LRESULT CALLBACK EditProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
static BOOL bHover;
static BYTE dwAlphaEnd;
static BYTE dwAlphaStart;
static BYTE dwAlphaStep;
switch (msg)
{
case WM_SYSCOMMAND:
if ((wParam & 0xFFF0) == SC_CLOSE) return SendMessage(GetParent(hWnd), WM_SYSCOMMAND, wParam, lParam);
break;
case WM_MOUSEMOVE:
if (!bHover)
{
if (hWnd != GetFocus()) SetFocus(hWnd);
bHover = TRUE;
TRACKMOUSEEVENT tme = { sizeof(tme), TME_LEAVE, hWnd, 0 };
TrackMouseEvent(&tme);
InvalidateRect(hWnd, 0, TRUE);
PostMessage(hWnd, WM_SETALPHA, SHOWEDITALPHA, 0);
}
break;
case WM_MOUSELEAVE:
bHover = FALSE;
PostMessage(hWnd, WM_SETALPHA, HIDEDITALPHA, 0);
break;
case WM_SETALPHA:
KillTimer(hWnd, 0x1234);
GetLayeredWindowAttributes(hWnd, 0, &dwAlphaStart, 0);
dwAlphaEnd = wParam;
dwAlphaStep = 0;
SetTimer(hWnd, 0x1234, 1, 0);
return 0;
case WM_TIMER:
if (dwAlphaStep > ANIMATION_STEP || dwAlphaStart == dwAlphaEnd)
{
KillTimer(hWnd, 0x1234);
SetLayeredWindowAttributes(hWnd, 0, dwAlphaEnd, LWA_ALPHA);
}
else
{
dwAlphaStep++;
const BYTE bByte = (dwAlphaStart < dwAlphaEnd) ? easeOutExpo(dwAlphaStep, dwAlphaStart, dwAlphaEnd - dwAlphaStart, ANIMATION_STEP) :
dwAlphaStart + dwAlphaEnd - easeOutExpo(dwAlphaStep, dwAlphaEnd, dwAlphaStart - dwAlphaEnd, ANIMATION_STEP);
SetLayeredWindowAttributes(hWnd, 0, bByte, LWA_ALPHA);
}
break;
case WM_DESTROY:
KillTimer(hWnd, 0x1234);
break;
}
return CallWindowProc(EditWndProc, hWnd, msg, wParam, lParam);
}
/**
* Easing equation function for an exponential (2^t) easing out/in: deceleration until halfway, then acceleration.
*
* @param t Current time (in frames or seconds).
* @return The correct value.
*/
static qreal easeOutInExpo(qreal t)
{
if (t < 0.5) return easeOutExpo (2*t)/2;
return easeInExpo(2*t - 1)/2 + 0.5;
}