Add aspect-ratio composition band and RAW DNG sidecar capture

src/utils/exportEngine.ts

@@ -3,7 +3,7 @@ import { File } from 'expo-file-system';
 import * as FileSystem from 'expo-file-system/legacy';
 import * as MediaLibrary from 'expo-media-library/legacy';
 import { Asset } from 'expo-asset';
-import { Recipe, GPSInfo, FrameId } from '../types';
+import { Recipe, GPSInfo, FrameId, AspectRatio, ASPECT_RATIO_W_H } from '../types';
 import { getSkiaColorMatrix, applyExposureGain } from './colorUtils';
 import { TONE_SKSL, getToneUniforms, toneIsActive } from './toneShader';
 import { CINEMA_SKSL, getCinemaUniforms, cinemaIsActive } from './cinemaShader';
@@ -25,6 +25,12 @@ export interface ExportOptions {
   // already applied as a hardware AE bias at capture, so no 2^EV matrix gain
   // should be added on top. Library stills omit this and get the matrix gain.
   evFromCamera?: boolean;
+  // Composition aspect-ratio crop (upright 4:3 or 3:2). Center-largest crop
+  // applied right after decode — every later step (frame/GPS/sharpen/size)
+  // then runs on the cropped pixels, so the export matches the ratio the
+  // viewfinder displayed. WALL FRAME ignores this (frame keeps its fixed
+  // opening and export size). 'full'/undefined = no crop.
+  aspect?: AspectRatio;
 }
 
 // Lightroom-style "Screen" output sharpen: subtle unsharp mask. A 3x3
@@ -87,18 +93,60 @@ export async function processAndExportPhoto(
       console.error('Failed to load image data from URI');
       return null;
     }
-    const skImage = Skia.Image.MakeImageFromEncoded(skiaData);
+    const skImage0 = Skia.Image.MakeImageFromEncoded(skiaData);
 
-    if (!skImage) {
+    if (!skImage0) {
       console.error('Failed to parse image from URI');
       return null;
     }
     console.error(`[export] decode ${Date.now() - t0}ms`);
 
-    const width = skImage.width();
-    const height = skImage.height();
+    let skImage = skImage0;
+    let width = skImage.width();
+    let height = skImage.height();
     console.error(`[export] BEGIN ${width}x${height} ev=${recipe.adjustments.exposureCompensation ?? 0} evFromCamera=${options?.evFromCamera ?? false}`);
 
+    // 1b. Aspect-ratio crop (composition): center-largest upright crop of the
+    // requested ratio. Runs BEFORE any processing so frame/GPS/grain/sharpen
+    // all apply to exactly the pixels the user framed. Wall Frame is exempt —
+    // its export is the fixed frame artwork whose opening cover-crops anyway.
+    const ratioWH = options?.aspect && options.aspect !== 'full' ? ASPECT_RATIO_W_H[options.aspect] : null;
+    if (ratioWH && frameId !== 'wallframe') {
+      const curAspect = width / height;
+      let cropW = width;
+      let cropH = height;
+      let srcX = 0;
+      let srcY = 0;
+      if (curAspect > ratioWH) {
+        cropW = Math.round(height * ratioWH);
+        srcX = Math.round((width - cropW) / 2);
+      } else {
+        cropH = Math.round(width / ratioWH);
+        srcY = Math.round((height - cropH) / 2);
+      }
+      const cropSurface = createSurface(cropW, cropH);
+      if (!cropSurface) {
+        console.error('Failed to create aspect-crop surface');
+        return null;
+      }
+      const cropCanvas = cropSurface.getCanvas();
+      cropCanvas.drawImageRect(
+        skImage,
+        Skia.XYWHRect(srcX, srcY, cropW, cropH),
+        Skia.XYWHRect(0, 0, cropW, cropH),
+        Skia.Paint()
+      );
+      const cropped = cropSurface.makeImageSnapshot();
+      if (!cropped) {
+        console.error('Failed to snapshot aspect crop');
+        return null;
+      }
+      skImage = cropped;
+      width = cropW;
+      height = cropH;
+      console.error(`[export] aspect-crop ${width}x${height}`);
+    }
+
     // 2. Create offscreen canvas (GPU-backed when available — see createSurface)
     const surface = createSurface(width, height);
     if (!surface) {