jellyfin/Jellyfin.Drawing.Skia/SplashscreenBuilder.cs
2022-01-10 10:59:32 -07:00

149 lines
5.4 KiB
C#

using System;
using System.Collections.Generic;
using SkiaSharp;
namespace Jellyfin.Drawing.Skia
{
/// <summary>
/// Used to build the splashscreen.
/// </summary>
public class SplashscreenBuilder
{
private const int FinalWidth = 1920;
private const int FinalHeight = 1080;
// generated collage resolution should be higher than the final resolution
private const int WallWidth = FinalWidth * 3;
private const int WallHeight = FinalHeight * 2;
private const int Rows = 6;
private const int Spacing = 20;
private readonly SkiaEncoder _skiaEncoder;
/// <summary>
/// Initializes a new instance of the <see cref="SplashscreenBuilder"/> class.
/// </summary>
/// <param name="skiaEncoder">The SkiaEncoder.</param>
public SplashscreenBuilder(SkiaEncoder skiaEncoder)
{
_skiaEncoder = skiaEncoder;
}
/// <summary>
/// Generate a splashscreen.
/// </summary>
/// <param name="posters">The poster paths.</param>
/// <param name="backdrops">The landscape paths.</param>
/// <param name="outputPath">The output path.</param>
public void GenerateSplash(IReadOnlyList<string> posters, IReadOnlyList<string> backdrops, string outputPath)
{
using var wall = GenerateCollage(posters, backdrops);
using var transformed = Transform3D(wall);
using var outputStream = new SKFileWStream(outputPath);
using var pixmap = new SKPixmap(new SKImageInfo(FinalWidth, FinalHeight), transformed.GetPixels());
pixmap.Encode(outputStream, StripCollageBuilder.GetEncodedFormat(outputPath), 90);
}
/// <summary>
/// Generates a collage of posters and landscape pictures.
/// </summary>
/// <param name="posters">The poster paths.</param>
/// <param name="backdrops">The landscape paths.</param>
/// <returns>The created collage as a bitmap.</returns>
private SKBitmap GenerateCollage(IReadOnlyList<string> posters, IReadOnlyList<string> backdrops)
{
var posterIndex = 0;
var backdropIndex = 0;
var bitmap = new SKBitmap(WallWidth, WallHeight);
using var canvas = new SKCanvas(bitmap);
canvas.Clear(SKColors.Black);
int posterHeight = WallHeight / 6;
for (int i = 0; i < Rows; i++)
{
int imageCounter = Random.Shared.Next(0, 5);
int currentWidthPos = i * 75;
int currentHeight = i * (posterHeight + Spacing);
while (currentWidthPos < WallWidth)
{
SKBitmap? currentImage;
switch (imageCounter)
{
case 0:
case 2:
case 3:
currentImage = SkiaHelper.GetNextValidImage(_skiaEncoder, posters, posterIndex, out int newPosterIndex);
posterIndex = newPosterIndex;
break;
default:
currentImage = SkiaHelper.GetNextValidImage(_skiaEncoder, backdrops, backdropIndex, out int newBackdropIndex);
backdropIndex = newBackdropIndex;
break;
}
if (currentImage == null)
{
throw new ArgumentException("Not enough valid pictures provided to create a splashscreen!");
}
// resize to the same aspect as the original
var imageWidth = Math.Abs(posterHeight * currentImage.Width / currentImage.Height);
using var resizedBitmap = new SKBitmap(imageWidth, posterHeight);
currentImage.ScalePixels(resizedBitmap, SKFilterQuality.High);
// draw on canvas
canvas.DrawBitmap(resizedBitmap, currentWidthPos, currentHeight);
currentWidthPos += imageWidth + Spacing;
currentImage.Dispose();
if (imageCounter >= 4)
{
imageCounter = 0;
}
else
{
imageCounter++;
}
}
}
return bitmap;
}
/// <summary>
/// Transform the collage in 3D space.
/// </summary>
/// <param name="input">The bitmap to transform.</param>
/// <returns>The transformed image.</returns>
private SKBitmap Transform3D(SKBitmap input)
{
var bitmap = new SKBitmap(FinalWidth, FinalHeight);
using var canvas = new SKCanvas(bitmap);
canvas.Clear(SKColors.Black);
var matrix = new SKMatrix
{
ScaleX = 0.324108899f,
ScaleY = 0.563934922f,
SkewX = -0.244337708f,
SkewY = 0.0377609022f,
TransX = 42.0407715f,
TransY = -198.104706f,
Persp0 = -9.08959337E-05f,
Persp1 = 6.85242048E-05f,
Persp2 = 0.988209724f
};
canvas.SetMatrix(matrix);
canvas.DrawBitmap(input, 0, 0);
return bitmap;
}
}
}