/*
* Copyright 2022 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.material.pullrefresh
import androidx.compose.animation.core.LinearOutSlowInEasing
import androidx.compose.material.ExperimentalMaterialApi
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.setValue
import androidx.compose.ui.Modifier
import androidx.compose.ui.composed
import androidx.compose.ui.graphics.graphicsLayer
import androidx.compose.ui.layout.onSizeChanged
import androidx.compose.ui.platform.debugInspectorInfo
/**
* A modifier for translating the position and scaling the size of a pull-to-refresh indicator
* based on the given [PullRefreshState].
*
* @sample androidx.compose.material.samples.PullRefreshIndicatorTransformSample
*
* @param state The [PullRefreshState] which determines the position of the indicator.
* @param scale A boolean controlling whether the indicator's size scales with pull progress or not.
*/
@ExperimentalMaterialApi
// TODO: Consider whether the state parameter should be replaced with lambdas.
fun Modifier.pullRefreshIndicatorTransform(
state: PullRefreshState,
scale: Boolean = false,
) = composed(inspectorInfo = debugInspectorInfo {
name = "pullRefreshIndicatorTransform"
properties["state"] = state
properties["scale"] = scale
}) {
var height by remember { mutableStateOf(0) }
Modifier
.onSizeChanged { height = it.height }
.graphicsLayer {
translationY = state.position - height
if (scale && !state.refreshing) {
val scaleFraction = LinearOutSlowInEasing
.transform(state.position / state.threshold)
.coerceIn(0f, 1f)
scaleX = scaleFraction
scaleY = scaleFraction
}
}
}