---
title: "Debugging with False Colours"
output: rmarkdown::html_vignette
vignette: >
  %\VignetteIndexEntry{Debugging with False Colours}
  %\VignetteEngine{knitr::rmarkdown}
  %\VignetteEncoding{UTF-8}
---

```{r, include = FALSE}
knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>",
  fig.height = 5, 
  fig.width = 5
)
set.seed(1)
```

```{r setup}
library(svgparser)
```

# Introduction

Sometimes when debugging an issue with an SVG it can be difficult to distinguish
adjacent areas that are similarly coloured.

`svgparser::read_svg()` allows you to specify the name of a false colour palette
which can be used to on the issues - or at least look like a 
work of Warhollian [pop art](https://en.wikipedia.org/wiki/Pop_art) while you try and figure it out!

# How

Simply set the `false_colour` argument to `svgparser::read_svg()` to one of:
'rainbow', 'hcl', 'heat', 'terrain', 'topo', and 'cm'.

`svgparser` will then sample randomly from these standard R colour palettes 
instead of using the correct colour.


## `Original Image


```{r}
tiger_filename <- system.file("tiger.svg", package = "svgparser")
tiger_grob <- svgparser::read_svg(tiger_filename)
grid::grid.draw(tiger_grob)
```

## `false_colour = 'rainbow'`


```{r}
tiger_filename <- system.file("tiger.svg", package = "svgparser")
tiger_grob <- svgparser::read_svg(tiger_filename, false_colour = 'rainbow')
grid::grid.draw(tiger_grob)
```


## `false_colour = 'hcl'`

```{r}
tiger_filename <- system.file("tiger.svg", package = "svgparser")
tiger_grob <- svgparser::read_svg(tiger_filename, false_colour = 'hcl')
grid::grid.draw(tiger_grob)
```


## `false_colour = 'heat'`

```{r}
tiger_filename <- system.file("tiger.svg", package = "svgparser")
tiger_grob <- svgparser::read_svg(tiger_filename, false_colour = 'heat')
grid::grid.draw(tiger_grob)
```


## `false_colour = 'terrain'`

```{r}
tiger_filename <- system.file("tiger.svg", package = "svgparser")
tiger_grob <- svgparser::read_svg(tiger_filename, false_colour = 'terrain')
grid::grid.draw(tiger_grob)
```