C / C++ / MFC Discussion Boards

laiju14-Jun-05 0:20

14-Jun-05 0:20

I tried to disable the "Save" toolbutton on the toolbar.
I tried to set the state of "Save" toolbutton to disabled mode by specifying
TBSTATE_INDETERMINATE . But this doesnt disable the save toolbutton.

TBBUTTONINFO buttonInfo;
buttonInfo.cbSize = sizeof( TBBUTTONINFO );
buttonInfo.dwMask = TBIF_COMMAND;
buttonInfo.fsState = TBSTATE_INDETERMINATE ;
m_wndToolBar.GetToolBarCtrl().SetButtonInfo(ID2_FILE_SAVE, &buttonInfo);

Let me know the exact procedure to do the same.
Thanx in advance

laiju

Re: Disabling toolbutton

David Crow14-Jun-05 1:33

David Crow

14-Jun-05 1:33

Check out ON_UPDATE_COMMAND_UI(ID2_FILE_SAVE, ...). In the handler function, you can easily enable/disable the Save button.

"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown

Re: Disabling toolbutton

laiju17-Jun-05 0:32

laiju

17-Jun-05 0:32

thank u

laiju

A very small performance issue in C++

Jagadeesh VN14-Jun-05 2:27

Jagadeesh VN

14-Jun-05 2:27

Hi,

I have a query on pointer arithmetic.

I declared a structure like this

struct myStruct{
int index;
char sz[124];
};

Inside the main(), I created 10000 objects of the structure and assigned it to a pointer variable.

myStruct* obj = new myStruct[10001];
memset( obj,0,sizeof(myStruct) * 10005);
myStruct* obj1 = obj;
long l1 = 0;

for( long l=0;l<100000000;l++)
{
obj++;
l1 += obj->index; //just an addition so that compiler wont remove the previous line

if( i % 10000 == 0 ){
obj = obj1;
l1 = 0; //reseting the values;
}

}

When I executed this, it took me 8 sec.

But if I reduce the size of myStruct to 64, it takes only 4 sec.
ie.
struct myStruct{
int index;
char sz[60];
};

and again reducing the size to 32, it takes only 2 secs.

I examined the assembly code which was generated by Disassembly, and the only change was in the 2nd line

obj++;
mov edx,dword ptr [ebp-14h]
add edx,100h
mov dword ptr [ebp-14h],edx

thats in
add edx,100h ( 256 b ) time : 8sec
add edx,20h ( 32 b ) time : 2sec

Can anybody pl. give me an explanation for this behaviour.

I was able to reproduce this behaviour in Unix also....

Thanks and Regards
Jagadeesh

"A robust program is resistant to errors -- it either works correctly, or it does not work at all; whereas a fault tolerant program must actually recover from errors."

Re: A very small performance issue in C++

Dezhi Zhao14-Jun-05 3:32

Dezhi Zhao

14-Jun-05 3:32

This is an effect of L1 cache. You did not mention the CPU you were using. I assume it was a P4. The L1 access line size is 64 bytes if my memory serves me right. If there are no alignment issues(your compiler often does a good job at this), the smaller size the structure is the more effective for a single L1 line access. Nowadays, people often talk about structure of arrary (SoA), that address such issues....

Re: A very small performance issue in C++

Bob Stanneveld14-Jun-05 1:28

Bob Stanneveld

14-Jun-05 1:28

Hello,

Jagadeesh VN wrote:
Inside the main(), I created 10000 objects of the structure and assigned it to a pointer variable.

myStruct* obj = new myStruct[10001]; memset( obj,0,sizeof(myStruct) * 10005);

Here you actually create 10.001 structs and initialize 10.005! This is very wrong!

Jagadeesh VN wrote:

for( long l=0;l<100000000;l++) { obj++; l1 += obj->index; //just an addition so that compiler wont remove the previous line if( i % 10000 == 0 ){ obj = obj1; l1 = 0; //reseting the values; }

A couple of questions on this piece of code:
<list>

Why the dummy addition (l1 += obj->index;) The compiler won't remove the line, since you use the object further down your code!

Why such a long loop?

Your loop does nothing usefull, why?
To get to an answer, I honestly don't think that the long loop is your problem. I think the problem lies with memset(). Let me explain: your execution time drops liniear with the size of the struct. So the size of the array decreases also liniear. (You halve the size of the stuct, so the size of the array is also halved.) So the amount of memory that memset() has to fill is also halved!

Besides that, your loop executes 100 million times! Don't expect that to finish in a few ms..

Behind every great black man...
... is the police. - Conspiracy brother

Blog[^]

copy jpg to clipboard

Stirfie14-Jun-05 2:08

Stirfie

14-Jun-05 2:08

I am trying to write a function that copies a jpg or a gif to the clipboard, when I pass the path to it.
ie
jpgclip("C:\test.jpg")

Can anybody help me?

Regards
Paul

Re: copy jpg to clipboard

David Crow14-Jun-05 3:12

David Crow

14-Jun-05 3:12

Have you looked at SetClipboardData()?

"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown

Re: copy jpg to clipboard

Stirfie14-Jun-05 23:24

Stirfie

14-Jun-05 23:24

Yes I have looked at this function, but could use a few pointers on how to use it. I know I can send a bmp to the clipboard with this, but is there anything I need to know when sending jpg or gif?

Re: copy jpg to clipboard

David Crow15-Jun-05 3:09

David Crow

15-Jun-05 3:09

See if this search helps.

"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown

saving a bitmap

Arrun14-Jun-05 1:30

Arrun

14-Jun-05 1:30

Hi Everybody

I am doing a project in image processing using MFC.
Could some one tell how to save a bitmap (1 bit,4,8,24 bits respectively).

Thanks in advance.

Re: saving a bitmap

Christian Graus14-Jun-05 2:01

Christian Graus

14-Jun-05 2:01

No 16 bit ?

If you're using GDI+, read my articles on the subject. Otherwise, I guess either save to bitmap only ( the format is well documented and simple ), or find some other library to use.

Christian Graus - Microsoft MVP - C++

converting byte to bit

Arrun14-Jun-05 1:24

Arrun

14-Jun-05 1:24

Hi I am doing a project in image processing using MFC. GetBitmapBits() stores the pixel value in a BYTE array. It works fine with 8 bits bitmap, but when working with 4 bits bitmap, it combines 2 pixel values and stores in the BYTE array.

How to overcome this problem

Re: converting byte to bit

Christian Graus14-Jun-05 1:29

Christian Graus

14-Jun-05 1:29

Use && and || to combine and mask values, instead of + or =. For example, FF && F0 == F0. If you take an 8 bit number and set it to equal itself && 15, you get only the low four bits, && 240 gives you the high four. In that way, you can set one pixel to zero. Then if you want to set the pixel in the low four bits, you just put oldVal || newval, that copies it in. to copy into the high four, do this: oldval || ( newVal << 4). this shifts the values up four bits first. To just set two pixels do this (pixelLeft << 4) + pixelRight. You can use plus here, because you're replacing both values.

Christian Graus - Microsoft MVP - C++

Re: converting byte to bit

PJ Arends14-Jun-05 7:08

PJ Arends

14-Jun-05 7:08

Close, but not quite. The operators he wants are | and & (bitwise operators as opposed to logical operators). See http://www.codeproject.com/cpp/bitbashing.asp[^]

Re: converting byte to bit

Christian Graus14-Jun-05 13:49

Christian Graus

14-Jun-05 13:49

Dagnamit. Sorry. Blush | :O

Christian Graus - Microsoft MVP - C++

how to debug a helper object?

ThinkingPrometheus14-Jun-05 0:54

ThinkingPrometheus

14-Jun-05 0:54

hiho@ll

i try to change the source of a browser helper object, which makes some strange things (like opening google, if i want to open a .js file Wink | ;-)

)

my question (because i don't really know much about helper objects) how can i debug the object?
it is visible as an Add on in Inernet Explorer
and when i try to debug the bho visual studio .net asks which application holds the debug information
i tried using Internet Explorer, but didn't work

the helper object is a dll
maybe the question should be how to debug a dll?

thx@ll

Release in _RecordsetPtr

Anonymous14-Jun-05 0:36

Anonymous

14-Jun-05 0:36

Is Release method in _RecordsetPtr must be called in the following code. Only Close is not Enough ?

fun()
{
_RecordsetPtr rs;

//...
//...
rs.Close();

}

Shell Extension On 64 bit Windows XP

Bond0414-Jun-05 0:10

Bond04

14-Jun-05 0:10

I am building the shell extension for 64 bit windows XP. While compiling the 32 bit shell extension code (working well on windows xp 32 bit) on visual studio.NET 2003 on 64 bit build environment getting the following errors:

myapp.obj : error LNK2001: unresolved external symbol _CLSID_BkgndCtxMenuExt
myapp.obj : error LNK2019: unresolved external symbol _LIBID_DIRBKGNDEXTLib referenced in function _DllMain@12
myapp.obj : error LNK2001: unresolved external symbol _IID_IBkgndCtxMenuExt

anybody please help me on this..
or is there any way to make 32 bit shell extension dll to work on 64 bit windows xp. on windows site its written that 32 shell extension will not work on 64 bit windows..

So what are the interfaces for shell extention in 64 bit windows XP.

thanks

need help!! please help me..

c_ngo13-Jun-05 20:39

c_ngo

13-Jun-05 20:39

hi guys! my name's candy..im having a little trouble with a school project of mine..i need to look for a "C programming using pointer" and i dont have any idea what it is..can somebody help me please..id really really really appreciate it if any of you guys can help me..thanks

Big Grin | :-D

Re: need help!! please help me..

Bob Stanneveld13-Jun-05 23:51

Bob Stanneveld

13-Jun-05 23:51

Hello,

Using a search engine also does some magic... Anyway, this[^] should help.

Behind every great black man...
... is the police. - Conspiracy brother

Blog[^]

Re: need help!! please help me..

Nilesh K.14-Jun-05 0:25

Nilesh K.

14-Jun-05 0:25

Check here[^]

<bold>- Nilesh
<italics>"Reading made Don Quixote a gentleman. Believing what he read made him mad" -George Bernard Shaw

Re: need help!! please help me..

Christian Graus14-Jun-05 1:21

Christian Graus

14-Jun-05 1:21

Is your name really Candy, or did you just think that was a name that would get guys to help ? :P

Seriously, the web is full of help, there is at least one article on this site, and your textbooks should be loaded with info also. However, by all means if you read your textbook and you're stuck on *specific* things, feel free to ask, whatever your name is....

Christian Graus - Microsoft MVP - C++

Re: need help!! please help me..

Bob Stanneveld14-Jun-05 3:32

Bob Stanneveld

14-Jun-05 3:32

Christian Graus wrote:
Is your name really Candy, or did you just think that was a name that would get guys to help ?

And no, I didn't answer because the name was Candy... Roll eyes | :rolleyes:

Behind every great black man...
... is the police. - Conspiracy brother

Blog[^]

Re: need help!! please help me..

c_ngo15-Jun-05 15:30

c_ngo

15-Jun-05 15:30

yes my name is really Candy Smile | :)

thanks for the help..i really appreciated it

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