On Wed, Mar 23, 2011 at 6:30 PM, Peter Hutterer <[email protected]> wrote: > On Wed, Mar 23, 2011 at 12:58:21PM -0700, Jason Gerecke wrote: >> As I'm working on the X11 wheel mapping, I'm finding a few weird >> quirks in the code. I pretty much understand 'how' things work, but >> I'm not sure why some things are the way they are... >> >> 1. Why does WACOM_PROP_BUTTON_ACTIONS have room for only 16 buttons, >> yet priv->btn_actions (storing the same data) have space for 32? The >> functional difference between WCM_MAX_BUTTONS and >> WCM_MAX_MOUSE_BUTTONS is not clear. > > 7d149431c63c43c0ab5b046387b565488ea3d159 has some explanation what > WCM_MAX_BUTTONS is, but I can't remember any more details. > They were introduced in 2debfce6f9d6bfb206da2e1711d04f42cddd71e1, but > the comments in that commit don't really clarify things for me. > I was hoping it was related to some kind of X server limitation, but if you don't have any ideas... I guess I'll stare at it and scratch my head some more :D
>> 2. Why maintain a seperate raw button codepath when the "actions" >> codepath already does the same thing when given a 'button' action? > > simplicity mainly (and the raw path was there before). note that the button > action can be combined with a key action, so "key +ctrl button 1 key -ctrl" > is a valid action. > Would there be any objection to me tearing the raw path out of the driver? The two paths are very similar, and nearly duplicate each other. The only substantial difference is that non-raw buttons have their keys[] interpreted. >> 3. Why does xsetwacom take X11 buttons as the first argument to >> "Button X"? I can't be alone in thinking it was weird my cintiq was >> missing two buttons (6 & 7) and that two other buttons (4 & 5) only >> responded to changes via the Strip(Left|Right)(Up|Down) command. > > This should be documented better. Button mapping in X is complicated to say > the least. http://who-t.blogspot.com/2009/06/button-mapping-in-x.html > > xsetwacom takes x11 buttons because for simple button mappings, it uses > XSetDeviceButtonMappings (which requires X buttons). > X buttons have the advantage of being easy to debug (for users). A > driver-internal button mapping is private to the driver and hard to figure > out at the best of times. e.g. which button on your device is Button 1? > running xev or xinput will only tell you the logical button 1, not the > physical button 1. > That's a pretty good argument, I suppose. It seems ugly and has non-intuitive side-effects, but it has its benefits. Jason --- Day xee-nee-svsh duu-'ushtlh-ts'it; nuu-wee-ya' duu-xan' 'vm-nvshtlh-ts'it. Huu-chan xuu naa~-gha. ------------------------------------------------------------------------------ Enable your software for Intel(R) Active Management Technology to meet the growing manageability and security demands of your customers. Businesses are taking advantage of Intel(R) vPro (TM) technology - will your software be a part of the solution? Download the Intel(R) Manageability Checker today! http://p.sf.net/sfu/intel-dev2devmar _______________________________________________ Linuxwacom-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/linuxwacom-devel
