patterns.py

"""
Bit and hachure patterns
========================

In addition to colors, PyGMT also allows using bit and hachure patterns to fill symbols,
polygons, and other areas, via the ``fill`` parameter or similar parameters.

Example method parameters that support bit and hachure patterns include:

- :meth:`pygmt.Figure.coast`: Land and water masses via ``land`` and ``water``
- :meth:`pygmt.Figure.histogram`: Histogram bars via ``fill``
- :meth:`pygmt.Figure.meca`: Focal mechanisms via ``compressionfill`` and
  ``extensionfill``
- :meth:`pygmt.Figure.plot`: Symbols and polygons via ``fill``
- :meth:`pygmt.Figure.rose`: Histogram sectors via ``fill``
- :meth:`pygmt.Figure.solar`: Day-light terminators via ``fill``
- :meth:`pygmt.Figure.ternary`: Symbols via ``fill``
- :meth:`pygmt.Figure.velo`: Uncertainty wedges and velocity error ellipses via
  ``uncertaintyfill``
- :meth:`pygmt.Figure.wiggle`: Anomalies via ``fillpositive`` and ``fillnegative``

GMT provides 90 predefined 1-bit patterns, which are numbered from 1 to 90. In addition,
custom 1-, 8-, or 24-bit image raster files can also be used as patterns.

Theses patterns can be specified via the :class:`pygmt.params.Pattern` class. The
patterns can be customized with different resolution and different foreground and
background colors. The foreground and background colors can also be reversed.
"""

# %%
import pygmt
from pygmt.params import Pattern

# A list of patterns that will be demonstrated.
# By default, a pattern is plotted in black and white with a resolution of 1200 dpi.
patterns = [
    # Predefined 1-bit pattern 8.
    Pattern(8),
    # Predefined 1-bit pattern 19.
    Pattern(19),
    # Pattern 19 with custom backgroud ("red3") and foreground ("lightbrown").
    Pattern(19, bgcolor="red3", fgcolor="lightbrown"),
    # Reverse the background and foreground.
    Pattern(19, reversed=True, bgcolor="red3", fgcolor="lightbrown"),
    # Same as above, but with a 100 dpi resolution.
    Pattern(19, bgcolor="red3", fgcolor="lightbrown", dpi=100),
    # Same as above, but with a transparent background by setting bgcolor to "".
    Pattern(19, bgcolor="", fgcolor="lightbrown", dpi=100),
]

fig = pygmt.Figure()
fig.basemap(
    region=[0, 10, 0, 12],
    projection="X18c/10c",
    frame="rlbt+glightgray+tBit and Hachure Patterns",
)
y = 11
for pattern in patterns:
    # Plot a square with the pattern as fill.
    # The square has a size of 2 centimeters with a 1 point thick, black outline.
    fig.plot(x=1, y=y, style="s2c", pen="1p,black", fill=pattern)
    # Add a description of the pattern.
    fig.text(x=2, y=y, text=str(repr(pattern)), font="Courier-Bold", justify="ML")
    y -= 2
fig.show()