Flicker/dead region issues maximizing an MFC window - windows

I'm trying to make an MFC window (a CDialog) go fullscreen whenever the user attempts to maximize it. The window is being used as an OpenGL context. I'm attempting to do everything inside of the CDialog::OnSize callback. Here's the code that I'm using:
void MyCDialogSubclass::OnSize(UINT action, int width, int height) {
CDialog::OnSize(action, width, height);
switch (action) {
case SIZE_MAXIMIZED:
if (GetStyle() & WS_OVERLAPPEDWINDOW) {
MONITORINFO screen;
screen.cbSize = sizeof(screen);
if (GetMonitorInfo(MonitorFromWindow(GetSafeHwnd(), MONITOR_DEFAULTTOPRIMARY), &screen)) {
ModifyStyle(WS_OVERLAPPEDWINDOW, 0, 0);
width = screen.rcMonitor.right - screen.rcMonitor.left;
height = screen.rcMonitor.bottom - screen.rcMonitor.top;
SetWindowPos(&wndTop, screen.rcMonitor.left, screen.rcMonitor.top, width, height, SWP_NOOWNERZORDER | SWP_FRAMECHANGED);
}
}
break;
case SIZE_MINIMIZED:
case SIZE_RESTORED:
if (!(GetStyle() & WS_OVERLAPPEDWINDOW)) {
ModifyStyle(0, WS_OVERLAPPEDWINDOW, 0);
SetWindowPos(NULL, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE | SWP_NOZORDER | SWP_NOOWNERZORDER | SWP_FRAMECHANGED);
}
break;
}
if (wglMakeCurrent(my_hdc, my_hglrc))
my_opengl_reshape_call(width, height);
wglMakeCurrent(NULL, NULL);
}
If I comment out the ModifyStyle() calls, everything works fine, with the obvious proviso that the window style stays normal, so there's a standard window title bar across the top of the screen that I want to get rid of. If I keep the ModifyStyle() calls and comment out the SetWindowPos() calls, the title bar and everything else disappears, but the window has a black region along the top of the screen that is the exact height of the title bar—as though it is being reserved. If I don't comment out either of the pairs of calls, as shown in the code above, the screen flickers violently. I believe it's flickering back and forth between the black region being present and not being present, but it's difficult to tell. This flickering also appears to corrupt video memory, as I get persistent artifacts in window title bars (in different applications, no less) and, once, the login picture in the Start menu was replaced with one of my OpenGL textures.
The code that I'm using is adapted from the code that Stefan linked in an answer below, from The Old New Thing, which is working better than my original code. I'm assuming this problem isn't arising from my decision not to insert code to save the window placement (per The Old New Thing), because this happens before I ever try to restore the window.

Don't maximize the window if you want it to be full screen.
Use this approach instead.

Related

winapi - rich edit control and vertical text layout (single line)

I have noticed that a text in the rich edit control (only a single line) is not centered vertically. A space between a text and a top border edge is larger than a space between a text and a botttom border edge. It is especially visible when a rich edit control height is only a little bit bigger that a text height. PARAMFORMAT only allow to set a horizontal alignment. How to set a vertical alignment / top-bottom margins ?
Edit:
This way I get PARAMFORMAT2 structure:
PARAFORMAT2 pf;
ZeroMemory(&pf, sizeof(pf));
pf.cbSize = sizeof(pf);
SendMessage(hwndRichEdit1, EM_GETPARAFORMAT, 0, (LPARAM)&pf);
dySpaceBefore is already initially set to 0 and the effect you can see on the attached screenshot.
I use Visual Studio 2017, MSFTEDIT_CLASS is defined in Richedit.h as L"RICHEDIT50W"
If you're using a Rich Edit 2.0 control, you can use the PARAFORMAT2 structure, which has the option to set the space before the text.
You haven't added a language tag, but here's how you would do it in C (see also the documentation for EM_SETPARAFORMAT):
//...
PARAFORMAT2 pf2;
pf2.cbSize = sizeof(PARAFORMAT2);
pf2.dwMask = PFM_SPACEBEFORE; // Of course, you can OR in other bits/options to set!
pf2.dySpaceBefore = 0; // Will align to the top; use a small +ve value, if you prefer
SendMessage(hWndEdit, EM_SETPARAFORMAT, 0, (LPARAM)&pf2);
//...
To get vertically centred text is bit more work, as you will need to get the height of the text (using GetTextExtent) and the height of the control's client rectangle, then use a 'space before' value of (client_height - text_height)/2.
Feel free to ask for further clarification and/or explanation. (I may even be able to offer you code in another language.)
I can reproduce this issue like this snapshot shows:
There seems no feature supported for vertical alignment center. I've submit a feature request internally.
A workaround is using EM_SETRECT which can move up text area via limiting rectangle into which the control draws the text. The following snapshots show its effects:
Then you can use it to adjust the text to display it in center between top and bottom.
Code example:
HWND hwndEdit = CreateWindowEx(
0,
MSFTEDIT_CLASS,
TEXT("EDIT"),
WS_BORDER | WS_VISIBLE | WS_CHILD,
20,
20,
100,
32,
hWnd,
NULL,
hInst,
NULL);
RECT rect;
SendMessage(hwndEdit, EM_GETRECT, 0, (LPARAM)&rect);
rect.top -= 2;
rect.bottom -= 2;
SendMessage(hwndEdit, EM_SETRECT, 1, (LPARAM)&rect);

GetWindowRect returns a size including "invisible" borders

I'm working on an app that positions windows on the screen in a grid style. When Running this on Windows 10, there is a huge gap between the windows. Further investigation shows that GetWindowRect is returning unexpected values, including an invisible border, but I can't get it to return the real values with the visible border.
1) This thread suggests this is by design and you can "fix" it by linking with winver=6. My environment does not allow this but I've tried changing the PE MajorOperatingSystemVersion and MajorSubsystemVersion to 6 with no affect
2) That same thread also suggests using DwmGetWindowAttribute with DWMWA_EXTENDED_FRAME_BOUNDS to get the real coordinates from DWM, which works, but means changing everywhere that gets the window coordinates. It also doesn't allow the value to be set, leaving us to reverse the process to be able to set the window size.
3) This question suggests it's lack of the DPI awareness in the process. Neither setting the DPI awareness flag in the manifest, or calling SetProcessDpiAwareness had any result.
4) On a whim, I've also tried adding the Windows Vista, 7, 8, 8.1 and 10 compatibility flags, and the Windows themes manifest with no change.
This window is moved to 0x0, 1280x1024, supposedly to fill the entire screen, and when querying the coordinates back, we get the same values.
The window however is actually 14 pixels narrower, to take into account the border on older versions of Windows.
How can I convince Windows to let me work with the real window coordinates?
Windows 10 has thin invisible borders on left, right, and bottom, it is used to grip the mouse for resizing. The borders might look like this: 7,0,7,7 (left, top, right, bottom)
When you call SetWindowPos to put the window at this coordinates:
0, 0, 1280, 1024
The window will pick those exact coordinates, and GetWindowRect will return the same coordinates. But visually, the window appears to be here:
7, 0, 1273, 1017
You can fool the window and tell it to go here instead:
-7, 0, 1287, 1031
To do that, we get Windows 10 border thickness:
RECT rect, frame;
GetWindowRect(hwnd, &rect);
DwmGetWindowAttribute(hwnd, DWMWA_EXTENDED_FRAME_BOUNDS, &frame, sizeof(RECT));
//rect should be `0, 0, 1280, 1024`
//frame should be `7, 0, 1273, 1017`
RECT border;
border.left = frame.left - rect.left;
border.top = frame.top - rect.top;
border.right = rect.right - frame.right;
border.bottom = rect.bottom - frame.bottom;
//border should be `7, 0, 7, 7`
Then offset the rectangle like so:
rect.left -= border.left;
rect.top -= border.top;
rect.right += border.left + border.right;
rect.bottom += border.top + border.bottom;
//new rect should be `-7, 0, 1287, 1031`
Unless there is a simpler solution!
How can I convince Windows to let me work with the real window coordinates?
You are already working with the real coordinates. Windows10 has simply chosen to hide the borders from your eyes. But nonetheless they are still there. Mousing past the edges of the window, your cursor will change to the resizing cursor, meaning that its still actually over the window.
If you want your eyes to match what Windows is telling you, you could try exposing those borders so that they are visible again, using the Aero Lite theme:
http://winaero.com/blog/enable-the-hidden-aero-lite-theme-in-windows-10/
AdjustWindowRectEx (or on Windows 10 and later AdjustWindowRectExForDpi) might be of use. These functions will convert a client rectangle into a window size.
I'm guessing you don't want to overlap the borders though, so this probably isn't a full solution--but it may be part of the solution and may be useful to other people coming across this question.
Here's a quick snippet from my codebase where I've successfully used these to set the window size to get a desired client size, pardon the error handling macros:
DWORD window_style = (DWORD)GetWindowLong(global_context->window, GWL_STYLE);
CHECK_CODE(window_style);
CHECK(window_style != WS_OVERLAPPED); // Required by AdjustWindowRectEx
DWORD window_style_ex = (DWORD)GetWindowLong(global_context->window, GWL_EXSTYLE);
CHECK_CODE(window_style_ex);
// XXX: Use DPI aware version?
RECT requested_size = {};
requested_size.right = width;
requested_size.bottom = height;
AdjustWindowRectEx(
&requested_size,
window_style,
false, // XXX: Why always false here?
window_style_ex
);
UINT set_window_pos_flags = SWP_NOACTIVATE | SWP_NOCOPYBITS | SWP_NOMOVE | SWP_NOOWNERZORDER | SWP_NOZORDER;
CHECK_CODE(SetWindowPos(
global_context->window,
nullptr,
0,
0,
requested_size.right - requested_size.left,
requested_size.bottom - requested_size.top,
set_window_pos_flags
));
There are still two ambiguities in the above use case:
My window does have a menu, but I have to pass in false for the menu param or I get the wrong size out. I'll update this answer with an explanation if I figure out why this is!
I haven't yet read about how Windows handles DPI awareness so I'm not sure when you want to use that function vs the non DPI aware one
You can respond to the WM_NCCALCSIZE message, modify WndProc's default behaviour to remove the invisible border.
As this document and this document explain, when wParam > 0, On request wParam.Rgrc[0] contains the new coordinates of the window and when the procedure returns, Response wParam.Rgrc[0] contains the coordinates of the new client rectangle.
The golang code sample:
case win.WM_NCCALCSIZE:
log.Println("----------------- WM_NCCALCSIZE:", wParam, lParam)
if wParam > 0 {
params := (*win.NCCALCSIZE_PARAMS)(unsafe.Pointer(lParam))
params.Rgrc[0].Top = params.Rgrc[2].Top
params.Rgrc[0].Left = params.Rgrc[0].Left + 1
params.Rgrc[0].Bottom = params.Rgrc[0].Bottom - 1
params.Rgrc[0].Right = params.Rgrc[0].Right - 1
return 0x0300
}

partially covered glut window doesn't redraw correctly after it is uncovered

Using free glut on windows 7 home ultimate with video card ati mobility radeon 5650
code snippet:
void ResizeFunction(int width, int height)
{
glViewport(0, 0, width, height);
}
void RenderFunction()
{
glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
//...drawing code based on some flag, I draw a triangle or a rectangle
//the flag is toggled on pressing 't' or 'T' key
glutSwapBuffers(); //double buffering is enabled
glutPostRedisplay();
}
void KeyboardFunction(unsigned char key, int x, int y)
{
switch(key)
{
case 't':
case 'T':
{
flag = !flag;
glutPostRedisplay();
break;
}
default:
break;
}
}
problem: The triangle or the rectangle is drawn covering the entire window first time. But if I partially cover the glut window with another window (say, with some notepad window) and then uncover it, subsequently, when I toggle, the object is drawn only in the covered portion of the glut window. If I re-size the glut window, drawing works correctly as before.
Any help will be appreciated.
regards,
fs
Glut only redraws on the screen when you tell it or when it decides. That is, if you don't do anything in the window, the scene is not redrawn. Advantage of this: less cpu/gpu usage. Disadvantage: Only good for non animated applications.
If you want to constantly update the screen (which is what is done in applications with lots of animations (games for example)), you can use glutIdleFunc
http://www.opengl.org/resources/libraries/glut/spec3/node63.html
That is in the beginning of the program when you set all the functions for glut, you also write:
glutIdleFunc(RenderFunction);
This way, when glut is idle, it keeps calling your render function.
If you want to render slower than possible (for example with a fixed frame rate), you could use a timer:
void RenderFunction()
{
glutTimerFunc(YOUR_DELAY_IN_MS, RenderFunction, 0);
/* rest of code */
}
and instead of glutIdleFunc(RenderFunction);, you write
`glutTimerFunc(YOUR_DELAY_IN_MS, RenderFunction, 0);`
To simply call the render function once (you could also just write RenderFunction() once) and the function keeps setting the timer for its next run.
As a side note, I suggest using SDL instead of glut.

If window spans multiple monitors, I can't draw to it

If I have a window that spans both monitors on a multimonitor system, I can't seem to erase (paint black) the entire window. Instead, only the primary window is drawn black. The secondary remains the original white color. Has anyone seen this behavior?
wxwidgets:
wxClientDC dc(this);
Erase(dc);
void SpriteWindowFrame::Erase(wxDC& dc)
{
dc.SetBackground(*wxBLACK_BRUSH);
dc.SetBrush(*wxBLACK_BRUSH);
dc.Clear();
//wxLogDebug("Erase called. Rect is %i, %i w:%i, h:%i", GetPosition().x, GetPosition().y, GetSize().GetWidth(), GetSize().GetHeight());
}
Inside dc.Clear() function, there is this code
wxwidgets:
void wxDC::Clear()
{
WXMICROWIN_CHECK_HDC
RECT rect;
if ( m_canvas )
{
GetClientRect((HWND) m_canvas->GetHWND(), &rect);
}
else
{
// No, I think we should simply ignore this if printing on e.g.
// a printer DC.
// wxCHECK_RET( m_selectedBitmap.Ok(), wxT("this DC can't be cleared") );
if (!m_selectedBitmap.Ok())
return;
rect.left = -m_deviceOriginX; rect.top = -m_deviceOriginY;
rect.right = m_selectedBitmap.GetWidth()-m_deviceOriginX;
rect.bottom = m_selectedBitmap.GetHeight()-m_deviceOriginY;
}
#ifndef __WXWINCE__
(void) ::SetMapMode(GetHdc(), MM_TEXT);
#endif
DWORD colour = ::GetBkColor(GetHdc());
HBRUSH brush = ::CreateSolidBrush(colour);
::FillRect(GetHdc(), &rect, brush);
::DeleteObject(brush);
#ifndef __WXWINCE__
int width = DeviceToLogicalXRel(VIEWPORT_EXTENT)*m_signX,
height = DeviceToLogicalYRel(VIEWPORT_EXTENT)*m_signY;
::SetMapMode(GetHdc(), MM_ANISOTROPIC);
::SetViewportExtEx(GetHdc(), VIEWPORT_EXTENT, VIEWPORT_EXTENT, NULL);
::SetWindowExtEx(GetHdc(), width, height, NULL);
::SetViewportOrgEx(GetHdc(), (int)m_deviceOriginX, (int)m_deviceOriginY, NULL);
::SetWindowOrgEx(GetHdc(), (int)m_logicalOriginX, (int)m_logicalOriginY, NULL);
#endif
}
Using the debugger, I checked what GetClientRect returned and sure enough it returns a rectange with location 0 and width/height of the combined two monitors so it's right. Maybe fillrect function is not capable of drawing to two displays?
Can you trace into the constructor of the wxClientDC?
wxClientDC dc(this);
A lot depends on what type of DC wx has given you. The windows API to retrieve a window DC is hdc = GetDC(hwnd), and, on multimonitor systems, it retrieves a handle to a 'mirror driver' DC, thats meant to reflect calls to all the underlying display device DCs that the monitor spans.
The only possible reason I can think of for this behaviour is wx is somehow retrieving a display DC rather than a window DC.
I'm sure Chris is correct, that the "overlapping window" case is handled somewhere for you. But where?
Rendering with windows GDI and "display contexts" such as you mention is very primitive and prone to all sorts of problems. GDI is one of poorest interfaces ever seen, poor even for Microsoft. Since most "window" programs work OK on multiple monitors, think of animating things in a "window" - and how that "window" makes its way to the "display" is best left a mystery.
Maybe DC is fundamentally not multi-monitor capable. Look for anything that allows multiple DCs to be treated uniformly. Rending graphics onto a grid of paper sheets would be like a tiled "printer DC". A video wall would be a tiled "display DC" and you would be happy with a 2-monitor hack, i.e. "multimon dc" echoes to "owning" display and "another one" if a window spans both.
If you want to do "real" animation on windows, you will need to move to DirectX. It is also a lot to learn, but much more capable: scene graphs, textures, video, alpha channels, ...

How to determine the size of the button portion of a Windows radio button

I'm drawing old school (unthemed - themed radios are a whole other problem) radio buttons myself using DrawFrameControl:
DrawFrameControl(dc, &rectRadio, DFC_BUTTON, isChecked() ? DFCS_BUTTONRADIO | DFCS_CHECKED : DFCS_BUTTONRADIO);
I've never been able to figure out a sure fire way to figure out what to pass for the RECT. I've been using a 12x12 rectangle but I'de like Windows to tell me the size of a radio button.
DrawFrameControl seems to scale the radio button to fit the rect I pass so I have to be close to the "right" size of the radio looks off from other (non-owner drawn) radios on the screen.
Anyone know how to do this?
This page shows some sizing guidelines for controls. Note that the sizes are given in both DLU (dialog units) and pixels, depending on whether you are placing the control on a dialog or not:
http://msdn.microsoft.com/en-us/library/aa511279.aspx#controlsizing
I thought the GetSystemMetrics API might return the standard size for some of the common controls, but I didn't find anything. There might be a common control specific API to determine sizing.
It has been a while since I worked on this, so what I am describing is what I did, and not necessarily a direct answer to the question.
I happen to use bit maps 13 x 13 rather than 12 x 12. The bitmap part of the check box seems to be passed in the WM_DRAWITEM. However, I had also set up WM_MEASUREITEM and fed it the same values, so my answer may well be "Begging the question" in the correct philosophical sense.
case WM_MEASUREITEM:
lpmis = (LPMEASUREITEMSTRUCT) lParam;
lpmis->itemHeight = 13;
lpmis->itemWidth = 13;
break;
case WM_DRAWITEM:
lpdis = (LPDRAWITEMSTRUCT) lParam;
hdcMem = CreateCompatibleDC(lpdis->hDC);
if (lpdis->itemState & ODS_CHECKED) // if selected
{
SelectObject(hdcMem, hbmChecked);
}
else
{
if (lpdis->itemState & ODS_GRAYED)
{
SelectObject(hdcMem, hbmDefault);
}
else
{
SelectObject(hdcMem, hbmUnChecked);
}
}
StretchBlt(
lpdis->hDC, // destination DC
lpdis->rcItem.left, // x upper left
lpdis->rcItem.top, // y upper left
// The next two lines specify the width and
// height.
lpdis->rcItem.right - lpdis->rcItem.left,
lpdis->rcItem.bottom - lpdis->rcItem.top,
hdcMem, // source device context
0, 0, // x and y upper left
13, // source bitmap width
13, // source bitmap height
SRCCOPY); // raster operation
DeleteDC(hdcMem);
return TRUE;
This seems to work well for both Win2000 and XP, though I have nbo idea what Vista might do.
It might be worth an experiment to see what leaving out WM_MEASUREITEM does, though I usually discover with old code that I usually had perfectly good reason for doing something that looks redundant.

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