Vojtech Pavlik <[EMAIL PROTECTED]> writes:
> On Wed, Feb 02, 2005 at 11:58:05PM +0100, Peter Osterlund wrote:
>
> > In practice I don't think it will make any significant difference. What
> > the code should do depends on what you want to happen if you move the
> > mouse pointer 1/2 pixel with one finger stroke, then move it another 1/2
> > pixel with a second stroke. The patch I posted will move the pointer one
> > pixel in this case and your code will move it 0 pixels. (The X driver does
> > not reset the fractions, but that doesn't of course mean that it's the
> > only right thing to do.)
> >
> > > Also, I think the extra unary minus is uncoth.
> >
> > The code was written like that to emphasize the fact that X and Y use the
> > same formula, with the only difference that the kernel Y axis is mirrored
> > compared to the touchpad Y axis.
> >
> > It didn't make any difference for the generated assembly code though,
> > using gcc 3.4.2 from Fedora Core 3.
> >
> > > + enum { FRACTION_DENOM = 100 };
> >
> > The enum is much nicer than my #define.
>
> OK. I like this patch, too. Can you guys send me a final version
> incorporating the changes of you both for inclusion in the input tree?
Here it is, with the suggestions from Pete and Dmitry included. The
patch does the following:
* Compensates for the lack of floating point arithmetic by keeping
track of remainders from the integer divisions.
* Removes the xres/yres scaling so that you get the same speed in the
X and Y directions even if your screen is not square.
* Sets scale factors to make the speed for synaptics and alps equal to
each other and equal to the synaptics speed from 2.6.10.
Signed-off-by: Peter Osterlund <[EMAIL PROTECTED]>
---
linux-petero/drivers/input/mousedev.c | 28 +++++++++++++++++++---------
1 files changed, 19 insertions(+), 9 deletions(-)
diff -puN drivers/input/mousedev.c~mousedev-roundoff drivers/input/mousedev.c
--- linux/drivers/input/mousedev.c~mousedev-roundoff 2005-02-02
20:54:23.000000000 +0100
+++ linux-petero/drivers/input/mousedev.c 2005-02-03 22:41:41.000000000
+0100
@@ -71,6 +71,7 @@ struct mousedev {
struct mousedev_hw_data packet;
unsigned int pkt_count;
int old_x[4], old_y[4];
+ int frac_dx, frac_dy;
unsigned long touch;
};
@@ -117,24 +118,31 @@ static struct mousedev mousedev_mix;
static void mousedev_touchpad_event(struct input_dev *dev, struct mousedev
*mousedev, unsigned int code, int value)
{
- int size;
+ int size, tmp;
+ enum { FRACTION_DENOM = 128 };
if (mousedev->touch) {
+ size = dev->absmax[ABS_X] - dev->absmin[ABS_X];
+ if (size == 0) size = 256 * 2;
switch (code) {
case ABS_X:
- size = dev->absmax[ABS_X] - dev->absmin[ABS_X];
- if (size == 0) size = xres;
fx(0) = value;
- if (mousedev->pkt_count >= 2)
- mousedev->packet.dx = ((fx(0) - fx(1))
/ 2 + (fx(1) - fx(2)) / 2) * xres / (size * 2);
+ if (mousedev->pkt_count >= 2) {
+ tmp = ((value - fx(2)) * (256 *
FRACTION_DENOM)) / size;
+ tmp += mousedev->frac_dx;
+ mousedev->packet.dx = tmp /
FRACTION_DENOM;
+ mousedev->frac_dx = tmp -
mousedev->packet.dx * FRACTION_DENOM;
+ }
break;
case ABS_Y:
- size = dev->absmax[ABS_Y] - dev->absmin[ABS_Y];
- if (size == 0) size = yres;
fy(0) = value;
- if (mousedev->pkt_count >= 2)
- mousedev->packet.dy = -((fy(0) - fy(1))
/ 2 + (fy(1) - fy(2)) / 2) * yres / (size * 2);
+ if (mousedev->pkt_count >= 2) {
+ tmp = -((value - fy(2)) * (256 *
FRACTION_DENOM)) / size;
+ tmp += mousedev->frac_dy;
+ mousedev->packet.dy = tmp /
FRACTION_DENOM;
+ mousedev->frac_dy = tmp -
mousedev->packet.dy * FRACTION_DENOM;
+ }
break;
}
}
@@ -268,6 +276,8 @@ static void mousedev_touchpad_touch(stru
clear_bit(0, &mousedev_mix.packet.buttons);
}
mousedev->touch = mousedev->pkt_count = 0;
+ mousedev->frac_dx = 0;
+ mousedev->frac_dy = 0;
}
else
if (!mousedev->touch)
_
--
Peter Osterlund - [EMAIL PROTECTED]
http://web.telia.com/~u89404340
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