/*
* Copyright 2019 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package androidx.compose.animation
import androidx.compose.animation.core.AnimationVector4D
import androidx.compose.animation.core.TwoWayConverter
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.graphics.colorspace.ColorSpace
import androidx.compose.ui.graphics.colorspace.ColorSpaces
import kotlin.math.pow
/**
* A lambda that takes a [ColorSpace] and returns a converter that can both convert a [Color] to
* a [AnimationVector4D], and convert a [AnimationVector4D]) back to a [Color] in the given
* [ColorSpace].
*/
private val ColorToVector: (colorSpace: ColorSpace) -> TwoWayConverter<Color, AnimationVector4D> =
{ colorSpace ->
TwoWayConverter(
convertToVector = { color ->
// TODO: use Oklab when it is public API
val colorXyz = color.convert(ColorSpaces.CieXyz)
val x = colorXyz.red
val y = colorXyz.green
val z = colorXyz.blue
val l = multiplyColumn(0, x, y, z, M1).pow(1f / 3f)
val a = multiplyColumn(1, x, y, z, M1).pow(1f / 3f)
val b = multiplyColumn(2, x, y, z, M1).pow(1f / 3f)
AnimationVector4D(color.alpha, l, a, b)
},
convertFromVector = {
val l = it.v2.pow(3f)
val a = it.v3.pow(3f)
val b = it.v4.pow(3f)
val x = multiplyColumn(0, l, a, b, InverseM1)
val y = multiplyColumn(1, l, a, b, InverseM1)
val z = multiplyColumn(2, l, a, b, InverseM1)
val colorXyz = Color(
alpha = it.v1.coerceIn(0f, 1f),
red = x.coerceIn(-2f, 2f),
green = y.coerceIn(-2f, 2f),
blue = z.coerceIn(-2f, 2f),
colorSpace = ColorSpaces.CieXyz // here we have the right color space
)
colorXyz.convert(colorSpace)
}
)
}
/**
* A lambda that takes a [ColorSpace] and returns a converter that can both convert a [Color] to
* a [AnimationVector4D], and convert a [AnimationVector4D]) back to a [Color] in the given
* [ColorSpace].
*/
val Color.Companion.VectorConverter:
(colorSpace: ColorSpace) -> TwoWayConverter<Color, AnimationVector4D>
get() = ColorToVector
// These are utilities and constants to emulate converting to/from Oklab color space.
// These can be removed when Oklab becomes public and we can use it directly in the conversion.
private val M1 = floatArrayOf(
0.80405736f, 0.026893456f, 0.04586542f,
0.3188387f, 0.9319606f, 0.26299807f,
-0.11419419f, 0.05105356f, 0.83999807f
)
private val InverseM1 = floatArrayOf(
1.2485008f, -0.032856926f, -0.057883114f,
-0.48331892f, 1.1044513f, -0.3194066f,
0.19910365f, -0.07159331f, 1.202023f
)
private fun multiplyColumn(column: Int, x: Float, y: Float, z: Float, matrix: FloatArray): Float {
return x * matrix[column] + y * matrix[3 + column] + z * matrix[6 + column]
}