On Sat, Jan 16, 2010 at 10:20 AM, Enlightenment SVN
<no-re...@enlightenment.org> wrote:
> Log:
> initial multi-touch support.
...
> +struct _Evas_Event_Multi_Down /** Multi button press event */
> +{
> + int device; /**< Multi device number that went down (1 or more) */
> + int radius, radius_x, radius_y;
> + struct {
> + int x, y;
> + } output;
> + struct {
> + Evas_Coord x, y;
> + } canvas;
> + void *data;
> + Evas_Modifier *modifiers;
> + Evas_Lock *locks;
> +
> + Evas_Button_Flags flags;
> + unsigned int timestamp;
> + Evas_Event_Flags event_flags;
> + Evas_Device *dev;
> +};
> +
> +struct _Evas_Event_Multi_Up /** Multi button release event */
> +{
> + int device; /**< Multi button number that was raised (1 - 32) */
> + int radius, radius_x, radius_y;
> + struct {
> + int x, y;
> + } output;
> + struct {
> + Evas_Coord x, y;
> + } canvas;
> + void *data;
> + Evas_Modifier *modifiers;
> + Evas_Lock *locks;
> +
> + Evas_Button_Flags flags;
> + unsigned int timestamp;
> + Evas_Event_Flags event_flags;
> + Evas_Device *dev;
> +};
> +
> +struct _Evas_Event_Multi_Move /** Multi button down event */
> +{
> + int device; /**< Button pressed mask, Bits set to 1 are buttons currently
> pressed (bit 0 = mouse button 1, bit 1 = mouse button 2 etc.) */
> + int radius, radius_x, radius_y;
> + struct {
> + struct {
> + int x, y;
> + } output;
> + struct {
> + Evas_Coord x, y;
> + } canvas;
> + } cur;
> + void *data;
> + Evas_Modifier *modifiers;
> + Evas_Lock *locks;
> + unsigned int timestamp;
> + Evas_Event_Flags event_flags;
> + Evas_Device *dev;
> +};
I have no clue about multi touch and specially the low level reporting
system, but what's good in this? I mean, there is no way to know
number of touchs at that time. Okay, down-up are fine, since they
might go at different time, but move should have a list of radius and
positions, no?
The way it is will make life hard to users, they will have to track
and mix down-up events to know the big picture of how many fingers are
there (it's just harder), but on move you're quite without relevant
data.
Again, I might be saying shit as I never saw low level reporting APIs
and Xi2 (if related), but for development POV, this would be better:
Multi_Touch_Base:
unsigned int count;
struct {
int radius, radius_x, radius_y;
Eina_Bool current; /* would flag activity in the event mode:
down, up or move */
struct {
int x, y;
} output;
struct {
Evas_Coord x, y;
} canvas;
} points[];
Dow:
<event-specific>
Multi_Touch_Base common;
Up:
<event-specific>
Multi_Touch_Base common;
Move:
<event-specific>
Multi_Touch_Base cur, prev;
Maybe this is even the way it is reported by the hardware, if not we
can keep this state inside evas and avoid doing it in every app that
wants to use multi-touch events. Some processing examples with these
new structures:
Double finger click:
if (down->common.count == 2)
Double finger click (considering some spacing):
if ((down->common.count == 2) &&
(abs(down->common.points[0].x - down->common.points[1].x) >
THRESHOLD) &&
(abs(down->common.points[0].y - down->common.points[1].y) > THRESHOLD))
pinch (iphone zooming):
if ((move->common.count == 2) &&
((down->cur.points[0].x - down->cur.points[1].x) >
(down->prev.points[0].x - down->prev.points[1].x)) &&
((down->cur.points[0].y - down->cur.points[1].y) >
(down->prev.points[0].y - down->prev.points[1].y)))
of course most real things will need some history and path-fitting to
smooth values and detect gestures and ignore errors from measurements
(that can go into another lib)
--
Gustavo Sverzut Barbieri
http://profusion.mobi embedded systems
--------------------------------------
MSN: barbi...@gmail.com
Skype: gsbarbieri
Mobile: +55 (19) 9225-2202
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