I'm new to the WTL C++. I'm really confused about the parameters that go into the RedrawWindows function especially for the flags. I'm just trying to update a window everytime I draw a line, but I don't exactly understand how
LRESULT CDrawView::OnLButtonUp(UINT uMsg, WPARAM wParam, LPARAM lParam, BOOL& bHandled)
{
int xPos= GET_X_LPARAM(lParam);
int yPos = GET_Y_LPARAM(lParam);
end.X = xPos;
end.Y = yPos;
Pen pen(Color(0, 0, 255));
m_GraphicsImage.DrawLine(&pen, start.X, start.Y, end.X, end.Y);
I try to call RedrawWindow here,
RedrawWIndow(NULL,NULL, NULL, RDW_INTERNALPAINT)
So everytime I release the left mouse button the window gets updated. I'm having a really hard time understanding the parameters that go into the Redraw Function. I tried putting them all null minus the last one but Visual studio says that the function doesn't take 4 parameters even though I read the msdn microsoft...
You are not calling the global RedrawWindow.
You're calling the member function CWindow::RedrawWindow, which takes 3 parameters.
BOOL RedrawWindow(
LPCRECT lpRectUpdate = NULL,
HRGN hRgnUpdate = NULL,
UINT flags = RDW_INVALIDATE | RDW_UPDATENOW | RDW_ERASE
); throw()
Edit:
These three parameters all have default arguments, meaning they don't need to be supplied an RedrawWindow() alone should work.
This is not the way you should use and you are supposed to be using the API. Your mouse button handler should call Invalidate() or InvalidateRect with specific part of the window you are marking as needing an update. Your window will then receive WM_PAINT event at the first OS convenience and your paint handler would paint the line.
RedrawWindow might work out this time, however is likely to be a base of a next problem very soon because you are already on the wrong way.
Related
I created a global mouse hook where I tried to change the x and y cursor position that the hooked application receives without actually moving the cursor. For some reason it did not work. So I tried to change the cursor position to see if it would change anything. But that didn't work either; the input reached the window before the cursor moved. Below is my code.
LRESULT CALLBACK procMouseMsg(int nCode, WPARAM wParam, LPARAM lParam){
//this is the hook procedure
if (wParam == WM_LBUTTONDOWN){
// Tactic #1 -problem: Nothing seems to happen...?
((PMSLLHOOKSTRUCT)lParam)->pt.x = 389; //
((PMSLLHOOKSTRUCT)lParam)->pt.y = 15;
// Tactic #2 -problem: cursor moves after input hits hooked application
SetPhysicalCursorPos(389, 15);
// Tactics were not used at the same time.
}
return CallNextHookEx(hkKey, nCode, wParam, lParam);
}
void __stdcall SetHook()
{
if (hkMouse == NULL){
hkMouse = SetWindowsHookEx(WH_MOUSE_LL, procMouseMsg, hInstHookDll, 0);
}
}
Am I missing something big here? Maybe I should just kill the input in CallNextHookEx and then move the cursor, manually send an input and then move the cursor back? I feel like this should be easier.
BTW I'm not writing a keylogger or anything sketchy. I'm trying to do an operating system overlay. It seems like people assume the worst.
I recently started coding in C++ and I am very new to it. (I code in Javascript, PHP, Java and Obj-C more often)
I'm practicing how to hook a message box and change its position. This is what I have in my .cpp file (after reading this SO post).
#include <iostream>
#pragma comment(lib,"User32.lib")
#include <windows.h>
HHOOK hhookCBTProc = 0;
LRESULT CALLBACK pfnCBTMsgBoxHook(int nCode, WPARAM wParam, LPARAM lParam){
if (nCode == HCBT_CREATEWND)
{
CREATESTRUCT *pcs = ((CBT_CREATEWND *)lParam)->lpcs;
if ((pcs->style & WS_DLGFRAME) || (pcs->style & WS_POPUP))
{
HWND hwnd = (HWND)wParam;
SetWindowPos(hwnd, HWND_TOP,130,122, 0, 0,SWP_NOSIZE);
}
}
return (CallNextHookEx(hhookCBTProc, nCode, wParam, lParam));
}
int main(void)
{
hhookCBTProc = SetWindowsHookEx(WH_CBT,pfnCBTMsgBoxHook,
0, GetCurrentThreadId());
int sResult = MessageBox ( NULL, "Hooked!", "oh my", MB_OK );
UnhookWindowsHookEx(hhookCBTProc);
return 0;
}
For some reason the position of the message box isn't changing. Where did it go wrong?
(I know I can create a customized window or dialog. But I am doing it this way because I want to learn how to hook a message box and where I did wrong.)
Firstly you should check in the debugger that your hook is actually being called, if you haven't already.
Secondly, at the time the HCBT_CREATEWND hook event is triggered, the window has only just been created - the system has yet to size and position it. It will do this with the values in the CREATESTRUCT after the hook returns - overriding your SetWindowPos call.
See the docs from MSDN on the lParam value for this particular hook event:
Specifies a long pointer to a CBT_CREATEWND structure containing
initialization parameters for the window. The parameters include the
coordinates and dimensions of the window. By changing these
parameters, a CBTProc hook procedure can set the initial size and
position of the window.
Therefore, the correct way to use this hook to change a window's position is to modify the values in the CREATESTRUCT directly.
Also note that it's quite possible that the dialog manager sizes and positions the window after creation, so if you find that this still isn't working for you, you may need to try watching for the HCBT_MOVESIZE event instead.
From the docs
At the time of the HCBT_CREATEWND notification, the window has been
created, but its final size and position may not have been determined
and its parent window may not have been established.
Maybe try hooking into CBT_ACTIVATE instead.
Does anybody know how to make a 'always-on-bottom'-windows, or a window pinned to the desktop? It should receive focus and mouseclicks, but should stay at the bottom of the Z-order. It would also be great if it could stay on the desktop even when user do a minimize all or show desktop operation.
Both delphi and c# solutions (or partial solutions/hints) would be great.
Warning It was suggested that you can accomplish this by calling SetParent and setting the window to be a child of the Desktop. If you do this, you cause the Win32 Window Manager to combine the input queue of the Desktop to your child window, this is a bad thing - Raymond Chen explains why.
Also, keep in mind that calling SetWindowPos with HWND_BOTTOM is incomplete. You need to do this whenever your window is changing zorder. Handle the WM_WINDOWPOSCHANGING event, look at SWP_NOZORDER for more info.
SetWindowPos can make windows AlwaysOnTop. Most likely it can give the opposite result. Try something along these lines:
[DllImport("user32.dll")]
static extern bool SetWindowPos(IntPtr hWnd, IntPtr hWndInsertAfter, int X,
int Y, int cx, int cy, uint uFlags);
public const uint SWP_NOSIZE = 0x0001;
public const uint SWP_NOMOVE = 0x0002;
public const uint SWP_NOACTIVATE = 0x0010;
public const int HWND_BOTTOM = 1;
SetWindowPos(hWnd, HWND_BOTTOM, 0, 0, 0, 0, SWP_NOSIZE | SWP_NOMOVE | SWP_NOACTIVATE);
Note:
Haven't tested this approach (for making windows always on bottom)
If it happens to work, then most likely the show desktop operation will hide the window. So maybe you should go even deeper into this 'nice' API.
EDIT: Done some searching along these lines to confirm whether it will do the trick and found something interesting - a duplicate.
Here is solution for ATL window.
If you can apply to c#, it will help you.
BEGIN_MSG_MAP(...)
...
MESSAGE_HANDLER(WM_WINDOWPOSCHANGING, OnWindowPosChanging)
...
END_MSG_MAP()
LRESULT OnWindowPosChanging(UINT uMsg, WPARAM wParam, LPARAM lParam, BOOL& bHandled)
{
if (_bStayOnBottom)
{
auto pwpos = (WINDOWPOS*)lParam;
pwpos->hwndInsertAfter = HWND_BOTTOM;
pwpos->flags &= (~SWP_NOZORDER);
}
return 0;
}
I need to invalidate two panes when splitter is moving in WTL. Currently one of them invalidating when splitter is moving and other is invalidating when splitter moving stopped.
How can I handle splitter moving?
You typically don't need to invalidate explicitly because splitter moves child windows and they receive regular messages like WM_SIZE causing UI updates. The question itself suggests that something is incorrect with child windows.
You certainly can overwrite splitter's UpdateWindow to handle end of splitter repositioning, but you don't normally need to do it. Splitter itself invalidates itself applies SetWindowPos to panes in its helper UpdateSplitterLayout method, which you can step through with debugger to make sure this code is being executed.
LRESULT OnMouseMove(UINT /*uMsg*/, WPARAM wParam, LPARAM lParam, BOOL& bHandled)
{
// [...]
if(m_bFullDrag)
{
if(pT->SetSplitterPos(xyNewSplitPos, true))
pT->UpdateWindow();
bool SetSplitterPos(int xyPos = -1, bool bUpdate = true)
{
// [...]
UpdateSplitterLayout();
void UpdateSplitterLayout()
{
// [...]
for(int nPane = 0; nPane < m_nPanesCount; nPane++)
{
// [...]
::SetWindowPos(m_hWndPane[nPane], NULL, rect.left, rect.top, rect.right - rect.left, rect.bottom - rect.top, SWP_NOZORDER);
You might want to ensure m_bFullDrag is set to TRUE to force repaints while moving is in progress.
I am creating a modeless property sheet using the following settings:
PROPSHEETHEADER pshdr = { 0 };
pshdr.dwSize = sizeof(PROPSHEETHEADER);
pshdr.dwFlags = PSH_NOAPPLYNOW | PSH_PROPSHEETPAGE |
PSH_MODELESS | PSH_USECALLBACK;
pshdr.pfnCallback = PropSheetProc;
pshdr.hwndParent = mGlobalState->trayWin;
pshdr.pszCaption = L"My Settings";
pshdr.nPages = mPages.size();
pshdr.ppsp = mWinPages;
In PropSheetProc, I catch the PSCB_PRECREATE message and modify the dialog template so that it gets the DS_CENTER style:
static int CALLBACK
PropSheetProc(HWND hwndDlg, // IN
UINT uMsg, // IN
LPARAM lParam) // IN
{
// Before the dialog is created, bless it with the DS_CENTER style.
if (uMsg == PSCB_PRECREATE) {
DLGTEMPLATE *dlgTemplate = (DLGTEMPLATE *)lParam;
_ASSERT(dlgTemplate);
dlgTemplate->style |= DS_CENTER;
}
return 0;
}
However this doesn't succeed in centering the dialog. I tried to catch PSCB_INITIALIZED instead and call a CenterWindow method on the hwnd passed to the PropSheetProc:
void
CenterWindow(HWND hwndWindow) // IN
{
int nX, nY, nScreenWidth, nScreenHeight;
RECT rectWindow;
nScreenWidth = GetSystemMetrics(SM_CXSCREEN);
nScreenHeight = GetSystemMetrics(SM_CYSCREEN);
GetWindowRect(hwndWindow, &rectWindow);
nX = (nScreenWidth - (rectWindow.right - rectWindow.left)) / 2;
nY = (nScreenHeight - (rectWindow.bottom - rectWindow.top)) / 2;
SetWindowPos(hwndWindow, 0, nX, nY, 0, 0,
SWP_NOZORDER | SWP_NOSIZE);
}
But that doesn't work either!
Finally, I moved the CenterWindow call to directly after the PropSheet call:
mHwnd = (HWND)PropertySheet(&pshdr);
CenterWindow(mHwnd);
return mHwnd != NULL;
And this DOES work, though on a heavily loaded system, the dialog flashes from its initial position over to its final position, which is suboptimal.
Using the PropSheetProc to modify the DLGTEMPLATE structure seems intuitive. Actually, I can apply other window styles. But DS_CENTER seems to have no effect. So what am I doing wrong? There's many ways I can work around this brokennness but why is it broken in the first place?
Overload the InitialUpdate() of the CPropertySheet, and place the CenterWindow() call there. This happens before the window is drawn on the screen, but after it is created, so it's hwnd will be valid. There is nothing broken. The dialog has to be Created to have a valid HWND. Alternatively, if your working with the resource editor you can set it's property to centered, and it will achieve the same result. Why are you overloading the WinProc for the propertysheet? The whole reason MFC uses message maps was to eliminate the need to even touch WinProc's.
If your using raw win api in a SDK style application ::
Handle WM_CREATE in the WinProc of the property sheet. The LPCREATE struct in the LPARAM will contain a valid HWND from the create call. Just make sure you pass the proper parameters back to WndProcDefault() otherwise window creation will fail.