Re: [Inkscape-devel] Hackfest 2018: Actions and Toolbars

Maren, On 2018-03-31 23:43, Maren Hachmann wrote: > If you want to hear and see Alex, Ryan, Bryce and Martin talk about this > (and other Hackfest things), there's one more video on youtube (got > posted to twitter, but not here yet, as far as I could see): > > youtu.be/IqQI2Y1PR38 Looks like there are only summaries for Day 1 and Day 4 so far? P.

> Maren > > Am 31.03.2018 um 02:03 schrieb Alex Valavanis: >> Hi All, >> >> Here's a summary of my work at the Boston Hackfest. >> >> Before I continue, I'd like to thank everyone who donated their money or >> time to support this Hackfest.  This has been a really useful event - >> it's so much easier to deal with tricky design challenges and project >> management stuff when we can meet face to face.  It has also brought >> together people with very diverse expertise across the project (UI, web, >> build, extensions, project management etc).  This week, we've figured >> out a path to deliver long desired features (multipage support etc), >> roadmapped our final route to deliver Inkscape 1.0, done some great >> website design work, and handled some tricky code structure issues that >> I'll discuss in this message. >> >> If you're able to donate some money to support Inkscape, and future >> Hackfests, we really appreciate this.  You can find the donation link on >> our website: https://inkscape.org/en/support-us/hackfests/ >> >> It would also be great to get some more of the regular contributors from >> our wider community to join us at future events (i.e., designers, >> bug-team, experienced users... not just C++ developers!).  The >> developers can learn so much more about the project by discussing it >> with you. >> >> So... what have I been doing this week? >> >> == What are Actions? == >> >> Basically, an "action" is a thing that Inkscape can do (e.g., flip an >> object horizontally), which we can identify using an ID code (e.g., >> "SP_VERB_OBJECT_FLIP_HORIZONTAL").  We can then hook up buttons, menu >> items etc to activate these actions.  In this example, we would set up >> our Flip Horizontal button in the select-tool toolbar so that when the >> user clicks it, it activates the required action. >> >> My work this week has focused on improving the way we implement actions >> in our code, which will >> >>  1. Allow Inkscape to run on machines with future versions of the Gtk+ >>     library (Gtk 4+) >>  2. Provide much better separation between the behaviour and user >>     interface (i.e.,, separate pieces of the code will describe what >>     Inkscape "does", and what it "looks like") >>  3. Make it much easier to create new "flavours" of the Inkscape user >>     interface - for example, an "Inkscape for Kids" or "Inkscape CAD" >>  4. Make it easier for "non-programmers" to create and reorganise custom >>     toolbars and dialogs >>  5. Allow us to remove a lot of older "C" code that is very difficult >>     for current "C++" developers to maintain >> >> == Where we are now? == >> >> In the Inkscape code, we have a mechanism called "verbs" that acts as a >> kind of action mechanism... it provides a way of using an ID code to >> look up the required commands to perform an action. >> >> On top of this, we have another structure called SPAction that >> essentially hooks up a couple of signals to the verb. >> >> Finally(ish), we use objects called GtkActions from the Gtk+ library, >> which let us create GUI elements (buttons etc) that we can add to our >> menus or toolbars that activate the required action. >> >> We have also got a few custom sub-classes of GtkAction that let us >> create special kinds of tool-item that can activate actions... for >> example, one of these creates a spin-button (a box with a number in it, >> and "up/down" arrows) that can also handle units, basic arithmetic, and >> provides a label. >> >> == What's the problem? == >> >> First, the GtkAction widget (and hence all our custom sub-classes) is >> deprecated and has been removed from Gtk+ 4, so we need to change.  >> Since Inkscape 1.0 is intended as a "stable" release, we want to make it >> as future-proof as possible. >> >> The main reason for this deprecation is that the GtkAction widget is a >> slightly weird mix of paradigms: it mixes information about how to >> display a tool/menu item with information about behaviour.  This causes >> some problems... what if we wanted to run a "headless" Inkscape on a >> system that has no display?  What if we wanted to provide several >> different GUI options for different kinds of user to trigger the same >> behaviour? >> >> This is one of the reasons why we have the "verbs" system is in place, >> as it separates behaviour from the GUI.  However, there is still quite a >> lot of code "overhead" needed if we want to hook up Inkscape's Verb >> behaviour to a GUI element.  Essentially, it's "programmers only" >> territory.  What if a designer wanted to add a new toolbar button to >> their Inkscape to handle a useful feature that is currently buried deep >> in a menu?  What if a teacher wanted to strip out a lot of "advanced" >> behaviour from the interface to make it easier to introduce Inkscape to >> their class?  At the moment, they have to edit the C++ code, and >> recompile it... a slow and complicated process! >> >> == Where are we going? == >> >> We need to move to using GActions (a feature in the Glib/GIO library).  >> This *only* describes the action's behaviour and provides an "activated" >> signal that we can trigger by simply knowing the action's name.  This is >> completely separated from the GUI.  These actions can be activated very >> easily from a whole range of places, for example: >> >>  1. By attaching the action's name to a GUI element in the C++ code >>     (replacing our SPAction/GtkAction code) >>  2. By activating the action (using its name) from a command-line >>     interface (replacing some of our verbs code) >>  3. By attaching the action's name to elements in a customised GUI file >>  4. From external applications, using the DBus system >> >> Number 3 in the list provides some very exciting opportunities for >> future releases, as non-programmers will be able to make a customised >> user interface by drawing one in the Glade application.  You then just >> attach the name of the required Inkscape action to each GUI element.  >> Want a new button?  Just edit Inkscape's user-interface file in Glade >> and see the changes immediately next time you start... no C++ knowledge >> needed! >> >> == What have I done so far? == >> >> I've started working through Inkscape's toolbars, and have replaced the >> deprecated GtkAction-based widgets with standard widgets (buttons etc).  >> Some of these now hook up to GAction descriptions of behaviour, while >> others are just based on handling GUI signals (e.g., Button::clicked). >> >> So far, I have migrated the toolbars for the Select, Dropper and >> Connector toolbar, and have killed off a couple of the custom >> GtkAction-based widgets that were only used in these. >> >> In the process, I have also migrated the toolbar code to C++, which >> should make it a little easier for the current core developers to >> maintain.  Since all the data is now stored as C++ member variables, >> rather than as GObject data, we now benefit from better compile-time and >> run-time type-checking that will help to safeguard against errors being >> introduced in the code in future. >> >> I have placed the updated toolbars in the Inkscape::UI::Toolbar >> namespace and made them into proper sub-classes of the Gtk::Toolbar >> class. >> >> == How can you help? == >> >> This important refactoring project must be done before Gtk+ 4 is widely >> used, and represents a major change to the way that our toolbars are >> implemented.  It represents a couple of thousand lines of code changes >> and will inevitably cause some regression bugs. I will need your help in >> thoroughly testing that all the toolbars work correcly! >> >> All of these changes are currently in a git branch >> ("gtk-actions-migration") and will not be merged into the master branch >> until preliminary testing has been completed.  In other words, this will >> not "mess up" your stable version of Inkscape and will never be part of >> the current 0.92.x release series! I intend to merge this work well in >> advance of the Inkscape 1.0 release, so that we have plenty of time for >> very thorough developer and user testing, and several preliminary >> bug-fix "alpha" pre-releases before the final stable release. >> >> For the very brave: please checkout the "gtk-actions-migration" branch >> in git, rebuild and test.  Please note that this is work-in progress.  >> Do not use this experimental branch for your regular Inkscape drawing >> work!!!  The Node toolbar will not work... the Select, Dropper and >> Connector toolbars are highly experimental; all the other toolbars are >> "at risk"!    If you don't know how to do this, check out our developer >> guide. >> >> For the quite brave: I'll merge this experimental branch into our master >> development branch in a few weeks once (a) I've completed the basic >> work, (b) I've had a good amount of feedback on the branch and know that >> it "works" to some extent.  I'll message you again at this stage and ask >> everyone to help look for bugs.  Again, this will only be visible to >> developers and users of our experimental "trunk" PPA in Ubuntu. >> >> For the intrepid: If you're interested in helping with the code >> migration - message me and I'll help to divide up the tasks. >> >> == The end == >> >> I hope this gives an insight into the work I've started doing this week, >> and will continue over the coming weeks.  Thanks once again to everyone >> who has contributed time, money or even just attention and enthusiasm >> for the Hackfest. >> >> Best wishes, >> >> >> >> Alex Valavanis (valavanisalex) >> >> Inkscape developer >> >> >> ------------------------------------------------------------------------------ >> >> Check out the vibrant tech community on one of the world's most >> engaging tech sites, Slashdot.org! http://sdm.link/slashdot >> >> >> >> _______________________________________________ >> Inkscape-devel mailing list >> Inkscape-devel(a)lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/inkscape-devel >> > > > ------------------------------------------------------------------------------ > > Check out the vibrant tech community on one of the world's most > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > Inkscape-devel mailing list > Inkscape-devel(a)lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/inkscape-devel