fix: encode photos up to the 512 KiB image budget

bitchat/Features/media/ImageUtils.swift

@@ -1,3 +1,4 @@
+import BitFoundation
 import Foundation
 import ImageIO
 import UniformTypeIdentifiers
@@ -14,10 +15,14 @@ enum ImageUtilsError: Error {
 
 enum ImageUtils {
     private static let compressionQuality: CGFloat = 0.82
-    private static let targetImageBytes: Int = 45_000
+    /// Encode against the protocol image budget, not a second magic squeeze.
+    /// Voice notes already travel at 512 KiB; photos should too. Android
+    /// encodes at 512px / q=85 with no 45 KB crush, so matching that budget
+    /// is what keeps a photo readable on the same radio.
+    private static let targetImageBytes: Int = FileTransferLimits.maxImageBytes
     private static let maxSourceImageBytes: Int = 10 * 1024 * 1024
 
-    static func processImage(at url: URL, maxDimension: CGFloat = 448, outputDirectory: URL? = nil) throws -> URL {
+    static func processImage(at url: URL, maxDimension: CGFloat = 512, outputDirectory: URL? = nil) throws -> URL {
         try validateImageSource(at: url)
 
         let data = try Data(contentsOf: url)
@@ -47,7 +52,7 @@ enum ImageUtils {
     }
 
     #if os(iOS)
-    static func processImage(_ image: UIImage, maxDimension: CGFloat = 448, outputDirectory: URL? = nil) throws -> URL {
+    static func processImage(_ image: UIImage, maxDimension: CGFloat = 512, outputDirectory: URL? = nil) throws -> URL {
         return try autoreleasepool {
             // Scale the image first
             let scaled = scaledImage(image, maxDimension: maxDimension)
@@ -82,11 +87,12 @@ enum ImageUtils {
     private static func scaledImage(_ image: UIImage, maxDimension: CGFloat) -> UIImage {
         let size = image.size
         let maxSide = max(size.width, size.height)
-        guard maxSide > maxDimension else { return image }
-        let scale = maxDimension / maxSide
+        let scale = maxSide > maxDimension ? maxDimension / maxSide : 1
         let newSize = CGSize(width: size.width * scale, height: size.height * scale)
 
-        // Draw into a new context to get a clean CGImage without metadata
+        // Always redraw so EXIF orientation is baked in even when the
+        // pixel size already fits. Returning the original left
+        // `image.cgImage` rotated for camera stills under 512px.
         UIGraphicsBeginImageContextWithOptions(newSize, true, 1.0)
         image.draw(in: CGRect(origin: .zero, size: newSize))
         let rendered = UIGraphicsGetImageFromCurrentImageContext()
@@ -115,7 +121,7 @@ enum ImageUtils {
         return data as Data
     }
     #else
-    static func processImage(_ image: NSImage, maxDimension: CGFloat = 448, outputDirectory: URL? = nil) throws -> URL {
+    static func processImage(_ image: NSImage, maxDimension: CGFloat = 512, outputDirectory: URL? = nil) throws -> URL {
         return try autoreleasepool {
             let scaled = scaledImage(image, maxDimension: maxDimension)
             guard let inputCG = scaled.cgImage(forProposedRect: nil, context: nil, hints: nil) else {
@@ -160,8 +166,7 @@ enum ImageUtils {
     private static func scaledImage(_ image: NSImage, maxDimension: CGFloat) -> NSImage {
         let size = image.size
         let maxSide = max(size.width, size.height)
-        guard maxSide > maxDimension else { return image }
-        let scale = maxDimension / maxSide
+        let scale = maxSide > maxDimension ? maxDimension / maxSide : 1
         let newSize = NSSize(width: size.width * scale, height: size.height * scale)
         let scaledImage = NSImage(size: newSize)
         scaledImage.lockFocus()

bitchatTests/Features/ImageUtilsTests.swift

@@ -1,5 +1,7 @@
 import Testing
 import Foundation
+import ImageIO
+import BitFoundation
 #if os(iOS)
 import UIKit
 #else
@@ -22,6 +24,24 @@ private func makePlatformImage(size: CGSize) -> UIImage {
         context.fill(CGRect(origin: .zero, size: size))
     }
 }
+
+private func makeNoisyPlatformImage(size: CGSize) -> UIImage {
+    UIGraphicsImageRenderer(size: size).image { _ in
+        for i in 0..<600 {
+            UIColor(
+                hue: CGFloat(i % 47) / 47,
+                saturation: 1,
+                brightness: CGFloat((i * 13) % 100) / 100,
+                alpha: 1
+            ).setStroke()
+            let path = UIBezierPath()
+            path.move(to: CGPoint(x: CGFloat(i * 3 % Int(size.width)), y: 0))
+            path.addLine(to: CGPoint(x: 0, y: CGFloat(i * 5 % Int(size.height))))
+            path.lineWidth = 2
+            path.stroke()
+        }
+    }
+}
 #else
 private func makePlatformImage(size: CGSize) -> NSImage {
     let image = NSImage(size: size)
@@ -31,8 +51,38 @@ private func makePlatformImage(size: CGSize) -> NSImage {
     image.unlockFocus()
     return image
 }
+
+private func makeNoisyPlatformImage(size: CGSize) -> NSImage {
+    let image = NSImage(size: size)
+    image.lockFocus()
+    for i in 0..<600 {
+        NSColor(
+            hue: CGFloat(i % 47) / 47,
+            saturation: 1,
+            brightness: CGFloat((i * 13) % 100) / 100,
+            alpha: 1
+        ).setStroke()
+        let path = NSBezierPath()
+        path.move(to: CGPoint(x: CGFloat(i * 3 % Int(size.width)), y: 0))
+        path.line(to: CGPoint(x: 0, y: CGFloat(i * 5 % Int(size.height))))
+        path.lineWidth = 2
+        path.stroke()
+    }
+    image.unlockFocus()
+    return image
+}
 #endif
 
+private func jpegPixelSize(_ data: Data) -> CGSize {
+    guard let source = CGImageSourceCreateWithData(data as CFData, nil),
+          let props = CGImageSourceCopyPropertiesAtIndex(source, 0, nil) as? [CFString: Any],
+          let width = props[kCGImagePropertyPixelWidth] as? Int,
+          let height = props[kCGImagePropertyPixelHeight] as? Int else {
+        return .zero
+    }
+    return CGSize(width: width, height: height)
+}
+
 struct ImageUtilsTests {
     @Test
     func processImage_rejectsOversizedSourceFile() throws {
@@ -72,6 +122,23 @@ struct ImageUtilsTests {
         #expect(data.count > 0)
     }
 
+    @Test
+    func processImage_usesThe512KiBBudgetInsteadOfCrushingTo45KB() throws {
+        let image = makeNoisyPlatformImage(size: CGSize(width: 1600, height: 1200))
+        let outputDirectory = makeTemporaryDirectoryURL("image-budget-\(UUID().uuidString)")
+        defer { try? FileManager.default.removeItem(at: outputDirectory) }
+
+        let outputURL = try ImageUtils.processImage(image, outputDirectory: outputDirectory)
+        let data = try Data(contentsOf: outputURL)
+        let pixelSize = jpegPixelSize(data)
+
+        #expect(data.count > 45_000)
+        #expect(data.count <= FileTransferLimits.maxImageBytes)
+        #expect(pixelSize.width <= 512)
+        #expect(pixelSize.height <= 512)
+        #expect(max(pixelSize.width, pixelSize.height) == 512)
+    }
+
     @Test
     func processImage_usesUniqueOutputURLs() throws {
         let image = makePlatformImage(size: CGSize(width: 64, height: 64))