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The basic idea is this :
1) you calculate the percent coverage of each pixel when drawing the line.
2) you set the pixel color based on the percent coverage.
For example, if drawing a white line RGB(255,255,255) :
* if the pixel is 100 % covered, set the pixel color to RGB(255,255,255)
* if the pixel is 50 % covered, set the pixel color to RGB(127,127,127)
etc.
The hard part is step 1. The way to see what coverage means is to take a piece of graph paper - each grid cell represents a pixel. Draw a line from a start pixel to an end pixel. But the line is really a long rectangle, in which 2 of the sides are of unit length. You will see that some pixels are nearly fully covered, others on slightly covered. Unfortunately, the details of calculating these coverage values are complex. Maybe some OLD graphics text book will have more info on how to calculate the values.
What graphics package are you using ? I know that both openGL and Direct3D support antialiasing. I have not used Direct3D, but the openGL implementation is very easy to use.
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Hi,
what is exact difference between aggragation and containment.
aggregation is 'has a' relationship between classes.
Inheritence is 'is a' relationship. is it correct?
what about containment?
thanks,
- Koteswara,
pkoti@staff.juno.com
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As I understand it, aggregation is a form of containment where the aggregating object is dependent on, and derives its properties from, the objects it aggregates, i.e. it is the sum of its aggregate parts. In simple containment this is not the case, the container is not absolutely dependent on the objects it contains, nor are the parts dependent on the container.
There is also an implied linkage of object lifetimes in aggregation which is absent from simple containment. In aggregation, the lifetime of the aggregate object is dependent on the lifetime of the parts, but not vice-versa, unlike the otherwise similar 'composition', where the lifetime of the parts is tied to the lifetime of the composed object.
These links may be of some help:
http://pespmc1.vub.ac.be/ASC/Aggregation.html
http://ootips.org/uml-hasa.html
http://www.intellicorp.com/ooieonline/relation4.html
Dave
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I am a new MFC programmer and I would like to know how to open and display a .tif image and get the 'matrix version' of it to do some Image processing...
Thanks to anybody who could help me,
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You might look in
http://www.libtiff.org
There is a link for down-loading tiff library
software near the top of this page.
Near the bottom is a link "Building the software distribution" . That link has instructions for creating
the library on Windows using Visual C++.
p.s. I have code to open a bitmap file(BMP) and get the
"matrix version" of it. I use the bitmap file
as a texture in openGL.
Hope this helps.
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Hi!
How do I create 'shapes' in VC++ 6?
Just like the ones in VisualBasic 6!
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I developing a webbrowser using CHtmlView.
But this browser is not repaint properly.
That is, i want to use CView::Invalidate() for browser repaint.
But this function is not work.
Anybody have sample code.
Thanks in advance.
dooly
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Hi
When I call InvalidateRect function my application
quits with error. Who can help me?
Hovo
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I wish to make a virtual input/output port to simulate the action of a digital I/O card in the PC. Is there any way that I can "trap" the I/O operations from a Win32 application and return suitable responses to simulate an actual I/O card?
This will allow program development using the virtual I/O card until the actual card is ready for installation.
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I really don't understand your question. You can't directly access I/O ports from Win32 applications (well, you can use a hack in 9x, but it's not portable to NT).
Generally you would write a device driver to access the ports. So, all you do is create a dummy device driver that does nothing.
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I have a dialog box, that creates an instance of a class. This class has a CDaoDatabase and a CDaoRecordset object withen it.
Withen the class I open and close both those objects.
The first time I open this dialog box.. everything runs fine.. the SECOND time it causes an ASSERT to fail.. now upon debugging this I find the ASSERT is being caused in the CDaoWorkspace..
I've found a temporary solution to this (I think).. if I call AfxDaoInit() at the start of the class, and AfxDaoTerm() at the end.. it seems to run fine.. But I'm guessing this isn't the proper way to go about fixing this problem..
Any suggestions on how to fix this? or clues as to why this is happening?
Thanks in advanced..
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This sounds like the problem described in
http://support.microsoft.com/support/kb/articles/Q145/9/92.asp
(knowledgebase article Q1459920)
The article offers two other 'workarounds', but you're quite right in that AfxDaoTerm is involved.
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I haven't been using WTL before but have recently been finding more and more stuff that made me interested... But with all this new .net stuff, is there any real point in learning this or should I just wait until the release of .net and then learn the new microsoft way?
/XTSea
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I'm trying to control an existing instance of Internet Explorer with DDE.
For example, I can change the URL, or close an existing window, but what i can't do is to retrieve the current URL.
A very small doc in msdn says that you must connect to the DEE service IExplore, with the topic name WWW_GetWindowInfo, and the item name WWW_GetWindowInfo. And it says that both an Execute or a Request should work. But it doesn't seem to work.
Can somebody send me an example of code to achieve what i said?
oh, btw, i'm not using MFC, and i'm using the DDEML library.
Gabriel Soubies, student in France
gabries.soubies@supelec.fr
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Hi,
I successfully crea the .chm file. But i want GUI like MSDN help.
Like two panes, on clicking an item in the left pane should give its contents on
right pane.
Thanks,
- Koteswara
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If you fire up HTML Help Workshop, and open your project, click on the 'Project' tab and then on the 'Window' icon (the third one down I think). Now fill in / edit the options to suit your needs. You will want to use the 'Navigation Pane' tab and chek the box that says somrthing like 'show navigation pane'.
Now hit recompile and you should see what you want.
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Hello,
I'm using throughout my application the macros __FILE__ and __LINE__ to write the position of some code into a log file. Now the (probably quite stupid) question. Why does this not work on the client side. I get NULL and 0 where __FILE__ and __LINE__ should appear in my log file.
What am I missing?
Best wishes,
Matthias Steinbart
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I have developped a drawing application like AUTOCAD.Using this application a user can draw a lot of shapes and save the picture to the disk.My application supports drawing area more than the client area.So my application supports scrolling to see all the objects in the drawing area.So I need a mechanism by which I can draw objects greater than the client area.ie,while drawing an object by dragging I must be able to scroll the view so that I can draw the object to any part of the draw area with out being limitted to the client area.
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How do I remove the focus on a focused item in a MFC TreeCtrl? I've tried the SetItemState but the flag TVIS_FOCUSED is not implemented and can not be used.
Suggestions?
/Jens
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I'm currently writing a FTP-client and I would like to implement a class which resumes downloads if they're broken. So what I need is an example of this (hopefully mfc...) or some links where I can get more info about this.
/XTSea
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Hi,
I want to prepare one compiled HTML file.
Looks like MSDN help etc (it should contain one left pane, and right pane,
on clicking on any item in left pane, the related html file come into right pane).
Ex: MSDN help
How to do this?
Any one has an idea, tell me some APIs or related ideas to solve this problem.
thanks in advance,
Perumalla Koteswara Rao.
---------------------------------------------------------------------
Genius is one percent inspiration and ninety-nine percent
perspiration. --Thomas Alva Edison
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Hi Koteswara,
You need to use the "HTML Help WorkShop", this is a freeware program from Microsoft, it includes an API to hook up the help to your program. Read the following article at codeguru to get started "Starting with HTML Help" by Joep Oude Veldhuis.
http://codeguru.earthweb.com/help/html_help.shtml
In the article there is a link to download the program.
Best regards
Jose
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I mean that I need something like a CScrollView which make much of the work for scrolling with code ready to go (and also I need zoom capability, but this is easier to do). Unfortunately it is not possible to have a CScrollView created in a dialog because the class is to much linked with doc and so on. So actually I need a kindof simple and ideal CScrollZoomWnd.
I have tried to put a CSplitter with CView inside my dialog since there are some good examples on www.codetools.com. But I found that it is not possible to have a CSplitter object with only one row and one column. The programm crashes.
Other ideas ?
Thanks
Pierre
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Why don't U try the above splitterwnd with 2 rows and 1 column and give the size of the second pane as CSize(0,0)???
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Hi All,
I'm new to MFC and am trying to write a dialog-based application which accesses an ODBC database. Multiple dialogs are involved and I can't figure out how to access the same CRecordSet object from each dialog class. Any help would be greatly appreciated.
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