70 lines
2.3 KiB
Kotlin
70 lines
2.3 KiB
Kotlin
/*
|
|
* Copyright (c) 2019 Hemanth Savarala.
|
|
*
|
|
* Licensed under the GNU General Public License v3
|
|
*
|
|
* This is free software: you can redistribute it and/or modify it under
|
|
* the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation either version 3 of the License, or (at your option) any later version.
|
|
*
|
|
* This software is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
|
|
* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
|
|
* See the GNU General Public License for more details.
|
|
*/
|
|
|
|
package code.name.monkey.retromusic.transform
|
|
|
|
import android.view.View
|
|
import androidx.viewpager.widget.ViewPager
|
|
import kotlin.math.abs
|
|
import kotlin.math.max
|
|
|
|
/**
|
|
* @author Hemanth S (h4h13).
|
|
*/
|
|
|
|
class NormalPageTransformer : ViewPager.PageTransformer {
|
|
|
|
override fun transformPage(view: View, position: Float) {
|
|
val pageWidth = view.width
|
|
val pageHeight = view.height
|
|
|
|
when {
|
|
position < -1 -> { // [-Infinity,-1)
|
|
// This page is way off-screen to the left.
|
|
view.alpha = 1f
|
|
view.scaleY = 0.7f
|
|
}
|
|
position <= 1 -> { // [-1,1]
|
|
// Modify the default slide transition to shrink the page as well
|
|
val scaleFactor = max(MIN_SCALE, 1 - abs(position))
|
|
val vertMargin = pageHeight * (1 - scaleFactor) / 2
|
|
val horzMargin = pageWidth * (1 - scaleFactor) / 2
|
|
if (position < 0) {
|
|
view.translationX = horzMargin - vertMargin / 2
|
|
} else {
|
|
view.translationX = -horzMargin + vertMargin / 2
|
|
}
|
|
|
|
// Scale the page down (between MIN_SCALE and 1)
|
|
view.scaleX = scaleFactor
|
|
view.scaleY = scaleFactor
|
|
|
|
// Fade the page relative to its size.
|
|
//view.setAlpha(MIN_ALPHA + (scaleFactor - MIN_SCALE) / (1 - MIN_SCALE) * (1 - MIN_ALPHA));
|
|
|
|
}
|
|
else -> { // (1,+Infinity]
|
|
// This page is way off-screen to the right.
|
|
view.alpha = 1f
|
|
view.scaleY = 0.7f
|
|
}
|
|
}
|
|
}
|
|
|
|
companion object {
|
|
private const val MIN_SCALE = 0.85f
|
|
private const val MIN_ALPHA = 0.5f
|
|
}
|
|
}
|