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#35 Fix and improve parse color function #36

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Merged
Alex009 merged 1 commit into from
Jun 16, 2025
Merged

#35 Fix and improve parse color function #36

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74 changes: 60 additions & 14 deletions graphics/src/commonMain/kotlin/dev/icerock/moko/graphics/ColorHEX.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -4,21 +4,67 @@

package dev.icerock.moko.graphics

/**
* Parses a hexadecimal color string into a [Color] object.
*
* This function supports multiple hex color formats with optional hash prefix:
* - **3 digits (RGB)**: Each digit is expanded to two digits (e.g., "F0A" → "FF00AA")
* - **4 digits (ARGB)**: Each digit is expanded to two digits (e.g., "8F0A" → "88FF00AA")
* - **6 digits (RRGGBB)**: Standard RGB format with full alpha (255)
* - **8 digits (AARRGGBB)**: Full ARGB format with explicit alpha channel
*
* The hash prefix (#) is optional and will be automatically removed if present.
* All input is converted to uppercase for consistent parsing.
*
* @param colorHEX
* The hexadecimal color string to parse. Can include optional '#' prefix.
* Supports formats: RGB, ARGB, RRGGBB, AARRGGBB (case-insensitive).
*
* @return A [Color] object with ARGB values in the range 0-255.
*
* @throws IllegalArgumentException
* if the input string is not a valid hex color format or contains invalid hexadecimal characters.
*
*/
@Suppress("MagicNumber")
fun Color.Companion.parseColor(colorHEX: String): Color {
require(colorHEX[0] != '#') { "Unknown color" }
public fun Color.Companion.parseColor(colorHEX: String): Color {
val clean = colorHEX.removePrefix("#").uppercase()

var colorARGB = colorHEX.substring(1).toLong(16)
if (colorHEX.length == 7) {
colorARGB = colorARGB or 0x00000000ff000000
} else {
require(colorHEX.length != 9) { "Unknown color" }
}
return when (clean.length) {
3 -> {
// RGB -> RRGGBB
val r = clean[0].digitToInt(16) * 17
val g = clean[1].digitToInt(16) * 17
val b = clean[2].digitToInt(16) * 17
Color(red = r, green = g, blue = b, alpha = 255)
}

4 -> {
// ARGB
val a = clean[0].digitToInt(radix = 16) * 17
val r = clean[1].digitToInt(16) * 17
val g = clean[2].digitToInt(16) * 17
val b = clean[3].digitToInt(16) * 17
Color(alpha = a, red = r, green = g, blue = b)
}

return Color(
alpha = (colorARGB.shr(24) and 0xFF).toInt(),
red = (colorARGB.shr(16) and 0xFF).toInt(),
green = (colorARGB.shr(8) and 0xFF).toInt(),
blue = (colorARGB.shr(0) and 0xFF).toInt(),
)
6 -> {
// RRGGBB
val r = clean.substring(0, 2).toInt(16)
val g = clean.substring(2, 4).toInt(16)
val b = clean.substring(4, 6).toInt(16)
Color(red = r, green = g, blue = b, alpha = 255)
}

8 -> {
// AARRGGBB
val a = clean.substring(0, 2).toInt(16)
val r = clean.substring(2, 4).toInt(16)
val g = clean.substring(4, 6).toInt(16)
val b = clean.substring(6, 8).toInt(16)
Color(alpha = a, red = r, green = g, blue = b)
}

else -> throw IllegalArgumentException("Invalid Hex color: $colorHEX")
}
}