feat(text): composite shared text rasters in output

Raster static text on UI-thread changes and reuse the same transparent BGRA frame in preview and all compositor paths. Cache text frame identity in the frame-pump signature and invalidate static bakes on edits. Follow OBS text-source conventions: https://obsproject.com/kb/text-sources
2026-11-04 15:01:47 -08:00
parent 58eb640c4e
commit 5c4acf141b
19 changed files with 622 additions and 81 deletions
@@ -0,0 +1,54 @@
+using System.Windows;
+using System.Windows.Controls;
+using System.Windows.Media.Imaging;
+using Xunit;
+using ytLive.Models;
+using ytLive.Services;
+
+namespace ytLive.Tests;
+
+[Collection("RealApp")]
+public sealed class TextOverlayRendererTests
+{
+    private readonly RealAppHost _app;
+
+    public TextOverlayRendererTests(RealAppHost app) => _app = app;
+
+    [Fact]
+    public void Raster_IsCached_And_PreviewBitmap_Uses_The_Same_Transparent_Pixels()
+    {
+        _app.Run(() =>
+        {
+            var source = new Source
+            {
+                Type = SourceType.TextOverlay,
+                TextContent = "Cached text",
+                Width = 220,
+                Height = 70,
+                TextFontSize = 36,
+                TextColor = "#80FFFFFF",
+                TextBold = true,
+                TextUnderline = true,
+            };
+            var renderer = new TextOverlayRenderer();
+            renderer.UpdatePreview(source);
+
+            var first = Assert.IsType<VideoFrame>(renderer.RenderFrame(source));
+            var preview = Assert.IsType<WriteableBitmap>(source.VideoImageSource);
+            var pixels = new byte[first.BgraPixels.Length];
+            preview.CopyPixels(pixels, first.Stride, 0);
+            Assert.Equal(first.BgraPixels, pixels);
+            Assert.Contains(first.BgraPixels.Where((_, index) => index % 4 == 3), alpha => alpha > 0);
+            Assert.Contains(first.BgraPixels.Where((_, index) => index % 4 == 3), alpha => alpha == 0);
+
+            renderer.UpdatePreview(source);
+            Assert.Same(first, renderer.RenderFrame(source));
+            Assert.Same(preview, source.VideoImageSource);
+
+            source.TextContent = "Changed";
+            renderer.UpdatePreview(source);
+            Assert.NotSame(first, renderer.RenderFrame(source));
+            Assert.NotSame(preview, source.VideoImageSource);
+        });
+    }
+}