SQL functions wrapping the Rust palette, csscolorparser and colorous color crates — 44 color spaces, conversion, blending, contrast, CSS, CAM16
Maintainer(s):
shijianjs
Compatibility Matrix
This table covers all DuckDB releases that have not reached end-of-life, including LTS releases, and shows the 2 most recent patch releases of each. Older patch releases are not listed, but the extension may be available for them as well.
| Platform | 1.4.4 | 1.4.5 | 1.5.5 | 1.5.6 | 2.0.0 |
|---|---|---|---|---|---|
| Linux AMD64 | |||||
| Linux ARM64 | |||||
| macOS AMD64 | |||||
| macOS ARM64 | |||||
| Windows AMD64 | |||||
| Windows ARM64 | |||||
| WebAssembly |
Installing and Loading
INSTALL duckfn_palette FROM community;
LOAD duckfn_palette;
Example
-- A color is one STRUCT, so it can live in a column
SELECT plt_to_hex(plt_convert(plt_srgb(1, 0.5, 0), 'oklch'));
-- #ff8000
SELECT plt_to_hex(plt_mix(plt_named('red'), plt_named('blue'), 0.5));
-- #800080
SELECT plt_contrast(plt_named('white'), plt_named('black'));
-- 21.0
About duckfn_palette
Documentation: user guide · function reference - installation, every function with a runnable example, and the NULL / error rules.
duckfn_palette wraps three Rust color crates with SQL functions:
palette for 44 color spaces, conversion, blending and
compositing, color-difference metrics and WCAG contrast, color schemes, white points, chromatic
adaptation, transfer functions, 3x3 matrices, CAM16 with custom viewing conditions and 8-bit
packing; csscolorparser for CSS Color Level 4 strings;
and colorous for the d3-scale-chromatic gradients and
categorical palettes. Together they register 160 functions under the plt_ prefix.
A color is a single STRUCT, so it can be stored in a column and compared like any other value:
STRUCT(space VARCHAR, c1 DOUBLE, c2 DOUBLE, c3 DOUBLE, alpha DOUBLE)
Every space has a constructor of its own name, with components in palette's Color::new order:
| Function | Kind | Input -> output |
|---|---|---|
plt_srgb(r, g, b) |
scalar | three DOUBLE -> plt_color
|
plt_convert(color, space) |
scalar |
plt_color, VARCHAR -> plt_color
|
plt_mix(a, b, factor) |
scalar | two plt_color + DOUBLE -> plt_color
|
plt_difference(a, b, metric[, space]) |
scalar | DOUBLE |
plt_contrast(a, b) |
scalar |
DOUBLE (WCAG 2.1 ratio, 1..21) |
plt_css_serialize(color, format) |
scalar |
plt_color, VARCHAR -> VARCHAR
|
NULL semantics are uniform: a NULL argument gives NULL, and anything palette cannot compute gives NULL
too - never NaN and never 0. A rejected argument fails the statement with a message that starts with
the function name (plt_convert: unknown color space 'nope'). Space, mode, metric and white-point
names are case-insensitive and treat hyphens and spaces as underscores. Operations that palette defines
only for certain spaces (saturation needs a hue space, blend modes an RGB-like one) fail with a hint
to convert first.
Requires DuckDB 1.4 or newer: the extension is built for DuckDB 2.0.0 but declares the C API floor it needs (v1.2.0), so one binary loads into 1.4.x, 1.5.x and 2.0.0 alike - the C API is binary compatible across these versions, so the 2.0 release asset is the one to install on all of them and there is no separate 1.5 build. Development notes and the full function table live in the repository: https://github.com/shijianjs/duckfn-palette.
Added Functions
| function_name | function_type | description | comment | examples |
|---|---|---|---|---|
| plt_adaptation_matrix | scalar | The 3x3 matrix adapting XYZ values from a source white point to a target one, row-major | NULL | [SELECT plt_adaptation_matrix('a', 'c', 'bradford')] |
| plt_adaptation_methods | scalar | Every supported chromatic adaptation method (bradford, von_kries, unit_matrix) | NULL | [SELECT plt_adaptation_methods()] |
| plt_adobe_rgb | scalar | Adobe RGB (1998) color: red, green, blue in 0..1 | NULL | [SELECT plt_adobe_rgb(1, 0, 0)] |
| plt_adobe_rgb_linear | scalar | Linear-light Adobe RGB color: red, green, blue in 0..1 | NULL | [SELECT plt_adobe_rgb_linear(1, 0, 0)] |
| plt_alpha | scalar | The alpha channel of a color (0 transparent, 1 opaque) | NULL | [SELECT plt_alpha(plt_color('srgb', 1, 0, 0, 0.25))] |
| plt_analogous | scalar | The two analogous colors (hue - 30 and + 30 degrees) of a color | NULL | [SELECT plt_analogous(plt_hsl(120, 1, 0.5))] |
| plt_analogous_secondary | scalar | The next two analogous colors (hue - 60 and + 60 degrees) of a color | NULL | [SELECT plt_analogous_secondary(plt_hsl(120, 1, 0.5))] |
| plt_apply_matrix | scalar | Apply a 3x3 matrix to a color's three components in its current space (the space tag is kept) | NULL | [SELECT plt_apply_matrix(plt_adaptation_matrix('d65', 'd50', 'bradford'), plt_xyz(0.5, 0.4, 0.3))] |
| plt_blend | scalar | Blend a source color onto a destination color with a separable mode (multiply, screen, overlay, darken, lighten, dodge, burn, hard_light, soft_light, difference, exclusion) | NULL | [SELECT plt_blend(plt_srgb(0.5, 0.2, 0.1), plt_srgb(0.4, 0.6, 0.8), 'multiply')] |
| plt_blend_equations | scalar | Blend a source color onto a destination color with OpenGL-style source/destination factors (zero, one, source_color, one_minus_source_color, destination_color, one_minus_destination_color, source_alpha, one_minus_source_alpha, destination_alpha, one_minus_destination_alpha) | NULL | [SELECT plt_blend_equations(plt_with_alpha(plt_srgb(1, 0, 0), 0.5), plt_with_alpha(plt_srgb(0, 0, 1), 0.5), 'source_alpha', 'one_minus_source_alpha')] |
| plt_blend_modes | scalar | All supported blend mode names, as accepted by plt_blend | NULL | [SELECT plt_blend_modes()] |
| plt_blend_parameters | scalar | All supported blend factor names, as accepted by plt_blend_equations | NULL | [SELECT plt_blend_parameters()] |
| plt_brighten | scalar | Brighten by adding an amount (0..1 of the channel range) to every sRGB channel, clamped, and converting back to the input space | NULL | [SELECT plt_brighten(plt_srgb(0.2, 0.3, 0.4), 0.1)] |
| plt_brightness | scalar | YIQ brightness (0 black .. 1 white) from the sRGB channels, clamped to 0..1; alpha is ignored | NULL | [SELECT plt_brightness(plt_srgb(0.2, 0.6, 0.9))] |
| plt_cam16_default_params | scalar | palette's default CAM16 viewing conditions (D65, La = 40, Yb = 0.2, average surround, auto discounting) | NULL | [SELECT plt_cam16_default_params()] |
| plt_cam16_from_xyz | scalar | Convert an xyz color into the full CAM16 attributes (lightness, chroma, hue, brightness, colorfulness, saturation) under custom viewing conditions | NULL | [SELECT plt_cam16_from_xyz(plt_xyz(0.4, 0.3, 0.2), plt_cam16_default_params())] |
| plt_cam16_jch | scalar | CAM16 (J, C, h) under palette's default viewing conditions: lightness, chroma, hue in degrees | NULL | [SELECT plt_cam16_jch(50, 40, 120)] |
| plt_cam16_jmh | scalar | CAM16 (J, M, h) under default viewing conditions: lightness, colorfulness, hue in degrees | NULL | [SELECT plt_cam16_jmh(50, 40, 120)] |
| plt_cam16_jsh | scalar | CAM16 (J, s, h) under default viewing conditions: lightness, saturation, hue in degrees | NULL | [SELECT plt_cam16_jsh(50, 40, 120)] |
| plt_cam16_params | scalar | CAM16 viewing conditions from a named white point with a custom discounting factor (0..1), instead of auto | NULL | [SELECT plt_cam16_params('d65', 40, 0.2, 'dim', 0.9); SELECT plt_cam16_params('d65', 40, 0.2, 'average')] |
| plt_cam16_params_xyz | scalar | CAM16 viewing conditions from a custom white point XYZ with a custom discounting factor (0..1) | NULL | [SELECT plt_cam16_params_xyz(0.95047, 1, 1.08883, 40, 0.2, 'average', 0.8); SELECT plt_cam16_params_xyz(0.95047, 1, 1.08883, 40, 0.2, 'average')] |
| plt_cam16_partial_from_xyz | scalar | Convert an xyz color into a partial CAM16 space (cam16_jch, cam16_jmh, cam16_jsh, cam16_qch, cam16_qmh, cam16_qsh, cam16_ucs_jab, cam16_ucs_jmh) under custom viewing conditions | NULL | [SELECT plt_cam16_partial_from_xyz(plt_xyz(0.4, 0.3, 0.2), 'cam16_jch', plt_cam16_default_params())] |
| plt_cam16_partial_to_xyz | scalar | Convert a partial CAM16 color (cam16_jch etc.) back into an xyz color under custom viewing conditions | NULL | [SELECT plt_cam16_partial_to_xyz(plt_cam16_jch(50, 40, 120), plt_cam16_default_params())] |
| plt_cam16_qch | scalar | CAM16 (Q, C, h) under default viewing conditions: brightness, chroma, hue in degrees | NULL | [SELECT plt_cam16_qch(50, 40, 120)] |
| plt_cam16_qmh | scalar | CAM16 (Q, M, h) under default viewing conditions: brightness, colorfulness, hue in degrees | NULL | [SELECT plt_cam16_qmh(50, 40, 120)] |
| plt_cam16_qsh | scalar | CAM16 (Q, s, h) under default viewing conditions: brightness, saturation, hue in degrees | NULL | [SELECT plt_cam16_qsh(50, 40, 120)] |
| plt_cam16_spaces | scalar | Every CAM16 space that can be produced with custom viewing conditions | NULL | [SELECT plt_cam16_spaces()] |
| plt_cam16_surrounds | scalar | The named CAM16 surround presets (dark, dim, average) and their percentages | NULL | [SELECT plt_cam16_surrounds()] |
| plt_cam16_to_xyz | scalar | Convert the full CAM16 attributes back into an xyz color under custom viewing conditions | NULL | [SELECT plt_cam16_to_xyz(plt_cam16_from_xyz(plt_xyz(0.4, 0.3, 0.2), plt_cam16_default_params()), plt_cam16_default_params())] |
| plt_cam16_ucs_jab | scalar | CAM16-UCS (J', a', b') under default viewing conditions | NULL | [SELECT plt_cam16_ucs_jab(50, 20, -30)] |
| plt_cam16_ucs_jmh | scalar | CAM16-UCS (J', M', h) under default viewing conditions: lightness, colorfulness, hue in degrees | NULL | [SELECT plt_cam16_ucs_jmh(50, 40, 120)] |
| plt_chromatic_adapt | scalar | Adapt an xyz color from a source white point to a target white point (the color's components are XYZ under the source) | NULL | [SELECT plt_chromatic_adapt(plt_xyz(0.315756, 0.162732, 0.015905), 'a', 'c', 'bradford'); SELECT plt_chromatic_adapt(plt_xyz(0.5, 0.4, 0.3), 'd50', 'bradford')] |
| plt_clamp | scalar | Clamp a color's components to its own space's standard range | NULL | [SELECT plt_components(plt_clamp(plt_lab(50, 200, 200)))] |
| plt_color | scalar | Build a color in any supported space from a space name, three components and an alpha value | NULL | [SELECT plt_color('oklch', 0.7, 0.1, 120, 0.5); SELECT plt_color('lab', 50, 20, -30)] |
| plt_color_schemes | scalar | All supported color theory scheme names, as accepted by plt_harmony | NULL | [SELECT plt_color_schemes()] |
| plt_color_spaces | scalar | All supported color space names, as accepted by plt_convert and plt_color | NULL | [SELECT plt_color_spaces()] |
| plt_colorous_categorical | scalar | A whole colorous categorical palette, as a LIST of sRGB colors | NULL | [SELECT plt_colorous_categorical('tableau10')] |
| plt_colorous_categoricals | scalar | Every colorous categorical palette name | NULL | [SELECT plt_colorous_categoricals()] |
| plt_colorous_gradient | scalar | Sample a colorous gradient at position t (clamped to [0, 1]), as an sRGB color | NULL | [SELECT plt_colorous_gradient('viridis', 0.5)] |
| plt_colorous_palette | scalar | n colors evenly sampled from a colorous gradient, as a LIST of sRGB colors; n must be at least 1 | NULL | [SELECT plt_colorous_palette('plasma', 5)] |
| plt_colorous_palettes | scalar | Every colorous continuous gradient name (sequential, diverging and cyclical) | NULL | [SELECT plt_colorous_palettes()] |
| plt_complementary | scalar | The complementary color (hue + 180 degrees) of a color; the color must have a hue | NULL | [SELECT plt_complementary(plt_hsl(120, 1, 0.5))] |
| plt_component | scalar | One component of a color by 1-based index (1..3) | NULL | [SELECT plt_component(plt_srgb(0.1, 0.2, 0.3), 2)] |
| plt_components | scalar | The three components of a color as a LIST(DOUBLE), in the space's natural order | NULL | [SELECT plt_components(plt_srgb(0.1, 0.2, 0.3))] |
| plt_compose | scalar | Composite a source color with a destination color using a Porter-Duff operator (over, inside, outside, atop, xor, plus) | NULL | [SELECT plt_compose(plt_with_alpha(plt_srgb(1, 0, 0), 0.5), plt_with_alpha(plt_srgb(0, 0, 1), 0.5), 'over')] |
| plt_compose_modes | scalar | All supported composition operator names, as accepted by plt_compose | NULL | [SELECT plt_compose_modes()] |
| plt_contrast | scalar | WCAG 2.1 relative contrast ratio between two colors (1 to 21), computed by converting both to sRGB | NULL | [SELECT plt_contrast(plt_srgb(1, 1, 1), plt_srgb(0, 0, 0))] |
| plt_contrast_check | scalar | Whether two colors meet a WCAG 2.1 contrast criterion (min_text, min_large_text, enhanced_text, enhanced_large_text, min_graphics) | NULL | [SELECT plt_contrast_check(plt_srgb(1, 1, 1), plt_srgb(0, 0, 0), 'min_text')] |
| plt_contrast_criteria | scalar | All supported WCAG 2.1 contrast criterion names, as accepted by plt_contrast_check | NULL | [SELECT plt_contrast_criteria()] |
| plt_convert | scalar | Convert a color to another space without gamut clamping (palette's unclamped conversion) | NULL | [SELECT plt_components(plt_convert(plt_srgb(1, 0, 0), 'lab'))] |
| plt_convert_clamped | scalar | Convert a color to another space, then clamp the result to that space's standard range | NULL | [SELECT plt_components(plt_convert_clamped(plt_lab(50, 200, 200), 'srgb'))] |
| plt_css_formats | scalar | All supported CSS serialization format names, as accepted by plt_css_serialize | NULL | [SELECT plt_css_formats()] |
| plt_css_is_valid | scalar | Whether a string is a valid CSS Color Level 4 color | NULL | [SELECT plt_css_is_valid('#ff0000')] |
| plt_css_name | scalar | The CSS keyword name of a color when its sRGB bytes match a named color exactly, or NULL | NULL | [SELECT plt_css_name(plt_srgb(1, 0, 0))] |
| plt_css_parse | scalar | Parse a CSS Color Level 4 string (named colors, #rgb/#rrggbb/#rrggbbaa, rgb(), hsl(), hwb(), lab(), lch(), oklab(), oklch(), color(…)) into an sRGB color; NULL when unparsable | NULL | [SELECT plt_css_parse('hsl(120 100% 50% / 0.5)')] |
| plt_css_serialize | scalar | Serialize a color into CSS syntax (format: hex, rgb, hsl, hwb, lab, lch, oklab, oklch) | NULL | [SELECT plt_css_serialize(plt_srgb(1, 0, 0), 'oklch')] |
| plt_darken | scalar | Darken a color by scaling its lightness towards the minimum (factor 0..1) | NULL | [SELECT plt_darken(plt_hsv(0, 1, 0.5), 0.5)] |
| plt_darken_fixed | scalar | Darken a color by an absolute amount of its lightness range (amount 0..1) | NULL | [SELECT plt_darken_fixed(plt_hsv(0, 1, 0.4), 0.2)] |
| plt_dci_p3 | scalar | DCI-P3 color (DCI-P3 white point, gamma 2.6): red, green, blue in 0..1 | NULL | [SELECT plt_dci_p3(1, 0, 0)] |
| plt_dci_p3_linear | scalar | Linear-light DCI-P3 color: red, green, blue in 0..1 | NULL | [SELECT plt_dci_p3_linear(1, 0, 0)] |
| plt_decode | scalar | Decode one encoded component value into linear light using the space's transfer function | NULL | [SELECT plt_decode('srgb', 0.5)] |
| plt_desaturate | scalar | Decrease saturation or chroma by scaling towards the minimum (factor 0..1) | NULL | [SELECT plt_desaturate(plt_hsl(0, 0.5, 0.5), 0.5)] |
| plt_desaturate_fixed | scalar | Decrease saturation or chroma by an absolute amount (amount 0..1) | NULL | [SELECT plt_desaturate_fixed(plt_hsl(0, 0.4, 0.5), 0.2)] |
| plt_diagonal_adaptation_matrix | scalar | The diagonal LMS gain matrix between two white points, to be used between plt_lms_matrix and plt_lms_to_xyz_matrix | NULL | [SELECT plt_diagonal_adaptation_matrix('a', 'c', 'bradford')] |
| plt_difference | scalar | Color difference between two colors with a metric, computed in the given color space | NULL | [SELECT plt_difference(plt_srgb(1, 0, 0), plt_srgb(0, 1, 0), 'euclidean', 'oklab'); SELECT plt_difference(plt_lab(50, 2.6772, -79.7751), plt_lab(50, 0, -82.7485), 'ciede2000')] |
| plt_difference_metrics | scalar | All supported color difference metric names, as accepted by plt_difference | NULL | [SELECT plt_difference_metrics()] |
| plt_display_p3 | scalar | Display P3 color (D65, sRGB transfer function): red, green, blue in 0..1 | NULL | [SELECT plt_display_p3(1, 0, 0)] |
| plt_display_p3_linear | scalar | Linear-light Display P3 color: red, green, blue in 0..1 | NULL | [SELECT plt_display_p3_linear(1, 0, 0)] |
| plt_encode | scalar | Encode one linear component value with the space's transfer function | NULL | [SELECT plt_encode('srgb', 0.21404114)] |
| plt_encoding_spaces | scalar | Spaces that have a transfer function (RGB spaces plus luma), as accepted by plt_decode and plt_encode | NULL | [SELECT plt_encoding_spaces()] |
| plt_equals | scalar | Whether two colors render as the same 8-bit sRGB value and alpha (rounded to two decimals), regardless of their spaces | NULL | [SELECT plt_equals(plt_srgb(1, 0, 0), plt_hsl(0, 1, 0.5))] |
| plt_from_components | scalar | Build a color from a space name and a LIST(DOUBLE) of exactly three components | NULL | [SELECT plt_from_components('lab', [50, 20, -30])] |
| plt_from_components_alpha | scalar | Build a color from a space name and a LIST(DOUBLE) of exactly four values (three components plus alpha) | NULL | [SELECT plt_from_components_alpha('lab', [50, 20, -30, 0.5])] |
| plt_from_hex | scalar | Parse a hexadecimal color (#rgb, #rgba, #rrggbb, #rrggbbaa, with or without '#') using palette's hex parser; NULL when invalid | NULL | [SELECT plt_from_hex('#ff800080')] |
| plt_greyscale | scalar | Greyscale a color by dropping its HSL saturation to zero, returning to the input space | NULL | [SELECT plt_greyscale(plt_srgb(1, 0, 0))] |
| plt_harmony | scalar | The other colors of a color theory scheme by name (complementary, split_complementary, analogous, analogous_secondary, triadic, tetradic) | NULL | [SELECT plt_harmony(plt_oklch(0.7, 0.1, 120), 'triadic')] |
| plt_hsl | scalar | HSL color: hue in degrees, saturation 0..1, lightness 0..1 (sRGB primaries) | NULL | [SELECT plt_hsl(120, 0.5, 0.5)] |
| plt_hsluv | scalar | HSLuv color (D65): hue in degrees, saturation 0..100, lightness 0..100 | NULL | [SELECT plt_hsluv(120, 50, 50)] |
| plt_hsv | scalar | HSV color: hue in degrees, saturation 0..1, value 0..1 (sRGB primaries) | NULL | [SELECT plt_hsv(120, 0.5, 0.5)] |
| plt_hue | scalar | The hue of a color in degrees (0..360); gray colors report 0 | NULL | [SELECT plt_hue(plt_srgb(1, 0, 0))] |
| plt_hwb | scalar | HWB color: hue in degrees, whiteness 0..1, blackness 0..1 (sRGB primaries) | NULL | [SELECT plt_hwb(120, 0.2, 0.2)] |
| plt_is_dark | scalar | Whether a color is dark by tinycolor's YIQ rule (brightness < 128/255); alpha is ignored | NULL | [SELECT plt_is_dark(plt_srgb(0, 0, 0))] |
| plt_is_light | scalar | Whether a color is light by tinycolor's YIQ rule (brightness >= 128/255); alpha is ignored | NULL | [SELECT plt_is_light(plt_srgb(1, 1, 1))] |
| plt_is_within_bounds | scalar | Whether all components of a color are already within its space's standard range | NULL | [SELECT plt_is_within_bounds(plt_lab(50, 200, 200))] |
| plt_lab | scalar | CIELAB color (D65): L* 0..100, a, b roughly -128..127 | NULL | [SELECT plt_lab(50, 20, -30)] |
| plt_lch | scalar | CIE LCH color (D65): L* 0..100, chroma >= 0, hue in degrees | NULL | [SELECT plt_lch(50, 40, 120)] |
| plt_lchuv | scalar | CIE LCHuv color (D65): L* 0..100, chroma >= 0, hue in degrees (same model as HSLuv) | NULL | [SELECT plt_lchuv(50, 40, 120)] |
| plt_lighten | scalar | Lighten a color by scaling its lightness towards the maximum (factor 0..1) | NULL | [SELECT plt_lighten(plt_hsl(0, 1, 0.5), 0.5)] |
| plt_lighten_fixed | scalar | Lighten a color by an absolute amount of its lightness range (amount 0..1) | NULL | [SELECT plt_lighten_fixed(plt_hsl(0, 1, 0.4), 0.2)] |
| plt_lms | scalar | LMS cone response (Bradford matrix, D65): long, medium, short | NULL | [SELECT plt_lms(0.5, 0.4, 0.3)] |
| plt_lms_matrix | scalar | The XYZ-to-LMS matrix used by an adaptation method, row-major | NULL | [SELECT plt_lms_matrix('bradford')] |
| plt_lms_to_xyz_matrix | scalar | The LMS-to-XYZ matrix used by an adaptation method, row-major | NULL | [SELECT plt_lms_to_xyz_matrix('bradford')] |
| plt_lms_von_kries | scalar | LMS cone response (von Kries / Hunt-Pointer-Estevez matrix, D65): long, medium, short | NULL | [SELECT plt_lms_von_kries(0.5, 0.4, 0.3)] |
| plt_luma | scalar | sRGB-encoded luminance (grayscale) color: one component in 0..1 | NULL | [SELECT plt_luma(0.5)] |
| plt_luma_gamma | scalar | Gamma 2.2 encoded luminance (grayscale) color: one component in 0..1 | NULL | [SELECT plt_luma_gamma(0.5)] |
| plt_luma_linear | scalar | Linear-light luminance (grayscale) color: one component in 0..1 | NULL | [SELECT plt_luma_linear(0.5)] |
| plt_luv | scalar | CIELUV color (D65): L* 0..100, u, v | NULL | [SELECT plt_luv(50, 20, -30)] |
| plt_matrix_apply | scalar | Apply a 3x3 matrix to three numbers, returning LIST(DOUBLE) of 3 | NULL | [SELECT plt_matrix_apply(plt_matrix_identity(), 1, 2, 3)] |
| plt_matrix_identity | scalar | The 3x3 identity matrix, row-major as LIST(DOUBLE) of 9 | NULL | [SELECT plt_matrix_identity()] |
| plt_matrix_inverse | scalar | Invert a 3x3 matrix (row-major LIST(DOUBLE) of 9) | NULL | [SELECT plt_matrix_inverse(plt_matrix_scale(2, 4, 0.5))] |
| plt_matrix_multiply | scalar | Multiply two 3x3 matrices, applying the first and then the second (row-major LIST(DOUBLE) of 9) | NULL | [SELECT plt_matrix_multiply(plt_matrix_identity(), plt_matrix_scale(2, 2, 2))] |
| plt_matrix_scale | scalar | A diagonal 3x3 matrix with the given diagonal entries, row-major | NULL | [SELECT plt_matrix_scale(0.5, 0.5, 0.5)] |
| plt_mix | scalar | Mix two colors by a factor (0 = first, 1 = second) in the first color's space; alpha is mixed too | NULL | [SELECT plt_mix(plt_oklch(0.6, 0.1, 30), plt_oklch(0.8, 0.1, 200), 0.5)] |
| plt_monochromatic | scalar | A monochromatic scheme: count colors with the same hue and saturation, cycling HSV value by 1/count from the input's value; count must be non-negative | NULL | [SELECT plt_monochromatic(plt_hsv(120, 1, 0.5), 4)] |
| plt_most_readable | scalar | The candidate with the highest WCAG contrast ratio against the base color; when none meets the criterion and include_fallback is true, the more contrasting of black and white instead | NULL | [SELECT plt_most_readable(plt_srgb(1, 1, 1), [plt_srgb(0.9, 0.9, 0.9)], 'min_text', true); SELECT plt_most_readable(plt_srgb(1, 1, 1), [plt_srgb(0.9, 0.9, 0.9)], 'min_text'); SELECT plt_most_readable(plt_srgb(1, 1, 1), [plt_srgb(0, 0, 0), plt_srgb(0.9, 0.9, 0.9)])] |
| plt_named | scalar | An SVG/CSS3 named color such as 'rebeccapurple' as an sRGB color, or NULL for an unknown name | NULL | [SELECT plt_named('rebeccapurple')] |
| plt_named_names | scalar | All SVG/CSS3 named color names, sorted alphabetically | NULL | [SELECT plt_named_names()] |
| plt_nearest_named | scalar | The closest SVG/CSS3 named color by CIEDE2000 distance, regardless of exact match; alpha is ignored | NULL | [SELECT plt_nearest_named(plt_srgb(0.95, 0.05, 0.05))] |
| plt_okhsl | scalar | Okhsl color: hue in degrees, saturation 0..1, lightness 0..1 | NULL | [SELECT plt_okhsl(120, 0.5, 0.5)] |
| plt_okhsv | scalar | Okhsv color: hue in degrees, saturation 0..1, value 0..1 | NULL | [SELECT plt_okhsv(120, 0.5, 0.5)] |
| plt_okhwb | scalar | Okhwb color: hue in degrees, whiteness 0..1, blackness 0..1 | NULL | [SELECT plt_okhwb(120, 0.2, 0.2)] |
| plt_oklab | scalar | Oklab color: lightness 0..1, a, b (nominally -1..1) | NULL | [SELECT plt_oklab(0.5, 0.1, 0.1)] |
| plt_oklch | scalar | Oklch color: lightness 0..1, chroma >= 0, hue in degrees | NULL | [SELECT plt_oklch(0.5, 0.1, 120)] |
| plt_opaque | scalar | Make a color fully opaque (alpha = 1) | NULL | [SELECT plt_alpha(plt_opaque(plt_color('srgb', 1, 0, 0, 0.25)))] |
| plt_pack | scalar | Pack a color into a 32-bit ARGB integer after converting to sRGB and quantizing to 8 bits per channel | NULL | [SELECT plt_pack(plt_srgb(1, 0.5, 0)); SELECT plt_pack(plt_srgb(1, 0.5, 0), 'rgba')] |
| plt_pack_orders | scalar | Channel orders accepted by plt_pack and plt_unpack (argb, rgba, abgr, bgra) | NULL | [SELECT plt_pack_orders()] |
| plt_premultiply | scalar | Premultiply a color by its alpha (components multiplied by alpha; alpha must be in 0..1) | NULL | [SELECT plt_premultiply(plt_with_alpha(plt_srgb(1, 0.5, 0.25), 0.5))] |
| plt_prophoto_rgb | scalar | ProPhoto RGB color (D50 white point, gamma 1.8): red, green, blue in 0..1 | NULL | [SELECT plt_prophoto_rgb(1, 0, 0)] |
| plt_prophoto_rgb_linear | scalar | Linear-light ProPhoto RGB color (D50 white point): red, green, blue in 0..1 | NULL | [SELECT plt_prophoto_rgb_linear(1, 0, 0)] |
| plt_random_color | scalar | A reproducible random color in the given space; the BIGINT seed identifies the sequence | NULL | [SELECT plt_random_color('oklch', 42)] |
| plt_random_colors | scalar | A LIST of reproducible random colors from one seeded sequence; count must be non-negative | NULL | [SELECT plt_random_colors('srgb', 5, 42)] |
| plt_random_spaces | scalar | Every color space that can be sampled randomly (palette implements a Standard distribution for it) | NULL | [SELECT plt_random_spaces()] |
| plt_rec2020 | scalar | Rec. 2020 color (D65, Rec. 2020 transfer function): red, green, blue in 0..1 | NULL | [SELECT plt_rec2020(1, 0, 0)] |
| plt_rec2020_linear | scalar | Linear-light Rec. 2020 color: red, green, blue in 0..1 | NULL | [SELECT plt_rec2020_linear(1, 0, 0)] |
| plt_rec709 | scalar | Rec. 709 color (sRGB primaries, Rec. 709 transfer function): red, green, blue in 0..1 | NULL | [SELECT plt_rec709(1, 0, 0)] |
| plt_rec709_linear | scalar | Linear-light Rec. 709 color: red, green, blue in 0..1 | NULL | [SELECT plt_rec709_linear(1, 0, 0)] |
| plt_relative_luminance | scalar | WCAG 2.1 relative luminance of a color (0 is black, 1 is white), computed by converting to sRGB | NULL | [SELECT plt_relative_luminance(plt_srgb(0.5, 0.5, 0.5))] |
| plt_rgb_primaries | scalar | The red, green and blue primaries of an RGB space, as three yxy colors | NULL | [SELECT plt_rgb_primaries('srgb')] |
| plt_rgb_to_xyz_matrix | scalar | The 3x3 RGB-to-XYZ matrix of an RGB space, row-major as LIST(DOUBLE) of 9 | NULL | [SELECT plt_rgb_to_xyz_matrix('srgb')] |
| plt_saturate | scalar | Increase saturation or chroma by scaling towards the maximum (factor 0..1) | NULL | [SELECT plt_saturate(plt_hsl(0, 0.5, 0.5), 0.5)] |
| plt_saturate_fixed | scalar | Increase saturation or chroma by an absolute amount (amount 0..1) | NULL | [SELECT plt_saturate_fixed(plt_hsl(0, 0.4, 0.5), 0.2)] |
| plt_shade | scalar | Shade a color by mixing it towards black in sRGB by amount (0 unchanged, 1 black); alpha is unchanged | NULL | [SELECT plt_shade(plt_srgb(1, 0, 0), 0.5)] |
| plt_shift_hue | scalar | Rotate the hue of a color by degrees (any real number; wraps at 360) | NULL | [SELECT plt_shift_hue(plt_hsl(120, 1, 0.5), 120)] |
| plt_space | scalar | The color space name of a color value (as returned by plt_color_spaces) | NULL | [SELECT plt_space(plt_srgb(1, 0, 0))] |
| plt_split_complementary | scalar | The two split complementary colors (hue + 150 and + 210 degrees) of a color | NULL | [SELECT plt_split_complementary(plt_hsl(120, 1, 0.5))] |
| plt_srgb | scalar | Gamma-encoded sRGB color: red, green, blue in 0..1 | NULL | [SELECT plt_srgb(1, 0, 0)] |
| plt_srgb_gamma | scalar | Gamma 2.2 encoded sRGB color (palette's deprecated GammaSrgb): red, green, blue in 0..1 | NULL | [SELECT plt_srgb_gamma(1, 0, 0)] |
| plt_srgb_linear | scalar | Linear-light sRGB color: red, green, blue in 0..1 | NULL | [SELECT plt_srgb_linear(1, 0, 0)] |
| plt_tetradic | scalar | The three tetradic (square) colors (hue + 90, + 180 and + 270 degrees) of a color | NULL | [SELECT plt_tetradic(plt_hsl(120, 1, 0.5))] |
| plt_tint | scalar | Tint a color by mixing it towards white in sRGB by amount (0 unchanged, 1 white); alpha is unchanged | NULL | [SELECT plt_tint(plt_srgb(1, 0, 0), 0.5)] |
| plt_to_hex | scalar | Format a color as hexadecimal (#rrggbb, or #rrggbbaa when alpha is not 1) by converting to sRGB and quantizing to 8 bits | NULL | [SELECT plt_to_hex(plt_srgb(1, 0.5, 0))] |
| plt_to_hex6 | scalar | Format a color as #rrggbb, always six digits; alpha is ignored | NULL | [SELECT plt_to_hex6(plt_color('srgb', 1, 0.5, 0, 0.5))] |
| plt_to_hex8 | scalar | Format a color as #rrggbbaa, always eight digits (alpha = ff when opaque) | NULL | [SELECT plt_to_hex8(plt_srgb(1, 0.5, 0))] |
| plt_to_hsv_string | scalar | Format a color as hsv(h, s%, v%), or hsva() when alpha is not 1; hue and percentages are rounded like tinycolor | NULL | [SELECT plt_to_hsv_string(plt_srgb(1, 0, 0))] |
| plt_to_percentage_rgb | scalar | Format a color as CSS rgb() with percentages, or rgba() when alpha is not 1; channels and alpha are rounded like tinycolor | NULL | [SELECT plt_to_percentage_rgb(plt_srgb(1, 0.5, 0))] |
| plt_transfer_function | scalar | The transfer function a space uses (linear, gamma_2_2, srgb, adobe_rgb, prophoto_rgb, p3_gamma or rec_oetf) | NULL | [SELECT plt_transfer_function('srgb')] |
| plt_transfer_functions | scalar | Every transfer function name used by the supported spaces | NULL | [SELECT plt_transfer_functions()] |
| plt_triadic | scalar | The two triadic colors (hue + 120 and + 240 degrees) of a color | NULL | [SELECT plt_triadic(plt_hsl(120, 1, 0.5))] |
| plt_unpack | scalar | Unpack a 32-bit integer in the given channel order into an sRGB color | NULL | [SELECT plt_unpack(4278190335, 'rgba'); SELECT plt_unpack(4294901760)] |
| plt_unpremultiply | scalar | Undo premultiplication (components divided by alpha; zero alpha yields zero components) | NULL | [SELECT plt_unpremultiply(plt_premultiply(plt_with_alpha(plt_srgb(1, 0.5, 0.25), 0.5)))] |
| plt_white_point_of | scalar | The white point a color space is defined against (e.g. d65 for srgb, d50 for prophoto_rgb) | NULL | [SELECT plt_white_point_of('prophoto_rgb')] |
| plt_white_point_xy | scalar | The chromaticity coordinates (x, y) of a white point, as LIST(DOUBLE) of 2 | NULL | [SELECT plt_white_point_xy('d50')] |
| plt_white_point_xyz | scalar | The tristimulus values (X, Y, Z) of a white point, as LIST(DOUBLE) of 3 with Y = 1 | NULL | [SELECT plt_white_point_xyz('d65')] |
| plt_white_points | scalar | Every supported white point name (CIE illuminants plus the DCI-P3 theatre white) | NULL | [SELECT plt_white_points()] |
| plt_with_alpha | scalar | Set the alpha channel of a color, leaving space and components unchanged | NULL | [SELECT plt_alpha(plt_with_alpha(plt_srgb(1, 0, 0), 0.5))] |
| plt_with_hue | scalar | Set the hue of a color to the given degrees | NULL | [SELECT plt_with_hue(plt_hsl(120, 1, 0.5), 240)] |
| plt_xyz | scalar | CIE XYZ color with D65 white point: X, Y, Z | NULL | [SELECT plt_xyz(0.5, 0.4, 0.3)] |
| plt_xyz_d50 | scalar | CIE XYZ color with D50 white point: X, Y, Z (conversions adapt to/from D65 with Bradford) | NULL | [SELECT plt_xyz_d50(0.5, 0.4, 0.3)] |
| plt_xyz_to_rgb_matrix | scalar | The 3x3 XYZ-to-RGB matrix of an RGB space (the inverse of plt_rgb_to_xyz_matrix), row-major | NULL | [SELECT plt_xyz_to_rgb_matrix('srgb')] |
| plt_yxy | scalar | CIE xyY color (D65): chromaticity x, y and luminance Y | NULL | [SELECT plt_yxy(0.3, 0.3, 0.5)] |
Overloaded Functions
This extension does not add any function overloads.
Added Types
| type_name | type_size | logical_type | type_category | internal |
|---|---|---|---|---|
| plt_cam16_full | 0 | STRUCT | COMPOSITE | false |
| plt_cam16_params | 0 | STRUCT | COMPOSITE | false |
| plt_color | 0 | STRUCT | COMPOSITE | false |
Added Settings
| name | description | input_type | scope | aliases | typed_value |
|---|---|---|---|---|---|
| temp_directory | Set the directory to which temporary files are written. | VARCHAR | GLOBAL | [] | post.db.tmp |
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