---------------------------------------------------------------------- This is the API documentation for the gdtest_navbar_color library. ---------------------------------------------------------------------- ## Functions Public functions contrast_ratio(bg_color: str, fg_color: str) -> float Compute the APCA contrast ratio between two colors. Parameters ---------- bg_color Background color as a hex string (e.g., ``"#2c3e50"``). fg_color Foreground (text) color as a hex string. Returns ------- float The APCA Lc contrast value. Higher absolute values indicate stronger contrast. Examples -------- >>> contrast_ratio("#000000", "#FFFFFF") 106.04 >>> contrast_ratio("#FFFFFF", "#000000") -107.88 ideal_text_color(bg_color: str) -> str Choose the best text color (light or dark) for a background. Uses the APCA algorithm to determine whether white or black text provides better contrast against the given background. Parameters ---------- bg_color Background color as a hex string or CSS named color. Returns ------- str Either ``"#FFFFFF"`` (white) or ``"#000000"`` (black). Examples -------- >>> ideal_text_color("#2c3e50") '#FFFFFF' >>> ideal_text_color("#e3f2fd") '#000000' >>> ideal_text_color("navy") '#FFFFFF' ---------------------------------------------------------------------- This is the User Guide documentation for the package. ---------------------------------------------------------------------- ## How `navbar_color` Works When you set `navbar_color` in your `great-docs.yml`, Great Docs uses the **APCA (Accessible Perceptual Contrast Algorithm)** to automatically determine whether the navbar text, icons, and controls should be **light** (white) or **dark** (black). This page shows the algorithm's choices across **97 different background colors** spanning the entire spectrum. ### Configuration for This Site This site uses per-mode navbar colors: ```yaml navbar_color: light: "#2c3e50" # Charcoal (gets white text) dark: "#1a237e" # Deep indigo (gets white text) ``` You can also set a single color for both modes: ```yaml navbar_color: steelblue ``` ## Color Swatch Grid Each row shows a background color with the APCA-selected text color rendered on top. The **Hex** and **Name** columns use the computed text color directly on the background, so you can judge readability at a glance.

Hex	Name	RGB	Text Choice
#FF0000	Red	rgb(255,0,0)	white
#DC143C	Crimson	rgb(220,20,60)	white
#8B0000	Dark Red	rgb(139,0,0)	white
#FF6347	Tomato	rgb(255,99,71)	white
#CD5C5C	Indian Red	rgb(205,92,92)	white
#F08080	Light Coral	rgb(240,128,128)	white
#FF4500	Orange Red	rgb(255,69,0)	white
#FF8C00	Dark Orange	rgb(255,140,0)	black
#FFA500	Orange	rgb(255,165,0)	black
#FF7F50	Coral	rgb(255,127,80)	black
#E9967A	Dark Salmon	rgb(233,150,122)	black
#FA8072	Salmon	rgb(250,128,114)	black
#FFD700	Gold	rgb(255,215,0)	black
#FFFF00	Yellow	rgb(255,255,0)	black
#F0E68C	Khaki	rgb(240,230,140)	black
#FAFAD2	Lt Goldenrod	rgb(250,250,210)	black
#FFFACD	Lemon Chiffon	rgb(255,250,205)	black
#EEE8AA	Pale Goldenrod	rgb(238,232,170)	black
#006400	Dark Green	rgb(0,100,0)	white
#008000	Green	rgb(0,128,0)	white
#228B22	Forest Green	rgb(34,139,34)	white
#2E8B57	Sea Green	rgb(46,139,87)	white
#32CD32	Lime Green	rgb(50,205,50)	black
#00FF00	Lime	rgb(0,255,0)	black
#90EE90	Light Green	rgb(144,238,144)	black
#98FB98	Pale Green	rgb(152,251,152)	black
#ADFF2F	Green Yellow	rgb(173,255,47)	black
#008080	Teal	rgb(0,128,128)	white
#008B8B	Dark Cyan	rgb(0,139,139)	white
#20B2AA	Lt Sea Green	rgb(32,178,170)	white
#00CED1	Dark Turquoise	rgb(0,206,209)	black
#40E0D0	Turquoise	rgb(64,224,208)	black
#00FFFF	Cyan	rgb(0,255,255)	black
#E0FFFF	Light Cyan	rgb(224,255,255)	black
#000080	Navy	rgb(0,0,128)	white
#00008B	Dark Blue	rgb(0,0,139)	white
#0000FF	Blue	rgb(0,0,255)	white
#191970	Midnight Blue	rgb(25,25,112)	white
#4169E1	Royal Blue	rgb(65,105,225)	white
#4682B4	Steel Blue	rgb(70,130,180)	white
#1E90FF	Dodger Blue	rgb(30,144,255)	white
#6495ED	Cornflower Blue	rgb(100,149,237)	white
#87CEEB	Sky Blue	rgb(135,206,235)	black
#ADD8E6	Light Blue	rgb(173,216,230)	black
#B0E0E6	Powder Blue	rgb(176,224,230)	black
#E3F2FD	Ice Blue	rgb(227,242,253)	black
#4B0082	Indigo	rgb(75,0,130)	white
#663399	Rebecca Purple	rgb(102,51,153)	white
#800080	Purple	rgb(128,0,128)	white
#8B008B	Dark Magenta	rgb(139,0,139)	white
#9370DB	Medium Purple	rgb(147,112,219)	white
#BA55D3	Medium Orchid	rgb(186,85,211)	white
#DA70D6	Orchid	rgb(218,112,214)	white
#DDA0DD	Plum	rgb(221,160,221)	black
#E6E6FA	Lavender	rgb(230,230,250)	black
#C71585	Med Violet Red	rgb(199,21,133)	white
#FF1493	Deep Pink	rgb(255,20,147)	white
#FF69B4	Hot Pink	rgb(255,105,180)	white
#FFB6C1	Light Pink	rgb(255,182,193)	black
#FFC0CB	Pink	rgb(255,192,203)	black
#FFF0F5	Lavender Blush	rgb(255,240,245)	black
#8B4513	Saddle Brown	rgb(139,69,19)	white
#A0522D	Sienna	rgb(160,82,45)	white
#D2691E	Chocolate	rgb(210,105,30)	white
#CD853F	Peru	rgb(205,133,63)	white
#DEB887	Burlywood	rgb(222,184,135)	black
#F5DEB3	Wheat	rgb(245,222,179)	black
#000000	Black	rgb(0,0,0)	white
#1a1a1a	#1a1a1a	rgb(26,26,26)	white
#333333	#333333	rgb(51,51,51)	white
#555555	#555555	rgb(85,85,85)	white
#696969	Dim Gray	rgb(105,105,105)	white
#808080	Gray	rgb(128,128,128)	white
#A9A9A9	Dark Gray	rgb(169,169,169)	black
#C0C0C0	Silver	rgb(192,192,192)	black
#D3D3D3	Light Gray	rgb(211,211,211)	black
#F5F5F5	White Smoke	rgb(245,245,245)	black
#FFFFFF	White	rgb(255,255,255)	black
#2c3e50	Charcoal	rgb(44,62,80)	white
#34495e	Wet Asphalt	rgb(52,73,94)	white
#1abc9c	Turquoise	rgb(26,188,156)	black
#2ecc71	Emerald	rgb(46,204,113)	black
#3498db	Peter River	rgb(52,152,219)	white
#9b59b6	Amethyst	rgb(155,89,182)	white
#e74c3c	Alizarin	rgb(231,76,60)	white
#f39c12	Sun Flower	rgb(243,156,18)	black
#e67e22	Carrot	rgb(230,126,34)	white
#ecf0f1	Clouds	rgb(236,240,241)	black
#bdc3c7	Silver Cloud	rgb(189,195,199)	black
#7f8c8d	Asbestos	rgb(127,140,141)	white
#27ae60	Nephritis	rgb(39,174,96)	white
#16a085	Green Sea	rgb(22,160,133)	white
#2980b9	Belize Hole	rgb(41,128,185)	white
#8e44ad	Wisteria	rgb(142,68,173)	white
#f1c40f	Sunflower	rgb(241,196,15)	black
#d35400	Pumpkin	rgb(211,84,0)	white
#c0392b	Pomegranate	rgb(192,57,43)	white

## About the APCA Algorithm The APCA (Accessible Perceptual Contrast Algorithm) is a modern replacement for the WCAG 2.x contrast ratio. Key advantages: - **Perceptually uniform**: matches how humans actually perceive contrast, unlike the simple luminance ratio in WCAG 2.x. - **Polarity-aware**: treats dark-on-light differently from light-on-dark, reflecting the asymmetry in human vision. - **Better mid-range decisions**: WCAG 2.x often fails for medium-tone colors; APCA handles these correctly. The implementation is ported from the [gt R package](https://github.com/rstudio/gt), using SAPC APCA Beta 0.0.98G-4g coefficients.