InvalidateRect and GDI
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LighthouseJ wrote: Can I only invalidate one rectangle specified by a couple CRect structures at a time? yes I believe!
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cheers, Alok Gupta VC Forum Q&A :- I/ IV
See, I have code like this:
if (first test statement) { (update data) (invalidate one rectangle) } if (second test statement) { (update other data) (invalidate another rectangle) }and both sections work independantly as far as what it tests for. The first if statement is run several times more than the second, but I let my program run and something I didn't expect to happens. What happens is that the screen is updated whenever the second statement is run (less often), but both the first and second rectangle are refreshed (with erases). I tried switching the order of the if statements but it still refreshes at the frequency of the lesser used if statement rectangle invalidation. I don't know what to do about it, right now at least. -
See, I have code like this:
if (first test statement) { (update data) (invalidate one rectangle) } if (second test statement) { (update other data) (invalidate another rectangle) }and both sections work independantly as far as what it tests for. The first if statement is run several times more than the second, but I let my program run and something I didn't expect to happens. What happens is that the screen is updated whenever the second statement is run (less often), but both the first and second rectangle are refreshed (with erases). I tried switching the order of the if statements but it still refreshes at the frequency of the lesser used if statement rectangle invalidation. I don't know what to do about it, right now at least.I'm not sure I understood your problem, but keep in mind that invalidating just means that it will be updated in then next paint cycle. If you want to make sure the window gets updated after each 'invalidate' you should also call UpdateWindow right after calling InvalidateRect -- jlr http://jlamas.blogspot.com/[^]
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I'm not sure I understood your problem, but keep in mind that invalidating just means that it will be updated in then next paint cycle. If you want to make sure the window gets updated after each 'invalidate' you should also call UpdateWindow right after calling InvalidateRect -- jlr http://jlamas.blogspot.com/[^]
I tried that by doing something like this:
bool bUpdateWindow = false; CWnd * pParent = ::AfxGetMainWnd(); if (first test) { (change data) pParent->InvalidateRect(pRect1, true); bUpdateWindow = true; } if (second test) { (change other data) pParent->InvalidateRect(pRect2, true); bUpdateWindow = true; } if (bUpdateWindow) { pParent->UpdateWindow(); }But the behavior isn't changed from before. -
I tried that by doing something like this:
bool bUpdateWindow = false; CWnd * pParent = ::AfxGetMainWnd(); if (first test) { (change data) pParent->InvalidateRect(pRect1, true); bUpdateWindow = true; } if (second test) { (change other data) pParent->InvalidateRect(pRect2, true); bUpdateWindow = true; } if (bUpdateWindow) { pParent->UpdateWindow(); }But the behavior isn't changed from before.Are you sure it's AfxGetMainWnd() the window you need to invalidate? What kind of window is the main one? Is it a dialog, MDI/SDI frame, or something else? -- jlr http://jlamas.blogspot.com/[^]
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Are you sure it's AfxGetMainWnd() the window you need to invalidate? What kind of window is the main one? Is it a dialog, MDI/SDI frame, or something else? -- jlr http://jlamas.blogspot.com/[^]
hmm, well I'm invalidating and updating the window in a thread... you raise an interesting question. The main window, in the file mainfrm.cpp, is CMainFrame, derived from CFrameWnd. Am I calling it's routines instead of the child and that's what's not right?
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hmm, well I'm invalidating and updating the window in a thread... you raise an interesting question. The main window, in the file mainfrm.cpp, is CMainFrame, derived from CFrameWnd. Am I calling it's routines instead of the child and that's what's not right?
I don't think invalidating CMainFrame would work, because it's unlikely CMainFrame is drawing something based on the data you change. You should be invalidating the specific window that needs to be updated. Better yet, if that's a CView-derived window, you should put the data in a document, modify the data using a document member function, which should call UpdateAllViews. Your view, in its OnUpdate member should invalidate and update itself based on that notification. -- jlr http://jlamas.blogspot.com/[^]
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I don't think invalidating CMainFrame would work, because it's unlikely CMainFrame is drawing something based on the data you change. You should be invalidating the specific window that needs to be updated. Better yet, if that's a CView-derived window, you should put the data in a document, modify the data using a document member function, which should call UpdateAllViews. Your view, in its OnUpdate member should invalidate and update itself based on that notification. -- jlr http://jlamas.blogspot.com/[^]
I'm trying to figure out a way to pass the instruction through from thread->CMainFrame(derived from CFrameWnd)->CChildView(derived from CWnd). There's no CView-derived thing in my project. I tried creating a message to pass but that's not working and I tried creating a function in CMainFrame to update the child view when it's called so the thread can call that, but it gives me access violations and it has question marks next to the values for the different window handles. I'm still checking it out.
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See, I have code like this:
if (first test statement) { (update data) (invalidate one rectangle) } if (second test statement) { (update other data) (invalidate another rectangle) }and both sections work independantly as far as what it tests for. The first if statement is run several times more than the second, but I let my program run and something I didn't expect to happens. What happens is that the screen is updated whenever the second statement is run (less often), but both the first and second rectangle are refreshed (with erases). I tried switching the order of the if statements but it still refreshes at the frequency of the lesser used if statement rectangle invalidation. I don't know what to do about it, right now at least.When you invalidate a rectangle/region, this area does not get updated straight away. It will get updated the next time Windows decides to send your app a WM_PAINT message. To force an update after you invalidate a region, call the UpdateWindow API James
http://www.catch22.net -
I'm trying to figure out a way to pass the instruction through from thread->CMainFrame(derived from CFrameWnd)->CChildView(derived from CWnd). There's no CView-derived thing in my project. I tried creating a message to pass but that's not working and I tried creating a function in CMainFrame to update the child view when it's called so the thread can call that, but it gives me access violations and it has question marks next to the values for the different window handles. I'm still checking it out.
If you are in a worker thread you can't make direct calls to CWnd objects created in the main (GUI) thread. Instead, you need to pass a window handle (HWND) to the thread function and use it there to send or post private messages (WM_USER + n) from the worker thread to that window. -- jlr http://jlamas.blogspot.com/[^]
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If you are in a worker thread you can't make direct calls to CWnd objects created in the main (GUI) thread. Instead, you need to pass a window handle (HWND) to the thread function and use it there to send or post private messages (WM_USER + n) from the worker thread to that window. -- jlr http://jlamas.blogspot.com/[^]
This thread is a user-interface thread, I overrode CWinThread and pass the runtime class name to AfxBeginThread just as the documentation say you're supposed to do for a user-interface thread. I was trying to figure out a way to use messages but maybe I don't know as much as I need to. I defined a message like:
#define WM_UPDATECHILD (WM_APP + 1)And tried to create a handler function for that message but it would never be run. I tried to override PreTranslateMessage, OnCmdMsg, and OnCommand to intercept this message, handle it, then return a nonzero result to show it was handled and none of this worked. I just don't know what to do.