reduce max image size on low-mem devices

Closes #3343
// FREEBIE

src/org/thoughtcrime/securesms/mms/MediaConstraints.java

@@ -21,8 +21,8 @@ public abstract class MediaConstraints {
   public static MediaConstraints MMS_CONSTRAINTS  = new MmsMediaConstraints();
   public static MediaConstraints PUSH_CONSTRAINTS = new PushMediaConstraints();
 
-  public abstract int getImageMaxWidth();
-  public abstract int getImageMaxHeight();
+  public abstract int getImageMaxWidth(Context context);
+  public abstract int getImageMaxHeight(Context context);
   public abstract int getImageMaxSize();
 
   public abstract int getVideoMaxSize();
@@ -44,8 +44,8 @@ public abstract class MediaConstraints {
   public boolean isWithinBounds(Context context, MasterSecret masterSecret, Uri uri) throws IOException {
     InputStream is = PartAuthority.getPartStream(context, masterSecret, uri);
     Pair<Integer, Integer> dimensions = BitmapUtil.getDimensions(is);
-    return dimensions.first  > 0 && dimensions.first  <= getImageMaxWidth() &&
-           dimensions.second > 0 && dimensions.second <= getImageMaxHeight();
+    return dimensions.first  > 0 && dimensions.first  <= getImageMaxWidth(context) &&
+           dimensions.second > 0 && dimensions.second <= getImageMaxHeight(context);
   }
 
   public boolean canResize(PduPart part) {
@@ -61,8 +61,8 @@ public abstract class MediaConstraints {
 
     try {
       return BitmapUtil.createScaledBytes(context, masterSecret, part.getDataUri(),
-                                          getImageMaxWidth(),
-                                          getImageMaxHeight(),
+                                          getImageMaxWidth(context),
+                                          getImageMaxHeight(context),
                                           getImageMaxSize());
     } catch (BitmapDecodingException bde) {
       throw new IOException(bde);

src/org/thoughtcrime/securesms/mms/MmsMediaConstraints.java

@@ -1,17 +1,22 @@
 package org.thoughtcrime.securesms.mms;
 
+import android.content.Context;
+
+import org.thoughtcrime.securesms.util.Util;
+
 public class MmsMediaConstraints extends MediaConstraints {
-  private static final int MAX_IMAGE_DIMEN  = 1024;
-  public  static final int MAX_MESSAGE_SIZE = 280 * 1024;
+  private static final int MAX_IMAGE_DIMEN_LOWMEM = 768;
+  private static final int MAX_IMAGE_DIMEN        = 1024;
+  public  static final int MAX_MESSAGE_SIZE       = 280 * 1024;
 
   @Override
-  public int getImageMaxWidth() {
-    return MAX_IMAGE_DIMEN;
+  public int getImageMaxWidth(Context context) {
+    return Util.isLowMemory(context) ? MAX_IMAGE_DIMEN_LOWMEM : MAX_IMAGE_DIMEN;
   }
 
   @Override
-  public int getImageMaxHeight() {
-    return MAX_IMAGE_DIMEN;
+  public int getImageMaxHeight(Context context) {
+    return getImageMaxWidth(context);
   }
 
   @Override

src/org/thoughtcrime/securesms/mms/PushMediaConstraints.java

@@ -1,18 +1,23 @@
 package org.thoughtcrime.securesms.mms;
 
+import android.content.Context;
+
+import org.thoughtcrime.securesms.util.Util;
+
 public class PushMediaConstraints extends MediaConstraints {
-  private static final int MAX_IMAGE_DIMEN  = 1280;
-  private static final int KB               = 1024;
-  private static final int MB               = 1024 * KB;
+  private static final int MAX_IMAGE_DIMEN_LOWMEM = 768;
+  private static final int MAX_IMAGE_DIMEN        = 1280;
+  private static final int KB                     = 1024;
+  private static final int MB                     = 1024 * KB;
 
   @Override
-  public int getImageMaxWidth() {
-    return MAX_IMAGE_DIMEN;
+  public int getImageMaxWidth(Context context) {
+    return Util.isLowMemory(context) ? MAX_IMAGE_DIMEN_LOWMEM : MAX_IMAGE_DIMEN;
   }
 
   @Override
-  public int getImageMaxHeight() {
-    return MAX_IMAGE_DIMEN;
+  public int getImageMaxHeight(Context context) {
+    return getImageMaxWidth(context);
   }
 
   @Override

src/org/thoughtcrime/securesms/util/Util.java

@@ -18,6 +18,7 @@ package org.thoughtcrime.securesms.util;
 
 import android.annotation.SuppressLint;
 import android.annotation.TargetApi;
+import android.app.ActivityManager;
 import android.content.Context;
 import android.content.pm.PackageManager;
 import android.graphics.Typeface;
@@ -324,4 +325,12 @@ public class Util {
   public static int hashCode(@Nullable Object... objects) {
     return Arrays.hashCode(objects);
   }
+
+  @TargetApi(VERSION_CODES.KITKAT)
+  public static boolean isLowMemory(Context context) {
+    ActivityManager activityManager = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
+
+    return (VERSION.SDK_INT >= VERSION_CODES.KITKAT && activityManager.isLowRamDevice()) ||
+           activityManager.getMemoryClass() <= 64;
+  }
 }