56 lines
1.7 KiB
Kotlin
56 lines
1.7 KiB
Kotlin
/*
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* Copyright (c) 2019 Hemanth Savarala.
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*
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* Licensed under the GNU General Public License v3
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*
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* This is free software: you can redistribute it and/or modify it under
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* the terms of the GNU General Public License as published by
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* the Free Software Foundation either version 3 of the License, or (at your option) any later version.
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*
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* This software is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
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* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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* See the GNU General Public License for more details.
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*/
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package code.name.monkey.retromusic.transform
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import android.view.View
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import androidx.viewpager.widget.ViewPager
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import kotlin.math.abs
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class VerticalFlipTransformation : ViewPager.PageTransformer {
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override fun transformPage(page: View, position: Float) {
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page.translationX = -position * page.width
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page.cameraDistance = 100000f
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if (position < 0.5 && position > -0.5) {
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page.visibility = View.VISIBLE
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} else {
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page.visibility = View.INVISIBLE
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}
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when {
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position < -1 -> { // [-Infinity,-1)
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// This page is way off-screen to the left.
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page.alpha = 0f
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}
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position <= 0 -> { // [-1,0]
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page.alpha = 1f
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page.rotationY = 180 * (1 - abs(position) + 1)
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}
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position <= 1 -> { // (0,1]
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page.alpha = 1f
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page.rotationY = -180 * (1 - abs(position) + 1)
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}
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else -> { // (1,+Infinity]
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// This page is way off-screen to the right.
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page.alpha = 0f
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}
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}
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}
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} |