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Object model for HTML5 canvas, and SVG-to-canvas parser. Backed by jsdom and node-canvas.
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JavaScript
/**
* Regex matching color in RGB or RGBA formats (ex: `rgb(0, 0, 0)`, `rgba(255, 100, 10, 0.5)`, `rgba( 255 , 100 , 10 , 0.5 )`, `rgb(1,1,1)`, `rgba(100%, 60%, 10%, 0.5)`)
* Also matching rgba(r g b / a) as per new specs
* https://developer.mozilla.org/en-US/docs/Web/CSS/color_value/rgb
* Formal syntax at the time of writing:
* <rgb()> =
* rgb( [ <percentage> | none ]{3} [ / [ <alpha-value> | none ] ]? ) |
* rgb( [ <number> | none ]{3} [ / [ <alpha-value> | none ] ]? )
* <alpha-value> = <number> | <percentage>
*
* For learners this is how you can read this regex
* Regular expression for matching an rgba or rgb CSS color value
*
* /^ # Beginning of the string
* rgba? # "rgb" or "rgba"
* \(\s* # Opening parenthesis and optional whitespace
* (\d{0,3} # 0 to three digits R channel
* (?:\.\d+)? # Optional decimal with one or more digits
* ) # End of capturing group for the first color component
* %? # Optional percent sign after the first color component
* \s* # Optional whitespace
* [\s|,] # Separator between color components can be a space or comma
* \s* # Optional whitespace
* (\d{0,3} # 0 to three digits G channel
* (?:\.\d+)? # Optional decimal with one or more digits
* ) # End of capturing group for the second color component
* %? # Optional percent sign after the second color component
* \s* # Optional whitespace
* [\s|,] # Separator between color components can be a space or comma
* \s* # Optional whitespace
* (\d{0,3} # 0 to three digits B channel
* (?:\.\d+)? # Optional decimal with one or more digits
* ) # End of capturing group for the third color component
* %? # Optional percent sign after the third color component
* \s* # Optional whitespace
* (?: # Beginning of non-capturing group for alpha value
* \s* # Optional whitespace
* [,/] # Comma or slash separator for alpha value
* \s* # Optional whitespace
* (\d{0,3} # Zero to three digits
* (?:\.\d+)? # Optional decimal with one or more digits
* ) # End of capturing group for alpha value
* %? # Optional percent sign after alpha value
* \s* # Optional whitespace
* )? # End of non-capturing group for alpha value (optional)
* \) # Closing parenthesis
* $ # End of the string
*
* The alpha channel can be in the format 0.4 .7 or 1 or 73%
*
* WARNING this regex doesn't fail on off spec colors. it matches everything that could be a color.
* So the spec does not allow for `rgba(30 , 45% 35, 49%)` but this will work anyways for us
*/
const reRGBa = () => /^rgba?\(\s*(\d{0,3}(?:\.\d+)?%?)\s*[\s|,]\s*(\d{0,3}(?:\.\d+)?%?)\s*[\s|,]\s*(\d{0,3}(?:\.\d+)?%?)\s*(?:\s*[,/]\s*(\d{0,3}(?:\.\d+)?%?)\s*)?\)$/i;
/**
* Regex matching color in HSL or HSLA formats (ex: hsl(0, 0, 0), rgba(255, 100, 10, 0.5), rgba( 255 , 100 , 10 , 0.5 ), rgb(1,1,1), rgba(100%, 60%, 10%, 0.5))
* Also matching rgba(r g b / a) as per new specs
* https://developer.mozilla.org/en-US/docs/Web/CSS/color_value/hsl
* Formal syntax at the time of writing:
* <hsl()> =
* hsl( [ <hue> | none ] [ <percentage> | none ] [ <percentage> | none ] [ / [ <alpha-value> | none ] ]? )
*
* <hue> =
* <number> |
* <angle>
*
* <alpha-value> =
* <number> |
* <percentage>
*
* For learners this is how you can read this regex
* Regular expression for matching an hsla or hsl CSS color value
*
* /^hsla?\( // Matches the beginning of the string and the opening parenthesis of "hsl" or "hsla"
* \s* // Matches any whitespace characters (space, tab, etc.) zero or more times
* (\d{0,3} // Hue: 0 to three digits - start capture in a group
* (?:\.\d+)? // Hue: Optional (non capture group) decimal with one or more digits.
* (?:deg|turn|rad)? // Hue: Optionally include suffix deg or turn or rad
* ) // Hue: End capture group
* \s* // Matches any whitespace characters zero or more times
* [\s|,] // Matches a space, tab or comma
* \s* // Matches any whitespace characters zero or more times
* (\d{0,3} // Saturation: 0 to three digits - start capture in a group
* (?:\.\d+)? // Saturation: Optional decimal with one or more digits in a non-capturing group
* %?) // Saturation: match optional % character and end capture group
* \s* // Matches any whitespace characters zero or more times
* [\s|,] // Matches a space, tab or comma
* \s* // Matches any whitespace characters zero or more times
* (\d{0,3} // Lightness: 0 to three digits - start capture in a group
* (?:\.\d+)? // Lightness: Optional decimal with one or more digits in a non-capturing group
* %?) // Lightness: match % character and end capture group
* \s* // Matches any whitespace characters zero or more times
* (?: // Alpha: Begins a non-capturing group for the alpha value
* \s* // Matches any whitespace characters zero or more times
* [,/] // Matches a comma or forward slash
* \s* // Matches any whitespace characters zero or more times
* (\d*(?:\.\d+)?%?) // Matches zero or more digits, optionally followed by a decimal point and one or more digits, followed by an optional percentage sign and captures it in a group
* \s* // Matches any whitespace characters zero or more times
* )? // Makes the alpha value group optional
* \) // Matches the closing parenthesis
* $/i // Matches the end of the string and sets the regular expression to case-insensitive mode
*
* WARNING this regex doesn't fail on off spec colors. It matches everything that could be a color.
* So the spec does not allow `hsl(30 , 45% 35, 49%)` but this will work anyways for us.
*/
const reHSLa = () => /^hsla?\(\s*([+-]?\d{0,3}(?:\.\d+)?(?:deg|turn|rad)?)\s*[\s|,]\s*(\d{0,3}(?:\.\d+)?%?)\s*[\s|,]\s*(\d{0,3}(?:\.\d+)?%?)\s*(?:\s*[,/]\s*(\d*(?:\.\d+)?%?)\s*)?\)$/i;
/**
* Regex matching color in HEX format (ex: #FF5544CC, #FF5555, 010155, aff)
*/
const reHex = () => /^#?(([0-9a-f]){3,4}|([0-9a-f]{2}){3,4})$/i;
export { reHSLa, reHex, reRGBa };
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