On Tue, Aug 21, 2018 at 10:34:03AM -0700, Jason Gerecke wrote:
> The default values for zoom, scroll, and spread distances were originally
> fine-tuned for use with a 3rd-gen Bamboo small tablet (e.g. CTH-470). The
> code tries to scale these values to work with other sensors, but there are
> a couple of problems with the actual logic:
>
> 1. The scaling is done based on the logical size of the tablet. This is
> problematic for some generations of tablet (including the 3rd-gen Bamboos)
> which use sensors with an identical logical size despite different physical
> size. This means that larger tablets in these generations require larger
> gestures to accomplish the same task.
>
> 2. The scale factor for the scroll distance is calculated with respect to
> the X axis, even though it is far more common to scroll vertically than
> horizontally. For devices with a different resolution in the X and Y axes,
> this means that calculated default won't be consistent with devices that
> have the same resolution in both the X and Y axes.
>
> This patch makes several modifications to simultaneously address all
> of the issues. We replace the logical Bamboo-referenced numbers with
> equivalent millimeters, calculate the logical distances based on the
> kernel-reported resolution (using the resolution of the Bamboo if not
> not available), and specifically scale scroll distances with respect
> to the Y axis.
>
> The end result is a scroll and zoom feel that is consistent across many
> more devices. No longer do you have to make physically-larger gestures
> on physically-larger tablets, or physically-smaller gestures on tablets
> with higher logical resolution.
>
> Ref: https://github.com/linuxwacom/input-wacom/issues/33
> Signed-off-by: Jason Gerecke <jason.gere...@wacom.com>
> ---
> src/wcmValidateDevice.c | 23 ++++++++++++-----------
> 1 file changed, 12 insertions(+), 11 deletions(-)
>
> diff --git a/src/wcmValidateDevice.c b/src/wcmValidateDevice.c
> index 95c8a2c..7b7bff2 100644
> --- a/src/wcmValidateDevice.c
> +++ b/src/wcmValidateDevice.c
> @@ -1044,11 +1044,12 @@ error:
> return FALSE;
> }
>
> -/* The values were based on trail and error. */
> -#define WCM_BAMBOO3_MAXX 4096.0
> -#define WCM_BAMBOO3_ZOOM_DISTANCE 180.0
> -#define WCM_BAMBOO3_SCROLL_DISTANCE 80.0
> -#define WCM_BAMBOO3_SCROLL_SPREAD_DISTANCE 350.0
> +/* The values were based on trial and error with a 3rd-gen Bamboo */
> +#define WCM_DEFAULT_MM_XRES (27.8 * 1000)
> +#define WCM_DEFAULT_MM_YRES (44.5 * 1000)
tbh I got confused by the naming here. Call it just xres with a units/mm
comment or something?
otherwise series Reviewed-by: Peter Hutterer <peter.hutte...@who-t.net>
Cheers,
Peter
> +#define WCM_ZOOM_DISTANCE_MM 6.5
> +#define WCM_SCROLL_DISTANCE_MM 1.8
> +#define WCM_SCROLL_SPREAD_DISTANCE_MM 12.6
>
> /**
> * Parse post-init options for this device. Useful for overriding HW
> @@ -1075,10 +1076,11 @@ Bool wcmPostInitParseOptions(InputInfoPtr pInfo, Bool
> is_primary,
> /* 2FG touch device */
> if (TabletHasFeature(common, WCM_2FGT) && IsTouch(priv))
> {
> - int zoom_distance = common->wcmMaxTouchX *
> - (WCM_BAMBOO3_ZOOM_DISTANCE / WCM_BAMBOO3_MAXX);
> - int scroll_distance = common->wcmMaxTouchX *
> - (WCM_BAMBOO3_SCROLL_DISTANCE / WCM_BAMBOO3_MAXX);
> + int x_res = common->wcmTouchResolX ? common->wcmTouchResolX :
> WCM_DEFAULT_MM_XRES;
> + int y_res = common->wcmTouchResolY ? common->wcmTouchResolY :
> WCM_DEFAULT_MM_YRES;
> + int zoom_distance = WCM_ZOOM_DISTANCE_MM * x_res / 1000;
> + int scroll_distance = WCM_SCROLL_DISTANCE_MM * y_res / 1000;
> + int spread_distance = WCM_SCROLL_SPREAD_DISTANCE_MM * x_res /
> 1000;
>
> common->wcmGestureParameters.wcmZoomDistance =
> xf86SetIntOption(pInfo->options, "ZoomDistance",
> @@ -1089,8 +1091,7 @@ Bool wcmPostInitParseOptions(InputInfoPtr pInfo, Bool
> is_primary,
> scroll_distance);
>
> common->wcmGestureParameters.wcmMaxScrollFingerSpread =
> - common->wcmMaxTouchX *
> - (WCM_BAMBOO3_SCROLL_SPREAD_DISTANCE / WCM_BAMBOO3_MAXX);
> + spread_distance;
> }
>
>
> --
> 2.18.0
>
>
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