annotation_raster()/_custom() respond to scale transformations (#6182)

* helper for annotation ranges

* use helper

* update snapshots

* use vctrs rules to preserve AsIs

* add test

* add news bullet

* allow mixing AsIs and numeric

* clarify AsIs change in news

NEWS.md

@@ -1,5 +1,8 @@
 # ggplot2 (development version)
 
+* Custom and raster annotation now respond to scale transformations, and can
+  use AsIs variables for relative placement (@teunbrand based on 
+  @yutannihilation's prior work, #3120)
 * When discrete breaks have names, they'll be used as labels by default 
   (@teunbrand, #6147).
 * The helper function `is.waiver()` is now exported to help extensions to work

R/annotation-custom.R

@@ -70,21 +70,12 @@ GeomCustomAnn <- ggproto("GeomCustomAnn", Geom,
 
   draw_panel = function(data, panel_params, coord, grob, xmin, xmax,
                         ymin, ymax) {
-    if (!inherits(coord, "CoordCartesian")) {
-      cli::cli_abort("{.fn annotation_custom} only works with {.fn coord_cartesian}.")
-    }
-    corners <- data_frame0(
-      x = c(xmin, xmax),
-      y = c(ymin, ymax),
-      .size = 2
+    range <- ranges_annotation(
+      coord, panel_params, xmin, xmax, ymin, ymax,
+      fun = "annotation_custom"
     )
-    data <- coord$transform(corners, panel_params)
-
-    x_rng <- range(data$x, na.rm = TRUE)
-    y_rng <- range(data$y, na.rm = TRUE)
-
-    vp <- viewport(x = mean(x_rng), y = mean(y_rng),
-                   width = diff(x_rng), height = diff(y_rng),
+    vp <- viewport(x = mean(range$x), y = mean(range$y),
+                   width = diff(range$x), height = diff(range$y),
                    just = c("center","center"))
     editGrob(grob, vp = vp, name = paste(grob$name, annotation_id()))
   },
@@ -99,3 +90,21 @@ annotation_id <- local({
     i
   }
 })
+
+ranges_annotation <- function(coord, panel_params, xmin, xmax, ymin, ymax, fun) {
+  if (!inherits(coord, "CoordCartesian")) {
+    cli::cli_abort("{.fn {fun}} only works with {.fn coord_cartesian}.")
+  }
+  data <- data_frame0(xmin = xmin, xmax = xmax, ymin = ymin, ymax = ymax)
+  data <- .ignore_data(data)[[1]]
+  x <- panel_params$x$scale$transform_df(data)
+  data[names(x)] <- x
+  y <- panel_params$y$scale$transform_df(data)
+  data[names(y)] <- y
+  data <- .expose_data(data)[[1]]
+  data <- coord$transform(data, panel_params)
+  list(
+    x = range(data$xmin, data$xmax, na.rm = TRUE),
+    y = range(data$ymin, data$ymax, na.rm = TRUE)
+  )
+}

R/annotation-raster.R

@@ -73,21 +73,13 @@ GeomRasterAnn <- ggproto("GeomRasterAnn", Geom,
 
   draw_panel = function(data, panel_params, coord, raster, xmin, xmax,
                         ymin, ymax, interpolate = FALSE) {
-    if (!inherits(coord, "CoordCartesian")) {
-      cli::cli_abort("{.fn annotation_raster} only works with {.fn coord_cartesian}.")
-    }
-    corners <- data_frame0(
-      x = c(xmin, xmax),
-      y = c(ymin, ymax),
-      .size = 2
+    range <- ranges_annotation(
+      coord, panel_params, xmin, xmax, ymin, ymax,
+      fun = "annotation_raster"
+    )
+    rasterGrob(raster, range$x[1], range$y[1],
+      diff(range$x), diff(range$y), default.units = "native",
+      just = c("left","bottom"), interpolate = interpolate
     )
-    data <- coord$transform(corners, panel_params)
-
-    x_rng <- range(data$x, na.rm = TRUE)
-    y_rng <- range(data$y, na.rm = TRUE)
-
-    rasterGrob(raster, x_rng[1], y_rng[1],
-      diff(x_rng), diff(y_rng), default.units = "native",
-      just = c("left","bottom"), interpolate = interpolate)
   }
 )

tests/testthat/_snaps/annotate.md

@@ -2,14 +2,14 @@
 
     Problem while converting geom to grob.
     i Error occurred in the 1st layer.
-    Caused by error in `draw_panel()`:
+    Caused by error in `ranges_annotation()`:
     ! `annotation_raster()` only works with `coord_cartesian()`.
 
 ---
 
     Problem while converting geom to grob.
     i Error occurred in the 1st layer.
-    Caused by error in `draw_panel()`:
+    Caused by error in `ranges_annotation()`:
     ! `annotation_custom()` only works with `coord_cartesian()`.
 
 # annotation_map() checks the input data

tests/testthat/test-annotate.R

@@ -86,3 +86,32 @@ test_that("annotate() warns about `stat` or `position` arguments", {
     annotate("point", 1:3, 1:3, stat = "density", position = "dodge")
   )
 })
+
+test_that("annotation_custom() and annotation_raster() adhere to scale transforms", {
+  rast <- matrix(rainbow(10), nrow = 1)
+
+  p <- ggplot() +
+    annotation_raster(rast, 1, 10, 1, 9) +
+    scale_x_continuous(transform = "log10", limits = c(0.1, 100), expand = FALSE) +
+    scale_y_continuous(limits = c(0, 10), expand = FALSE)
+  ann <- get_layer_grob(p)[[1]]
+
+  expect_equal(as.numeric(ann$x), 1/3)
+  expect_equal(as.numeric(ann$y), 1/10)
+  expect_equal(as.numeric(ann$width), 1/3)
+  expect_equal(as.numeric(ann$height), 8/10)
+
+  rast <- rasterGrob(rast, width = 1, height = 1)
+
+  p <- ggplot() +
+    annotation_custom(rast, 1, 10, 1, 9) +
+    scale_x_continuous(transform = "log10", limits = c(0.1, 100), expand = FALSE) +
+    scale_y_continuous(limits = c(0, 10), expand = FALSE)
+  ann <- get_layer_grob(p)[[1]]$vp
+
+  expect_equal(as.numeric(ann$x), 1/2)
+  expect_equal(as.numeric(ann$y), 1/2)
+  expect_equal(as.numeric(ann$width), 1/3)
+  expect_equal(as.numeric(ann$height), 8/10)
+
+})