Rectangles (#168)

* add resolution helper

* Add rect geom with flexible parameter specification

Implements a new rect geom that supports flexible rectangle specification:
- X-direction: any 2 of {x (center), width, xmin, xmax}
- Y-direction: any 2 of {y (center), height, ymin, ymax}

Key features:
- Stat-based parameter consolidation via SQL generation
- Automatic discrete vs continuous scale detection using Schema
- Validates exactly 2 params per direction
- Generates appropriate SQL for all 6 parameter combinations per axis
- Returns different stat columns based on scale type:
  - Continuous: pos1min, pos1max, pos2min, pos2max
  - Discrete: pos1, pos2 (for band-based rendering)

Implementation follows existing patterns from histogram and bar geoms.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

* Add rect to grammar and parser

- Add 'rect' to tree-sitter grammar geom_type rule
- Add "rect" case to parser builder geom type mapping

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

* Fix rect geom: width/height as aesthetics only

Changes:
- Remove width/height from default_params() (use trait default)
- Treat width/height as aesthetics (columns or literals), not parameters
- RectRenderer handles x and y directions independently
- For discrete scales: extract literal width/height from encoding or default to 0.9
- Error if width/height are mapped to variable columns on discrete scales
- Support mixed continuous/discrete (e.g., continuous x + discrete y)
- Extract band size logic into helper function with early returns
- Early return from modify_spec when both directions are continuous

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

* fix: enable scale training for width/height in rect geom

Key changes:
- Add width/height to gets_default_scale() so they get proper scales with domains
  instead of Identity scales (which have scale: null)
- Simplify rect.rs stat transform using get_column_name() directly
- Merge discrete checking blocks to build SELECT and stat_columns together
- Refactor RectRenderer to avoid Result<Option<>> anti-pattern
- Flatten nesting with early exits and error closure for DRY

This fixes discrete rect layers with literal width/height (e.g., 0.7 AS width)
by ensuring scales are trained and domains are available for constant detection.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

* test: add comprehensive tests for rect geom

Add 10 parameterized tests covering:
- All 6 x-direction parameter combinations (continuous)
- All 6 y-direction parameter combinations (continuous)
- Discrete scales with width/height
- Validation errors (param count, discrete+min/max)
- Group by filtering for width/height

Tests use a grid/loop approach to systematically verify all
rect parameter combinations and error cases.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

* tests for the rectrenderer

* fix(rect): preserve non-positional aesthetics in stat transform

The rect stat transform was only including group_by columns in its
SELECT list, causing non-positional aesthetics like fill and color
to be dropped unless they were literal values.

Now uses the schema to determine which columns to pass through:
- Defines consumed aesthetics once (positional params that get transformed)
- Iterates through schema and includes all non-consumed columns
- Eliminates duplicate "consumed columns" logic

Also increases default rect opacity from 0.5 to 0.8 for better visibility.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

* Revert "add resolution helper"

This reverts commit a0c7092.

* delete tile layer

* feat: default width/height to 1.0 for rect geom

Allow rect to work with just x (or y) specified, defaulting width (or
height) to 1.0 for both discrete and continuous scales.

Changes:
- Split position expression generation into discrete and continuous variants
  - generate_discrete_position_expressions: returns (center, size) with
    size defaulting to "1.0" when not provided
  - generate_continuous_position_expressions: returns (min_expr, max_expr)
    with 7 valid parameter combinations including center-only
- Discrete scales: center-only specification defaults to 1.0 bandwidth
- Continuous scales: center-only specification defaults to width=1.0
  (xmin = x - 0.5, xmax = x + 0.5)
- Improved variable naming: x_expr_1/x_expr_2 instead of x_expr_min/x_expr_max
  to reflect dual usage (center/size for discrete, min/max for continuous)
- Updated tests to verify default behavior

All 18 rect tests passing.

* feat: support SETTING width/height for rect geom

Add support for specifying width/height via SETTING clause in addition to
MAPPING. Implements precedence: MAPPING > SETTING > default 1.0.

Changes:
- stat_rect now checks both aesthetics (MAPPING) and parameters (SETTING)
  for width/height values
- Uses ParameterValue::to_string() to convert SETTING values to SQL literals
- Precedence order ensures MAPPING columns take priority over SETTING literals,
  which take priority over default 1.0
- Stat transform happens before resolve_aesthetics(), so we check parameters
  directly rather than relying on aesthetic resolution

Example usage:
  DRAW rect MAPPING x AS x, ymin AS ymin, ymax AS ymax SETTING width => 0.8

All 19 rect tests passing.

* refactor: unify x/y direction logic in rect stat transform

Extract duplicated x and y direction logic into a single process_direction
helper function that handles both axes.

Changes:
- New process_direction() function processes a single direction
  - Takes only axis ("x" or "y"), derives all aesthetic names from it
  - Returns SELECT parts and stat column names
  - Handles both discrete and continuous cases
- Determine stat_cols first, then format SELECT parts outside if-block
  to eliminate duplication of format! calls
- stat_rect() now calls process_direction() twice (once for x, once for y)
- Eliminates ~100 lines of duplicated logic

Call sites simplified from:
  process_direction("pos1", "pos1min", "pos1max", "width", "width", "x", ...)
to:
  process_direction("x", aesthetics, parameters, schema)

Net reduction: 26 lines (114 deletions, 88 additions)
All 19 rect tests passing.

* add docs

* cargo fmt

* add position parameter

* update docs

* simplify discrete variable widths

* remove accidentally committed file

* cargo fmt

---------

Co-authored-by: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: teunbrand

CLAUDE.md

@@ -330,7 +330,7 @@ pub struct Layer {
 
 pub enum Geom {
     // Basic geoms
-    Point, Line, Path, Bar, Col, Area, Tile, Polygon, Ribbon,
+    Point, Line, Path, Bar, Col, Area, Rect, Polygon, Ribbon,
     // Statistical geoms
     Histogram, Density, Smooth, Boxplot, Violin,
     // Annotation geoms
@@ -1200,7 +1200,7 @@ All clauses (MAPPING, SETTING, PARTITION BY, FILTER) are optional.
 
 **Geom Types**:
 
-- **Basic**: `point`, `line`, `path`, `bar`, `col`, `area`, `tile`, `polygon`, `ribbon`
+- **Basic**: `point`, `line`, `path`, `bar`, `col`, `area`, `rect`, `polygon`, `ribbon`
 - **Statistical**: `histogram`, `density`, `smooth`, `boxplot`, `violin`
 - **Annotation**: `text`, `label`, `segment`, `arrow`, `rule`, `linear`, `errorbar`
 

doc/ggsql.xml

@@ -129,7 +129,7 @@
       <item>bar</item>
       <item>col</item>
       <item>area</item>
-      <item>tile</item>
+      <item>rect</item>
       <item>polygon</item>
       <item>ribbon</item>
       <item>histogram</item>

doc/syntax/layer/type/rect.qmd

@@ -0,0 +1,108 @@
+---
+title: "Rectangle"
+---
+
+> 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.
+
+Rectangles can be used to draw heatmaps or indicate ranges.
+
+## Aesthetics
+The following aesthetics are recognised by the rectangle layer.
+
+### Required
+
+* Pick two of the following for the primary axis:
+    * Center (e.g. `x`)
+    * `width`
+    * Start position (e.g. `xmin`). Unavailable when the center is discrete.
+    * End position (e.g. `xmax`). Unavailable when the center is discrete.
+
+Alternatively, use only the center, which will set `width` to 1 by default.
+
+* Pick two of the following for the secondary axis:
+    * Center (e.g. `y`)
+    * `height`: The size of the rectangle in the vertical dimension.
+    * Start position (e.g. `ymin`). Unavailable when the center is discrete.
+    * End position (e.g. `ymax`) Unavailable when the center is discrete.
+
+Alternatively, use only the center, which will set `height` to 1 by default.
+
+### Optional
+* `stroke`: The colour of the contour lines.
+* `fill`: The colour of the inner area.
+* `colour`: Shorthand for setting `stroke` and `fill` simultaneously.
+* `opacity`: The opacity of colours.
+* `linewidth`: The width of the contour lines.
+* `linetype`: The dash pattern of the contour line.
+
+## Settings
+* `position`: Determines the position adjustment to use for the layer (default is `'identity'`)
+
+## Data transformation.
+When the primary aesthetics are continuous, primary data is reparameterised to {start, end}, e.g. `xmin` and `xmax`.
+When the secondary aesthetics are continuous, secondary data is reparameterised to {start, end}, e.g. `ymin` and `ymax`.
+
+## Orientation
+The rectangle layer has no orientation. The axes are treated symmetrically.
+
+## Examples
+
+Just using `x` and `y`. Note that `width` and `height` are set to 1.
+
+```{ggsql}
+VISUALISE Day AS x, Month AS y, Temp AS colour FROM ggsql:airquality
+  DRAW rect 
+```
+
+Customising `width` and `height` with either the `MAPPING` or `SETTING` clauses.
+
+```{ggsql}
+VISUALISE Day AS x, Month AS y, Temp AS colour FROM ggsql:airquality
+  DRAW rect MAPPING 0.5 AS width SETTING height => 0.8
+```
+
+If `x` is continuous, then `width` can be variable. Likewise for `y` and `height`.
+
+```{ggsql}
+SELECT *, Temp / (SELECT MAX(Temp) FROM ggsql:airquality) AS norm_temp 
+FROM ggsql:airquality
+VISUALISE 
+    Day AS x, 
+    Month AS y, 
+    Temp AS colour
+  DRAW rect 
+    MAPPING 
+      norm_temp AS width, 
+      norm_temp AS height
+```
+
+Using top, right, bottom, left parameterisation instead.
+
+```{ggsql}
+SELECT
+  MIN(Date) AS start,
+  MAX(Date) AS end,
+  MIN(Temp) AS min,
+  MAX(Temp) AS max
+FROM ggsql:airquality
+GROUP BY
+  WEEKOFYEAR(Date)
+
+VISUALISE start AS xmin, end AS xmax, min AS ymin, max AS ymax
+  DRAW rect
+```
+
+Using a rectangle as an annotation.
+
+<!-- When annotations work, replace this with an annotation layer -->
+
+```{ggsql}
+VISUALISE FROM ggsql:airquality
+  DRAW rect MAPPING
+    '1973-06-01' AS xmin,
+    '1973-06-30' AS xmax,
+    50 AS ymin, 
+    100 AS ymax,
+    'June' AS colour
+  DRAW line MAPPING Date AS x, Temp AS y
+```

ggsql-vscode/syntaxes/ggsql.tmLanguage.json

@@ -294,7 +294,7 @@
       "patterns": [
         {
           "name": "support.type.geom.ggsql",
-          "match": "\\b(point|line|path|bar|col|area|tile|polygon|ribbon|histogram|density|smooth|boxplot|violin|text|label|segment|arrow|rule|linear|errorbar)\\b"
+          "match": "\\b(point|line|path|bar|col|area|rect|polygon|ribbon|histogram|density|smooth|boxplot|violin|text|label|segment|arrow|rule|linear|errorbar)\\b"
         },
         { "include": "#common-clause-patterns" }
       ]

src/parser/builder.rs

@@ -602,7 +602,7 @@ fn parse_geom_type(text: &str) -> Result<Geom> {
         "path" => Ok(Geom::path()),
         "bar" => Ok(Geom::bar()),
         "area" => Ok(Geom::area()),
-        "tile" => Ok(Geom::tile()),
+        "rect" => Ok(Geom::rect()),
         "polygon" => Ok(Geom::polygon()),
         "ribbon" => Ok(Geom::ribbon()),
         "histogram" => Ok(Geom::histogram()),

src/parser/mod.rs

@@ -146,12 +146,12 @@ mod tests {
         let query = r#"
             SELECT x, y FROM data
             VISUALIZE x, y
-            DRAW tile
+            DRAW point
         "#;
 
         let specs = parse_query(query).unwrap();
         assert_eq!(specs.len(), 1);
-        assert_eq!(specs[0].layers[0].geom, Geom::tile());
+        assert_eq!(specs[0].layers[0].geom, Geom::point());
     }
 
     #[test]
@@ -163,7 +163,7 @@ mod tests {
             VISUALIZE
             DRAW bar MAPPING x AS x, y AS y
             VISUALISE z AS x, y AS y
-            DRAW tile
+            DRAW point
         "#;
 
         let specs = parse_query(query).unwrap();
@@ -219,15 +219,15 @@ mod tests {
             VISUALISE x, y
             DRAW line
             VISUALIZE
-            DRAW tile MAPPING x AS x, y AS y
+            DRAW point MAPPING x AS x, y AS y
             VISUALISE
             DRAW bar MAPPING x AS x, y AS y
         "#;
 
         let specs = parse_query(query).unwrap();
         assert_eq!(specs.len(), 3);
         assert_eq!(specs[0].layers[0].geom, Geom::line());
-        assert_eq!(specs[1].layers[0].geom, Geom::tile());
+        assert_eq!(specs[1].layers[0].geom, Geom::point());
         assert_eq!(specs[2].layers[0].geom, Geom::bar());
     }
 
@@ -245,7 +245,7 @@ mod tests {
             VISUALIZE
             DRAW bar MAPPING date AS x, revenue AS y
             VISUALISE
-            DRAW tile MAPPING date AS x, revenue AS y
+            DRAW point MAPPING date AS x, revenue AS y
         "#;
 
         let specs = parse_query(query).unwrap();

src/plot/layer/geom/mod.rs

@@ -40,12 +40,12 @@ mod linear;
 mod path;
 mod point;
 mod polygon;
+mod rect;
 mod ribbon;
 mod rule;
 mod segment;
 mod smooth;
 mod text;
-mod tile;
 mod violin;
 
 // Re-export types
@@ -64,12 +64,12 @@ pub use linear::Linear;
 pub use path::Path;
 pub use point::Point;
 pub use polygon::Polygon;
+pub use rect::Rect;
 pub use ribbon::Ribbon;
 pub use rule::Rule;
 pub use segment::Segment;
 pub use smooth::Smooth;
 pub use text::Text;
-pub use tile::Tile;
 pub use violin::Violin;
 
 use crate::plot::types::{DefaultAestheticValue, ParameterValue, Schema};
@@ -84,7 +84,7 @@ pub enum GeomType {
     Path,
     Bar,
     Area,
-    Tile,
+    Rect,
     Polygon,
     Ribbon,
     Histogram,
@@ -108,7 +108,7 @@ impl std::fmt::Display for GeomType {
             GeomType::Path => "path",
             GeomType::Bar => "bar",
             GeomType::Area => "area",
-            GeomType::Tile => "tile",
+            GeomType::Rect => "rect",
             GeomType::Polygon => "polygon",
             GeomType::Ribbon => "ribbon",
             GeomType::Histogram => "histogram",
@@ -262,9 +262,9 @@ impl Geom {
         Self(Arc::new(Area))
     }
 
-    /// Create a Tile geom
-    pub fn tile() -> Self {
-        Self(Arc::new(Tile))
+    /// Create a Rect geom
+    pub fn rect() -> Self {
+        Self(Arc::new(Rect))
     }
 
     /// Create a Polygon geom
@@ -340,7 +340,7 @@ impl Geom {
             GeomType::Path => Self::path(),
             GeomType::Bar => Self::bar(),
             GeomType::Area => Self::area(),
-            GeomType::Tile => Self::tile(),
+            GeomType::Rect => Self::rect(),
             GeomType::Polygon => Self::polygon(),
             GeomType::Ribbon => Self::ribbon(),
             GeomType::Histogram => Self::histogram(),