Added button and circular bar widgets.

SVGHMI: added more meaningful namespaces to emit javascript code from.

SVGHMI: moved JS code of foreach and jump widget in corresponding widget_*.ysl2. To be continued.

SVGHMI: spread JS code from svghmi/scripts.ysl2 in other .ysl2 files, using dedicated preamble and epilogue namespaces

SVGHMI: Introduced "emit" to simplify producing per-topic code and content from anywhere in code. Applied to debug output, next to JS.

SVGHMI: Move reflective debug tags from "reflect" to "debug" namespace, preparing for per-purpose namespaces.

SVGHMI: Added scripts.ysl2

SVGHMI: moving code wher it belongs, and reformulate some declarations for better readability.

SVGHMI: HMI:DropDown: more documentation.

SVGHMI: Comments in HMI:DropDown source code

SVGHMI: HMI:DropDown menu aligns to selected when opening

SVGHMI: When clicking outside of opened HMI:DropDown box, close it.

SVGHMI: Fix HMI:DropDown flicker on close.

SVGHMI: HMI:DropDown now temporarily takes content from widget's arguments, until HMI:List is implemented.

SVGHMI: Connect HMI:DropDown to value in HMI Tree, in svghmi test as well.

SVGHMI: fix probable problem in HMI:Input, where value could be applied to wrong index if used in relative page.

SVGHMI: HMI:DropDown element is brought in front when opened, so that it isn't occulted by other widgets at the same level.

SVGHMI: HMI:DropDown now catches all clicks when open

SVGHMI: Add button element to HMI:DropDown, also fix problem with computed box margins.

SVGHMI: HMI:DropDown now scrolls forward and backward

SVGHMI: progress on HMI:DropDown - now selects some value on click, and close

SVGHMI: HMI:DropDown work in progress, intermediate commit. Now menu's rectangle grows up to viewport borders.

SVGHMI: intermediate commit while working on dropdown widget.

Here is the plan :
HMI:DropDown : svg:g of svg:rect + svg:text
rect is extended to match content size, and if content size exceed page size, user can scroll
HMI:List : either HMI:List:ListName as svg:text, one tspan per list entry
or HMI:List:ListName:Foreach:HMI_CLASS:SUB/PATH/TO/VALUE@/ROOT/PATH as empty svg:g

SVGHMI: HMI is not speculating on PLC variable update anymore when sending new variable value.

HMI variable cache in JS was changed in advance for more responsive behaviour when updating a HMI tree variable. This was leading to display value different from hmi tree variable in case the expected update did not happen because PLC program did revert it.

SVGHMI: finished shift and capslock support n keypad widget. Added a helper in widgets_common to collect subelements likle active/inactive/disabled...

SVGHMI: fixed keypad JS regarding shift/capslock and other details

Fix unmatched "Courier" font for monospace fonts on latest ubuntu 20.04. Selected "FreeMono" instead, present since at least 18.04

SVGHMI: Keypad working for HMI_STRING, still Shift/CapsLock not finished.

SVGHMI: fix keyboard not showing

SVGHMI: Added keypads to svghmi test's SVG file

merge

SVGHMI: Keypad: added code to re-attach keypad when starting edit.

SVGHMI: removed debug code

SVGHMI: More infrastructure for editing values with a keypad.

SVGHMI: Widget input buttons should be clickable through svg:use (onclick attribute instead of addEventListener)

SVGHMI: moved dead code to where it belongs

SVGHMI: empty widget_keypad.ysl2, WIP

SVGHMI: HMI:Switch now accepts boolean values 'true' and 'false'

SVGHMI: Jump widget, if it has a 'disabled' labeled element, reflects value of the pointed HMITree variable by showing this element when value is False, and behaving normaly otherwise.

SVGHMI: prevent man-made memory leak by limiting back button history items count to 42

SVGHMI: collect debug data through xslt reflectivity instead of yml2/python trick

SVGHMI: Jump widget can now display as active or inactive, if corresponfing "active" and "inactive labeled elements are provided.

SVGHMI: added Back widget.

SVGHMI: Jump widget now make errors if path given for relative jump doesn't match target page reference path class.

SVGHMI: Check that explicit relative page jump path is consistant with destination page reference path.

SVGHMI: ForEach Widget now has a better wrap-around when scrolling : hit the boundary systematically before wrapping

SVGHMI: Alow relative relative Jump. (i.e, relative jump from a foreach widget)

SVGHMI: Generalize applying cache to widgets, be it from page or ForEach widgets. Now ForEach widget buttons work as expected.

SVGHMI: Widget ForEach buttons now call corresponding methods.

SVGHMI: ForEach now has working (un)subscribe. Fixed PageSwitch that wasn't behaving when jumping to current page with another path.

SVGHMI: Easier way to match HMI tree elements to paths. ForEach widget now looks for paths and indexes of all items, and enforce path to be consistent with ForEach items sub widgets

SVGHMI: added func:get_hmi_tree_elt to match HMI tree node from path. Continue implementing ForEach widget : force order and completeness of items list. Now also collecting ForEach buttons.

SVGHMI: ForEach knows its own widgets

SVGHMI: add widget_foreach.ysl2

SVGHMI: make root HMI tree node a HMI_NODE, droped HMI_ROOT node type

SVGHMI: reworked widget (un)subscription now a method of widgect object, allowing special subscription methods

SVGHMI: Exclude (again) sub-widgets of forEach widget from page-switch managed widget.

SVGHMI: cosmetic changes

SVGHMI: Simplification and optimization. func:parselabel becomes a template.

All labels are parsed into a global variable containing resulting widget
description as a node-set. func:widget(id) was added for random access to
widget description.

SVGHMI: intermediate untested state. Excluded ForEach widget from pages handled widgets.

SVGHMI: update Makefile to pick all changes to any dependency

SVGHMI: created widget_*.ysl2. Renamed widget_common in widgets_common, so that it doesn't match globing.

SVGHMI: moving comments

SVGHMI: added widget_common.ysl2

SVGHMI: More readable debug output gen code

SVGHMI: Cosmetic changes

SVGHMI: added inline_svg.ysl2

SVGHMI: detachable_elements.ysl2 becomes detachable_pages.ysl2, and includes logic to process pages elements. Other minor code moves.

SVGHMI: moved debug code

SVGHMI: created detachable_elements.ysl2

SVGHMI: more debug code moved to hmi_tree.ysl2

SVGHMI : create hmi_tree.ysl2, rename bbox_intersect.ysl2 into geometry.ysl2 and move more code into. Add per included ysl2 file debug output.

SVGHMI: created bbox_intersect.ysl2

SVGHMI: Re-enable dispatch to arrays of functions in case of multiple suscription per widget. Still unused, but disabled for reasons not any more true.

SVGHMI: relative pages and page jumps

SVGHMI: take care of path given in HMI:Page and HMI:Jump, but do not apply subscription offset for now. Intermediate commit in a "working" state.

SVGHMI: significant whitespace changes

SVGHMI: unsignificant changes or changes in generated code

SVGHMI: Stop ignoring HMI_NODE in HMI tree, and count it as a BOOL. Soon we use those nodes as reference for relative page jump, and as an "enable" bit for features associated to an HMI tree fragment.

SVGHMI: cosmetic code moving

SVGHMI: split page switch into switching subscription and switching elements in the DOM, to ensure that subscriptions have been send before changing DOM, and avoid some flicker.

SVGHMI: fix wrong updates of HMI variables on each change, especially when not subscribed.

SVGHMI: whitespaces

SVGHMI: fixed repeated error when Input widget is missing 'value' element

SVGHMI: more decoupling in between UI related and the rest of JS code, still in the aim of enhancing robustness under heavy load.

SVGHMI: use requestAnimationFrame to delegate rendering of updates from network. Should help prevent browser collapse leading to watchdog in case of overload.

SVGHMI: Fix disapearing elements in case of nested detachable elements.

SVGHMI: Meter widget accepts 2 arguments : min and max, taken in account when min or max text element is missing

SVGHMI: More precise error message on missing HMI path. Meter widget now defaults 0-100 range when min and max elements arent's present, without error.

SVGHMI: more whitespace fixes

SVGHMI: unlink clones (i.e. deep copy elements refered by svg:use) inside widget.

Designer can use Inkscape clones to duplicate similar assets accross widget. Those clones are unliked so that elements can be independently transformed by individual widgets.

SVGHMI: whitespaces and comments

SVGHMI: completely fixed indentation of generated widget description. Lets try to keep it as-is until we can use yslt indentation.

SVGHMI: re-indent generated JS

SVGHMI: detach/re-attach elements required by pages on page switch

This is meant to optimize performances with large drawings leading to long restyle or reflow.

SVGHMI: re-indenting

SVGHMI: declares pages detachable requirements as an object, to find more efficiently common requirements

SVGHMI: fix some JS + add generation of detachable elements, to be continued

SVGHMI: now compute discardable elements first so that we can do better grouping of required elements when sumarizing.

SVGHMI : documentation for new geometry intersection computation code + little fixes...

SVGHMI: detachable and discardable elements sets, Reworked geometric intersection, toward more accurate page content detection.

Moved page's widget/element dependency crawling functions so that it is possible to compute a global detachable and discardable elements sets.
Reworked geometric intersection detection logic to distinguish ovelapping and inclusion.
Goal is to include englobing and overlapping graphical elements, but not groups (would then include everything around...). Intermediate commit, to be continued.

SVGHMI : still trying to optimize. Added xslt code to identitfy minimum set of elements needed by a particular page. Plan is to remove unseen/unused elements from the DOM, and re-appending them later when used, on page switch. Disabled previous optimization.

SVGHMI: attempt to optimize for webkit, because of really slow style recompute in svg:use : "unlink clones" (as in inkscape) but stop deep-copy when meeting a widget, and create a new clone instead.

SVGHMI: optimize browser work by hiding (display:none) pages that are not displayed.

SVGHMI: Better and less verbose SVG namespace handling in XSLT transform

SVGHMI: Added mostly untested switch widget

SVGHMI: HMI:Page can now be a svg:g group or a svg:use clone, and included/linked widget are included in page. HMI:Jump was updated to be clickable through svg:use, to be generalized.

SVGHMI: ensure that coordinate in CSV file generated by inkscape are both matching svg default unit and in default reference frame

SVGHMI : still behave, even if important things are missing in SVG widget definitions (ex: needle missing for Meter widget)

SVGHMI : fix watchdog exception when timeout null

SVGHMI: be a bit more tolerant with missing HMI paths or missing elements in widgets : continue build (with warning) and fail silently at runtime.

SVGHMI : fixed bug happening when some SVG ids are containing dashes

SVGHMI : wait for initial timeout after watchdog is triggered, since it generaly induces HMI restart

SVGHMI : watchdog is now taking an initial and interval duration as CTN fields.

SVGHMI : avoid caching of xhtml file by forcing cache-control header in http response.

SVGHMI : HMI_STRING now also supported from HMI to PLC

SVGHMI : cosmetic

SVGHMI non significant fixes

SVGHMI : support for HMI_STRING and HMI_BOOL

plc_debug.c/var_acces.c : whitespace cleanup and other cosmetic changes

SVGHMI : Added python fomating {port} and {name} to commands so that command can build target URL

SVGHMI : add on Start, Stop and Watchdog command fields to configuration

SVGHMI: added a watchdog. To ensure that the whole chain is checked, watchdog use a periodic echo of a hearteat variable. JS client code systematically register /HEARTBEAT at 1s update freq, and reacts on updates of /HEARTBEAT by systematically incrementing it. C code catch /HEARTBEAT update and feeds python-implemented watchdog. For now, watchdog does nothing when tiggered

Add --on-plc-start --on-plc-stop and --status-change to runtime command line, calling given command respectively on start stop or any event. Command line string is python formated (to eventually include status with {}) before being split (supports quoted strings) and passed to Popen for non-blocking execution.

SVGHMI : had to move the problem of wkaing up python thread from plc thread to platform specific code.
Since Xenomai's cobalt thread are definitely incompatible with normal posix python interpreter binary's thread, we must synchronize them with arcane rt_pipes (the only ones that really work cross domain) as already done in debug and python async eval blocks.

SVGHMI: change collect/send thread looping condition to fix infinite loop in some cases

SVGHMI: re-implemented tree view with classic wxTreeCtl

Non significant changes, whitespaces, etc.