Vertical panel mode(s)

[Andrzej]

Hi,

I've recently started using a laptop with a wide screen (difficult to
find anything else these days) and so I started looking closer into
the vertical panel mode. It looks to me that in XFCE the "vertical
mode" means a "rotated panel placed along the left or right edge of
the screen". However, in many use cases it would make sens to use a
wide "panel (dock?) placed along the left or right edge of the screen
with items arranged horizontally".

I've noticed some work on making panel items work in both scenarios
has already been done (e.g. "Rotate buttons in vertical panel" in
"Window buttons") but most other items are hard-coded for the "rotated
panel" use case. If other panel items were to follow this path,
similar options would have to be added to almost all of them. This
would not only be tricky to configure but also would also make
difficult to switch between panel orientations (the user would have to
reconfigure all the panel items after the change).

My proposal is:

1. Acknowledge that there are two very distinct use cases for vertical
panel mode and add an option to panel preferences.
   Specifically, "Orientation" panel property could have three values:
     - Vertical,
     - Horizontal,
     - Vertical (dock).     (The name is not very good, I know. Please
propose something better)
   In "Vertical (dock)" mode all items should arrange themselves horizontally.

2. Add an "icon size" property only active in "vertical (dock)" mode
(in other modes "icon size" should IMHO be derived from the panel
size, as it is now).
   Currently many icons become very large when panel size is e.g. 128
pixels. This might be a desired behavior but I think most users would
expect icon sizes of e.g. 24 pixels (like icon sizes used in "Window
buttons" or "Notification area" items).

I've been fiddling with these ideas in my private git repository but
would like to hear from you whether you like these changes or not
(this work only makes sense if at least the 2 ideas above make their
way into Xfce repository).

Also, another (related) question. I've noticed there are multiple
enums defining the orientation of panel w.r.t. the screen, like:
    XFCE_SCREEN_POSITION_NW_V,          /* North West Vertical   */
    XFCE_SCREEN_POSITION_W,             /* West                  */
    XFCE_SCREEN_POSITION_SW_V,          /* South West Vertical   */

Are they only for API compatibility with older XFCE versions? I didn't
notice anything in XFCE-4.8 GUI that would rely on these enums. Should
I follow this convention for new enums or is it OK to simplify them
(e.g. *_E_VD, *_W_VD)?

Cheers,

Andrzej