Rotate scale bar

.github/workflows/ci.yml

@@ -35,7 +35,7 @@ jobs:
           python -m pip install --upgrade pip codecov
           pip install --upgrade -e .
           pip install -r requirements-test.txt
-      - name: Test with nose
-        run: nosetests
+      - name: Test
+        run: pytest
       - name: Upload coverage to Codecov
         uses: codecov/codecov-action@v1

README.md

@@ -0,0 +1,362 @@
+# matplotlib-scalebar
+
+![CI](https://github.com/ppinard/matplotlib-scalebar/workflows/CI/badge.svg)
+![PyPI](https://img.shields.io/pypi/v/matplotlib-scalebar)
+
+Provides a new artist for [matplotlib](https://matplotlib.org) to display a scale bar, aka micron bar.
+It is particularly useful when displaying calibrated images plotted using
+`plt.imshow(...)`.
+
+![Example of scale bar](doc/splashscreen.png)
+
+The artist supports customization either directly from the **ScaleBar** object or from the matplotlibrc.
+
+## Installation
+
+Easiest way to install using `pip`:
+
+```bash
+pip install matplotlib-scalebar
+```
+
+For development installation from the git repository:
+
+```bash
+git clone [email protected]:ppinard/matplotlib-scalebar.git
+pip install -e matplotlib-scalebar
+```
+
+## Getting started
+
+There are many ways to customize the scale bar.
+Examples and explanations of the arguments of the **ScaleBar** class are given [below](#scalebar-arguments), but here is a quick start guide.
+
+The constructor arguments *dx* and *units* specify the pixel dimension.
+For example `ScaleBar(0.2, 'um')` indicates that each pixel is equal to 0.2 micrometer.
+By default, the scale bar uses SI units of length (e.g. m, cm, um, km, etc.).
+See examples below for other system of units.
+
+In this example, we load a sample image from the matplotlib library, create a subplot, plot image, create scale bar and add scale bar as an "artist" of the subplot.
+
+```python
+import numpy as np
+import matplotlib.pyplot as plt
+import matplotlib.cbook as cbook
+from matplotlib_scalebar.scalebar import ScaleBar
+
+# Load image
+with cbook.get_sample_data("s1045.ima.gz") as dfile:
+    im = np.frombuffer(dfile.read(), np.uint16).reshape((256, 256))
+
+# Create subplot
+fig, ax = plt.subplots()
+ax.axis("off")
+
+# Plot image
+ax.imshow(im, cmap="gray")
+
+# Create scale bar
+scalebar = ScaleBar(0.08, "cm", length_fraction=0.25)
+ax.add_artist(scalebar)
+
+# Show
+plt.show()
+```
+
+![Example of scale bar](doc/getting_started.png)
+
+## ScaleBar arguments
+
+Here are arguments of the **ScaleBar** class constructor and examples how to use them.
+
+```python
+scalebar = ScaleBar(
+        dx,
+        units="m",
+        dimension="si-length",
+        label=None,
+        length_fraction=None,
+        height_fraction=None,
+        width_fraction=None,
+        location=None,
+        pad=None,
+        border_pad=None,
+        sep=None,
+        frameon=None,
+        color=None,
+        box_color=None,
+        box_alpha=None,
+        scale_loc=None,
+        label_loc=None,
+        font_properties=None,
+        label_formatter=None,
+        scale_formatter=None,
+        fixed_value=None,
+        fixed_units=None,
+        animated=False,
+        rotation=None,
+    )
+```
+
+Each argument can also be changed afterwards using their respective property.
+
+```python
+scalebar.dx = 2.0
+```
+
+The following schematic illustrates the nomenclature used in the definition of the arguments.
+
+![nomenclature](doc/nomenclature.png)
+
+### dx (required)
+
+Size of one pixel in *units* specified by the next argument.
+
+Set *dx* to 1.0 if the axes image has already been calibrated by setting its *extent*.
+
+```python
+fig, ax = plt.subplots()
+ax.axis("off")
+
+ax.imshow(im, cmap="gray", extent=[0, 20.48, 0, 20.48])
+
+scalebar = ScaleBar(1, "cm", length_fraction=0.25)
+ax.add_artist(scalebar)
+```
+
+![dx with extent](doc/argument_dx.png)
+
+**Special notes for geospatial plots**:
+If you are plotting geospatial coordinates (such as scatterplots of the location of structures, [geopandas](http://geopandas.org) geodataframe plots, etc.), *dx* needs to be set differently depending on the coordinate system:
+
+* For UTM based coordinate system, where the X and Y are in meters, simply set `dx = 1`.
+* For WGS or NAD based coordinate system, where X and Y are in latitude (Y) and longitude (X), compute the distance between two points at the latitude (Y) you wish to have the scale represented and are also one full degree of longitude (X) apart, in meters. For example, `dx = great_circle_distance((X, Y), (X + 1, Y))`
+
+### units
+
+Units of *dx*.
+The units needs to be valid for the specified *dimension*.
+Default: `m`.
+
+### dimension
+
+Dimension of *dx* and *units*. It can either be equal:
+
+* `si-length` (default): scale bar showing km, m, cm, etc.
+* `imperial-length`: scale bar showing in, ft, yd, mi, etc.
+* `si-length-reciprocal`: scale bar showing 1/m, 1/cm, etc.
+* `pixel-length`: scale bar showing px, kpx, Mpx, etc.
+* `angle`: scale bar showing °, ʹ (minute of arc) or ʹʹ (second of arc)
+* a `matplotlib_scalebar.dimension._Dimension` object
+
+```python
+fig, ax = plt.subplots()
+ax.axis("off")
+
+ax.imshow(im, cmap="gray")
+
+scalebar = ScaleBar(0.0315, "in", dimension="imperial-length", length_fraction=0.25)
+ax.add_artist(scalebar)
+```
+
+![imperial dimension](doc/argument_dimension.png)
+
+### label
+
+Optional label associated with the scale bar.
+Default: `None`, no label is shown.
+The position of the label with respect to the scale bar can be adjusted using *label_loc* argument.
+
+### length_fraction
+
+Desired length of the scale bar as a fraction of the subplot's width.
+Default: `None`, value from matplotlibrc or `0.2`.
+The actual length of the scale bar is automatically determined based on the specified pixel size (*dx* and *units*) and the contraint that the scale value can only take the following numbers: 1, 2, 5, 10, 15, 20, 25, 50, 75, 100, 125, 150, 200, 500 or 750.
+If you want a specific value, see [*fixed_value*](#fixed_value) and [*fixed_units*](#fixed_units).
+
+In the example below, the scale bar for a *length_fraction* of 0.25 and 0.5 is the same because the scale cannot have a value between 2 and 5 mm.
+
+![length fraction](doc/argument_length_fraction.png)
+
+### height_fraction
+
+**Deprecated**, use *width_fraction*.
+
+### width_fraction
+
+Width of the scale bar as a fraction of the subplot's height.
+Default: `None`, value from matplotlibrc or `0.01`.
+
+### location
+
+A location code, same as matplotlib's legend, either: `upper right`, `upper left`, `lower left`, `lower right`, `right`, `center left`, `center right`, `lower center`, `upper center` or `center`.
+Default: `None`, value from matplotlibrc or `upper right`.
+
+### loc
+
+Alias for *location*.
+
+### pad
+
+Padding inside the box, as a fraction of the font size.
+Default: `None`, value from matplotlibrc or `0.2`.
+
+### border_pad
+
+Padding outside the box, fraction of the font size.
+Default: `None`, value from matplotlibrc or `0.1`.
+
+### sep
+
+Separation in points between the scale bar and scale, and between the scale bar and label.
+Default: `None`, value from matplotlibrc or `5`.
+
+### frameon
+
+Whether to draw a box behind the scale bar, scale and label.
+Default: `None`, value from matplotlibrc or `True`.
+
+### color
+
+Color for the scale bar, scale and label.
+Default: `None`, value from matplotlibrc or `k` (black).
+
+### box_color
+
+Background color of the box.
+Default: `None`, value from matplotlibrc or `w` (white).
+
+### box_alpha
+
+Transparency of box.
+Default: `None`, value from matplotlibrc or `1.0` (opaque).
+
+### scale_loc
+
+Location of the scale with respect to the scale bar.
+Either `bottom`, `top`, `left`, `right`.
+Default: `None`, value from matplotlibrc or `bottom`.
+
+![scale_loc](doc/argument_scale_loc.png)
+
+### label_loc
+
+Location of the label with respect to the scale bar.
+Either `bottom`, `top`, `left`, `right`.
+Default: `None`, value from matplotlibrc or `top`.
+
+### font_properties
+
+Font properties of the scale and label text, specified either as `dict` or `str`.
+See [`FontProperties`](https://matplotlib.org/api/font_manager_api.html#matplotlib.font_manager.FontProperties) for the arguments.
+Default: `None`, default font properties of matplotlib.
+
+### label_formatter
+
+**Deprecated**, use *scale_formatter*.
+
+### scale_formatter
+
+Custom function called to format the scale.
+Needs to take 2 arguments - the scale value and the unit.
+Default: `None` which results in
+
+```python
+scale_formatter = lambda value, unit: f"{value} {unit}"
+```
+
+### fixed_value
+
+Value for the scale.
+The length of the scale bar is calculated based on the specified pixel size *dx*.
+Default: `None`, the value is automatically determined based on *length_fraction*.
+
+### fixed_units
+
+Units of the *fixed_value*.
+Default: `None`, if *fixed value* is not `None`, the units of *dx* are used.
+
+### animated
+
+Animation state.
+Default: `False`
+
+### rotation
+
+Whether to create a scale bar based on the x-axis (default) or y-axis.
+*rotation* can either be `horizontal` or `vertical`.
+Note you might have to adjust *scale_loc* and *label_loc* to achieve desired layout.
+Default: `None`, value from matplotlibrc or `horizontal`.
+
+```python
+fig, ax = plt.subplots()
+ax.axis("off")
+
+ax.imshow(im, cmap="gray")
+
+scalebar = ScaleBar(
+    0.08,
+    "cm",
+    length_fraction=0.25,
+    rotation="vertical",
+    scale_loc="right",
+    border_pad=1,
+    pad=0.5,
+)
+ax.add_artist(scalebar)
+```
+
+![rotation](doc/argument_rotation.png)
+
+## Release notes
+
+### dev
+
+* Add rotation to display scale bar for the y-axis (#30)
+* New documentation (#32)
+* Deprecate argument *height_fraction*, replaced by *width_fraction* (#32)
+* Deprecate argument *label_formatter*, replaced by *scale_formatter* (#32)
+* Add alias *loc* for *location* (#32)
+
+### 0.6.2
+
+* Fix reciprocal unit (#29)
+
+### 0.6.1
+
+* Add notes about for geospatial plots (#20)
+
+### 0.6.0
+
+* Add angular units (#19)
+* Add blit support and fix documentation (#22)
+* Fix issue with getting the wrong preferred values for the scale bar (#23)
+* Package LICENSE file to distribution (#24)
+
+### 0.5.1
+
+* Remove leftover print statement (#18)
+
+### 0.5.0
+
+* Add pixel unit (#12)
+* Display micro symbol in text mode (#15)
+* Fix error in length of scale bar (#14), the bar was drawn with an edge around it which made it longer than the actual size.
+
+### 0.4.1
+
+* Fix deprecated usage of is_string_like (#11)
+
+### 0.4.0
+
+* Add possibility to specified a fixed value for the scale bar (#9))
+
+## Contributors
+
+@maweigert, @crosbyla, @joschkazj, @AKuederle, @habi, @huangziwei,@SirJohnFranklin, @alexandrejaguar, @parishcm, @wiai, @cosmicshear,@ericore, @seangrogan, @PhilipeRLeal, @din14970
+
+## License
+
+License under the BSD License, compatible with matplotlib.
+
+Copyright (c) 2015-2021 Philippe Pinard