gazeHeatmap & JPEG

[garyfeng]

Temporarily put gazeHeapmap() here; may want to move it out to an eye-tracking library in the future. But for now it's convenient.

It only supports PNG now. But we can easily add the JPEG library: https://cran.r-project.org/web/packages/jpeg/jpeg.pdf, which also uses a similar syntax.

[garyfeng]

m <- readJPEG("./Bones MC 1 Form 9 - Duration 5 Sec.jpg")
> dim(m)
[1] 1001 1263    3

> transparancyLevel =0.5
> if (length(dim(m))==2) {
+     # grayscale
+     g <- matrix(rgb(m, m, m, transparancyLevel), nrow=dim(m)[1])
+ } else if (dim(m)[3]==3){
+     g <- matrix(rgb(m[,,1],m[,,2],m[,,3], transparancyLevel), nrow=dim(m)[1])
+ } else if(dim(m)[3]==4){
+     g <- matrix(rgb(m[,,1],m[,,2],m[,,3],m[,,4]*transparancyLevel), nrow=dim(m)[1])
+ }
> 

> require(grDevices)
> op <- par(bg = "thistle")
> plot(c(100, 250), c(300, 450), type = "n", xlab = "", ylab = "")
> 
> rasterImage(g, 0,0,1000,1000)
par(op)