Issue #795: avoid sorting preview sizes

android-core/src/main/java/com/google/zxing/client/android/camera/CameraConfigurationUtils.java

@@ -22,11 +22,9 @@
 import android.os.Build;
 import android.util.Log;
 
-import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
-import java.util.Comparator;
 import java.util.Iterator;
 import java.util.List;
 import java.util.regex.Pattern;
@@ -284,42 +282,24 @@ public static Point findBestPreviewSizeValue(Camera.Parameters parameters, Point
       return new Point(defaultSize.width, defaultSize.height);
     }
 
-    // Sort by size, descending
-    List<Camera.Size> supportedPreviewSizes = new ArrayList<>(rawSupportedSizes);
-    Collections.sort(supportedPreviewSizes, new Comparator<Camera.Size>() {
-      @Override
-      public int compare(Camera.Size a, Camera.Size b) {
-        int aPixels = a.height * a.width;
-        int bPixels = b.height * b.width;
-        if (bPixels < aPixels) {
-          return -1;
-        }
-        if (bPixels > aPixels) {
-          return 1;
-        }
-        return 0;
-      }
-    });
-
     if (Log.isLoggable(TAG, Log.INFO)) {
       StringBuilder previewSizesString = new StringBuilder();
-      for (Camera.Size supportedPreviewSize : supportedPreviewSizes) {
-        previewSizesString.append(supportedPreviewSize.width).append('x')
-            .append(supportedPreviewSize.height).append(' ');
+      for (Camera.Size size : rawSupportedSizes) {
+        previewSizesString.append(size.width).append('x').append(size.height).append(' ');
       }
       Log.i(TAG, "Supported preview sizes: " + previewSizesString);
     }
 
     double screenAspectRatio = screenResolution.x / (double) screenResolution.y;
 
-    // Remove sizes that are unsuitable
-    Iterator<Camera.Size> it = supportedPreviewSizes.iterator();
-    while (it.hasNext()) {
-      Camera.Size supportedPreviewSize = it.next();
-      int realWidth = supportedPreviewSize.width;
-      int realHeight = supportedPreviewSize.height;
-      if (realWidth * realHeight < MIN_PREVIEW_PIXELS) {
-        it.remove();
+    // Find a suitable size, with max resolution
+    int maxResolution = 0;
+    Camera.Size maxResPreviewSize = null;
+    for (Camera.Size size : rawSupportedSizes) {
+      int realWidth = size.width;
+      int realHeight = size.height;
+      int resolution = realWidth * realHeight;
+      if (resolution < MIN_PREVIEW_PIXELS) {
         continue;
       }
 
@@ -329,7 +309,6 @@ public int compare(Camera.Size a, Camera.Size b) {
       double aspectRatio = maybeFlippedWidth / (double) maybeFlippedHeight;
       double distortion = Math.abs(aspectRatio - screenAspectRatio);
       if (distortion > MAX_ASPECT_DISTORTION) {
-        it.remove();
         continue;
       }
 
@@ -338,14 +317,19 @@ public int compare(Camera.Size a, Camera.Size b) {
         Log.i(TAG, "Found preview size exactly matching screen size: " + exactPoint);
         return exactPoint;
       }
+
+      // Resolution is suitable; record the one with max resolution
+      if (resolution > maxResolution) {
+        maxResolution = resolution;
+        maxResPreviewSize = size;
+      }
     }
 
     // If no exact match, use largest preview size. This was not a great idea on older devices because
     // of the additional computation needed. We're likely to get here on newer Android 4+ devices, where
     // the CPU is much more powerful.
-    if (!supportedPreviewSizes.isEmpty()) {
-      Camera.Size largestPreview = supportedPreviewSizes.get(0);
-      Point largestSize = new Point(largestPreview.width, largestPreview.height);
+    if (maxResPreviewSize != null) {
+      Point largestSize = new Point(maxResPreviewSize.width, maxResPreviewSize.height);
       Log.i(TAG, "Using largest suitable preview size: " + largestSize);
       return largestSize;
     }