static void filterCurveToLine(int* pCurve, int nMax, double x0, double y0,
double x1, double y1, double x2, double y2,
double x3, double y3)
{
double x01,y01,x32,y32,xm,ym;
double c1,d1,c2,d2,e,f;
/* check if control points are on line */
if (filterOnLine(x0,y0,x3,y3,x1,y1) && filterOnLine(x0,y0,x3,y3,x2,y2))
{
filterLine(pCurve,nMax,
(int)(x0*nMax),(int)(y0*nMax),
(int)(x3*nMax),(int)(y3*nMax));
return;
}
/* calculate midpoints */
x01 = (x0 + x1) / 2; y01 = (y0 + y1) / 2;
x32 = (x3 + x2) / 2; y32 = (y3 + y2) / 2;
/* calc split point */
xm = (x1 + x2) / 2; ym = (y1 + y2) / 2;
/* calc control points and midpoint */
c1 = (x01 + xm) / 2; d1 = (y01 + ym) / 2;
c2 = (x32 + xm) / 2; d2 = (y32 + ym) / 2;
e = (c1 + c2) / 2; f = (d1 + d2) / 2;
/* do each side */
filterCurveToLine(pCurve,nMax,x0,y0,x01,y01,c1,d1,e,f);
filterCurveToLine(pCurve,nMax,e,f,c2,d2,x32,y32,x3,y3);
}
/*****************************************************************************
* wcmSetPressureCurve -- apply user-defined curve to pressure values
****************************************************************************/
void wcmSetPressureCurve(WacomDevicePtr pDev, int x0, int y0,
int x1, int y1)
{
int i;
/* sanity check values */
if (!wcmCheckPressureCurveValues(x0, y0, x1, y1))
return;
/* linear by default */
for (i=0; i<=FILTER_PRESSURE_RES; ++i)
pDev->pPressCurve[i] = i;
/* draw bezier line from bottom-left to top-right using ctrl points */
filterCurveToLine(pDev->pPressCurve,
FILTER_PRESSURE_RES,
0.0, 0.0, /* bottom left */
x0/100.0, y0/100.0, /* control point 1 */
x1/100.0, y1/100.0, /* control point 2 */
1.0, 1.0); /* top right */
pDev->nPressCtrl[0] = x0;
pDev->nPressCtrl[1] = y0;
pDev->nPressCtrl[2] = x1;
pDev->nPressCtrl[3] = y1;
}
/*****************************************************************************
* wcmSetPressureCurve -- apply user-defined curve to pressure values
****************************************************************************/
void wcmSetPressureCurve(WacomDevicePtr pDev, int x0, int y0,
int x1, int y1)
{
/* sanity check values */
if (!wcmCheckPressureCurveValues(x0, y0, x1, y1))
return;
/* A NULL pPressCurve indicates the (default) linear curve */
if (x0 == 0 && y0 == 0 && x1 == 100 && y1 == 100) {
free(pDev->pPressCurve);
pDev->pPressCurve = NULL;
}
else if (!pDev->pPressCurve) {
pDev->pPressCurve = calloc(FILTER_PRESSURE_RES+1, sizeof(*pDev->pPressCurve));
if (!pDev->pPressCurve) {
LogMessageVerbSigSafe(X_WARNING, 0,
"Unable to allocate memory for pressure curve; using default.\n");
x0 = 0;
y0 = 0;
x1 = 100;
y1 = 100;
}
}
if (pDev->pPressCurve)
filterCurveToLine(pDev->pPressCurve,
FILTER_PRESSURE_RES,
0.0, 0.0, /* bottom left */
x0/100.0, y0/100.0, /* control point 1 */
x1/100.0, y1/100.0, /* control point 2 */
1.0, 1.0); /* top right */
pDev->nPressCtrl[0] = x0;
pDev->nPressCtrl[1] = y0;
pDev->nPressCtrl[2] = x1;
pDev->nPressCtrl[3] = y1;
}