fixed problem with equal axes

R/ggplotly.R

@@ -226,7 +226,7 @@ gg2list <- function(p) {
     range.values <- if(use.ranges){
       range.name <- paste0(xy, ".range")
       sapply(built$panel$ranges, "[[", range.name)
-    }else{
+    } else{
       ## for categorical variables on the axes, panel$ranges info is
       ## meaningless.
       name.name <- paste0(xy, ".name")
@@ -829,6 +829,22 @@ gg2list <- function(p) {
     stop("No exportable traces")
   }
 
+  # fixed coordinates: if the coordinates ratio is not NULL, then
+  # we make the size of the plot according to the specified ratio
+  # note: we set the biggest dimension to 600
+  if (!is.null(p$coordinates$ratio)) {
+    x_range <- range(built[[2]]$ranges[[1]]$x.major_source, na.rm = TRUE)
+    y_range <- range(built[[2]]$ranges[[1]]$y.major_source, na.rm = TRUE)
+    yx_ratio <- (y_range[2] - y_range[1]) / (x_range[2] - x_range[1])
+    if (yx_ratio > 1) {
+      layout$height <- 600
+      layout$width <- layout$height * (1 / p$coordinates$ratio) * (1 / yx_ratio) 
+    } else {
+      layout$width <- 600
+      layout$height <- layout$height * (1 / p$coordinates$ratio) * yx_ratio 
+    }
+  }
+
   mode.mat <- matrix(NA, 3, 3)
   rownames(mode.mat) <- colnames(mode.mat) <- c("markers", "lines", "none")
   mode.mat["markers", "lines"] <-

tests/testthat/test-ggplot-coord.R

@@ -0,0 +1,50 @@
+context("Fixed coordinates")
+
+# Expect trace function
+expect_traces <- function(gg, n_traces, name) {
+  stopifnot(is.ggplot(gg))
+  stopifnot(is.numeric(n_traces))
+  save_outputs(gg, paste0("coord_fixed-", name))
+  L <- gg2list(gg)
+  all_traces <- L$data
+  no_data <- sapply(all_traces, function(tr) {
+    is.null(tr[["x"]]) && is.null(tr[["y"]])
+  })
+  has_data <- all_traces[!no_data]
+  expect_equal(length(has_data), n_traces)
+  list(traces = has_data, layout = L$layout)
+}
+
+# Data where x ranges from 0-10, y ranges from 0-30
+set.seed(202)
+dat <- data.frame(xval = runif(40,0,10), yval = runif(40,0,30))
+
+# Force equal scaling
+p <- ggplot(dat, aes(xval, yval)) + geom_point() + coord_fixed()
+# Test 
+test_that("coord_fixed() is translated to the right height-width ratio", {
+  info <- expect_traces(p, 1, "force_equal_scaling")
+  tr <- info$traces[[1]]
+  la <- info$layout
+  expect_identical(tr$type, "scatter")
+  # height-width ratio check
+  x_range <- range(p$data$xval, na.rm = TRUE)
+  y_range <- range(p$data$yval, na.rm = TRUE)
+  yx_ratio <- (y_range[2] - y_range[1]) / (x_range[2] - x_range[1])
+  expect_equal(la$height/la$width, yx_ratio * p$coordinates$ratio, tolerance = 0.10)
+})
+
+# Equal scaling, with each 1 on the x axis the same length as y on x axis
+p <- ggplot(dat, aes(xval, yval)) + geom_point() + coord_fixed(1/3)
+# Test 
+test_that("coord_fixed() is translated to the right height-width ratio", {
+  info <- expect_traces(p, 1, "force_equal_scaling")
+  tr <- info$traces[[1]]
+  la <- info$layout
+  expect_identical(tr$type, "scatter")
+  # height-width ratio check
+  x_range <- range(p$data$xval, na.rm = TRUE)
+  y_range <- range(p$data$yval, na.rm = TRUE)
+  yx_ratio <- (y_range[2] - y_range[1]) / (x_range[2] - x_range[1])
+  expect_equal(la$height/la$width, yx_ratio * p$coordinates$ratio, tolerance = 0.10)
+})