Rename test_pygmtlogo function to test_pygmtlogo_circle_no_wordmark and improve it

[seisman]

As shown in the table in PR #4616, we will likely have 24 PyGMT logo variants. Maintaining 24 separate baseline images is impractical, so we plan to group multiple variants into a single test. A reasonable approach is to define six tests based on logo shape and wordmark configuration. Each test would include four variants: colored and black-and-white logos in both light and dark themes.

This PR renames the existing test from test_pygmtlogo (which is too general) to test_pygmtlogo_circle_no_wordmark. It also adds a basemap to make the default logo size easier to inspect.

It appears that the default width/height of the logos is slightly smaller than 2 cm, although I am not sure why this value is used.

[seisman]

Other tests will be named like

• test_pygmtlogo_circle_horizontal_wordmark
• test_pygmtlogo_circle_vertical_wordmark
• test_pygmtlogo_hexagon_no_wordmark
• test_pygmtlogo_hexagon_horizontal_wordmark
• test_pygmtlogo_hexagon_vertical_wordmark

[seisman]

Plan to add the two black-and-white logos below the colored versions in later PRs.

[github-actions]

Summary of changed images

This is an auto-generated report of images that have changed on the DVC remote

Status	Path
added	pygmt/tests/baseline/test_pygmtlogo_circle_no_wordmark.png

Image diff(s)

Details

Added images

• test_pygmtlogo_circle_no_wordmark.png

Modified images

Path	Old	New

Report last updated at commit de990cc

[seisman]

It appears that the default width/height of the logos is slightly smaller than 2 cm, although I am not sure why this value is used.

One question, should we use the default logo size? I have no idea how the value is determined.

The default GMT logo is 2.54 cm high, and the "no label" version is close to 2 cm. Maybe we should force the PyGMT logo height to 2-cm for the no-wordmark and horizontal-wordmark version, and width to 2-cm for the vertical-wordmark version?

import pygmt
from pygmt.params import Position

fig = pygmt.Figure()
fig.basemap(region=[0, 8, 0, 2], projection="x1c", frame="g1")
fig.logo(style="no_label")
fig.pygmtlogo(position=(6, 0))
fig.show()

[yvonnefroehlich]

It appears that the default width/height of the logos is slightly smaller than 2 cm, although I am not sure why this value is used.

One question, should we use the default logo size? I have no idea how the value is determined.

The default GMT logo is 2.54 cm high, and the "no label" version is close to 2 cm. Maybe we should force the PyGMT logo height to 2-cm for the no-wordmark and horizontal-wordmark version, and width to 2-cm for the vertical-wordmark version?

Hmm. This is an interesting question! I have to think about this tomorrow in more detail to understand the behaviour.

Currently we have in _create_logo:

size = 4
region = [-size, size] * 2   # -> 8 plot-units
proj = "x1c"   # -> 1 cm per plot-units

I thougth the PyGMT logo saved to a file will have a size (diameter) of 8 cm for the circle version without wordmark.
For the PNG format (right), the default size is as expected when adding the image via Figure.image (code is at the end of the comment). But for the EPS format (left), the default size seems to be different:

---

Generating the PNG and EPS files with

size = 1
region = [-size, size] * 2
proj = "x1c"

Leads to:

---

Setting position="jMC+jMC+w2c gives:

---

Code:

import pygmt

fig = pygmt.Figure()

fig.basemap(region=[-4, 4] * 2, projection="x1c", frame=1)
fig.image(imagefile="pygmt_logo_saved_external.eps")#, position="jMC+jMC+w2c")
fig.basemap(frame="g1")

fig.shift_origin(xshift="+w+1c")

fig.basemap(region=[-4, 4] * 2, projection="x1c", frame=1)
fig.image(imagefile="pygmt_logo_saved_external.png")#, position="jMC+jMC+w2c")
fig.basemap(frame="g1")

fig.show()