Fix plot zoom

DESCRIPTION

@@ -65,6 +65,7 @@ Collate:
     'ternary_segments.R'
     'ternary_text.R'
     'ternary_title.R'
+    'ternary_window.R'
     'triangle_phase.R'
     'triangle_soil.R'
     'zzz.R'

R/AllGenerics.R

@@ -76,11 +76,11 @@ setGeneric(
 #'  interpret `x` in a suitable way (see [grDevices::xyz.coords()]).
 #' @param center A [`logical`] scalar: should the data be centered?
 #' @param scale A [`logical`] scalar: should the data be scaled?
-#' @param xlim A length-two [`numeric`] vector giving the `x` limits in the
+#' @param xlim A length-three [`numeric`] vector giving the `x` limits in the
 #'  range \eqn{[0,1]}.
-#' @param ylim A length-two [`numeric`] vector giving the `y` limits in the
+#' @param ylim A length-three [`numeric`] vector giving the `y` limits in the
 #'  range \eqn{[0,1]}.
-#' @param zlim A length-two [`numeric`] vector giving the `z` limits in the
+#' @param zlim A length-three [`numeric`] vector giving the `z` limits in the
 #'  range \eqn{[0,1]}.
 #' @param xlab,ylab,zlab A [`character`] string giving a label for the x, y and
 #'  z axes.

R/ternary_plot.R

@@ -30,23 +30,9 @@ setMethod(
     graphics::plot.new()
 
     ## Set plotting coordinates
-    if (is.null(xlim) && is.null(ylim) && is.null(zlim)) {
-      dx <- max(graphics::strwidth(c(xlab, ylab, zlab), cex = cex.lab)) / 2
-      rx <- expand_range(c(0, 1), add = dx)
-      lim <- list(
-        x = rx,
-        y = .top / 2 + c(-1, 1) * diff(rx) / 2
-      )
-    } else {
-      xrange <- yrange <- zrange <- NULL
-      if (!is.null(xlim)) xrange <- boundary(1, xlim)
-      if (!is.null(ylim)) yrange <- boundary(2, ylim)
-      if (!is.null(zlim)) zrange <- boundary(3, zlim)
-      lim <- coordinates_ternary(rbind(xrange, yrange, zrange))
-      lim$x <- range(lim$x)
-      lim$y <- range(lim$y)
-    }
-    graphics::plot.window(xlim = lim$x, ylim = lim$y, asp = 1)
+    ternary_window(xlim = xlim, ylim = ylim, zlim = zlim,
+                   xlab = xlab, ylab = ylab, zlab = zlab,
+                   cex = cex.lab)
 
     ## Reset center and scale
     options(isopleuros.center = NULL)
@@ -122,13 +108,3 @@ setMethod(
     invisible(pt)
   }
 )
-
-boundary <- function(side, limits) {
-  limits <- range(limits)
-  side_min <- diag(1, 3, 3) - limits[1L]
-  side_max <- diag(1, 3, 3) - limits[2L]
-  side_range <- rbind(side_min, side_max)
-  side_range[side_range < 0] <- 0
-  side_range[, side] <- rep(limits, each = 3)
-  side_range[rowSums(side_range) == 1, ]
-}

R/ternary_window.R

@@ -0,0 +1,51 @@
+# TERNARY WINDOW
+#' @include AllGenerics.R
+NULL
+
+#' Set up Ternary Coordinates for Graphics Window
+#'
+#' @param xlim A length-three [`numeric`] vector giving the `x` limits in the
+#'  range \eqn{[0,1]}.
+#' @param ylim A length-three [`numeric`] vector giving the `y` limits in the
+#'  range \eqn{[0,1]}.
+#' @param zlim A length-three [`numeric`] vector giving the `z` limits in the
+#'  range \eqn{[0,1]}.
+#' @param xlab,ylab,zlab A [`character`] string giving a label for the x, y and
+#'  z axes.
+#' @return
+#'  `ternary_window()` is called it for its side-effects
+#'  (see [graphics::plot.window()]).
+#' @keywords internal
+#' @noRd
+ternary_window <- function(xlim = NULL, ylim = NULL, zlim = NULL,
+                           xlab = NULL, ylab = NULL, zlab = NULL,
+                           cex = 1) {
+
+  n_null <- is.null(xlim) + is.null(ylim) + is.null(zlim)
+
+  if (n_null == 3) {
+    dx <- max(graphics::strwidth(c(xlab, ylab, zlab), cex = cex)) / 2
+    rx <- expand_range(c(0, 1), add = dx)
+    lim <- list(
+      x = rx,
+      y = .top / 2 + c(-1, 1) * diff(rx) / 2
+    )
+  }
+  if (n_null == 2) {
+    stop("You must provide at least two coordinates ranges.", call. = FALSE)
+  }
+  if (n_null < 2) {
+    xlims <- if (is.null(xlim)) 1 - ylim - zlim else xlim
+    ylims <- if (is.null(ylim)) 1 - xlim - zlim else ylim
+    zlims <- if (is.null(zlim)) 1 - xlim - ylim else zlim
+
+    assert_length(xlims, 3)
+    assert_length(ylims, 3)
+    assert_length(zlims, 3)
+
+    lim <- coordinates_ternary(abs(xlims), abs(ylims), abs(zlims))
+    lim$x <- range(lim$x)
+    lim$y <- range(lim$y)
+  }
+  graphics::plot.window(xlim = lim$x, ylim = lim$y, asp = 1)
+}

inst/examples/ex-plot.R

@@ -15,9 +15,12 @@ ternary_plot(coda, pch = 16, col = "red")
 ternary_plot(coda, panel.first = ternary_grid(5, 10))
 
 ## Zoom
-ternary_plot(coda, xlim = c(0.5, 1), panel.first = ternary_grid())
-ternary_plot(coda, ylim = c(0.5, 1), panel.first = ternary_grid())
-ternary_plot(coda, zlim = c(0.5, 1), panel.first = ternary_grid())
+ternary_plot(coda, ylim = c(0, 0.4, 0), zlim = c(0, 0, 0.4),
+             panel.first = ternary_grid())
+ternary_plot(coda, xlim = c(0, 0.4, 0), zlim = c(0, 0, 0.4),
+             panel.first = ternary_grid())
+ternary_plot(coda, xlim = c(0.4, 0, 0), ylim = c(0, 0.4, 0),
+             panel.first = ternary_grid())
 
 ## Color according to a supplementary variable
 ## Data from Aitchison 1986