feat(camera): share jpeg transcoder + default maxWidth

apps/shared/ClawdisKit/Tests/ClawdisKitTests/JPEGTranscoderTests.swift

@@ -0,0 +1,73 @@
+import ClawdisKit
+import CoreGraphics
+import ImageIO
+import Testing
+import UniformTypeIdentifiers
+
+@Suite struct JPEGTranscoderTests {
+    private func makeSolidJPEG(width: Int, height: Int, orientation: Int? = nil) throws -> Data {
+        let cs = CGColorSpaceCreateDeviceRGB()
+        let bitmapInfo = CGImageAlphaInfo.premultipliedLast.rawValue
+        guard
+            let ctx = CGContext(
+                data: nil,
+                width: width,
+                height: height,
+                bitsPerComponent: 8,
+                bytesPerRow: 0,
+                space: cs,
+                bitmapInfo: bitmapInfo)
+        else {
+            throw NSError(domain: "JPEGTranscoderTests", code: 1)
+        }
+
+        ctx.setFillColor(red: 1, green: 0, blue: 0, alpha: 1)
+        ctx.fill(CGRect(x: 0, y: 0, width: width, height: height))
+        guard let img = ctx.makeImage() else {
+            throw NSError(domain: "JPEGTranscoderTests", code: 5)
+        }
+
+        let out = NSMutableData()
+        guard let dest = CGImageDestinationCreateWithData(out, UTType.jpeg.identifier as CFString, 1, nil) else {
+            throw NSError(domain: "JPEGTranscoderTests", code: 2)
+        }
+
+        var props: [CFString: Any] = [
+            kCGImageDestinationLossyCompressionQuality: 1.0,
+        ]
+        if let orientation {
+            props[kCGImagePropertyOrientation] = orientation
+        }
+
+        CGImageDestinationAddImage(dest, img, props as CFDictionary)
+        guard CGImageDestinationFinalize(dest) else {
+            throw NSError(domain: "JPEGTranscoderTests", code: 3)
+        }
+
+        return out as Data
+    }
+
+    @Test func downscalesToMaxWidthPx() throws {
+        let input = try makeSolidJPEG(width: 2000, height: 1000)
+        let out = try JPEGTranscoder.transcodeToJPEG(imageData: input, maxWidthPx: 1600, quality: 0.9)
+        #expect(out.widthPx == 1600)
+        #expect(abs(out.heightPx - 800) <= 1)
+        #expect(out.data.count > 0)
+    }
+
+    @Test func doesNotUpscaleWhenSmallerThanMaxWidthPx() throws {
+        let input = try makeSolidJPEG(width: 800, height: 600)
+        let out = try JPEGTranscoder.transcodeToJPEG(imageData: input, maxWidthPx: 1600, quality: 0.9)
+        #expect(out.widthPx == 800)
+        #expect(out.heightPx == 600)
+    }
+
+    @Test func normalizesOrientationAndUsesOrientedWidthForMaxWidthPx() throws {
+        // Encode a landscape image but mark it rotated 90° (orientation 6). Oriented width becomes 1000.
+        let input = try makeSolidJPEG(width: 2000, height: 1000, orientation: 6)
+        let out = try JPEGTranscoder.transcodeToJPEG(imageData: input, maxWidthPx: 1600, quality: 0.9)
+        #expect(out.widthPx == 1000)
+        #expect(out.heightPx == 2000)
+    }
+}
+