63 lines
1.5 KiB
Plaintext
63 lines
1.5 KiB
Plaintext
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---
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title: "Regular polygons and ellipses in grid graphics"
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author: "Baptiste Auguie"
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date: '`r Sys.Date()`'
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vignette: >
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%\VignetteEngine{knitr::rmarkdown}
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%\VignetteIndexEntry{ngonGrob: regular polygons and ellipses in grid graphics}
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output:
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knitr:::html_vignette:
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toc: yes
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---
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```{r setup, echo=FALSE, results='hide'}
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library(knitr)
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opts_chunk$set(message=FALSE, fig.width=4, fig.height=3)
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```
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The `gridExtra` package provides a basic implementation of regular polygons, `ngonGrob()/grid.ngon`, and a convenience function to draw ellipses, `ellipseGrob()/grid.ellipse()`. We illustrate below the basic usage of these vectorised functions.
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## Basic usage
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```{r basic}
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library(gridExtra)
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library(grid)
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library(grid)
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N <- 5
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xy <- polygon_regular(N)*2
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# draw multiple polygons
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g <- ngonGrob(unit(xy[,1],"cm") + unit(0.5,"npc"),
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unit(xy[,2],"cm") + unit(0.5,"npc"),
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n=seq_len(N)+2, gp=gpar(fill=1:N))
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grid.newpage()
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grid.draw(g)
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```
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## Rotated and stretched polygons
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```{r rotated}
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g2 <- ngonGrob(unit(xy[,1],"cm") + unit(0.5,"npc"),
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unit(xy[,2],"cm") + unit(0.5,"npc"),
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n=seq_len(N)+2, ar=seq_len(N),
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phase=0, angle=pi/(seq_len(N)+2),
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size=1:N+5, gp=gpar(fill=1:N))
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grid.newpage()
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grid.draw(g2)
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```
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## Ellipses
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```{r ellipse}
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g3 <- ellipseGrob(unit(xy[,1],"cm") + unit(0.5,"npc"),
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unit(xy[,2],"cm") + unit(0.5,"npc"),
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angle=-2*seq(0,N-1)*pi/N+pi/2,
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size=5, ar=3, gp=gpar(fill=1:N))
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grid.newpage()
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grid.draw(g3)
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```
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