Function onMSNH_VScroll

outdated/sys/wince/mhmap.c:727–785

on WM_VSCROLL */

/* on WM_VSCROLL */
void
onMSNH_VScroll(HWND hWnd, WPARAM wParam, LPARAM lParam)
{
    PNHMapWindow data;
    SCROLLINFO si;
    int yNewPos;
    int yDelta;

    /* get window data */
    data = (PNHMapWindow) GetWindowLong(hWnd, GWL_USERDATA);

    switch (LOWORD(wParam)) {
    /* User clicked shaft left of the scroll box. */
    case SB_PAGEUP:
        yNewPos = data->yPos - data->yPageSize;
        break;

    /* User clicked shaft right of the scroll box. */
    case SB_PAGEDOWN:
        yNewPos = data->yPos + data->yPageSize;
        break;

    /* User clicked the left arrow. */
    case SB_LINEUP:
        yNewPos = data->yPos - 1;
        break;

    /* User clicked the right arrow. */
    case SB_LINEDOWN:
        yNewPos = data->yPos + 1;
        break;

    /* User dragged the scroll box. */
    case SB_THUMBTRACK:
        yNewPos = HIWORD(wParam);
        break;

    default:
        yNewPos = data->yPos;
    }

    yNewPos = max(0, min(ROWNO - data->yPageSize + 1, yNewPos));
    if (yNewPos == data->yPos)
        return;

    yDelta = yNewPos - data->yPos;
    data->yPos = yNewPos;

    ScrollWindowEx(hWnd, 0, -data->yScrTile * yDelta, (CONST RECT *) NULL,
                   (CONST RECT *) NULL, (HRGN) NULL, (LPRECT) NULL,
                   SW_INVALIDATE | SW_ERASE);

    if (!GetNHApp()->bHideScrollBars) {
        si.cbSize = sizeof(si);
        si.fMask = SIF_POS;
        si.nPos = data->yPos;
        SetScrollInfo(hWnd, SB_VERT, &si, TRUE);
    }