first stab at a rebase

Author: thomasp85

doc/syntax/layer/type/bar.qmd

@@ -13,8 +13,8 @@ The following aesthetics are recognised by the bar layer.
 The bar layer has no required aesthetics
 
 ### Optional
-* `x`: Position on the x-axis. If missing all records will be shown in the same bar
-* `y`: The height of the plot. If missing, it will be calculated by the layer
+* Primary axis (e.g. `x`): The categories to create bars for. If missing all records will be shown in the same bar
+* Secondary axis (e.g. `y`): The height of the bars. If missing, it will be calculated by the layer
 * `colour`: The default colour of each bar
 * `stroke`: The colour of the stroke around each bar. Overrides `colour`
 * `fill`: The fill colour of each bar. Overrides `colour`
@@ -27,7 +27,7 @@ The bar layer has no required aesthetics
 * `width`: The width of the bars as a proportion of the available width
 
 ## Data transformation
-If `y` has not been mapped the layer will calculate it for you.
+If the secondary axis has not been mapped the layer will calculate it for you.
 
 ### Properties
 
@@ -40,7 +40,10 @@ If `y` has not been mapped the layer will calculate it for you.
 
 ### Default remappings
 
-* `count AS y`: By default the barplot will show count as the height of the bars
+* `count AS <secondary axis>`: By default the barplot will show count as the height of the bars
+
+## Orientation
+Bar plots have categories along their primary axis. The orientation can be deduced purely from the mapping. To create a horizontal bar plot you map the categories to `y` instead of `x` (assuming a default Cartesian coordinate system).
 
 ## Examples
 
@@ -100,3 +103,11 @@ SCALE BINNED x
 And use with a polar coordinate system to create a pie chart
 
 **TBD**
+
+Create a horizontal bar plot by changing the mapping
+
+```{ggsql}
+VISUALISE FROM ggsql:penguins
+DRAW bar
+    MAPPING species AS y
+```

doc/syntax/layer/type/boxplot.qmd

@@ -9,8 +9,8 @@ Boxplots display a summary of a continuous distribution. In the style of Tukey,
 The following aesthetics are recognised by the boxplot layer.
 
 ### Required
-* `x`: Position on the x-axis
-* `y`: Position on the y-axis
+* Primary axis (e.g. `x`): The categorical variable to group by
+* Secondary axis (e.g. `y`): The continuous variable to summarize
 
 ### Optional
 * `stroke`: The colour of the box contours, whiskers, median line and outliers.
@@ -43,7 +43,10 @@ Observations are considered outliers when they are more extreme than the whisker
 
 ### Default remapping
 
-* `value AS y`: By default the values are displayed along the y-axis.
+* `value AS <secondary axis>`: By default the values are displayed along the secondary axis.
+
+## Orientation
+The boxplot has its categorical groups along the primary axis and the continuous values along the secondary axis. The orientation can be deduced from the scale types or from the mapping. To create a horizontal boxplot, map the categorical variable to `y` and the continuous variable to `x` (assuming a default Cartesian coordinate system).
 
 ### Examples
 
@@ -83,3 +86,11 @@ DRAW boxplot
   MAPPING species AS x, bill_len AS y
   SETTING coef => 0.1
 ```
+
+Create a horizontal boxplot by swapping x and y:
+
+```{ggsql}
+VISUALISE FROM ggsql:penguins
+DRAW boxplot
+  MAPPING species AS y, bill_len AS x
+```

doc/syntax/layer/type/density.qmd

@@ -10,7 +10,7 @@ Visualise the distribution of a single continuous variable by computing a kernel
 The following aesthetics are recognised by the density layer.
 
 ### Required
-* `x`: Position on the x-axis.
+* Primary axis (e.g. `x`): The continuous variable to estimate density for.
 
 ### Optional
 * `stroke`: The colour of the contour lines.
@@ -62,7 +62,10 @@ $$
 
 ### Default remappings
 
-* `density AS y`: By default the density layer will display the computed density along the y-axis.
+* `density AS <secondary axis>`: By default the density layer will display the computed density along the secondary axis.
+
+## Orientation
+The density has its primary axis along the variable for which density is computed. The orientation can be deduced from the mapping. To create a horizontal density plot, map the variable to `y` instead of `x` (assuming a default Cartesian coordinate system).
 
 ## Examples
 

doc/syntax/layer/type/histogram.qmd

@@ -4,13 +4,13 @@ title: "Histogram"
 
 > Layers are declared with the [`DRAW` clause](../../clause/draw.qmd). Read the documentation for this clause for a thorough description of how to use it.
 
-Visualise the distribution of a single continuous variable by dividing the x axis into bins and counting the number of observations in each bin. If providing a weight then a weighted histogram is calculated instead.
+Visualise the distribution of a single continuous variable by dividing the primary axis into bins and counting the number of observations in each bin. If providing a weight then a weighted histogram is calculated instead.
 
 ## Aesthetics
 The following aesthetics are recognised by the bar layer.
 
 ### Required
-* `x`: Position on the x-axis
+* Primary axis (e.g. `x`): The continuous variable to bin
 
 ### Optional
 * `colour`: The default colour of each bar
@@ -40,7 +40,10 @@ The histogram layer will bin the records in each group and count them. By defaul
 
 ### Default remappings
 
-* `count AS y`: By default the histogram will show count as the height of the bars
+* `count AS <secondary axis>`: By default the histogram will show count as the height of the bars
+
+## Orientation
+The histogram has its primary axis along the binned variable. The orientation can be deduced from the mapping. To create a horizontal histogram you map the variable to `y` instead of `x` (assuming a default Cartesian coordinate system).
 
 ## Examples
 
@@ -86,3 +89,11 @@ DRAW histogram
     MAPPING body_mass AS x
     SETTING binwidth => 100
 ```
+
+Create a horizontal histogram by changing the mapping
+
+```{ggsql}
+VISUALISE FROM ggsql:penguins
+DRAW histogram
+    MAPPING body_mass AS y
+```

doc/syntax/layer/type/ribbon.qmd

@@ -10,9 +10,9 @@ The ribbon layer is used to display extrema over a sorted x-axis. It can be seen
 The following aesthetics are recognised by the ribbon layer.
 
 ### Required
-* `x`: Position along the x-axis
-* `ymin`: Lower position along the y-axis.
-* `ymax`: Upper position along the y-axis.
+* Primary axis (e.g. `x`): Position along the primary (domain) axis
+* Secondary axis min (e.g. `ymin`): Lower position along the secondary (value) axis.
+* Secondary axis max (e.g. `ymax`): Upper position along the secondary (value) axis.
 
 ### Optional
 * `stroke`: The colour of the contour lines.
@@ -27,6 +27,9 @@ The following aesthetics are recognised by the ribbon layer.
 ## Data transformation
 The ribbon layer does not transform its data but passes it through unchanged.
 
+## Orientation
+The ribbon has its domain axis as the primary axis and the value range on the secondary axis. The orientation can be deduced from the mapping. To create a horizontal ribbon, map the domain to `y` and use `xmin`/`xmax` for the value range (assuming a default Cartesian coordinate system).
+
 ## Examples
 
 A ribbon plot with arbitrary values as minima/maxima

doc/syntax/layer/type/violin.qmd

@@ -11,8 +11,8 @@ The violins are mirrored kernel density estimates, similar to the [density](dens
 The following aesthetics are recognised by the violin layer.
 
 ### Required
-* `x`: Position on the x-axis (categorical).
-* `y`: Value on the y-axis for which to compute density.
+* Primary axis (e.g. `x`): The categorical variable for grouping.
+* Secondary axis (e.g. `y`): The continuous variable to compute density for.
 
 ### Optional
 * `stroke`: The colour of the contour lines.
@@ -52,6 +52,9 @@ The major difference between a violin layer and a density layer is just the matt
 
 * `density AS offset`: By default the offsets around a centerline reflect the computed density.
 
+## Orientation
+The violin plot has its categorical groups along the primary axis and the continuous values along the secondary axis. The orientation can be deduced from the scale types or from the mapping. To create horizontal violins, swap `x` and `y` in the mapping (assuming a default Cartesian coordinate system).
+
 ## Examples
 
 A typical violin plot.
@@ -83,3 +86,10 @@ VISUALISE species AS x, bill_dep AS y, island AS fill FROM ggsql:penguins
   DRAW violin
 ```
 
+Create horizontal violins by swapping x and y:
+
+```{ggsql}
+VISUALISE species AS y, bill_dep AS x FROM ggsql:penguins
+  DRAW violin
+```
+

src/execute/layer.rs

@@ -337,6 +337,7 @@ pub fn build_layer_base_query(
 /// * `schema` - The layer's schema (with min/max from base_query)
 /// * `scales` - All resolved scales
 /// * `type_names` - SQL type names for the database backend
+/// * `aesthetic_ctx` - Aesthetic context for name transformations
 /// * `execute_query` - Function to execute queries (needed for some stat transforms)
 ///
 /// # Returns
@@ -348,15 +349,23 @@ pub fn apply_layer_transforms<F>(
     schema: &Schema,
     scales: &[Scale],
     type_names: &SqlTypeNames,
+    aesthetic_ctx: &crate::plot::aesthetic::AestheticContext,
     execute_query: &F,
 ) -> Result<String>
 where
     F: Fn(&str) -> Result<DataFrame>,
 {
+    use crate::plot::layer::orientation::{flip_mappings, flip_remappings, Orientation};
+
     // Clone order_by early to avoid borrow conflicts
     let order_by = layer.order_by.clone();
 
+    // Orientation detection and initial flip was already done in mod.rs before
+    // build_layer_base_query. We just check if we need to flip back after stat.
+    let needs_flip = layer.orientation == Some(Orientation::Transposed);
+
     // Build the aesthetic-named schema for stat transforms
+    // Note: Mappings were already flipped in mod.rs if needed, so schema reflects normalized orientation
     let aesthetic_schema: Schema = build_aesthetic_schema(layer, schema);
 
     // Collect literal aesthetic column names BEFORE conversion to Column values.
@@ -418,8 +427,17 @@ where
         execute_query,
     )?;
 
+    // Flip user remappings BEFORE merging defaults for Transposed orientation.
+    // User remappings are in user orientation (e.g., `count AS x` for horizontal histogram).
+    // We flip them to aligned orientation so they're uniform with defaults.
+    // At the end, we flip everything back together.
+    if needs_flip {
+        flip_remappings(layer);
+    }
+
     // Apply literal default remappings from geom defaults (e.g., y2 => 0.0 for bar baseline).
     // These apply regardless of stat transform, but only if user hasn't overridden them.
+    // Defaults are always in aligned orientation.
     for (aesthetic, default_value) in layer.geom.default_remappings() {
         // Only process literal values here (Column values are handled in Transformed branch)
         if !matches!(default_value, DefaultAestheticValue::Column(_)) {
@@ -555,7 +573,22 @@ where
         StatResult::Identity => query,
     };
 
-    // Apply ORDER BY
+    // Flip mappings back after stat transforms if we flipped them earlier
+    // Now pos1/pos2 map to the user's intended x/y positions
+    // Note: We only flip mappings here, not remappings. Remappings are flipped
+    // later in mod.rs after apply_remappings_post_query creates the columns,
+    // so that Phase 4.5 can flip those columns along with everything else.
+    if needs_flip {
+        flip_mappings(layer);
+
+        // Normalize mapping column names to match their aesthetic keys.
+        // After flip_mappings, pos1 might point to __ggsql_aes_pos2__ (and vice versa).
+        // We update the column names so pos1 → __ggsql_aes_pos1__, etc.
+        // The DataFrame columns will be renamed correspondingly in mod.rs.
+        normalize_mapping_column_names(layer, aesthetic_ctx);
+    }
+
+    // Apply explicit ORDER BY if provided
     let final_query = if let Some(ref o) = order_by {
         format!("{} ORDER BY {}", final_query, o.as_str())
     } else {
@@ -564,3 +597,57 @@ where
 
     Ok(final_query)
 }
+
+/// Normalize mapping column names to match their aesthetic keys after flip-back.
+///
+/// After `flip_mappings`, the mapping values (column names) may not match the keys.
+/// For example, pos1 might point to `__ggsql_aes_pos2__`.
+/// This function updates the column names so pos1 → `__ggsql_aes_pos1__`, etc.
+///
+/// This should be called after flip_mappings during flip-back.
+/// The DataFrame columns should be renamed correspondingly using `flip_dataframe_columns`.
+fn normalize_mapping_column_names(
+    layer: &mut Layer,
+    aesthetic_ctx: &crate::plot::aesthetic::AestheticContext,
+) {
+    // Collect the aesthetics to update (to avoid borrowing issues)
+    let aesthetics_to_update: Vec<String> = layer
+        .mappings
+        .aesthetics
+        .keys()
+        .filter(|aes| crate::plot::aesthetic::is_positional_aesthetic(aes))
+        .cloned()
+        .collect();
+
+    for aesthetic in aesthetics_to_update {
+        if let Some(value) = layer.mappings.aesthetics.get_mut(&aesthetic) {
+            let expected_col = naming::aesthetic_column(&aesthetic);
+            match value {
+                AestheticValue::Column {
+                    name,
+                    original_name,
+                    ..
+                } => {
+                    // The current column name might be wrong (e.g., __ggsql_aes_pos2__ for pos1)
+                    // We need to flip it to match the aesthetic key
+                    let current_col_aesthetic =
+                        naming::extract_aesthetic_name(name).unwrap_or_default();
+                    let flipped_aesthetic = aesthetic_ctx.flip_positional(current_col_aesthetic);
+
+                    // If flipping results in the correct aesthetic, update the column name
+                    if flipped_aesthetic == aesthetic {
+                        *name = expected_col;
+                    }
+                    // Preserve original_name for axis labels
+                    if original_name.is_none() {
+                        *original_name = Some(aesthetic.clone());
+                    }
+                }
+                AestheticValue::Literal(_) => {
+                    // Literals become columns with the expected name
+                    *value = AestheticValue::standard_column(expected_col);
+                }
+            }
+        }
+    }
+}