Generation of non-intercept data in hline/vline should respect coord_…

…flip(), closes #1519

R/layers2traces.R

@@ -417,8 +417,10 @@ to_basic.GeomHline <- function(data, prestats_data, layout, params, p, ...) {
   data$group <- do.call(paste,
     data[!grepl("group", names(data)) & !vapply(data, anyNA, logical(1))]
   )
-  lay <- tidyr::gather_(layout$layout, "variable", "x", c("x_min", "x_max"))
-  data <- merge(lay[c("PANEL", "x")], data, by = "PANEL")
+  x <- if (inherits(p$coordinates, "CoordFlip")) "y" else "x"
+  lay <- tidyr::gather_(layout$layout, "variable", x, paste0(x, c("_min", "_max")))
+  data <- merge(lay[c("PANEL", x)], data, by = "PANEL")
+  data[["x"]] <- data[[x]]
   data[["y"]] <- data$yintercept
   prefix_class(data, c("GeomHline", "GeomPath"))
 }
@@ -429,8 +431,10 @@ to_basic.GeomVline <- function(data, prestats_data, layout, params, p, ...) {
   data$group <- do.call(paste,
     data[!grepl("group", names(data)) & !vapply(data, anyNA, logical(1))]
   )
-  lay <- tidyr::gather_(layout$layout, "variable", "y", c("y_min", "y_max"))
-  data <- merge(lay[c("PANEL", "y")], data, by = "PANEL")
+  y <- if (inherits(p$coordinates, "CoordFlip")) "x" else "y"
+  lay <- tidyr::gather_(layout$layout, "variable", y, paste0(y, c("_min", "_max")))
+  data <- merge(lay[c("PANEL", y)], data, by = "PANEL")
+  data[["y"]] <- data[[y]]
   data[["x"]] <- data$xintercept
   prefix_class(data, c("GeomVline", "GeomPath"))
 }

tests/testthat/test-ggplot-hline.R

@@ -75,3 +75,16 @@ test_that("hline/vline/abline split on linetype/colour/size", {
     unique(vapply(l$data, function(x) x$line$width, numeric(1))), 4
   )
 })
+
+
+test_that("hline works with coord_flip", {
+
+  gg <- ggplot() + 
+    geom_point(aes(6, 5)) + 
+    geom_hline(yintercept = 5) + 
+    coord_flip()
+
+  l <- plotly_build(gg)$x
+  expect_equivalent(l$data[[2]]$x, c(5, 5))
+  expect_equivalent(l$data[[2]]$y, c(5.95, 6.05))
+})

tests/testthat/test-ggplot-vline.R

@@ -33,3 +33,17 @@ test_that("vector xintercept results in multiple vertical lines", {
   expect_true(l$mode == "lines")
   expect_true(l$line$color == "rgba(0,0,255,1)")
 })
+
+
+
+test_that("vline works with coord_flip", {
+
+  gg <- ggplot() + 
+    geom_point(aes(5, 6)) + 
+    geom_vline(xintercept = 5) + 
+    coord_flip()
+
+  l <- plotly_build(gg)$x
+  expect_equivalent(l$data[[2]]$x, c(5.95, 6.05))
+  expect_equivalent(l$data[[2]]$y, c(5, 5))
+})