Use latex in plots when using tikzDevice

7 files changed, 29 insertions, 5 deletions

diff --git a/.Rbuildignore b/.Rbuildignore
index b037b763..c491eb32 100644
--- a/.Rbuildignore
+++ b/.Rbuildignore
@@ -9,6 +9,7 @@
 ^docs/*
 ^vignettes/.build.timestamp$
 ^vignettes/*_cache$
+^vignettes/*cache$
 ^vignettes/*_files$
 ^vignettes/*.aux$
 ^vignettes/*.bbl$
diff --git a/DESCRIPTION b/DESCRIPTION
index 1a29ec35..b3b0d22d 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -18,7 +18,7 @@ Description: Calculation routines based on the FOCUS Kinetics Report (2006,
   purpose.
 Depends: minpack.lm, rootSolve, inline, parallel
 Imports: stats, graphics, methods, FME, deSolve, R6
-Suggests: knitr, testthat, microbenchmark, ggplot2
+Suggests: knitr, testthat, microbenchmark, ggplot2, tikzDevice
 License: GPL
 LazyLoad: yes
 LazyData: yes
diff --git a/NAMESPACE b/NAMESPACE
index 3c71a845..458d5310 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -20,3 +20,4 @@ import(
 importFrom(deSolve, ode)
 importFrom(methods, signature)
 importFrom(R6, R6Class)
+importFrom(grDevices, dev.cur)
diff --git a/R/plot.mkinfit.R b/R/plot.mkinfit.R
index 3df6c81c..b42ce097 100644
--- a/R/plot.mkinfit.R
+++ b/R/plot.mkinfit.R
@@ -172,8 +172,15 @@ plot.mkinfit <- function(x, fit = x,
         }
       }
 
-      chi2 <- paste0(signif(100 * mkinerrmin(fit)[errmin_var, "err.min"], errmin_digits), "%")
-      mtext(bquote(chi^2 ~ "error level" == .(chi2)), cex = 0.7, line = 0.4)
+      chi2 <- signif(100 * mkinerrmin(fit)[errmin_var, "err.min"], errmin_digits)
+      # Use LateX if the current plotting device is tikz
+      if (names(dev.cur()) == "tikz output") {
+        chi2_text <- paste0("$\\chi^2$ error level = ", chi2, "\\%")
+      } else {
+        chi2_perc <- paste0(chi2, "%")
+        chi2_text <- bquote(chi^2 ~ "error level" == .(chi2_perc))
+      }
+      mtext(chi2_text, cex = 0.7, line = 0.4)
     }
 
     # Show residuals if requested
diff --git a/R/plot.mmkin.R b/R/plot.mmkin.R
index 562bbb71..ee7075d3 100644
--- a/R/plot.mmkin.R
+++ b/R/plot.mmkin.R
@@ -79,8 +79,16 @@ plot.mmkin <- function(x, main = "auto", legends = 1, errmin_var = "All data", e
                        datasets = colnames(x)[i.fit],
                        none = "")
 
-    chi2 <- paste0(signif(100 * mkinerrmin(fit)[errmin_var, "err.min"], errmin_digits), "%")
-    mtext(bquote(.(fit_name) ~ chi^2 ~ "error level" == .(chi2)), cex = cex, line = 0.4)
+    chi2 <- signif(100 * mkinerrmin(fit)[errmin_var, "err.min"], errmin_digits)
+
+    # Use LateX if the current plotting device is tikz
+    if (names(dev.cur()) == "tikz output") {
+      chi2_text <- paste0(fit_name, " $\\chi^2$ error level = ", chi2, "\\%")
+    } else {
+      chi2_perc <- paste0(chi2, "%")
+      chi2_text <- bquote(.(fit_name) ~ chi^2 ~ "error level" == .(chi2_perc))
+    }
+    mtext(chi2_text, cex = cex, line = 0.4)
 
     mkinresplot(fit, legend = FALSE, ...)
     mtext(paste(fit_name, "residuals"), cex = cex, line = 0.4)
diff --git a/man/plot.mkinfit.Rd b/man/plot.mkinfit.Rd
index a54bbbf6..42f2559c 100644
--- a/man/plot.mkinfit.Rd
+++ b/man/plot.mkinfit.Rd
@@ -8,6 +8,10 @@
   Solves the differential equations with the optimised and fixed parameters
   from a previous successful call to \code{\link{mkinfit}} and plots
   the observed data together with the solution of the fitted model.
+
+  If the current plot device is a \code{\link[tikzDevice]{tikz}} device,
+  then latex is being used for the formatting of the chi2 error level, 
+  if \code{show_errmin = TRUE}.
 }
 \usage{
 \method{plot}{mkinfit}(x, fit = x,
diff --git a/man/plot.mmkin.Rd b/man/plot.mmkin.Rd
index 7f3460d3..23f35c4b 100644
--- a/man/plot.mmkin.Rd
+++ b/man/plot.mmkin.Rd
@@ -7,6 +7,9 @@
   When x is a row selected from an mmkin object (\code{\link{[.mmkin}}), the same model
   fitted for at least one dataset is shown. When it is a column, the fit of at least one model
   to the same dataset is shown.
+
+  If the current plot device is a \code{\link[tikzDevice]{tikz}} device,
+  then latex is being used for the formatting of the chi2 error level.
 }
 \usage{
 \method{plot}{mmkin}(x, main = "auto", legends = 1, errmin_var = "All data", errmin_digits = 3,