[PATCH] dix: add 3x3 transformation matrix xinput property for multi-head handling
Peter Korsgaard
peter.korsgaard at barco.com
Wed May 5 08:54:07 PDT 2010
For absolute input devices (E.G. touchscreens) in multi-head setups,
we need a way to bind the device to an randr output. This adds the
infrastructure to the server to allow us to do so.
positionSprite() scales input coordinates to the dimensions of the shared
(total) screen frame buffer, so to restrict motion to an output we need to
scale/rotate/translate device coordinates to a subset of the frame buffer
before passing them on to positionSprite.
This is done here using a 3x3 transformation matrix, which is applied to
the device coordinates using homogeneous coordinates, E.G.:
[ c0 c1 c2 ] [ x ]
[ c3 c4 c5 ] * [ y ]
[ c6 c7 c8 ] [ 1 ]
Notice: As input devices have varying input ranges, the coordinates are
first scaled to the [0..1] range for generality, and afterwards scaled
back up.
E.G. for a dual head setup (using same resolution) next to each other, you
would want to scale the X coordinates of the touchscreen connected to the
both heads by 50%, and translate (offset) the coordinates of the rightmost
head by 50%, or in matrix form:
left: right:
[ 0.5 0 0 ] [ 0.5 0 0.5 ]
[ 0 1 0 ] [ 0 1 0 ]
[ 0 0 1 ] [ 0 0 0 ]
Which can be done using xinput:
xinput set-prop <left> --type=float "Coordinate Transformation Matrix" \
0.5 0 0 0 1 0 0 0 1
xinput set-prop <right> --type=float "Coordinate Transformation Matrix" \
0.5 0 0.5 0 1 0 0 0 1
Likewise more complication setups involving more heads, rotation or
different resolution can be handled.
Signed-off-by: Peter Korsgaard <peter.korsgaard at barco.com>
---
This is equivalent to the evdev patch sent earlier:
http://thread.gmane.org/gmane.comp.freedesktop.xorg.devel/7336
But moved into the server as requested as requested by Simon and Peter,
so it's available for all input drivers.
Xi/xiproperty.c | 3 +-
dix/devices.c | 82 ++++++++++++++++++++++++++++++++++++++++++
dix/getevents.c | 33 +++++++++++++++++
include/inputstr.h | 3 ++
include/xserver-properties.h | 7 ++++
5 files changed, 127 insertions(+), 1 deletions(-)
diff --git a/Xi/xiproperty.c b/Xi/xiproperty.c
index d265b67..b9bc102 100644
--- a/Xi/xiproperty.c
+++ b/Xi/xiproperty.c
@@ -179,7 +179,8 @@ static struct dev_properties
{0, BTN_LABEL_PROP_BTN_GEAR_DOWN},
{0, BTN_LABEL_PROP_BTN_GEAR_UP},
- {0, XI_PROP_DEVICE_NODE}
+ {0, XI_PROP_DEVICE_NODE},
+ {0, XI_PROP_TRANSFORM}
};
static long XIPropHandlerID = 1;
diff --git a/dix/devices.c b/dix/devices.c
index a33df4d..8596ae4 100644
--- a/dix/devices.c
+++ b/dix/devices.c
@@ -91,6 +91,70 @@ SOFTWARE.
static void RecalculateMasterButtons(DeviceIntPtr slave);
+/* a *= b */
+static void
+DeviceMatrixMul(float *a, float *b)
+{
+ int i, j, k;
+ float t[3];
+
+ for (i=0; i<3; i++)
+ {
+ for (j=0; j<3; j++)
+ {
+ t[j] = 0;
+
+ for (k=0; k<3; k++)
+ {
+ t[j] += a[i*3 + k]*b[k*3 + j];
+ }
+ }
+ memcpy(&a[i*3], t, sizeof(t));
+ }
+}
+
+static void
+DeviceSetTransform(DeviceIntPtr dev, float *transform)
+{
+ float scale[9], *t;
+ float sx, sy;
+
+ /**
+ * calculate combined transformation matrix:
+ *
+ * M = InvScale * Transform * Scale
+ *
+ * So we can later transform points using M * p
+ *
+ * Where:
+ * Scale scales coordinates into 0..1 range
+ * Transform is the user supplied (affine) transform
+ * InvScale scales coordinates back up into their native range
+ */
+ sx = dev->valuator->axes[0].max_value - dev->valuator->axes[0].min_value;
+ sy = dev->valuator->axes[1].max_value - dev->valuator->axes[1].min_value;
+
+ t = dev->transform;
+ memset(t, 0, sizeof(dev->transform));
+
+ t[0] = sx;
+ t[2] = dev->valuator->axes[0].min_value;
+ t[4] = sy;
+ t[5] = dev->valuator->axes[1].min_value;
+ t[8] = 1.0;
+
+ DeviceMatrixMul(t, transform);
+
+ memset(scale, 0, sizeof(scale));
+ scale[0] = 1.0 / sx;
+ scale[2] = -dev->valuator->axes[0].min_value / sx;
+ scale[4] = 1.0 / sy;
+ scale[5] = -dev->valuator->axes[1].min_value / sy;
+ scale[8] = 1.0;
+
+ DeviceMatrixMul(t, scale);
+}
+
/**
* DIX property handler.
*/
@@ -115,6 +179,14 @@ DeviceSetProperty(DeviceIntPtr dev, Atom property, XIPropertyValuePtr prop,
else if (!(*((CARD8*)prop->data)) && dev->enabled)
DisableDevice(dev, TRUE);
}
+ } else if (property == XIGetKnownProperty(XI_PROP_TRANSFORM))
+ {
+ if (prop->format != 32 || prop->size != 9 ||
+ prop->type != XIGetKnownProperty(XATOM_FLOAT))
+ return BadValue;
+
+ if (!checkonly)
+ DeviceSetTransform(dev, prop->data);
}
return Success;
@@ -215,6 +287,9 @@ AddInputDevice(ClientPtr client, DeviceProc deviceProc, Bool autoStart)
/* sprite defaults */
dev->spriteInfo = (SpriteInfoPtr)&dev[1];
+ /* unity matrix */
+ dev->transform[0] = dev->transform[4] = dev->transform[8] = 1.0f;
+
/* security creation/labeling check
*/
if (XaceHook(XACE_DEVICE_ACCESS, client, dev, DixCreateAccess)) {
@@ -234,6 +309,13 @@ AddInputDevice(ClientPtr client, DeviceProc deviceProc, Bool autoStart)
XA_INTEGER, 8, PropModeReplace, 1, &enabled,
FALSE);
XISetDevicePropertyDeletable(dev, XIGetKnownProperty(XI_PROP_ENABLED), FALSE);
+
+ XIChangeDeviceProperty(dev, XIGetKnownProperty(XI_PROP_TRANSFORM),
+ XIGetKnownProperty(XATOM_FLOAT), 32,
+ PropModeReplace, 9, dev->transform, FALSE);
+ XISetDevicePropertyDeletable(dev, XIGetKnownProperty(XI_PROP_TRANSFORM),
+ FALSE);
+
XIRegisterPropertyHandler(dev, DeviceSetProperty, NULL, NULL);
return dev;
diff --git a/dix/getevents.c b/dix/getevents.c
index 197deb4..b45762c 100644
--- a/dix/getevents.c
+++ b/dix/getevents.c
@@ -33,6 +33,7 @@
#include <X11/X.h>
#include <X11/keysym.h>
#include <X11/Xproto.h>
+#include <math.h>
#include "misc.h"
#include "resource.h"
@@ -997,6 +998,37 @@ FreeEventList(EventListPtr list, int num_events)
xfree(list);
}
+static int
+DeviceClip(DeviceIntPtr dev, float f, AxisInfoPtr axis)
+{
+ int v;
+
+ v = lroundf(f);
+
+ if (v > axis->max_value)
+ v = axis->max_value;
+ else if (v < axis->min_value)
+ v = axis->min_value;
+
+ return v;
+}
+
+static void
+TransformAbsolute(DeviceIntPtr dev, int v[MAX_VALUATORS])
+{
+ float x, y, *m = dev->transform;
+
+ /**
+ * v' = M * v in homogeneous coordinates,
+ * lowest row of matrix is assumed to be 0 0 1
+ */
+ x = m[0]*v[0] + m[1]*v[1] + m[2];
+ y = m[3]*v[0] + m[4]*v[1] + m[5];
+
+ v[0] = DeviceClip(dev, x, &dev->valuator->axes[0]);
+ v[1] = DeviceClip(dev, y, &dev->valuator->axes[1]);
+}
+
/**
* Generate a series of xEvents (filled into the EventList) representing
* pointer motion, or button presses. Xi and XKB-aware.
@@ -1068,6 +1100,7 @@ GetPointerEvents(EventList *events, DeviceIntPtr pDev, int type, int buttons,
scr->height);
}
+ TransformAbsolute(pDev, valuators);
moveAbsolute(pDev, &x, &y, first_valuator, num_valuators, valuators);
} else {
if (flags & POINTER_ACCELERATE) {
diff --git a/include/inputstr.h b/include/inputstr.h
index 6da3f38..db75ace 100644
--- a/include/inputstr.h
+++ b/include/inputstr.h
@@ -542,6 +542,9 @@ typedef struct _DeviceIntRec {
XIPropertyPtr properties;
XIPropertyHandlerPtr handlers; /* NULL-terminated */
} properties;
+
+ /* 3x3 coordinate transformation matrix for abs devs in row major order */
+ float transform[9];
} DeviceIntRec;
typedef struct {
diff --git a/include/xserver-properties.h b/include/xserver-properties.h
index 6a05178..5a645f3 100644
--- a/include/xserver-properties.h
+++ b/include/xserver-properties.h
@@ -38,6 +38,13 @@
/* STRING. Device node path of device */
#define XI_PROP_DEVICE_NODE "Device Node"
+/* Coordinate transformation matrix for absolute input devices
+ * FLOAT, 9 values in row-major order, coordinates in 0..1 range:
+ * [c0 c1 c2] [x]
+ * [c3 c4 c5] * [y]
+ * [c6 c7 c8] [1] */
+#define XI_PROP_TRANSFORM "Coordinate Transformation Matrix"
+
/* Pointer acceleration properties */
/* INTEGER of any format */
#define ACCEL_PROP_PROFILE_NUMBER "Device Accel Profile"
--
1.7.0
More information about the xorg-devel
mailing list