I need to change the colors of the background, the text, the color of the dropdown button of
CDateTimeCtrl in MFC. I created new class derived from CDateTimeCtrl and tried overwritten OnCtlColor and CtlColor, but these functions are never called (the message map has been added using the Class Wizard). How should I achieve this without writing a completely new datetimectrl class of my own?
You can try something like this:
// header
CBrush* m_pBkgBrush { nullptr };
COLORREF m_bkgColor { RGB(255, 255, 255) };
COLORREF SetBackgroundColor(BOOL bSysColor, COLORREF cr);
and implementation now:
CYourDateTimeCtrl::CYourDateTimeCtrl()
: CDateTimeCtrl()
, m_bkgColor(::GetSysColor(COLOR_WINDOW))
{
m_pBkgBrush = new CBrush(::GetSysColor(COLOR_WINDOW));
}
CYourDateTimeCtrl::~CYourDateTimeCtrl()
{
if (nullptr != m_pBkgBrush)
delete m_pBkgBrush;
}
COLORREF CYourDateTimeCtrl::SetBackgroundColor(BOOL bSysColor, COLORREF cr)
{
COLORREF color = m_bkgColor;
m_bkgColor = bSysColor ? ::GetSysColor(COLOR_WINDOW) : cr;
if (color != m_bkgColor)
{
delete m_pBkgBrush;
m_pBkgBrush = new CBrush(m_bkgColor);
Invalidate();
}
return color;
}
BOOL CYourDateTimeCtrl::OnEraseBkgnd(CDC* pDC)
{
CBrush* pOldBrush = pDC->SelectObject(m_pBkgBrush);
CRect rect;
pDC->GetClipBox(&rect);
pDC->PatBlt(rect.left, rect.top, rect.Width(), rect.Height(), PATCOPY);
pDC->SelectObject(pOldBrush);
return TRUE;
}
When you use, you do:
MyMonthCalCtrl.SetBackgroundColor(FALSE, RGB(255, 255, 0));
I hope it helps.
I try to make some easy application which scrolling ECG singal which is drawing on bitmap grid. Environment which I use is Visual Studio 2013 with C++ MFC.
My problem is with transfer gdi object like LineTo or Rectangle() function from dcMemory to my main device context (cdc). Before I make similar application using WinAPI and all go well. I spent a lot time with studying msdn and looking answer with google, and I have no idea why only bitmap from Bitmap.LoadBitmapW(IDB_BITMAP2) is printing. Can anybody help me?
Message when button from menu was calling:
void CToradex_MFC_BitmapView::OnBitmapDraw()
{
Bitmap.LoadBitmapW(IDB_BITMAP2);
cdc.CreateDC(L"DISPLAY", NULL, NULL, NULL);
dcMemory.CreateCompatibleDC(&cdc);
LoadData();
GetObject(Bitmap, sizeof(bmpInfo), &bmpInfo);
dcMemory.SelectObject(&Pen);
dcMemory.Rectangle(100, 100, 200, 200);
dcMemory.LineTo(100, 300);
dcMemory.SelectObject(&Bitmap);
druk.DrawECG(&dcMemory, pointer, 3, SIGN_LEN);
}
Message on mouse button down:
void CToradex_MFC_BitmapView::OnLButtonDown(UINT,CPoint)
{
CToradex_MFC_BitmapDoc* pDoc = GetDocument();
ASSERT_VALID(pDoc);
POINT p;
GetCursorPos(&p);
x_start = p.x;
y_start = p.y;
}
Message on mouse move:
void CToradex_MFC_BitmapView::OnMouseMove(UINT, CPoint)
{
POINT d;
//CDC * pDC = this->GetDC();
//this->GetClientRect(&rect);
//rect = CRect(rect.left, rect.top, rect.right, rect.bottom);
if (GetCursorPos(&d))
{
move_x = d.x - x_start;
move_y = d.y - y_start;
cdc.BitBlt(move_x, move_y, bmpInfo.bmWidth, bmpInfo.bmHeight, &dcMemory, 0, 0, SRCCOPY);
x_start = d.x;
y_start = d.y;
//Invalidate();
Sleep(10);
}
Below link for all .cpp file:
https://pastebin.com/h7hcLJbz
You need to select a bitmap into your DC first, then draw on top of it:
dcMemory.SelectObject(&Bitmap);
dcMemory.SelectObject(&Pen);
dcMemory.Rectangle(100, 100, 200, 200);
dcMemory.LineTo(100, 300);
druk.DrawECG(&dcMemory, pointer, 3, SIGN_LEN);
I have the color picked from my CMFCColorButton and now I want to set it to the background (if it's not already the current color).
I can't seem to figure out how, so I would really appreciate your help and explanation.
void CMainFrame::OnColor()
{
// m_TextColors is the ID of the color button I created in the resource editor.
CMFCRibbonColorButton* pColorBtn = DYNAMIC_DOWNCAST(CMFCRibbonColorButton, m_wndRibbonBar.FindByID(m_TextColors));
COLORREF color = pColorBtn->GetColor();
CWnd* pwndParent = this->GetParent();
CRect rcClient;
pwndParent->GetClientRect(&rcClient);
if (color != GetSysColor(COLOR_BACKGROUND)) {
CBrush brush;
CClientDC dc(this);
brush.CreateSolidBrush(color);
dc.FillRect(rcClient, &brush);
}
else {
MessageBox(_T("Same Color."), MB_OK);
}
}
I made some changes:
void CMainFrame::OnColor()
{
// m_TextColors is the ID of the color button I created in the resource editor.
CMFCRibbonColorButton* pColorBtn = DYNAMIC_DOWNCAST(CMFCRibbonColorButton, m_wndRibbonBar.FindByID(m_TextColors));
COLORREF color = pColorBtn->GetColor();
CBrush brush;
brush.CreateSolidBrush(color);
CRect rc;
GetClientRect(&rc);
GetWindowRect(&rc);
CClientDC dc(this);
dc.SelectObject(&rc);
if (color != GetSysColor(COLOR_WINDOW)) {
dc.FillRect(rc, &brush);
} else {
MessageBox(_T("Same Color."), MB_OK);
}
}
And this is the result:
It's tracing the document's color but not changing it, it's changing the whole window's color.
Update: I've tried the invalidateRect function, this is the result:
It seems like it's adding color on top of my MDI client area not in it in the background like i intended,
Have you tried:
void CMainFrame::OnButColor()
{
HBRUSH hBrush=CreateSolidBrush(RGB(0,0,255));
SetClassLong(m_hWndMDIClient, BGCL_HBRBACKGROUND,(LONG)hBrush);
::InvalidateRect(m_hWndMDIClient,0,TRUE);
}
I have a fairly standard MFC application that consists of a main window, and occasionally brings up modal dialogs. As we all know nothing can be done outside a modal dialog until it is closed.
Therefore, a nice UI feature is to "dim" the rest of the main window behind the dialog, to visually indicate you can't use it until you're done with the modal dialog. Some web apps and java/mac apps do this, but I've never seen it done in a traditional C++/MFC application. I'd like to give it a try, even if it's unusual for the platform.
How can this be done? I have several modal dialogs in the application, used in this pattern:
// pMainFrame is available as a pointer to the CWnd of the main window
CMyDialog dialog;
dialog.DoModal(); // invoke modal dialog; returns after dialog closed
Is there an easy way to have the window dimmed before any DoModal() and restored afterwards? I'm using Visual Studio 2010 in case the updated MFC has any features that might help.
Edit: I've posted a solution based on oystein's answer, but I'm starting a bounty in case anyone can improve on it - especially with a smooth fade in/fade out.
You can create another window, completely black, on top of the window you want to dim, and set the black window's opacity with SetLayeredWindowAttributes. It doesn't have to be black, of course, but I guess that's the best dimming color.
EDIT: I hacked together an example - but note that I am not an MFC developer, I usually use the Windows API directly. It seems to work okay, though.
Here is a pastebin. Feel free to add fade-ins etc. yourself. Also note that this dims the entire screen, you'll have to resize my dimming-window if you don't want this behaviour. See code comments.
/**********************************************************************************************
MFC screen dim test
:: oystein :: November 2010
Creates a simple window - click it to toggle whether a translucent black "dimmer" window
is shown. The dimmer-window covers the entire screen, but the taskbar ("superbar" in
Windows 7) will jump on top of it if clicked - it seems. Simple suggestions to fix that
are welcome.
Should work on Windows 2000 and later.
Disclaimer: This is my first MFC program ever, so if anything seems wrong, it probably is.
I have previously only coded with pure Win32 API, and hacked this together using online
tutorials. Code provided "as-is" with no guarantees - I can not be held responsible for
anything bad that happens if you run this program.
***********************************************************************************************/
#include "stdafx.h"
#undef WINVER
#define WINVER 0x500 // Windows 2000 & above, because of layered windows
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
//
// Black window used to dim everything else
//
class CDimWnd : public CFrameWnd
{
public:
CDimWnd()
{
// Get screen res into rect
RECT rc;
GetDesktopWindow()->GetWindowRect(&rc);
CreateEx(WS_EX_LAYERED | // Layered window for translucency
WS_EX_TRANSPARENT | // Click through
WS_EX_TOPMOST | // Always on top
WS_EX_TOOLWINDOW, // Do not appear in taskbar & similar
NULL, TEXT(""),
WS_POPUP, // No frame/borders - though there is
// still some border left - we'll remove
// it with regions
0, 0, rc.right + 10, rc.bottom + 10, // Make the window 10px larger
// than screen resolution in both
// directions - it is still positioned
// at 0,0
NULL, NULL);
// Grab a part of the window the size of the desktop - but 5px into it
// Because the window is larger than the desktop res, the borders are removed
CRgn rgn;
rgn.CreateRectRgn(rc.left + 5, rc.top + 5, rc.right + 5, rc.bottom + 5);
SetWindowRgn((HRGN)rgn, FALSE);
rgn.Detach();
// We have to reposition window - (0,0) of window has not changed
SetWindowPos(NULL, -5, -5, 0, 0, SWP_NOSIZE | SWP_NOZORDER);
// This is where we set the opacity of the window: 0-255
SetLayeredWindowAttributes(RGB(0,0,0), 150, LWA_ALPHA);
}
void Close()
{
CFrameWnd::OnClose();
}
BOOL CDimWnd::OnEraseBkgnd(CDC* pDC); // Set BKG color
DECLARE_MESSAGE_MAP()
};
BOOL CDimWnd::OnEraseBkgnd(CDC* pDC)
{
// Set brush to desired background color
CBrush backBrush(RGB(0, 0, 0));
// Save old brush
CBrush* pOldBrush = pDC->SelectObject(&backBrush);
CRect rect;
pDC->GetClipBox(&rect); // Erase the area needed
pDC->PatBlt(rect.left, rect.top, rect.Width(), rect.Height(), PATCOPY);
pDC->SelectObject(pOldBrush);
return TRUE;
}
BEGIN_MESSAGE_MAP(CDimWnd, CFrameWnd)
ON_WM_ERASEBKGND()
END_MESSAGE_MAP()
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// Global variable - is screen dimmed?
bool g_bIsDimmed = false;
// The main window
class CMainWnd : public CFrameWnd
{
// Contains a CDimWnd - I'm not sure if this is the "MFC way" of doing things
CDimWnd dimmer;
public:
CMainWnd()
{
Create(NULL, TEXT("Screen dimmer - Press left mouse button on window to toggle"),
WS_OVERLAPPEDWINDOW, CRect(50, 50, 400, 250));
}
// Left mouse button toggles dimming
afx_msg void OnLButtonDown(UINT Flags, CPoint Point)
{
if(!g_bIsDimmed)
{
dimmer.ShowWindow(SW_SHOW);
dimmer.BringWindowToTop();
g_bIsDimmed = true;
}
else
{
dimmer.ShowWindow(SW_HIDE);
g_bIsDimmed = false;
}
}
DECLARE_MESSAGE_MAP()
};
BEGIN_MESSAGE_MAP(CMainWnd, CFrameWnd)
ON_WM_LBUTTONDOWN()
END_MESSAGE_MAP()
// The app
class CApp : public CWinApp
{
public:
virtual BOOL InitInstance();
};
BOOL CApp::InitInstance()
{
m_pMainWnd = new CMainWnd();
m_pMainWnd->ShowWindow(m_nCmdShow);
m_pMainWnd->UpdateWindow();
return TRUE;
}
CApp HelloApp;
UPDATE:
I hacked together some more code for you, to handle the fading. I'm still no MFC dev, and I left the code in a "rough" state (little error handling, not very robust) to give you something to do too. :) Anyway, here's one way to do it, that I think is fairly clean:
To use it, make your main window contain a dimmer window
class CMainFrm : public CFrameWnd
{
CDimWnd* dimmer;
public:
CMainFrm()
{
// constructor code here ...
dimmer = new CDimWnd();
}
// rest of class ...
};
It can then be used e.g. like this:
dimmer->Show();
MessageBox(TEXT("Hello world"));
dimmer->Hide();
Alternatively I guess you could put this code (Show()/Hide() calls) in the constructor and destructor of the modal dialog, if you want to keep the code there. If you want a "scope"-dim, like in the example you posted, this code would have to go in the constructor & destructor of the CDimWnd class, and you would need something like a static member variable to ensure that only one dimmer is running at a time (unless you want to use a global variable).
For the dimmer window - I did this:
CDimWnd.h
#define TARGET_OPACITY 70 // Target opacity 0-255 for dimmed window
#define FADE_TIME 20 // Time between each fade step in milliseconds
#define FADE_STEP 5 // How much to add to/remove from opacity each fade step
#define ID_FADE_TIMER 1
// Call Show() and Hide() to fade in/fade out dimmer.
// Creates the dimmer window in constructor.
class CDimWnd : public CFrameWnd
{
bool m_isDimming;
public:
CDimWnd();
void Show();
void Hide();
protected:
BOOL OnEraseBkgnd(CDC* pDC);
void OnTimer(UINT_PTR nIDEvent);
DECLARE_MESSAGE_MAP()
};
CDimWnd.cpp
#include "stdafx.h"
#include "CDimWnd.h"
#include "MainFrm.h"
BEGIN_MESSAGE_MAP(CDimWnd, CFrameWnd)
ON_WM_ERASEBKGND()
END_MESSAGE_MAP()
CDimWnd::CDimWnd()
{
// Get the main frame of the application which we want to dim.
CMainFrame* pParent = theApp.pMainFrame;
// Don't do anything if the main frame doesn't appear to be there
if (pParent != NULL)
{
// Get the client area of the window to dim.
CRect rc;
pParent->GetClientRect(&rc);
pParent->ClientToScreen(&rc); // convert to screen coordinates
// Do some fudging to fit the client area exactly.
// Other applications may not need this if the above client area fits already.
rc.top += GetSystemMetrics(SM_CYFRAME);
rc.top += GetSystemMetrics(SM_CYCAPTION); // MFC feature pack seems to include caption in client area
rc.left -= GetSystemMetrics(SM_CXBORDER);
rc.right += GetSystemMetrics(SM_CXBORDER) + 1;
rc.bottom += GetSystemMetrics(SM_CYBORDER) + 1;
// Create a layered window for transparency, with no caption/border.
CreateEx(WS_EX_LAYERED | WS_EX_TRANSPARENT | WS_EX_TOOLWINDOW, NULL, TEXT(""),
WS_POPUP, rc.left, rc.top, rc.Width(), rc.Height(),
pParent->GetSafeHwnd(), NULL);
}
}
void CDimWnd::Show()
{
// If we are not already dimming, go for it
if(!m_isDimming)
{
// Bring in front of main window.
BringWindowToTop();
// Set opacity to 0
SetLayeredWindowAttributes(RGB(0,0,0), 0, LWA_ALPHA);
// Show the dimmer window
ShowWindow(SW_SHOW);
// Create timer - the rest is handled in OnTimer() function
SetTimer(ID_FADE_TIMER, FADE_TIME, NULL);
}
}
void CDimWnd::Hide()
{
// If we are dimming, go for it
if(m_isDimming)
{
// Create timer - the rest is handled in OnTimer() function
SetTimer(ID_FADE_TIMER, FADE_TIME, NULL);
}
}
void CDimWnd::OnTimer(UINT_PTR nIDEvent)
{
static int fade = 0;
if(nIDEvent == ID_FADE_TIMER)
{
// We are dimming => we want to fade out
if(m_isDimming)
{
if(fade < 0)
{
// Fading finished - hide window completely, update status & destroy timer
fade = 0;
ShowWindow(SW_HIDE);
KillTimer(nIDEvent);
m_isDimming = false;
}
else
{
// Set window opacity & update fade counter
SetLayeredWindowAttributes(RGB(0,0,0), fade, LWA_ALPHA);
fade -= FADE_STEP;
}
}
else
// fade in
{
if(fade > TARGET_OPACITY)
{
// Fading finished - destroy timer & update status
fade = TARGET_OPACITY; // but first, let's be accurate.
SetLayeredWindowAttributes(RGB(0,0,0), fade, LWA_ALPHA);
KillTimer(nIDEvent);
m_isDimming = true;
}
else
{
// Set window opacity & update fade counter
SetLayeredWindowAttributes(RGB(0,0,0), fade, LWA_ALPHA);
fade += FADE_STEP;
}
}
}
}
BOOL CDimWnd::OnEraseBkgnd(CDC* pDC)
{
// Fill with black
CBrush backBrush(RGB(0, 0, 0));
CBrush* pOldBrush = pDC->SelectObject(&backBrush);
CRect rect;
pDC->GetClipBox(&rect); // Erase the area needed
pDC->PatBlt(rect.left, rect.top, rect.Width(), rect.Height(), PATCOPY);
pDC->SelectObject(pOldBrush);
return TRUE;
}
Okay. As I said, this was thrown together fairly quickly and is in a rough state, but it should give you some code to work from, and a general idea of how (I think) timers are used in MFC. I am definitely not the right person to think anything about that, though :)
I've accepted oystein's answer, since it led me to the solution, but I thought I'd post my modifications. I had to modify it a bit to make it work for me, so it might come in useful to someone else.
For the record, the dimming works well, but it doesn't look as natural as I hoped. In an application which frequently brings up dialogs, the dimming becomes distracting in its regularity of seemingly switching the main window on and off. To compromise, I've made the dimming fairly subtle (about 25% opacity) which gently highlights the active dialog; the instant dimming is still a little distracting, but I'm not sure how to have it fade in or fade out smoothly, especially when scoped.
Also, I'm not a UI expert, but the dimming gave me a sort of impression that the dialog was less related to the window content behind it. This made it feel a bit detached from what I was working on in the application, even though the dialogs are directly manipulating that content. This might be another distraction.
Here it is anyway:
CDimWnd.h
// Dim the application main window over a scope. Creates dimmer window in constructor.
class CDimWnd : public CFrameWnd
{
public:
CDimWnd();
BOOL OnEraseBkgnd(CDC* pDC);
~CDimWnd();
protected:
DECLARE_MESSAGE_MAP()
};
CDimWnd.cpp
#include "stdafx.h"
#include "CDimWnd.h"
#include "MainFrm.h"
BEGIN_MESSAGE_MAP(CDimWnd, CFrameWnd)
ON_WM_ERASEBKGND()
END_MESSAGE_MAP()
// For preventing two dimmer windows ever appearing
bool is_dimmer_active = false;
CDimWnd::CDimWnd()
{
// Get the main frame of the application which we want to dim.
CMainFrame* pParent = theApp.pMainFrame;
// Don't do anything if the main frame doesn't appear to be there,
// or if there is already dimming happening.
if (pParent != NULL && !is_dimmer_active)
{
// Get the client area of the window to dim.
CRect rc;
pParent->GetClientRect(&rc);
pParent->ClientToScreen(&rc); // convert to screen coordinates
// Do some fudging to fit the client area exactly.
// Other applications may not need this if the above client area fits already.
rc.top += GetSystemMetrics(SM_CYFRAME);
rc.top += GetSystemMetrics(SM_CYCAPTION); // MFC feature pack seems to include caption in client area
rc.left -= GetSystemMetrics(SM_CXBORDER);
rc.right += GetSystemMetrics(SM_CXBORDER) + 1;
rc.bottom += GetSystemMetrics(SM_CYBORDER) + 1;
// Create a layered window for transparency, with no caption/border.
CreateEx(WS_EX_LAYERED | WS_EX_TRANSPARENT | WS_EX_TOOLWINDOW, NULL, TEXT(""),
WS_POPUP, rc.left, rc.top, rc.Width(), rc.Height(),
pParent->GetSafeHwnd(), NULL);
// Bring in front of main window.
BringWindowToTop();
// Apply 25% opacity
SetLayeredWindowAttributes(RGB(0,0,0), 64, LWA_ALPHA);
// Show the dimmer window
ShowWindow(SW_SHOW);
is_dimmer_active = true;
}
}
CDimWnd::~CDimWnd()
{
is_dimmer_active = false;
}
BOOL CDimWnd::OnEraseBkgnd(CDC* pDC)
{
// Fill with black
CBrush backBrush(RGB(0, 0, 0));
CBrush* pOldBrush = pDC->SelectObject(&backBrush);
CRect rect;
pDC->GetClipBox(&rect); // Erase the area needed
pDC->PatBlt(rect.left, rect.top, rect.Width(), rect.Height(), PATCOPY);
pDC->SelectObject(pOldBrush);
return TRUE;
}
Usage is dead simple: because CDimWnd creates itself in its constructor, all you need to do is add CDimWnd dimmer as a member of the dialog class, and it automatically dims the main window, no matter where you call the dialog from.
You can also use it within a scope to dim system modal dialogs:
{
CDimWnd dimmer;
MessageBox(...);
}
I couldn't resist doing it.
It's your code with added timers and implemented a fade in / fade out. Also I changed to use mid grey rather than black for the obscuring block.
You can tweak the constants that control the fade to make it smoother by increasing the duration or the increasing the rate. Experiment shows me that a rate of 10hz is smooth for me, but YMMV
// DimWnd.h : header file
#pragma once
class CDimWnd : public CFrameWnd
{
public:
CDimWnd(class CWnd * pParent);
virtual ~CDimWnd();
BOOL OnEraseBkgnd(CDC* pDC);
int opacity, opacity_increment;
protected:
DECLARE_MESSAGE_MAP()
public:
afx_msg void OnTimer(UINT_PTR nIDEvent);
void fadeOut();
};
// DimWnd.cpp : implementation file
//
#include "stdafx.h"
#include "dimmer.h"
#include "DimWnd.h"
#include "MainFrm.h"
#include <math.h>
const int TIMER_ID = 111;
// For preventing two dimmer windows ever appearing
bool is_dimmer_active = false;
// constants to control the fade.
int ticks_per_second = 1000; // ms
int start_opacity = 44; // 20%
int max_opacity = 220; // 0->255
double fade_in_duration = 4; // seconds to fade in (appear)
double fade_out_duration = 0.2; // seconds to fade out (disappear)
int rate = 100; // Timer rate (ms
CDimWnd::CDimWnd(CWnd * pParent)
{
// Don't do anything if the main frame doesn't appear to be there,
// or if there is already dimming happening.
if (pParent != NULL && !is_dimmer_active)
{
// Get the client area of the window to dim.
CRect rc;
pParent->GetClientRect(&rc);
pParent->ClientToScreen(&rc); // convert to screen coordinates
// Do some fudging to fit the client area exactly.
// Other applications may not need this if the above client area fits already.
rc.top += GetSystemMetrics(SM_CYFRAME);
rc.top += GetSystemMetrics(SM_CYCAPTION); // MFC feature pack seems to include caption in client area
rc.left -= GetSystemMetrics(SM_CXBORDER);
rc.right += GetSystemMetrics(SM_CXBORDER) + 1;
rc.bottom += GetSystemMetrics(SM_CYBORDER) + 1;
// Create a layered window for transparency, with no caption/border.
CreateEx(WS_EX_LAYERED | WS_EX_TRANSPARENT | WS_EX_TOOLWINDOW, NULL, TEXT(""),
WS_POPUP, rc.left, rc.top, rc.Width(), rc.Height(),
pParent->GetSafeHwnd(), NULL);
// Bring in front of main window.
BringWindowToTop();
// Show the dimmer window
ShowWindow(SW_SHOW);
double increment_per_second = ((max_opacity - start_opacity) / fade_in_duration);
opacity_increment = ceil( increment_per_second / (ticks_per_second / rate) ) ;
is_dimmer_active = true;
opacity = start_opacity;
SetLayeredWindowAttributes(RGB(0,0,0), opacity, LWA_ALPHA);
SetTimer(TIMER_ID, rate,NULL);
}
}
CDimWnd::~CDimWnd()
{
fadeOut(); // fade the window out rather than just disappearing.
is_dimmer_active = false;
}
void CDimWnd::fadeOut()
{
// can't use timers as may be in the process of being destroyed so make it quick..
double increment_per_second = ((opacity - start_opacity) / fade_out_duration);
opacity_increment = ceil( increment_per_second / (ticks_per_second / rate) ) ;
while(opacity > start_opacity)
{
opacity -= opacity_increment;
SetLayeredWindowAttributes(RGB(0,0,0), opacity, LWA_ALPHA);
Sleep(100);
}
}
BOOL CDimWnd::OnEraseBkgnd(CDC* pDC)
{
// Fill with midgray
CBrush backBrush(RGB(128,128,128));
CBrush* pOldBrush = pDC->SelectObject(&backBrush);
CRect rect;
pDC->GetClipBox(&rect); // Erase the area needed
pDC->PatBlt(rect.left, rect.top, rect.Width(), rect.Height(), PATCOPY);
pDC->SelectObject(pOldBrush);
return TRUE;
}
BEGIN_MESSAGE_MAP(CDimWnd, CFrameWnd)
ON_WM_ERASEBKGND()
ON_WM_TIMER()
END_MESSAGE_MAP()
void CDimWnd::OnTimer(UINT_PTR nIDEvent)
{
if (opacity >= max_opacity)
{
// stop the timer when fade in finished.
KillTimer(TIMER_ID);
return;
}
opacity += opacity_increment;
SetLayeredWindowAttributes(RGB(0,0,0), opacity, LWA_ALPHA);
CFrameWnd::OnTimer(nIDEvent);
}
I'm using a CListCtrl/CListView report view (LVS_REPORT) in virtual mode (LVS_OWNERDATA) with LVS_EX_DOUBLEBUFFER enabled and I encounter ugly flickering. Double buffer have a real effect but it doesn't stop all flickering (without it very slow).
I'm not looking for switching to other controls that would require a high amount of rework (like ObjectListView)
How does the flickering behaves:
on column resize - the background is first clean using lightgray and after this is displayed the text (background is white)
on mouse scroll (animated) - for a very short time there is lightgray-bar displayed in the area where new lines are to be displayed.
It looks like it does clean the background using the default window background color (lightgray) for the area where it has to redraw.
How do I solve the flickering problem?
Try to do the following:
- Set Clip Children and Clip Sibling for paremt dialog of List Control.
- Make dirived from CListCtrl class. In this class overwrite OnEraseBkgnd. In the OnEraseBkgnd fill with background color area around of visible items of the list.
The OnEraseBkgnd can look like:
BOOL CListCtrlEx::OnEraseBkgnd(CDC* pDC)
{
CBrush br;
CRect rcCli;
CRect rcItemsRect(0, 0, 0, 0);
int nHeadHeight = 0;
int nItems = GetItemCount();
GetClientRect(&rcCli);
CHeaderCtrl* pHeadCtrl = GetHeaderCtrl();
if (pHeadCtrl)
{
CRect rcHead;
pHeadCtrl->GetWindowRect(&rcHead);
nHeadHeight = rcHead.Height();
}
rcCli.top += nHeadHeight;
if (nItems > 0)
{
CPoint ptItem;
CRect rcItem;
GetItemRect(nItems - 1, &rcItem, LVIR_BOUNDS);
GetItemPosition(nItems - 1, &ptItem);
rcItemsRect.top = rcCli.top;
rcItemsRect.left = ptItem.x;
rcItemsRect.right = rcItem.right;
rcItemsRect.bottom = rcItem.bottom;
if (GetExtendedStyle() & LVS_EX_CHECKBOXES)
rcItemsRect.left -= GetSystemMetrics(SM_CXEDGE) + 16;
}
br.CreateSolidBrush(GetBkColor());
if (rcItemsRect.IsRectEmpty())
pDC->FillRect(rcCli, &br);
else
{
if (rcItemsRect.left > rcCli.left) // fill left rectangle
pDC->FillRect(
CRect(0, rcCli.top, rcItemsRect.left, rcCli.bottom), &br);
if (rcItemsRect.bottom < rcCli.bottom) // fill bottom rectangle
pDC->FillRect(
CRect(0, rcItemsRect.bottom, rcCli.right, rcCli.bottom), &br);
if (rcItemsRect.right < rcCli.right) // fill right rectangle
pDC->FillRect(
CRect(rcItemsRect.right, rcCli.top, rcCli.right, rcCli.bottom), &br);
}
return TRUE;
}
I know only way to have flicker free is using double buffering or MemDC.
have found this article: Flicker-free-drawing-of-any-control
This article explains it well how to quickly perform Non Flickering drawing on your CListCtrl.
And it works excellent.
PS: VS 2005 doesn't have CMemDC class you will need to implement it your self, or use the following code:
//
// CMemDC.h header file
//
#pragma once
class CMemDC
{
public:
CMemDC(CDC& dc, CWnd* pWnd);
CMemDC(CDC& dc, const CRect& rect);
virtual ~CMemDC();
CDC& GetDC() { return m_bMemDC ? m_dcMem : m_dc; }
BOOL IsMemDC() const { return m_bMemDC; }
BOOL IsVistaDC() const { return m_hBufferedPaint != NULL; }
void EraseBkClip();
protected:
CDC& m_dc;
BOOL m_bMemDC;
HANDLE m_hBufferedPaint;
CDC m_dcMem;
CBitmap m_bmp;
CBitmap* m_pOldBmp;
CRect m_rect;
};
//
// CMemDC.cpp source file
//
#include "CMemDC.h"
CMemDC::CMemDC(CDC& dc, CWnd* pWnd) :
m_dc(dc), m_bMemDC(FALSE), m_hBufferedPaint(NULL), m_pOldBmp(NULL)
{
ASSERT_VALID(pWnd);
pWnd->GetClientRect(m_rect);
m_rect.right += pWnd->GetScrollPos(SB_HORZ);
m_rect.bottom += pWnd->GetScrollPos(SB_VERT);
if (m_dcMem.CreateCompatibleDC(&m_dc) &&
m_bmp.CreateCompatibleBitmap(&m_dc, m_rect.Width(), m_rect.Height()))
{
m_bMemDC = TRUE;
m_pOldBmp = m_dcMem.SelectObject(&m_bmp);
}
}
CMemDC::CMemDC(CDC& dc, const CRect& rect) :
m_dc(dc), m_bMemDC(FALSE), m_hBufferedPaint(NULL), m_pOldBmp(NULL), m_rect(rect)
{
ASSERT(!m_rect.IsRectEmpty());
if (m_dcMem.CreateCompatibleDC(&m_dc) &&
m_bmp.CreateCompatibleBitmap(&m_dc, m_rect.Width(), m_rect.Height()))
{
m_bMemDC = TRUE;
m_pOldBmp = m_dcMem.SelectObject(&m_bmp);
}
}
CMemDC::~CMemDC()
{
if (m_bMemDC)
{
CRect rectClip;
int nClipType = m_dc.GetClipBox(rectClip);
if (nClipType != NULLREGION)
{
if (nClipType != SIMPLEREGION)
{
rectClip = m_rect;
}
m_dc.BitBlt(rectClip.left, rectClip.top, rectClip.Width(), rectClip.Height(), &m_dcMem, rectClip.left, rectClip.top, SRCCOPY);
}
m_dcMem.SelectObject(m_pOldBmp);
}
}
void CMemDC::EraseBkClip()
{
CRect clip;
m_dcMem.GetClipBox(&clip);
m_dcMem.FillSolidRect(clip, GetSysColor(COLOR_WINDOW));
}
There is an ultra simple way I found that worked for me:
Turn off redraw with m_List1.SetRedraw(false)
Reset contents with m_List1.ResetContents()
Add new strings in loop with m_List1.AddString()
Then finalize by turning back on redraw and a m_List1.UpdateWindow().