diff options
Diffstat (limited to 'xorg-server/hw/xfree86/common/xf86Xinput.c')
| -rw-r--r-- | xorg-server/hw/xfree86/common/xf86Xinput.c | 35 |
1 files changed, 19 insertions, 16 deletions
diff --git a/xorg-server/hw/xfree86/common/xf86Xinput.c b/xorg-server/hw/xfree86/common/xf86Xinput.c index 585be69a5..3542abd4a 100644 --- a/xorg-server/hw/xfree86/common/xf86Xinput.c +++ b/xorg-server/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;
}
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