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Article #216How to Scroll?
From: ARRA SHRAVAN KUMAR
Date: Wed, 08 Apr 1992 02:51
Date: Wed, 08 Apr 1992 02:51
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1589 bytes
Dear Netters, My application draws a data structure like a tree or a linked list, in a window. The size of the tree grows dynamically and is so big that it goes beyond the screen. So I need to provide scrolling so that th euser can see all parts of the tree. Obviously, I have to paint the uncovered portion of the window when the user scrolls. If I were dealing with text files I would read from the text file the uncovered portion of the text and paint it in the window. However I am dealing with bitmaps and other graphic objects. How do I do this? My idea was to draw everything into a temporary drawing area(like a memory DC) and display a part of it that corresponds to the window whenever a WM_PAINT message comes. I tried to do this but failed. I heard from someone that I cannot have a memory DC that is larger than the screen. Is this true? This is like a paint application where your drawing area is much larger than the screen. How can I provide graphic scrolling when my drawing area is much larger (about 5 times) than the screen? Please help me. It is very important for my thesis. Thanks in advance. Shravan arra@a.cs.okstate.edu
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Path: arc1-ca.pugleaf.net!sparky!uunet!ogicse!unmvax!constellation!a.cs.okstate.edu!arra From: arra@a.cs.okstate.edu (ARRA SHRAVAN KUMAR) Newsgroups: comp.windows.ms.programmer Subject: How to Scroll? Message-ID: <1992Apr8.025125.29711@a.cs.okstate.edu> Date: 8 Apr 92 02:51:25 GMT Article-I.D.: a.1992Apr8.025125.29711 Distribution: usa Organization: Oklahoma State University, Computer Science, Stillwater Lines: 23