Fix position of bar annotation when specifying a reverse scale.

demo/plot-common/src/commonMain/kotlin/demo/plot/common/model/plotConfig/BarAnnotations.kt

@@ -10,7 +10,9 @@ import demoAndTestShared.parsePlotSpec
 class BarAnnotations {
  fun plotSpecList(): List<MutableMap<String, Any>> {
  return listOf(
- //barPlot(grouped = false, flip = false),
+ barPlot(grouped = false, flip = false),
+ barPlot(grouped = false, flip = false, reversed = true),
+
  barPlot("dodge", flip = false),
  barPlot("stack", flip = false),
  barPlot("stack", flip = false, yLim = "[3, 30]"),
@@ -20,16 +22,16 @@ class BarAnnotations {
  //barPlot("dodge", flip = true),
  //barPlot("stack", flip = true),
  barPlot("fill", flip = true),
- barPlot("fill", flip = true, yLim = "[0.4, 0.8]"),
+ //barPlot("fill", flip = true, yLim = "[0.4, 0.8]"),
 
  withNegativeValues("stack", flip = false),
  withNegativeValues("stack", flip = false, yLim = "[2, 8]"),
  //withNegativeValues("fill", flip = false),
  //withNegativeValues("dodge", flip = false),
 
  //withNegativeValues("stack", flip = true),
- withNegativeValues("fill", flip = true),
- withNegativeValues("fill", flip = true, yLim = "[-0.5, 0.5]"),
+ //withNegativeValues("fill", flip = true),
+ //withNegativeValues("fill", flip = true, yLim = "[-0.5, 0.5]"),
  //withNegativeValues("dodge", flip = true),
  )
  }
@@ -45,20 +47,24 @@ class BarAnnotations {
  position: String = "stack",
  flip: Boolean = false,
  grouped: Boolean = true,
- yLim: String? = null
+ yLim: String? = null,
+ reversed: Boolean = false
  ): MutableMap<String, Any> {
  val coordSpec = when {
  flip -> "'coord': {'name': 'flip', 'flip': true, 'ylim': $yLim},"
  yLim != null -> "'coord': {'name': 'cartesian', 'ylim': $yLim},"
  else -> ""
  }
  val mappingSpec = "'x': 'x'" + if (grouped) ", 'fill': 'v'" else ""
+ val scales = if (reversed) "'scales': [{'aesthetic': 'y', 'trans': 'reverse'}]," else ""
+
  val spec = """
  {
  'kind': 'plot',
  'ggtitle': { 'text': 'position=\'$position\', coord_cartesian(ylim=$yLim)'},
  $coordSpec
  'mapping': { $mappingSpec },
+ $scales
  'layers': [
  {
  'geom': 'bar',
@@ -83,18 +89,25 @@ class BarAnnotations {
  "value" to listOf(0.5, 5, -1.5, 3, 1, 2, 4, 0.5, -1, 6, 5, -0.2, 5, -2, 5, 4)
  )
 
- private fun withNegativeValues(position: String, flip: Boolean, yLim: String? = null): MutableMap<String, Any> {
+ private fun withNegativeValues(
+ position: String,
+ flip: Boolean,
+ yLim: String? = null,
+ reversed: Boolean = false
+ ): MutableMap<String, Any> {
  val coordSpec = when {
  flip -> "'coord': {'name': 'flip', 'flip': true, 'ylim': $yLim},"
  yLim != null -> "'coord': {'name': 'cartesian', 'ylim': $yLim},"
  else -> ""
  }
+ val scales = if (reversed) "'scales': [{'aesthetic': 'y', 'trans': 'reverse'}]," else ""
  val spec = """
  {
  'kind': 'plot',
  'ggtitle': { 'text': 'position=\'$position\', coord_cartesian(ylim=$yLim)'},
  'mapping': { 'x': 'x', 'y': 'value', 'fill': 'group' },
  $coordSpec
+ $scales
  'layers': [
  {
  'geom': 'bar',

plot-base/src/commonMain/kotlin/org/jetbrains/letsPlot/core/plot/base/geom/annotation/BarAnnotation.kt

@@ -96,8 +96,8 @@ object BarAnnotation {
  ?.intersect(viewPort) // use the visible part of bar to place annotation on it
  ?: return@iterateRectangleGeometry
 
- val isNegative = rect.dimension.y < 0
- rectangles.add(Triple(p, clientRect, isNegative))
+ val isUpsideDown = with(rect) { dimension.y < 0 || top < 0 } // bar with base at the top
+ rectangles.add(Triple(p, clientRect, isUpsideDown))
  }
 
  rectangles
@@ -110,7 +110,7 @@ object BarAnnotation {
  .sortedBy { (_, rect) ->
  if (isHorizontallyOriented) rect.center.x else rect.center.y
  }
- .forEachIndexed { index, (p, barRect, isNegative) ->
+ .forEachIndexed { index, (p, barRect, isUpsideDown) ->
  val text = annotation.getAnnotationText(p.index(), ctx.plotContext)
  val textSize = AnnotationUtil.textSizeGetter(annotation.textStyle, ctx).invoke(text, p)
 
@@ -122,7 +122,7 @@ object BarAnnotation {
  padding,
  viewPort,
  isHorizontallyOriented,
- isNegative
+ isUpsideDown
  )
  ?: return@forEachIndexed
 
@@ -182,7 +182,7 @@ object BarAnnotation {
  padding: Double,
  viewPort: DoubleRectangle,
  isHorizontallyOriented: Boolean,
- isNegative: Boolean
+ isUpsideDown: Boolean
  ): Pair<Text.HorizontalAnchor, DoubleRectangle>? {
 
  val coordSelector: (DoubleVector) -> Double =
@@ -191,9 +191,10 @@ object BarAnnotation {
  var insideBar = when {
  barsCount == 1 -> {
  // use left (for horizontally orientated) or bottom (of the vertical bar)
- if (isHorizontallyOriented) PlacementInsideBar.MIN else PlacementInsideBar.MAX
+ (if (isHorizontallyOriented) PlacementInsideBar.MIN else PlacementInsideBar.MAX).let {
+ if (isUpsideDown) it.flip() else it
+ }
  }
-
  index == 0 -> PlacementInsideBar.MIN
  index == barsCount - 1 -> PlacementInsideBar.MAX
  else -> PlacementInsideBar.MIDDLE
@@ -231,7 +232,7 @@ object BarAnnotation {
  if (barsCount == 1) {
  // move to the right (for horizontally orientated) or to the top (of the vertical bar)
  insideBar = if (isHorizontallyOriented) PlacementInsideBar.MAX else PlacementInsideBar.MIN
- if (isNegative) insideBar = insideBar.flip()
+ if (isUpsideDown) insideBar = insideBar.flip()
  }
 
  fun DoubleRectangle.moveTo(value: Double): DoubleRectangle {