Add Shorts look preview and visual crop editor

Show opening/closing 9:16 stills from the same filtergraph, and let users drag a keep-region on a source frame to fill the crop insets.
2026-08-15 21:08:36 +02:00
parent 8a734d58d9
commit 323324d713
9 changed files with 958 additions and 12 deletions
@@ -0,0 +1,111 @@
+namespace AmiReel.Models;
+
+/// <summary>Edge insets, in source pixels, removed by a manual crop.</summary>
+public readonly record struct PixelInsets(int Left, int Right, int Top, int Bottom)
+{
+    public bool IsEmpty => Left == 0 && Right == 0 && Top == 0 && Bottom == 0;
+}
+
+/// <summary>Maps a dragged display rectangle onto source-pixel crop insets.</summary>
+public static class SourceCropSelection
+{
+    public const int MinimumSize = 16;
+
+    public static (double OffsetX, double OffsetY, double DisplayWidth, double DisplayHeight) FitUniform(
+        double containerWidth, double containerHeight, int pixelWidth, int pixelHeight)
+    {
+        if (containerWidth <= 0 || containerHeight <= 0 || pixelWidth <= 0 || pixelHeight <= 0)
+            return (0, 0, 0, 0);
+
+        double containerAspect = containerWidth / containerHeight;
+        double imageAspect = pixelWidth / (double)pixelHeight;
+        double displayWidth;
+        double displayHeight;
+        if (containerAspect > imageAspect)
+        {
+            displayHeight = containerHeight;
+            displayWidth = containerHeight * imageAspect;
+        }
+        else
+        {
+            displayWidth = containerWidth;
+            displayHeight = containerWidth / imageAspect;
+        }
+
+        return ((containerWidth - displayWidth) / 2, (containerHeight - displayHeight) / 2, displayWidth, displayHeight);
+    }
+
+    public static PixelInsets ToInsets(
+        int pixelWidth,
+        int pixelHeight,
+        double displayWidth,
+        double displayHeight,
+        double x,
+        double y,
+        double width,
+        double height)
+    {
+        if (pixelWidth <= 0 || pixelHeight <= 0 || displayWidth <= 0 || displayHeight <= 0)
+            return default;
+
+        Normalize(ref x, ref y, ref width, ref height);
+        x = Math.Clamp(x, 0, displayWidth);
+        y = Math.Clamp(y, 0, displayHeight);
+        width = Math.Clamp(width, 0, displayWidth - x);
+        height = Math.Clamp(height, 0, displayHeight - y);
+
+        double scaleX = pixelWidth / displayWidth;
+        double scaleY = pixelHeight / displayHeight;
+        int left = ToEvenPixel(x * scaleX, pixelWidth - MinimumSize);
+        int top = ToEvenPixel(y * scaleY, pixelHeight - MinimumSize);
+        int right = ToEvenPixel((displayWidth - x - width) * scaleX, pixelWidth - MinimumSize - left);
+        int bottom = ToEvenPixel((displayHeight - y - height) * scaleY, pixelHeight - MinimumSize - top);
+
+        if (pixelWidth - left - right < MinimumSize)
+            right = Math.Max(0, pixelWidth - left - MinimumSize);
+        if (pixelHeight - top - bottom < MinimumSize)
+            bottom = Math.Max(0, pixelHeight - top - MinimumSize);
+
+        return new PixelInsets(left, right, top, bottom);
+    }
+
+    public static (double X, double Y, double Width, double Height) ToDisplayRect(
+        int pixelWidth, int pixelHeight, double displayWidth, double displayHeight, PixelInsets insets)
+    {
+        if (pixelWidth <= 0 || pixelHeight <= 0 || displayWidth <= 0 || displayHeight <= 0)
+            return (0, 0, Math.Max(0, displayWidth), Math.Max(0, displayHeight));
+
+        double scaleX = displayWidth / pixelWidth;
+        double scaleY = displayHeight / pixelHeight;
+        double x = insets.Left * scaleX;
+        double y = insets.Top * scaleY;
+        double width = Math.Max(1, (pixelWidth - insets.Left - insets.Right) * scaleX);
+        double height = Math.Max(1, (pixelHeight - insets.Top - insets.Bottom) * scaleY);
+        return (x, y, width, height);
+    }
+
+    public static (double X, double Y) ClampToDisplay(double x, double y, double displayWidth, double displayHeight) =>
+        (Math.Clamp(x, 0, Math.Max(0, displayWidth)), Math.Clamp(y, 0, Math.Max(0, displayHeight)));
+
+    private static void Normalize(ref double x, ref double y, ref double width, ref double height)
+    {
+        if (width < 0)
+        {
+            x += width;
+            width = -width;
+        }
+
+        if (height < 0)
+        {
+            y += height;
+            height = -height;
+        }
+    }
+
+    private static int ToEvenPixel(double value, int max)
+    {
+        int rounded = (int)Math.Round(value, MidpointRounding.AwayFromZero);
+        int clamped = Math.Clamp(rounded, 0, Math.Max(0, max));
+        return (clamped / 2) * 2;
+    }
+}