Placard 1.0.0 — bake library names onto backdrops

Jellyfin 10.11 plugin: a scheduled task that labels each library card with the library name over a representative backdrop (Noto Sans, centered, soft shadow), matching Jellyfin's default cover style. Supports source rules (top-rated / random / newest) and per-library pinned sources. Sets images via the internal provider API so the home-screen view cache updates without a server restart.
2026-07-19 19:35:06 +00:00
commit 0c59673e91
14 changed files with 630 additions and 0 deletions
@@ -0,0 +1,117 @@
+using System.Reflection;
+using SkiaSharp;
+
+namespace Jellyfin.Plugin.Placard;
+
+/// <summary>Composites a library name onto a backdrop, matching Jellyfin's default cover style.</summary>
+public static class CardRenderer
+{
+    private static SKTypeface? _typeface;
+
+    private static SKTypeface Typeface
+    {
+        get
+        {
+            if (_typeface != null)
+            {
+                return _typeface;
+            }
+
+            var asm = Assembly.GetExecutingAssembly();
+            using var s = asm.GetManifestResourceStream("Jellyfin.Plugin.Placard.Fonts.NotoSans-Bold.ttf");
+            _typeface = s != null
+                ? SKTypeface.FromStream(s)
+                : SKTypeface.FromFamilyName("sans-serif", SKFontStyle.Bold);
+            return _typeface;
+        }
+    }
+
+    /// <summary>Render <paramref name="label"/> centered on the image at <paramref name="backdropPath"/>.</summary>
+    public static byte[] Render(string backdropPath, string label, int scrim, int fontHeightPct)
+    {
+        using var input = SKBitmap.Decode(backdropPath);
+        return RenderBitmap(input, label, scrim, fontHeightPct);
+    }
+
+    /// <summary>Generate SMPTE color bars and label them (for Live TV, which has no media backdrop).</summary>
+    public static byte[] RenderColorBars(string label, int scrim)
+    {
+        const int w = 1920;
+        const int h = 1080;
+        using var bmp = new SKBitmap(w, h);
+        using (var canvas = new SKCanvas(bmp))
+        {
+            var cols = new[]
+            {
+                new SKColor(192, 192, 192), new SKColor(192, 192, 0), new SKColor(0, 192, 192),
+                new SKColor(0, 192, 0), new SKColor(192, 0, 192), new SKColor(192, 0, 0), new SKColor(0, 0, 192)
+            };
+            float bw = (float)w / cols.Length;
+            for (int i = 0; i < cols.Length; i++)
+            {
+                using var p = new SKPaint { Color = cols[i] };
+                canvas.DrawRect(i * bw, 0, bw + 1, h, p);
+            }
+        }
+
+        return RenderBitmap(bmp, label, scrim, 20);
+    }
+
+    private static byte[] RenderBitmap(SKBitmap input, string label, int scrim, int fontHeightPct)
+    {
+        int w = input.Width;
+        int h = input.Height;
+        using var surface = SKSurface.Create(new SKImageInfo(w, h));
+        var canvas = surface.Canvas;
+        canvas.DrawBitmap(input, 0, 0);
+
+        using (var scrimPaint = new SKPaint { Color = new SKColor(0, 0, 0, (byte)scrim) })
+        {
+            canvas.DrawRect(0, 0, w, h, scrimPaint);
+        }
+
+        float size = h * fontHeightPct / 100f;
+        using var measure = new SKPaint { Typeface = Typeface, IsAntialias = true };
+        for (; size > 12; size -= 4)
+        {
+            measure.TextSize = size;
+            if (measure.MeasureText(label) <= w * 0.90f)
+            {
+                break;
+            }
+        }
+
+        measure.TextSize = size;
+        SKRect bounds = default;
+        measure.MeasureText(label, ref bounds);
+        float x = ((w - bounds.Width) / 2f) - bounds.Left;
+        float y = ((h - bounds.Height) / 2f) - bounds.Top;
+
+        using (var shadow = new SKPaint
+        {
+            Typeface = Typeface,
+            TextSize = size,
+            IsAntialias = true,
+            Color = new SKColor(0, 0, 0, 205),
+            MaskFilter = SKMaskFilter.CreateBlur(SKBlurStyle.Normal, size / 20f)
+        })
+        {
+            canvas.DrawText(label, x, y + (size / 28f), shadow);
+        }
+
+        using (var text = new SKPaint
+        {
+            Typeface = Typeface,
+            TextSize = size,
+            IsAntialias = true,
+            Color = SKColors.White
+        })
+        {
+            canvas.DrawText(label, x, y, text);
+        }
+
+        using var image = surface.Snapshot();
+        using var data = image.Encode(SKEncodedImageFormat.Jpeg, 92);
+        return data.ToArray();
+    }
+}