Support for tiling image view and large image viewing

Fixes #5949
Fixes #5574
Fixes #4380
// FREEBIE

src/org/thoughtcrime/securesms/components/subsampling/AttachmentRegionDecoder.java

@@ -0,0 +1,95 @@
+package org.thoughtcrime.securesms.components.subsampling;
+
+
+import android.content.Context;
+import android.graphics.Bitmap;
+import android.graphics.BitmapFactory;
+import android.graphics.BitmapRegionDecoder;
+import android.graphics.Point;
+import android.graphics.Rect;
+import android.net.Uri;
+import android.os.Build;
+import android.support.annotation.RequiresApi;
+import android.util.Log;
+
+import com.davemorrissey.labs.subscaleview.decoder.ImageRegionDecoder;
+import com.davemorrissey.labs.subscaleview.decoder.SkiaImageRegionDecoder;
+
+import org.thoughtcrime.securesms.crypto.MasterSecret;
+import org.thoughtcrime.securesms.mms.PartAuthority;
+import org.thoughtcrime.securesms.service.KeyCachingService;
+
+import java.io.InputStream;
+
+public class AttachmentRegionDecoder implements ImageRegionDecoder {
+
+  private static final String TAG = AttachmentRegionDecoder.class.getName();
+
+  private SkiaImageRegionDecoder passthrough;
+
+  private BitmapRegionDecoder bitmapRegionDecoder;
+
+  @RequiresApi(api = Build.VERSION_CODES.GINGERBREAD_MR1)
+  @Override
+  public Point init(Context context, Uri uri) throws Exception {
+    Log.w(TAG, "Init!");
+    if (!PartAuthority.isLocalUri(uri)) {
+      passthrough = new SkiaImageRegionDecoder();
+      return passthrough.init(context, uri);
+    }
+
+    MasterSecret masterSecret = KeyCachingService.getMasterSecret(context);
+
+    if (masterSecret == null) {
+      throw new IllegalStateException("No master secret available...");
+    }
+
+    InputStream inputStream = PartAuthority.getAttachmentStream(context, masterSecret, uri);
+
+    this.bitmapRegionDecoder = BitmapRegionDecoder.newInstance(inputStream, false);
+    inputStream.close();
+
+    return new Point(bitmapRegionDecoder.getWidth(), bitmapRegionDecoder.getHeight());
+  }
+
+  @RequiresApi(api = Build.VERSION_CODES.GINGERBREAD_MR1)
+  @Override
+  public Bitmap decodeRegion(Rect rect, int sampleSize) {
+    Log.w(TAG, "Decode region: " + rect);
+
+    if (passthrough != null) {
+      return passthrough.decodeRegion(rect, sampleSize);
+    }
+
+    synchronized(this) {
+      BitmapFactory.Options options = new BitmapFactory.Options();
+      options.inSampleSize      = sampleSize;
+      options.inPreferredConfig = Bitmap.Config.RGB_565;
+
+      Bitmap bitmap = bitmapRegionDecoder.decodeRegion(rect, options);
+
+      if (bitmap == null) {
+        throw new RuntimeException("Skia image decoder returned null bitmap - image format may not be supported");
+      }
+
+      return bitmap;
+    }
+  }
+
+  @RequiresApi(api = Build.VERSION_CODES.GINGERBREAD_MR1)
+  public boolean isReady() {
+    Log.w(TAG, "isReady");
+    return (passthrough != null && passthrough.isReady()) ||
+           (bitmapRegionDecoder != null && !bitmapRegionDecoder.isRecycled());
+  }
+
+  @RequiresApi(api = Build.VERSION_CODES.GINGERBREAD_MR1)
+  public void recycle() {
+    if (passthrough != null) {
+      passthrough.recycle();
+      passthrough = null;
+    } else {
+      bitmapRegionDecoder.recycle();
+    }
+  }
+}