| ======================== | |
| MEP22: Toolbar rewrite | |
| ======================== | |
| .. contents:: | |
| :local: | |
| Status | |
| ====== | |
| **Progress** | |
| Branches and Pull requests | |
| ========================== | |
| Previous work: | |
| * https://github.com/matplotlib/matplotlib/pull/1849 | |
| * https://github.com/matplotlib/matplotlib/pull/2557 | |
| * https://github.com/matplotlib/matplotlib/pull/2465 | |
| Pull Requests: | |
| * Removing the NavigationToolbar classes | |
| https://github.com/matplotlib/matplotlib/pull/2740 **CLOSED** | |
| * Keeping the NavigationToolbar classes https://github.com/matplotlib/matplotlib/pull/2759 **CLOSED** | |
| * Navigation by events: https://github.com/matplotlib/matplotlib/pull/3652 | |
| Abstract | |
| ======== | |
| The main goal of this MEP is to make it easier to modify (add, change, | |
| remove) the way the user interacts with the figures. | |
| The user interaction with the figure is deeply integrated within the | |
| Canvas and Toolbar. Making extremely difficult to do any modification. | |
| This MEP proposes the separation of this interaction into Toolbar, | |
| Navigation and Tools to provide independent access and | |
| reconfiguration. | |
| This approach will make easier to create and share tools among | |
| users. In the far future, we can even foresee a kind of Marketplace | |
| for ``Tool``\s where the most popular can be added into the main | |
| distribution. | |
| Detailed description | |
| ==================== | |
| The reconfiguration of the Toolbar is complex, most of the time it | |
| requires a custom backend. | |
| The creation of custom Tools sometimes interferes with the Toolbar, as | |
| example see https://github.com/matplotlib/matplotlib/issues/2694 also | |
| the shortcuts are hardcoded and again not easily modifiable | |
| https://github.com/matplotlib/matplotlib/issues/2699 | |
| The proposed solution is to take the actions out of the ``Toolbar`` and the | |
| shortcuts out of the ``Canvas``. The actions and shortcuts will be in the form | |
| of ``Tool``\s. | |
| A new class ``Navigation`` will be the bridge between the events from the | |
| ``Canvas`` and ``Toolbar`` and redirect them to the appropriate ``Tool``. | |
| At the end the user interaction will be divided into three classes: | |
| * NavigationBase: This class is instantiated for each FigureManager | |
| and connect the all user interactions with the Tools | |
| * ToolbarBase: This existing class is relegated only as a GUI access | |
| to Tools. | |
| * ToolBase: Is the basic definition of Tools. | |
| Implementation | |
| ============== | |
| ToolBase(object) | |
| ---------------- | |
| Tools can have a graphical representation as the ``SubplotTool`` or not even be | |
| present in the Toolbar as ``Quit``. | |
| The `.ToolBase` has the following class attributes for configuration at definition time | |
| * keymap = None: Key(s) to be used to trigger the tool | |
| * description = '': Small description of the tool | |
| * image = None: Image that is used in the toolbar | |
| The following instance attributes are set at instantiation: | |
| * name | |
| * navigation | |
| Methods | |
| ~~~~~~~ | |
| * ``trigger(self, event)``: This is the main method of the Tool, it is called | |
| when the Tool is triggered by: | |
| * Toolbar button click | |
| * keypress associated with the Tool Keymap | |
| * Call to navigation.trigger_tool(name) | |
| * ``set_figure(self, figure)``: Set the figure and navigation attributes | |
| * ``destroy(self, *args)``: Destroy the ``Tool`` graphical interface (if | |
| exists) | |
| Available Tools | |
| ~~~~~~~~~~~~~~~ | |
| * ToolQuit | |
| * ToolEnableAllNavigation | |
| * ToolEnableNavigation | |
| * ToolToggleGrid | |
| * ToolToggleFullScreen | |
| * ToolToggleYScale | |
| * ToolToggleXScale | |
| * ToolHome | |
| * ToolBack | |
| * ToolForward | |
| * SaveFigureBase | |
| * ConfigureSubplotsBase | |
| ToolToggleBase(ToolBase) | |
| ------------------------ | |
| The `.ToolToggleBase` has the following class attributes for | |
| configuration at definition time | |
| * radio_group = None: Attribute to group 'radio' like tools (mutually | |
| exclusive) | |
| * cursor = None: Cursor to use when the tool is active | |
| The **Toggleable** Tools, can capture keypress, mouse moves, and mouse | |
| button press | |
| Methods | |
| ~~~~~~~ | |
| * ``enable(self, event)``: Called by `.ToolToggleBase.trigger` method | |
| * ``disable(self, event)``: Called when the tool is untoggled | |
| * ``toggled``: **Property** True or False | |
| Available Tools | |
| ~~~~~~~~~~~~~~~ | |
| * ToolZoom | |
| * ToolPan | |
| NavigationBase | |
| -------------- | |
| Defines the following attributes: | |
| * canvas: | |
| * keypresslock: Lock to know if the ``canvas`` ``key_press_event`` is | |
| available and process it | |
| * messagelock: Lock to know if the message is available to write | |
| Methods (intended for the end user) | |
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | |
| * ``nav_connect(self, s, func)``: Connect to navigation for events | |
| * ``nav_disconnect(self, cid)``: Disconnect from navigation event | |
| * ``message_event(self, message, sender=None)``: Emit a | |
| tool_message_event event | |
| * ``active_toggle(self)``: **Property** The currently toggled tools or | |
| None | |
| * ``get_tool_keymap(self, name)``: Return a list of keys that are | |
| associated with the tool | |
| * ``set_tool_keymap(self, name, ``*keys``)``: Set the keys for the given tool | |
| * ``remove_tool(self, name)``: Removes tool from the navigation control. | |
| * ``add_tools(self, tools)``: Add multiple tools to ``Navigation`` | |
| * ``add_tool(self, name, tool, group=None, position=None)``: Add a tool | |
| to the ``Navigation`` | |
| * ``tool_trigger_event(self, name, sender=None, canvasevent=None, | |
| data=None)``: Trigger a tool and fire the event | |
| * ``tools``: **Property** A dict with available tools with | |
| corresponding keymaps, descriptions and objects | |
| * ``get_tool(self, name)``: Return the tool object | |
| ToolbarBase | |
| ----------- | |
| Methods (for backend implementation) | |
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | |
| * ``add_toolitem(self, name, group, position, image, description, toggle)``: | |
| Add a toolitem to the toolbar. This method is a callback from | |
| ``tool_added_event`` (emitted by navigation) | |
| * ``set_message(self, s)``: Display a message on toolbar or in status bar | |
| * ``toggle_toolitem(self, name)``: Toggle the toolitem without firing event. | |
| * ``remove_toolitem(self, name)``: Remove a toolitem from the ``Toolbar`` | |
| Backward compatibility | |
| ====================== | |
| For backward compatibility added 'navigation' to the list of values | |
| supported by :rc:`toolbar`, that is used for ``Navigation`` classes | |
| instantiation instead of the NavigationToolbar classes | |
| With this parameter, it makes it transparent to anyone using the | |
| existing backends. | |
| [@pelson comment: This also gives us an opportunity to avoid needing | |
| to implement all of this in the same PR - some backends can | |
| potentially exist without the new functionality for a short while (but | |
| it must be done at some point).] | |