diff options
Diffstat (limited to 'hw/xfree86/common/xf86Xinput.c')
| -rw-r--r-- | hw/xfree86/common/xf86Xinput.c | 35 |
1 files changed, 19 insertions, 16 deletions
diff --git a/hw/xfree86/common/xf86Xinput.c b/hw/xfree86/common/xf86Xinput.c index 877eb0382..e71b09cd2 100644 --- a/hw/xfree86/common/xf86Xinput.c +++ b/hw/xfree86/common/xf86Xinput.c @@ -1238,40 +1238,43 @@ xf86FirstLocalDevice(void) /* * Cx - raw data from touch screen - * Sxhigh - scaled highest dimension + * to_max - scaled highest dimension * (remember, this is of rows - 1 because of 0 origin) - * Sxlow - scaled lowest dimension - * Rxhigh - highest raw value from touch screen calibration - * Rxlow - lowest raw value from touch screen calibration + * to_min - scaled lowest dimension + * from_max - highest raw value from touch screen calibration + * from_min - lowest raw value from touch screen calibration * * This function is the same for X or Y coordinates. * You may have to reverse the high and low values to compensate for * different orgins on the touch screen vs X. + * + * e.g. to scale from device coordinates into screen coordinates, call + * xf86ScaleAxis(x, 0, screen_width, dev_min, dev_max); */ int xf86ScaleAxis(int Cx, - int Sxhigh, - int Sxlow, - int Rxhigh, - int Rxlow ) + int to_max, + int to_min, + int from_max, + int from_min ) { int X; - int64_t dSx = Sxhigh - Sxlow; - int64_t dRx = Rxhigh - Rxlow; + int64_t to_width = to_max - to_min; + int64_t from_width = from_max - from_min; - if (dRx) { - X = (int)(((dSx * (Cx - Rxlow)) / dRx) + Sxlow); + if (from_width) { + X = (int)(((to_width * (Cx - from_min)) / from_width) + to_min); } else { X = 0; ErrorF ("Divide by Zero in xf86ScaleAxis"); } - if (X > Sxhigh) - X = Sxhigh; - if (X < Sxlow) - X = Sxlow; + if (X > to_max) + X = to_max; + if (X < to_min) + X = to_min; return X; } |