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osu-lazer/osu.Game/Graphics/Containers/UprightAspectMaintainingContainer.cs
2022-08-31 22:04:28 +01:00

120 lines
3.7 KiB
C#

// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
// See the LICENCE file in the repository root for full licence text.
using System;
using osu.Framework.Graphics;
using osu.Framework.Graphics.Containers;
using osu.Framework.Layout;
using osuTK;
namespace osu.Game.Graphics.Containers
{
/// <summary>
/// A container that reverts any rotation (and optionally scale) applied by its direct parent.
/// </summary>
public class UprightAspectMaintainingContainer : Container
{
/// <summary>
/// Controls how much this container scales compared to its parent (default is 1.0f).
/// </summary>
public float ScalingFactor { get; set; } = 1;
/// <summary>
/// Controls the scaling of this container.
/// </summary>
public ScaleMode Scaling { get; set; } = ScaleMode.Vertical;
private readonly LayoutValue layout = new LayoutValue(Invalidation.DrawInfo, InvalidationSource.Parent);
public UprightAspectMaintainingContainer()
{
AddLayout(layout);
}
protected override void Update()
{
base.Update();
if (!layout.IsValid)
{
keepUprightAndUnstretched();
layout.Validate();
}
}
/// <summary>
/// Keeps the drawable upright and unstretched preventing it from being rotated, sheared, scaled or flipped with its Parent.
/// </summary>
private void keepUprightAndUnstretched()
{
// Decomposes the inverse of the parent DrawInfo.Matrix into rotation, shear and scale.
var parentMatrix = Parent.DrawInfo.Matrix;
// Remove Translation.>
parentMatrix.M31 = 0.0f;
parentMatrix.M32 = 0.0f;
Matrix3 reversedParent = parentMatrix.Inverted();
// Extract the rotation.
float angle = MathF.Atan2(reversedParent.M12, reversedParent.M11);
Rotation = MathHelper.RadiansToDegrees(angle);
// Remove rotation from the C matrix so that it only contains shear and scale.
Matrix3 m = Matrix3.CreateRotationZ(-angle);
reversedParent *= m;
// Extract shear.
float alpha = reversedParent.M21 / reversedParent.M22;
Shear = new Vector2(-alpha, 0);
// Etract scale.
float sx = reversedParent.M11;
float sy = reversedParent.M22;
Vector3 parentScale = parentMatrix.ExtractScale();
float usedScale = 1.0f;
switch (Scaling)
{
case ScaleMode.Horizontal:
usedScale = parentScale.X;
break;
case ScaleMode.Vertical:
usedScale = parentScale.Y;
break;
}
if (Scaling != ScaleMode.NoScaling)
{
if (ScalingFactor < 1.0f)
usedScale = 1.0f + (usedScale - 1.0f) * ScalingFactor;
if (ScalingFactor > 1.0f)
usedScale = (usedScale < 1.0f) ? usedScale * (1.0f / ScalingFactor) : usedScale * ScalingFactor;
}
Scale = new Vector2(sx * usedScale, sy * usedScale);
}
}
public enum ScaleMode
{
/// <summary>
/// Prevent this container from scaling.
/// </summary>
NoScaling,
/// <summary>
/// Scale uniformly (maintaining aspect ratio) based on the vertical scale of the parent.
/// </summary>
Vertical,
/// <summary>
/// Scale uniformly (maintaining aspect ratio) based on the horizontal scale of the parent.
/// </summary>
Horizontal,
}
}