Free scale facet axes

R/facet.R

@@ -152,7 +152,7 @@ draw_facet_window = function(grid, ...) {
         if (!(nfacet_rows == 2 && nfacet_cols == 2)) fmar = fmar * .75
       }
       # Extra reduction if no plot frame to reduce whitespace
-      if (isFALSE(frame.plot)) {
+      if (isFALSE(frame.plot) && !isTRUE(facet.args[["free"]])) {
         fmar = fmar - 0.5
       }
 
@@ -236,9 +236,54 @@ draw_facet_window = function(grid, ...) {
         yside = 2
       }
 
+
       # axes, frame.plot and grid
-      if (isTRUE(axes)) {
-        if (isTRUE(frame.plot)) {
+      if (isTRUE(axes) || isTRUE(facet.args[["free"]])) {
+
+        if (isTRUE(facet.args[["free"]]) && (par("xlog") || par("ylog"))) {
+          warning(
+            "\nFree scale axes for faceted plots are currently not supported if the axes are logged. Reverting back to fixed scales.",
+            "\nIf support for this feature is important to you, please raise an issue on our GitHub repo:",
+            "\nhttps://github.com/grantmcdermott/tinyplot/issues\n"
+          )
+          facet.args[["free"]] = FALSE
+        }
+
+        # Special logic if facets are free...
+        if (isTRUE(facet.args[["free"]])) {
+          # First, we need to calculate the plot extent and axes range of each
+          # individual facet.
+          xfree = split(c(x, xmin, xmax), facet)[[ii]]
+          yfree = split(c(y, ymin, ymax), facet)[[ii]]
+          xlim = range(xfree, na.rm = TRUE) 
+          ylim = range(yfree, na.rm = TRUE)
+          xext = extendrange(xlim, f = 0.04)
+          yext = extendrange(ylim, f = 0.04)
+          # We'll save this in a special .fusr env var (list) that we'll re-use
+          # when it comes to plotting the actual elements later
+          if (ii==1) {
+            fusr = replicate(4, vector("double", length = nfacets), simplify = FALSE)
+            assign(".fusr", fusr, envir = get(".tinyplot_env", envir = parent.env(environment())))
+          }
+          fusr = get(".fusr", envir = get(".tinyplot_env", envir = parent.env(environment())))
+          fusr[[ii]] = c(xext, yext)
+          assign(".fusr", fusr, envir = get(".tinyplot_env", envir = parent.env(environment())))
+          # Explicitly set (override) the current facet extent
+          par(usr = fusr[[ii]])
+          # if plot frame is true then print axes per normal...
+          if (type %in% c("pointrange", "errorbar", "ribbon", "boxplot", "p") && !is.null(xlabs)) {
+            tinyAxis(xfree, side = xside, at = xlabs, labels = names(xlabs), type = xaxt)
+          } else {
+            tinyAxis(xfree, side = xside, type = xaxt)
+          }
+          if (isTRUE(flip) && type %in% c("pointrange", "errorbar", "ribbon", "boxplot", "p") && !is.null(ylabs)) {
+            tinyAxis(yfree, side = yside, at = ylabs, labels = names(ylabs), type = yaxt)
+          } else {
+            tinyAxis(yfree, side = yside, type = yaxt)
+          }
+
+        # For fixed facets we can just reuse the same plot extent and axes limits   
+        } else if (isTRUE(frame.plot)) {
           # if plot frame is true then print axes per normal...
           if (type %in% c("pointrange", "errorbar", "ribbon", "boxplot", "p") && !is.null(xlabs)) {
             tinyAxis(x, side = xside, at = xlabs, labels = names(xlabs), type = xaxt)

R/tinyplot.R

@@ -49,6 +49,11 @@
 #'   precedence if both are specified together. Ignored if a two-sided formula
 #'   is passed to the main `facet` argument, since the layout is arranged in a
 #'   fixed grid.
+#'   - `free` a logical value indicating whether the axis limits (scales) for 
+#'   each individual facet should adjust independently to match the range of 
+#'   the data within that facet. Default is `FALSE`. Separate free scaling of
+#'   the x- or y-axis (i.e., whilst holding the other axis fixed) is not
+#'   currently supported.
 #'   - `fmar` a vector of form `c(b,l,t,r)` for controlling the base margin
 #'   between facets in terms of lines. Defaults to the value of `tpar("fmar")`,
 #'   which should be `c(1,1,1,1)`, i.e. a single line of padding around each
@@ -1096,6 +1101,14 @@ tinyplot.default = function(
         mfgj = ii %% nfacet_cols
         if (mfgj == 0) mfgj = nfacet_cols
         par(mfg = c(mfgi, mfgj))
+
+        # For free facets, we need to reset par(usr) based extent of that
+        # particular facet... which we calculated and saved to the .fusr env var
+        # (list) back in draw_facet_window()
+        if (isTRUE(facet.args[["free"]])) {
+          fusr = get(".fusr", envir = get(".tinyplot_env", envir = parent.env(environment())))
+          par(usr = fusr[[ii]])
+        }
       }
 
       # empty plot flag