LRESULT CustomCaptionFrameProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam, bool *callDef, WindowInfo *win)
{
if (dwm::IsCompositionEnabled()) {
// Pass the messages to DwmDefWindowProc first. It serves the hit testing for the buttons.
LRESULT res;
if (TRUE == dwm::DefWindowProc_(hwnd, msg, wParam, lParam, &res)) {
*callDef = false;
return res;
}
switch (msg)
{
case WM_ERASEBKGND:
{
// Erase the background only under the extended frame.
*callDef = false;
if (win->extendedFrameHeight == 0)
return TRUE;
ClientRect rc(hwnd);
rc.dy = win->extendedFrameHeight;
HRGN extendedFrameRegion = CreateRectRgn(rc.x, rc.y, rc.x + rc.dx, rc.y + rc.dy);
int newRegionComplexity = ExtSelectClipRgn((HDC)wParam, extendedFrameRegion, RGN_AND);
DeleteObject(extendedFrameRegion);
if (newRegionComplexity == NULLREGION)
return TRUE;
}
return DefWindowProc(hwnd, msg, wParam, lParam);
case WM_SIZE:
// Extend the translucent frame in the client area.
if (wParam == SIZE_MAXIMIZED || wParam == SIZE_RESTORED) {
long ws = GetWindowLong(hwnd, GWL_STYLE);
int frameThickness = !(ws & WS_THICKFRAME) ? 0 : GetSystemMetrics(SM_CYFRAME) + GetSystemMetrics(SM_CXPADDEDBORDER);
int captionHeight = !(ws & WS_CAPTION) ? 0 : GetTabbarHeight(win, IsZoomed(hwnd) ? 1.f : CAPTION_TABBAR_HEIGHT_FACTOR);
MARGINS margins = {0, 0, frameThickness + captionHeight, 0};
dwm::ExtendFrameIntoClientArea(hwnd, &margins);
win->extendedFrameHeight = frameThickness + captionHeight;
}
break;
case WM_NCACTIVATE:
win->caption->UpdateColors((bool)wParam);
if (!IsIconic(hwnd))
RedrawWindow(win->hwndCaption, NULL, NULL, RDW_ERASE | RDW_INVALIDATE | RDW_UPDATENOW | RDW_ALLCHILDREN);
break;
}
}
else {
switch (msg)
{
case WM_SETTINGCHANGE:
if (wParam == SPI_SETNONCLIENTMETRICS)
RelayoutCaption(win);
break;
case WM_NCPAINT:
DrawFrame(hwnd, win);
*callDef = false;
return 0;
case WM_NCACTIVATE:
win->caption->UpdateColors((bool)wParam);
for (int i = CB_BTN_FIRST; i < CB_BTN_COUNT; i++)
win->caption->btn[i].inactive = wParam == FALSE;
if (!IsIconic(hwnd)) {
DrawFrame(hwnd, win);
RedrawWindow(win->hwndCaption, NULL, NULL, RDW_ERASE | RDW_INVALIDATE | RDW_UPDATENOW | RDW_ALLCHILDREN);
*callDef = false;
return TRUE;
}
break;
case WM_NCUAHDRAWCAPTION:
case WM_NCUAHDRAWFRAME:
DrawFrame(hwnd, win);
*callDef = false;
return TRUE;
case WM_POPUPSYSTEMMENU:
case WM_SETCURSOR:
case WM_SETTEXT:
case WM_SETICON:
if (!win->caption->theme) {
// Remove the WS_VISIBLE style to prevent DefWindowProc from drawing
// in the caption's area when processing these mesages.
ToggleWindowStyle(hwnd, WS_VISIBLE, false);
LRESULT res = DefWindowProc(hwnd, msg, wParam, lParam);
ToggleWindowStyle(hwnd, WS_VISIBLE, true);
*callDef = false;
return res;
}
break;
}
}
// These messages must be handled in both modes - with or without DWM composition.
switch (msg)
{
case WM_NCCALCSIZE:
{
// In order to have custom caption, we have to include its area in the client rectangle.
RECT *r = wParam == TRUE ? &((LPNCCALCSIZE_PARAMS)lParam)->rgrc[0] : (RECT *)lParam;
RECT rWindow = *r;
// Let DefWindowProc calculate the client rectangle.
DefWindowProc(hwnd, msg, wParam, lParam);
RECT rClient = *r;
// Modify the client rectangle to include the caption's area.
if (dwm::IsCompositionEnabled())
rClient.top = rWindow.top;
else
rClient.top = rWindow.top + rWindow.bottom - rClient.bottom;
rClient.bottom--; // prevents the hiding of the topmost windows, when this window is maximized
*r = rClient;
*callDef = false;
}
return 0;
case WM_NCHITTEST:
{
// Provide hit testing for the caption.
PointI pt(GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam));
RectI rClient = MapRectToWindow(ClientRect(hwnd), hwnd, HWND_DESKTOP);
WindowRect rCaption(win->hwndCaption);
if (rClient.Contains(pt) && pt.y < rCaption.y + rCaption.dy) {
*callDef = false;
if (pt.y < rCaption.y)
return HTTOP;
return HTCAPTION;
}
}
break;
case WM_NCRBUTTONUP:
// Prepare and show the system menu.
if (wParam == HTCAPTION) {
HMENU menu = GetUpdatedSystemMenu(hwnd);
UINT flags = TPM_RIGHTBUTTON | TPM_NONOTIFY | TPM_RETURNCMD;
if (GetSystemMetrics(SM_MENUDROPALIGNMENT))
flags |= TPM_RIGHTALIGN;
WPARAM cmd = TrackPopupMenu(menu, flags, GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam), 0, hwnd, NULL);
if (cmd)
PostMessage(hwnd, WM_SYSCOMMAND, cmd, 0);
*callDef = false;
return 0;
}
break;
case WM_SYSCOMMAND:
if (wParam == SC_KEYMENU) {
// Show the "menu bar" (and the desired submenu)
gMenuAccelPressed = (WCHAR)lParam;
if (' ' == gMenuAccelPressed) {
// map space to the accelerator of the Window menu
if (str::FindChar(_TR("&Window"), '&'))
gMenuAccelPressed = *(str::FindChar(_TR("&Window"), '&') + 1);
}
PostMessage(win->hwndCaption, WM_COMMAND, MAKELONG(BTN_ID_FIRST + CB_MENU, BN_CLICKED), 0);
*callDef = false;
return 0;
}
break;
case WM_INITMENUPOPUP:
if (gMenuAccelPressed) {
// poorly documented hack: find the menu window and send it the accelerator key
HWND hMenu = FindWindow(UNDOCUMENTED_MENU_CLASS_NAME, NULL);
if (hMenu)
PostMessage(hMenu, WM_CHAR, gMenuAccelPressed, 0);
gMenuAccelPressed = 0;
}
break;
case WM_SYSCOLORCHANGE:
win->caption->UpdateColors(hwnd == GetForegroundWindow());
break;
case WM_DWMCOMPOSITIONCHANGED:
win->caption->UpdateBackgroundAlpha();
ClientRect cr(hwnd);
SetWindowPos(hwnd, NULL, 0, 0, 0, 0, SWP_FRAMECHANGED | SWP_NOZORDER | SWP_NOSIZE | SWP_NOMOVE);
if (ClientRect(hwnd) == cr)
SendMessage(hwnd, WM_SIZE, 0, MAKELONG(cr.dx, cr.dy));
*callDef = false;
return 0;
}
*callDef = true;
return 0;
}
