Files

106 lines
4.1 KiB
C#

using System.Collections.Generic;
using System.Linq;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Media.Effects;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;
using ytLive.Models;
namespace ytLive.Services.Compositor;
/// <summary>
/// Rasterizes the global social bar into a transparent BGRA8 strip the output
/// compositor overlays onto the master frame (top or bottom edge). Replicates the
/// preview's bar DataTemplate in code — one Path (logo) + one TextBlock (handle)
/// per entry, white on transparent, green glow — then software-renders it via
/// <c>RenderTargetBitmap</c> and converts Pbgra32 (premultiplied) to straight-alpha
/// BGRA for the compositor. WPF glue like <see cref="StaticPixelCache"/>: the
/// compositor core itself stays pure byte-math. Renders on the UI thread only;
/// the returned frame is immutable afterwards, so the frame pump may read it from
/// any thread.
/// </summary>
public static class SocialBarRenderer
{
/// <summary>Icon size + the preview's 8px top/bottom margins.</summary>
private const int ContentHeight = 40;
/// <summary>Room for the green DropShadowEffect blur to bleed past the content.</summary>
private const int GlowPad = 24;
/// <summary>Master-frame width — the bar spans the full 1920px output.</summary>
public const int Width = 1920;
/// <summary>Returns the strip frame, or null when there is nothing to render.</summary>
public static VideoFrame? Render(IEnumerable<SocialEntry>? entries)
{
var list = entries?.Where(e => e != null).ToList();
if (list == null || list.Count == 0) return null;
var height = ContentHeight + GlowPad * 2;
var row = new StackPanel { Orientation = Orientation.Horizontal };
foreach (var entry in list)
{
var item = new StackPanel
{
Orientation = Orientation.Horizontal,
Margin = new Thickness(0, 0, 20, 0),
};
item.Children.Add(new Path
{
Data = Geometry.Parse(entry.LogoData),
Fill = Brushes.White,
Width = 24,
Height = 24,
Stretch = Stretch.Uniform,
VerticalAlignment = VerticalAlignment.Center,
});
item.Children.Add(new TextBlock
{
Text = entry.Handle,
Foreground = Brushes.White,
FontSize = 14,
VerticalAlignment = VerticalAlignment.Center,
Margin = new Thickness(8, 0, 0, 0),
});
row.Children.Add(item);
}
// The glow is baked in so the output bar matches the preview's green halo.
var container = new Grid
{
Width = Width,
Height = height,
Background = Brushes.Transparent,
Effect = new DropShadowEffect { Color = Color.FromRgb(0x2e, 0xcc, 0x71), BlurRadius = 18, ShadowDepth = 0, Opacity = 0.9 },
};
var centered = new Grid { HorizontalAlignment = HorizontalAlignment.Center, Margin = new Thickness(0, GlowPad, 0, 0) };
centered.Children.Add(row);
container.Children.Add(centered);
container.Measure(new Size(Width, height));
container.Arrange(new Rect(0, 0, Width, height));
var bitmap = new RenderTargetBitmap(Width, height, 96, 96, PixelFormats.Pbgra32);
bitmap.Render(container);
var pixels = new byte[Width * height * 4];
bitmap.CopyPixels(pixels, Width * 4, 0);
// Pbgra32 is premultiplied — unpremultiply so the compositor's straight-alpha
// source-over blend doesn't darken the logo edges with a halo.
for (var i = 0; i < pixels.Length; i += 4)
{
var a = pixels[i + 3];
if (a == 0 || a == 255) continue;
pixels[i] = (byte)(pixels[i] * 255 / a);
pixels[i + 1] = (byte)(pixels[i + 1] * 255 / a);
pixels[i + 2] = (byte)(pixels[i + 2] * 255 / a);
}
return new VideoFrame(Width, height, pixels);
}
}