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feat: improve contrast utilities #120

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Merged
naveensingh merged 1 commit into from
Jun 5, 2025
Merged

feat: improve contrast utilities #120

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29 changes: 21 additions & 8 deletions commons/src/main/kotlin/org/fossify/commons/extensions/Int.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -6,15 +6,17 @@ import android.graphics.Color
import android.media.ExifInterface
import android.os.Handler
import android.os.Looper
import androidx.core.graphics.ColorUtils
import androidx.core.os.postDelayed
import org.fossify.commons.helpers.DARK_GREY
import org.fossify.commons.helpers.WCAG_AA_NORMAL
import java.text.DecimalFormat
import java.util.Locale
import java.util.Random

fun Int.getContrastColor(): Int {
val y = (299 * Color.red(this) + 587 * Color.green(this) + 114 * Color.blue(this)) / 1000
return if (y >= 149 && this != Color.BLACK) DARK_GREY else Color.WHITE
val luminance = ColorUtils.calculateLuminance(this)
return if (luminance > 0.5) DARK_GREY else Color.WHITE
}

fun Int.toHex() = String.format("#%06X", 0xFFFFFF and this).uppercase(Locale.getDefault())
Expand Down Expand Up @@ -192,11 +194,22 @@ fun Int.countdown(intervalMillis: Long, callback: (count: Int) -> Unit) {
}
}

fun Int.adjustSimColorForBackground(bg: Int): Int {
val hsv = FloatArray(3)
Color.colorToHSV(bg, hsv)
if (hsv[2] < 0.5) {
return this.lightenColor(24)
fun Int.adjustForContrast(
background: Int,
minContrast: Double = WCAG_AA_NORMAL,
): Int {
var color = this
var alpha = 0f
val target = if (ColorUtils.calculateLuminance(background) < 0.5) {
Color.WHITE
} else {
Color.BLACK
}

while (ColorUtils.calculateContrast(color, background) < minContrast && alpha < 1f) {
alpha += 0.05f
color = ColorUtils.blendARGB(this, target, alpha)
}
return this

return color
}
3 changes: 3 additions & 0 deletions commons/src/main/kotlin/org/fossify/commons/helpers/Constants.kt
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Expand Up @@ -60,6 +60,9 @@ const val HIGHER_ALPHA = 0.75f
const val LOWER_ALPHA_INT = 30
const val MEDIUM_ALPHA_INT = 90

const val WCAG_AA_NORMAL = 4.5
const val WCAG_AA_LARGE = 3.0

const val HOUR_MINUTES = 60
const val DAY_MINUTES = 24 * HOUR_MINUTES
const val WEEK_MINUTES = DAY_MINUTES * 7
Expand Down
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