ColorFilter.kt
/*
* Copyright 2018 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.ui.graphics
import androidx.compose.runtime.Immutable
import androidx.compose.runtime.Stable
// TODO mark internal once https://youtrack.jetbrains.com/issue/KT-36695 is fixed
/* internal */ expect class NativeColorFilter
/**
* Effect used to modify the color of each pixel drawn on a [Paint] that it is installed on
*/
@Immutable
class ColorFilter internal constructor(internal val nativeColorFilter: NativeColorFilter) {
companion object {
/**
* Creates a color filter that applies the blend mode given as the second
* argument. The source color is the one given as the first argument, and the
* destination color is the one from the layer being composited.
*
* The output of this filter is then composited into the background according
* to the [Paint.blendMode], using the output of this filter as the source
* and the background as the destination.
*
* @param color Color used to blend source content
* @param blendMode BlendMode used when compositing the tint color to the destination
*/
@Stable
fun tint(color: Color, blendMode: BlendMode = BlendMode.SrcIn): ColorFilter =
actualTintColorFilter(color, blendMode)
/**
* Create a [ColorFilter] that transforms colors through a 4x5 color matrix. This filter can
* be used to change the saturation of pixels, convert from YUV to RGB, etc.
*
* @param colorMatrix ColorMatrix used to transform pixel values when drawn
*/
@Stable
fun colorMatrix(colorMatrix: ColorMatrix): ColorFilter =
actualColorMatrixColorFilter(colorMatrix)
/**
* Create a [ColorFilter] that can be used to simulate simple lighting effects.
* A lighting ColorFilter is defined by two parameters, one used to multiply the source
* color and one used to add to the source color
*
* @param multiply Color that will be added to the source color when the color
* filter is applied
* @param add Color used to multiply the source color when the color filter is applied.
*/
@Stable
fun lighting(multiply: Color, add: Color): ColorFilter =
actualLightingColorFilter(multiply, add)
}
}
internal expect fun actualTintColorFilter(color: Color, blendMode: BlendMode): ColorFilter
internal expect fun actualColorMatrixColorFilter(colorMatrix: ColorMatrix): ColorFilter
internal expect fun actualLightingColorFilter(multiply: Color, add: Color): ColorFilter