This answer might be a bit late, but in case it helps anyone, here it goes:
An important aspect is of the mixtool package is that each input data point is actually assigned a posterior probability of belonging to one of the components that you have selected a priory (in your case 3, according to your graph). We can retrieve the data by using the following code:
yourdata <- as.data.frame(cbind(x = mixmdl$x, mixmdl$posterior))
head(post.df, 10) # Retrieve first 10 rows
And you will see the probabilities of each data point to belong to the first, second or third distribution.
An example of the probabilities for each data point in a 2 distribution to belong to the first or second distribution:
## x comp.1 comp.2
## 1 79 0.0001030875283 0.999896912472
## 2 54 0.9999093397312 0.000090660269
## 3 74 0.0041357268361 0.995864273164
## 4 62 0.9673819082244 0.032618091776
## 5 85 0.0000012235720 0.999998776428
## 6 55 0.9998100114503 0.000189988550
## 7 88 0.0000001333596 0.999999866640
## 8 85 0.0000012235720 0.999998776428
## 9 51 0.9999901530788 0.000009846921
## 10 85 0.0000012235720 0.999998776428
Data extracted from
http://tinyheero.github.io/2015/10/13/mixture-model.html)
You might find the link very useful