| ================================= |
| MEP13: Use properties for Artists |
| ================================= |
|
|
| .. contents:: |
| :local: |
|
|
| Status |
| ====== |
|
|
| - **Discussion** |
|
|
| Branches and Pull requests |
| ========================== |
|
|
| None |
|
|
| Abstract |
| ======== |
|
|
| Wrap all of the matplotlib getter and setter methods with python |
| `properties |
| <https://docs.python.org/3/library/functions.html#property>`_, allowing |
| them to be read and written like class attributes. |
|
|
| Detailed description |
| ==================== |
|
|
| Currently matplotlib uses getter and setter functions (usually |
| prefixed with get\_ and set\_, respectively) for reading and writing |
| data related to classes. However, since 2.6 python supports |
| properties, which allow such setter and getter functions to be |
| accessed as though they were attributes. This proposal would |
| implement all existing setter and getter methods as properties. |
|
|
| Implementation |
| ============== |
|
|
| 1. All existing getter and setter methods will need to have two |
| aliases, one with the get\_ or set\_ prefix and one without. |
| Getter methods that currently lack prefixes should be recording in |
| a text file. |
| 2. Classes should be reorganized so setter and getter methods are |
| sequential in the code, with getter methods first. |
| 3. Getter and setter methods that provide additional optional arguments should |
| have those arguments accessible in another manner, either as additional |
| getter or setter methods or attributes of other classes. If those classes |
| are not accessible, getters for them should be added. |
| 4. Property decorators will be added to the setter and getter methods |
| without the prefix. Those with the prefix will be marked as |
| deprecated. |
| 5. Docstrings will need to be rewritten so the getter with the prefix |
| has the current docstring and the getter without the prefix has a |
| generic docstring appropriate for an attribute. |
| 6. Automatic alias generation will need to be modified so it will also |
| create aliases for the properties. |
| 7. All instances of getter and setter method calls will need to be |
| changed to attribute access. |
| 8. All setter and getter aliases with prefixes will be removed |
|
|
| The following steps can be done simultaneously: 1, 2, and 3; 4 and 5; |
| 6 and 7. |
|
|
| Only the following steps must be done in the same release: 4, 5, |
| and 6. All other changes can be done in separate releases. 8 should |
| be done several major releases after everything else. |
|
|
| Backward compatibility |
| ====================== |
|
|
| All existing getter methods that do not have a prefix (such as get\_) |
| will need to be changed from function calls to attribute access. In |
| most cases this will only require removing the parenthesis. |
|
|
| setter and getter methods that have additional optional arguments will |
| need to have those arguments implemented in another way, either as a |
| separate property in the same class or as attributes or properties of |
| another class. |
|
|
| Cases where the setter returns a value will need to be changed to |
| using the setter followed by the getter. |
|
|
| Cases where there are set_ATTR_on() and set_ATTR_off() methods will be |
| changed to ATTR_on properties. |
|
|
| Examples |
| ======== |
|
|
| axes.Axes.set_axis_off/set_axis_on |
| ---------------------------------- |
|
|
| Current implementation: :: |
| |
| axes.Axes.set_axis_off() |
| axes.Axes.set_axis_on() |
|
|
| New implementation: :: |
| |
| True = axes.Axes.axis_on |
| False = axes.Axes.axis_on |
| axes.Axes.axis_on = True |
| axes.Axes.axis_on = False |
|
|
| axes.Axes.get_xlim/set_xlim and get_autoscalex_on/set_autoscalex_on |
| ------------------------------------------------------------------- |
|
|
| Current implementation: :: |
| |
| [left, right] = axes.Axes.get_xlim() |
| auto = axes.Axes.get_autoscalex_on() |
|
|
| [left, right] = axes.Axes.set_xlim(left=left, right=right, emit=emit, auto=auto) |
| [left, right] = axes.Axes.set_xlim(left=left, right=None, emit=emit, auto=auto) |
| [left, right] = axes.Axes.set_xlim(left=None, right=right, emit=emit, auto=auto) |
| [left, right] = axes.Axes.set_xlim(left=left, emit=emit, auto=auto) |
| [left, right] = axes.Axes.set_xlim(right=right, emit=emit, auto=auto) |
|
|
| axes.Axes.set_autoscalex_on(auto) |
|
|
| New implementation: :: |
| |
| [left, right] = axes.Axes.axes_xlim |
| auto = axes.Axes.autoscalex_on |
|
|
| axes.Axes.axes_xlim = [left, right] |
| axes.Axes.axes_xlim = [left, None] |
| axes.Axes.axes_xlim = [None, right] |
| axes.Axes.axes_xlim[0] = left |
| axes.Axes.axes_xlim[1] = right |
|
|
| axes.Axes.autoscalex_on = auto |
|
|
| axes.Axes.emit_xlim = emit |
|
|
| axes.Axes.get_title/set_title |
| ----------------------------- |
|
|
| Current implementation: :: |
| |
| string = axes.Axes.get_title() |
| axes.Axes.set_title(string, fontdict=fontdict, **kwargs) |
|
|
| New implementation: :: |
| |
| string = axes.Axes.title |
| string = axes.Axes.title_text.text |
|
|
| text.Text = axes.Axes.title_text |
| text.Text.<attribute> = attribute |
| text.Text.fontdict = fontdict |
|
|
| axes.Axes.title = string |
| axes.Axes.title = text.Text |
| axes.Axes.title_text = string |
| axes.Axes.title_text = text.Text |
|
|
| axes.Axes.get_xticklabels/set_xticklabels |
| ----------------------------------------- |
|
|
| Current implementation: :: |
| |
| [text.Text] = axes.Axes.get_xticklabels() |
| [text.Text] = axes.Axes.get_xticklabels(minor=False) |
| [text.Text] = axes.Axes.get_xticklabels(minor=True) |
| [text.Text] = axes.Axes.([string], fontdict=None, **kwargs) |
| [text.Text] = axes.Axes.([string], fontdict=None, minor=False, **kwargs) |
| [text.Text] = axes.Axes.([string], fontdict=None, minor=True, **kwargs) |
|
|
| New implementation: :: |
| |
| [text.Text] = axes.Axes.xticklabels |
| [text.Text] = axes.Axes.xminorticklabels |
| axes.Axes.xticklabels = [string] |
| axes.Axes.xminorticklabels = [string] |
| axes.Axes.xticklabels = [text.Text] |
| axes.Axes.xminorticklabels = [text.Text] |
|
|
| Alternatives |
| ============ |
|
|
| Instead of using decorators, it is also possible to use the property |
| function. This would change the procedure so that all getter methods |
| that lack a prefix will need to be renamed or removed. This makes |
| handling docstrings more difficult and harder to read. |
|
|
| It is not necessary to deprecate the setter and getter methods, but |
| leaving them in will complicate the code. |
|
|
| This could also serve as an opportunity to rewrite or even remove |
| automatic alias generation. |
|
|
| Another alternate proposal: |
|
|
| Convert ``set_xlim``, ``set_xlabel``, ``set_title``, etc. to ``xlim``, |
| ``xlabel``, ``title``,... to make the transition from ``plt`` |
| functions to ``axes`` methods significantly simpler. These would still |
| be methods, not properties, but it's still a great usability |
| enhancement while retaining the interface. |
|
|
