I can't do this.

u can do the following

int (*array_T)[2] = new int[1024][2];

"When allocating a multidimensional array, all dimensions except the first must be constant expressions that evaluate to positive values"

hence

int (*array_T)[2] = new int[size][2]; //is possible // bracket in(*array_T) is important

int *array_T = new int[size1][size2]; is not possible

convert byte array to long

jov10-Feb-08 21:03

jov

10-Feb-08 21:03

i would like to copy the contents of a byte array to a long variable. my code looks like this:

long key = 0;
for (i = 0; i < 8; i++) {
key <<= 8;
key |= (long)(buffer[i]); //<- this line causes the problem
}

however, when i run the program, there is an error message saying "unable to handle exception". what may have cause this problem?

Re: convert byte array to long [modified]

Cedric Moonen10-Feb-08 21:37

Cedric Moonen

10-Feb-08 21:37

You could also copy the byte array into your long directly:

long key = 0;
memcpy(buffer,&key,4);

In that case, you need to take care of the byte ordering in your byte array.

Cédric Moonen
Software developer

Charting control [v1.2]

modified on Monday, February 11, 2008 4:36 AM

Re: convert byte array to long

CPallini10-Feb-08 22:17

CPallini

10-Feb-08 22:17

How is declared buffer?
BTW long data type is only 4 bytes wide.

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke

Re: convert byte array to long

Cedric Moonen10-Feb-08 22:36

Cedric Moonen

10-Feb-08 22:36

CPallini wrote:
BTW long data type is only 4 bytes wide.

And I didn't even noticed that Dead | X|

. This is a slow monday morning...

Cédric Moonen
Software developer

Charting control [v1.2]

extern sample in MSDN

George_George10-Feb-08 19:43

George_George

10-Feb-08 19:43

Hello everyone,

I think in practical experience, extern is useful only when we have more than one compile unit (cpp file) and making cross-reference between compile units.

In the MSDN extern sample,

http://msdn2.microsoft.com/en-us/library/0603949d.aspx

It only uses one source file (compile unit) to demonstrate the usage of extern, is it correct and practical?

thanks in advance,
George

Re: extern sample in MSDN

Don Box10-Feb-08 19:45

Don Box

10-Feb-08 19:45

It only shows the its usage. U'rs thinking is absolutely correct.

Come online at:-
jubinc@skype

Re: extern sample in MSDN

George_George10-Feb-08 20:04

George_George

10-Feb-08 20:04

Hi Don,

I also think it is correct. But do we achieve special benefits if we use extern in the same compile unit?

regards,
George

Re: extern sample in MSDN

Stephen Hewitt10-Feb-08 20:26

Stephen Hewitt

10-Feb-08 20:26

No. The reason for extern is to differentiate between a declaration and a definition:
int num; // Is this a definition or a declaration?
In this case the compiler assumes it’s a definition. If you want to share num between two compilation units this will not do the trick and will result in a linker error – there will be two variables with the same name.
extern int num; // This is a declaration.
Now this referrers to a “num” defined elsewhere.

Steve

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