ggplot: line styles and width

[pedrodz]

Summary:

• Fix typo in line style mapping (dotted -> dot);
• Add multiplier (2x) for converting line size from ggplot2 to line width in Plotly;
• Fix some tests. For example, they were using dotted line type - there's no such thing in Plotly; and,
• Some styling.

Line width default was 2, that means when line size was not defined, an 1 in ggplot2 was a 2 in Plotly. Now when size was defined it had the same value in Plotly, when it should be 2x - a 1.5 in ggplot2 should be a 3 in Plotly.
ggplot2: http://www.cookbook-r.com/Graphs/Bar_and_line_graphs_%28ggplot2%29/line-red-dotted-shape.png):
Plotly before: https://plot.ly/~pdespouy/1807
Plotly after: https://plot.ly/~pdespouy/1806

[pedrodz]

Images can be find here: a6d3230. There's a lot of plots that don't look good, but they were fixed with the following commits: 529a277 and 563b0c4. Bottom line, the only image that changed is tests/testthat/test-ggplot-abline-plotly.png, where the markers size got fixed with commit 529a277 - see 64e75ae.

/cc @mkcor

[chriddyp]

Looking good! Is it possible to see how the cookbook examples changed?

[pedrodz]

Good idea. OK, retrieved the plots that changed: 275f6ad (lines.R) and bfaf60e (bars_and_lines.R)
Thank you, @chriddyp!

[pedrodz]

If you wonder why geom_density2d(), geom_step() and geom_contour() size/width went from 2 to 1: that's because the default value in ggplot2 is 0.5. See:
https://github.com/hadley/ggplot2/blob/4bb9270ef4d5d5062353438fd99d17b6f6de98a2/R/geom-path-density2d.r#L28
https://github.com/hadley/ggplot2/blob/4bb9270ef4d5d5062353438fd99d17b6f6de98a2/R/geom-path-contour.r#L21
https://github.com/hadley/ggplot2/blob/4bb9270ef4d5d5062353438fd99d17b6f6de98a2/R/geom-path-step.r#L39

[chriddyp]

Looking good!

[chriddyp]

💃