First commit

.gitignore

@@ -0,0 +1,7 @@
+.Rproj.user
+.Rhistory
+.RData
+.Ruserdata
+*.jpg
+*.png
+*.Rproj

README.md

@@ -0,0 +1,34 @@
+# The Travelling Salesman Portrait
+
+After completing this experiment you will be able to create *one line drawing* from your favorite images. Resulting drawings are obtained using an algorithm to solve The Travelling Salesman Problem (TSP).
+
+For example, if you load this image:
+
+<img src="https://fronkonstin.com/wp-content/uploads/2018/04/frankenstein.jpg" height="400" align="middle">
+
+The resulting portrait is this one:
+
+<img src="https://fronkonstin.com/wp-content/uploads/2018/04/frankyTSP.png" height="400" align="middle">
+
+## Getting Started
+
+### Prerequisites
+
+You will need to install the following packages (if you don't have them already):
+
+```
+install.packages("imager")
+install.packages("dplyr")
+install.packages("ggplot2")
+install.packages("scales")
+install.packages("TSP")
+```
+
+## More info
+
+A complete explanation of the experiment can be found [at fronkonstin](https://fronkonstin.com/2018/04/04/the-travelling-salesman-portrait/)
+
+## Authors
+
+* **Antonio Sánchez Chinchón** - [@aschinchon](https://twitter.com/aschinchon)
+

frankenstein_TSP.R

@@ -0,0 +1,46 @@
+library(imager)
+library(dplyr)
+library(ggplot2)
+library(scales)
+library(TSP)
+
+# Download the image
+urlfile="http://ereaderbackgrounds.com/movies/bw/Frankenstein.jpg"
+
+file="frankenstein.jpg"
+if (!file.exists(file)) download.file(urlfile, destfile = file, mode = 'wb')
+
+# Load, convert to grayscale, filter image (to convert it to bw) and sample
+load.image(file) %>% 
+  grayscale() %>%
+  threshold("45%") %>% 
+  as.cimg() %>% 
+  as.data.frame()  %>% 
+  sample_n(8000, weight=(1-value)) %>% 
+  select(x,y) -> data
+
+# Compute distances and solve TSP (it may take a minute)
+as.TSP(dist(data)) %>% 
+  solve_TSP(method = "arbitrary_insertion") %>% 
+  as.integer() -> solution
+
+# Create a dataframe with the output of TSP
+data.frame(id=solution) %>% 
+  mutate(order=row_number()) -> order
+
+# Rearrange the original points according the TSP output
+data %>% 
+  mutate(id=row_number()) %>% 
+  inner_join(order, by="id") %>% arrange(order) %>% 
+  select(x,y) -> data_to_plot
+
+# A little bit of ggplot to plot results
+ggplot(data_to_plot, aes(x,y)) +
+    geom_path() +
+    scale_y_continuous(trans=reverse_trans())+
+    coord_fixed()+
+    theme_void()
+
+# Do you like the result? Save it! (Change the filename if you want)
+ggsave("frankyTSP.png", dpi=600, width = 4, height = 5)
+