|
I'm writing a CAD program, which will have a lot of commands like create various types of entities, move, scale and rotate entities, knot edit, etc. And the drawing file may probably grow to a large size.
In general, there are two approaches to implement undo and redo, the first is Command Pattern, and the second is CheckPoint method.
CheckPoint method saves the WHOLE file into memory every times when there's document changing. The advantage of it is command independent, but this will be unendurable when the file grows very large.
Command pattern consumes less memory, but it requires almost every command implementing inverse operation, it will be a heavy burden. And in some cases, inverse operation is hard to do.
Is there any other method that implement undo/redo, for example, using checkpoint, but only saving the changing part of the drawing?
|
|
|
|
|
I am thinking the Command pattern is the way to go. If an operation is difficult to make an inverse operation the program can reload the commands from the beginning. In this method the data file will be the list of commands the user did in the GUI. Backing up is as simple as erasing a command from this list then reloading the entire list.
John
|
|
|
|
|
I am trying to set the default folder view the explorer uses for ALL USERS on a machine to details view.
I would prefer to do this programmatically, but anything would help.
Thank you for your time,
XP
|
|
|
|
|
 How can I use a Dll to link 2 different Static Lib in Visual C++ 6.0? Pls reply asap. thanx.
braderbear
|
|
|
|
|
How can I register a Win32 DLL in regisret so that it can be accessible to a VB client?
|
|
|
|
|
regsvr32 dllname
this command will register the dll in the registry...
This is done for COM inproc dll. I guess you dont have to register a win32 dll to be accessed by vb client.
The dll should be in the path or in the same folder where the vb binary lies.
Besides it is same as using "user32.dll" of windows.
"When death smiles at you, only thing you can do is smile back at it" - Russel Crowe (Gladiator)
|
|
|
|
|
If I register using regsvr32 it gives error the it cannot "Find DllEntryPoint"
|
|
|
|
|
That means that its not a com dll, so no point in registring it,
I dont know how to do it in VB but i guess you will find plenty of examples how to use win32 dll in vb.
"When death smiles at you, only thing you can do is smile back at it" - Russel Crowe (Gladiator)
|
|
|
|
|
For VB6 there's an add-in which lets you generate definitions and stuff to allow direct use of the Win32 API when appropriate.
Essentially, you have a code module within which the DLL exported entry points are declared, along with their parameters. You can also alias the entry points, to give them friendly names, then use them like regular VB sub/functions.
Steve S
(Me, write in VB? - No, you must be confusing me with someone else...)
|
|
|
|
|
Write the dll as a com component and do what the other person said.
John
|
|
|
|
|
John M. Drescher wrote:
what the other person said
The other person??
"When death smiles at you, only thing you can do is smile back at it" - Russel Crowe (Gladiator)
|
|
|
|
|
You, Sorry I was in a hurry and did not copy your name...
John
|
|
|
|
|
Hi,
im currently working on a MDI project. it concerns displaying waveforms, with data read from a text file.
iv added the zoom in and zoom out feature in the UI, but im having trouble in having the display updated within the same window.once a user clicks on the zoom in/out button, he needs to click on the "new" icon to have the zoomed picture displayed.im aware that the OnFileNew() is within the CWinApp class, therefore i cant call it from my CView class.
can someone please tell me how to call the OnFileNew() function from within the CView class? or am i suppose to do it another way?
thanks alot..
|
|
|
|
|
If I'm understanding the problem correctly (I'm not an MFC guy), it sounds like calling the OnFileNew() function would just be a work around anyway. I think you should probably be storing, inside your CView subclass, the necessary data to reconstruct the display when zooming. If that overhead is too large (i.e. too memory intensive), then I'd recommend creating some sort of object to encapsulate access to the file, with the necessary functions to read the data as many times as necessary. Then you should be able to share that object between the CWinApp object and the CView object.
|
|
|
|
|
Dear sir,
im still unclear about the solution uv put forth.
do u mean that im suppose to derive an object from the CWinApp, so that i can access the OnFileNew() with it? how do i do that?
can u please show me a code sample please?
secondly, would it be too much if u can explain to me how to close the present window when the new window is loaded?
on the second thought...is there any other method where i can have the new zoomed display updated from within the same window, without having to close and open a new window instead?
many thanx
|
|
|
|
|
I can't give you a code sample. I'm not experienced with MFC.
I'm certain that you can update the display from within the same window, but again, I don't use MFC, so I can't give you details. Sorry, but the best I can do is recommend that you read some documentation and figure it out yourself.
It just sounds like your program is doing things in a very round-about manner. There's got to be a simpler way.
|
|
|
|
|
Hello .. i want to have a window displaying train traffic ! http://www.cti-electronics.com/screen.gif <-- just as this application.
Can u use vc++ to design such an application? and how can i make such a window inside a SDI ?
|
|
|
|
|
Anonymous wrote:
Can u use vc++ to design such an application?
Yes.
Anonymous wrote:
and how can i make such a window inside a SDI ?
It is probably not SDI but rather MDI.
John
|
|
|
|
|
I am looking for a good visual c++ book for reference and guiding me along...I have heard both pos and neg things about teach yourself c++ in 21 days...And some other simular...If anyone could help with some advice it would be greatly appreciated...
Thanks in advance Strider
|
|
|
|
|
C++ all in one desk reference for dummies is a good book. it's seven books in one and by Jeff Cogswell. It has taught me alot ISBN 0-7645-1795-3
|
|
|
|
|
Hello!! dear~~ 
I write this text because I have a serious question about DLL...
I should develope a appication that "produces" specific DLLs, have specific functions.
Is it possible? Through my thinking, My application must has data structures for make dll source code and has dll Compiler...
I want excellect skill or thinking or Documents about that... Please...
Sorry for my foolish English...
I hope your Help!!
|
|
|
|
|
Solid77 wrote:
Sorry for my foolish English...
It is a little hard to read your question but I understand.
I don't have any good links but I do have a suggestion.
Use the appwizard (in vc6) to create a win32 dynamic link library. Then select an application that exports some symbols. VC++ will do all the hard parts for you. Take a look at the code especially the header file where most of the work is done. When you want to add it to your application you must include the main header file from the dll, copy the .dll and .lib to same place your exeutable is and link with the .lib file that was produced along with the dll. This all sounds difficult but after you try it things should make sense...
John
|
|
|
|
|
Dear John M. Drescher ...
Thanks for your Attention... I read your reply. Sorry for my poor English again...
My original Question is How make a dll file on my application program(Like a Symphonia...
related website is http://www.orionhealth.com/symphonia_overview.htm )
for example...
simple senario...
application excute -> select principal component in contents -> click "Make dll" or "Make ocx" button -> producing dll (not in visual studio!!)
in all respects, my question was not clear because my poor english. 
anyway thanks very much John... I will wait your useful reply...
|
|
|
|
|
I see Symphonia and now understand the question. http://www.orionhealth.com/symphonia_technical_general.htm[^]
My first guess is that it generates C++ statements and has a built-in compiler/linker that will compile the code it generates into a dll. Or maybe it has a dll already produced that it modifies the dll directly (by adding data to a data segment and changing function names). The second option is more difficult to do but will not require as much code to do that as the first.
John
|
|
|
|
|
General 
News 
Suggestion 
Question 
Bug 
Answer 
Joke 
Praise 
Rant 
Admin 
Submit an article or tip
