Preview windows changes

config/runtime-host.json

@@ -11,6 +11,6 @@
   "autoReload": true,
   "maxTemporalHistoryFrames": 12,
   "previewEnabled": true,
-  "previewFps": 30,
+  "previewFps": 59.94,
   "enableExternalKeying": true
 }

src/README.md

@@ -208,7 +208,7 @@ Currently consumed fields:
 - `previewFps`
 - `enableExternalKeying`
 
-When `previewEnabled` is true, the preview window runs on `PreviewWindowThread`. It paints BGRA8 system-memory frames with Win32/GDI after render readback has already completed, so it does not bind GL and does not consume frames from DeckLink output.
+When `previewEnabled` is true, the preview window runs on `PreviewWindowThread`. It paints BGRA8 system-memory frames with Win32/GDI after render readback has already completed, so it does not bind GL and does not consume frames from DeckLink output. `previewFps` controls the preview repaint cadence; the default is 60 fps and `config/runtime-host.json` tracks the shipped 59.94 output cadence.
 
 The loaded config is treated as a read-only startup snapshot. Subsystems that need config should receive this snapshot or a narrowed config struct from app orchestration; they should not reload files independently.
 

src/preview/PreviewConfig.h

@@ -4,7 +4,7 @@
 
 namespace RenderCadenceCompositor
 {
-constexpr double kDefaultPreviewFps = 30.0;
+constexpr double kDefaultPreviewFps = 60.0;
 constexpr double kMinimumPreviewFps = 1.0;
 
 struct PreviewWindowConfig

src/preview/PreviewWindowThread.cpp

@@ -210,6 +210,10 @@ void PreviewWindowThread::Paint(HWND window)
 		frame.height > 0;
 	if (canPaintFrame)
 	{
+		const int previousStretchMode = SetStretchBltMode(dc, HALFTONE);
+		POINT previousBrushOrigin = {};
+		SetBrushOrgEx(dc, 0, 0, &previousBrushOrigin);
+
 		BITMAPINFO bitmapInfo = {};
 		bitmapInfo.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
 		bitmapInfo.bmiHeader.biWidth = static_cast<LONG>(frame.width);
@@ -232,6 +236,10 @@ void PreviewWindowThread::Paint(HWND window)
 			&bitmapInfo,
 			DIB_RGB_COLORS,
 			SRCCOPY);
+
+		if (previousStretchMode != 0)
+			SetStretchBltMode(dc, previousStretchMode);
+		SetBrushOrgEx(dc, previousBrushOrigin.x, previousBrushOrigin.y, nullptr);
 	}
 	else
 	{

tests/RenderCadenceCompositorAppConfigProviderTests.cpp

@@ -99,7 +99,7 @@ void TestPreviewDefaultsAreOptIn()
 
 	const AppConfig config = DefaultAppConfig();
 	Expect(!config.previewEnabled, "preview is disabled by default");
-	Expect(config.previewFps == 30.0, "preview fps default is 30");
+	Expect(config.previewFps == 60.0, "preview fps default is 60");
 }
 
 void TestHelpers()

tests/RenderCadenceCompositorPreviewConfigTests.cpp

@@ -19,6 +19,7 @@ void TestTimerIntervalUsesConfiguredFps()
 {
 	Expect(RenderCadenceCompositor::PreviewTimerIntervalMilliseconds(25.0) == 40, "25 fps maps to 40 ms");
 	Expect(RenderCadenceCompositor::PreviewTimerIntervalMilliseconds(50.0) == 20, "50 fps maps to 20 ms");
+	Expect(RenderCadenceCompositor::PreviewTimerIntervalMilliseconds(59.94) == 16, "59.94 fps maps to 16 ms");
 }
 
 void TestInvalidFpsUsesDefault()