Heatmap with continuous rainbow colours

Question

First of all I have to say that I read many threads about heatmap and ggplot2 here in stackoverflow and elsewhere. But my problem isn\'t solved yet.

I have got the foll

Answer 1

ggheatmap <- ggplot(data = dat.plot, aes(x=Var1, y=Var2, fill=value)) + 
  geom_raster(interpolate=TRUE)+
  scale_fill_gradientn(colors=rev(c("darkred", "red", "orange", "yellow",    "green", "lightgreen", "lightblue", "darkblue")))+
  theme(axis.text.x = element_text(angle = 0))+ 
  coord_fixed()
print(ggheatmap)

Now it looks blurred. But o.k. If you think it can't be done better, I let it as it is. Thank you very much!