Convert geom_hline the same way geom_abline is handled

Author: mkcor

R/trace_generation.R

@@ -294,6 +294,11 @@ toBasic <- list(
     g$params$xend <- max(g$prestats.data$globxmax)
     g
   },
+  hline=function(g) {
+    g$params$xstart <- min(g$prestats.data$globxmin)
+    g$params$xend <- max(g$prestats.data$globxmax)
+    g
+  },
   point=function(g) {
     if ("size" %in% names(g$data)) {
       g$params$sizemin <- min(g$prestats.data$globsizemin)
@@ -510,5 +515,13 @@ geom2trace <- list(
          type="scatter",
          mode="lines",
          line=paramORdefault(params, aes2line, line.defaults))
+  },
+  hline=function(data, params) {
+    list(x=c(params$xstart, params$xend),
+         y=c(data$yintercept, data$yintercept),
+         name=params$name,
+         type="scatter",
+         mode="lines",
+         line=paramORdefault(params, aes2line, line.defaults))
   }
 )

tests/testthat/test-ggplot-hline.R

@@ -0,0 +1,25 @@
+context("Hline")
+
+# Horizontal line
+
+test_that("Second trace be the hline", {
+  
+  x1 <- seq(from=0, to=3.5, by=0.5)
+  x2 <- x1 * 0.95
+  df <- data.frame("x1"=x1, "x2"=x2)
+  
+  gg <- ggplot(df) + geom_point(aes(x=x1, y=x2)) +
+    geom_hline(yintercept=1.1, colour="green", size=3)
+  
+  L <- gg2list(gg)
+  
+  expect_equal(length(L), 3)
+  expect_true(L[[2]]$x[1] <= 0)
+  expect_true(L[[2]]$x[2] >= 3.5)
+  expect_identical(L[[2]]$mode, "lines")
+  expect_identical(L[[2]]$line$shape, "linear")
+  expect_equal(L[[2]]$line$width, 3)
+  expect_identical(L[[2]]$line$color, "rgb(0,255,0)")
+  
+  save_outputs(gg, "hline")
+})