/**
* Convert an (X, Y) value pair in screen co-ordinates (starting from 1) to a
* value from VMMDEV_MOUSE_RANGE_MIN to VMMDEV_MOUSE_RANGE_MAX. Sets the
* optional validity value to false if the pair is not on an active screen and
* to true otherwise.
* @note since guests with recent versions of X.Org use a different method
* to everyone else to map the valuator value to a screen pixel (they
* multiply by the screen dimension, do a floating point divide by
* the valuator maximum and round the result, while everyone else
* does truncating integer operations) we adjust the value we send
* so that it maps to the right pixel both when the result is rounded
* and when it is truncated.
*
* @returns COM status value
*/
HRESULT Mouse::convertDisplayRes(LONG x, LONG y, int32_t *pcX, int32_t *pcY,
bool *pfValid)
{
AssertPtrReturn(pcX, E_POINTER);
AssertPtrReturn(pcY, E_POINTER);
AssertPtrNullReturn(pfValid, E_POINTER);
Display *pDisplay = mParent->getDisplay();
ComAssertRet(pDisplay, E_FAIL);
/** The amount to add to the result (multiplied by the screen width/height)
* to compensate for differences in guest methods for mapping back to
* pixels */
enum { ADJUST_RANGE = - 3 * VMMDEV_MOUSE_RANGE / 4 };
if (pfValid)
*pfValid = true;
if (!(mfVMMDevGuestCaps & VMMDEV_MOUSE_NEW_PROTOCOL))
{
ULONG displayWidth, displayHeight;
/* Takes the display lock */
HRESULT rc = pDisplay->GetScreenResolution(0, &displayWidth,
&displayHeight, NULL);
if (FAILED(rc))
return rc;
*pcX = displayWidth ? (x * VMMDEV_MOUSE_RANGE + ADJUST_RANGE)
/ (LONG) displayWidth: 0;
*pcY = displayHeight ? (y * VMMDEV_MOUSE_RANGE + ADJUST_RANGE)
/ (LONG) displayHeight: 0;
}
else
{
int32_t x1, y1, x2, y2;
/* Takes the display lock */
pDisplay->getFramebufferDimensions(&x1, &y1, &x2, &y2);
*pcX = x1 < x2 ? ((x - x1) * VMMDEV_MOUSE_RANGE + ADJUST_RANGE)
/ (x2 - x1) : 0;
*pcY = y1 < y2 ? ((y - y1) * VMMDEV_MOUSE_RANGE + ADJUST_RANGE)
/ (y2 - y1) : 0;
if ( *pcX < VMMDEV_MOUSE_RANGE_MIN || *pcX > VMMDEV_MOUSE_RANGE_MAX
|| *pcY < VMMDEV_MOUSE_RANGE_MIN || *pcY > VMMDEV_MOUSE_RANGE_MAX)
if (pfValid)
*pfValid = false;
}
return S_OK;
}
