Scale attached images before display to save memory

app/src/main/java/eu/faircode/email/AdapterImage.java

@@ -23,6 +23,8 @@ import android.content.Context;
 import android.content.Intent;
 import android.content.pm.PackageManager;
 import android.content.pm.ResolveInfo;
+import android.graphics.Bitmap;
+import android.graphics.BitmapFactory;
 import android.graphics.drawable.BitmapDrawable;
 import android.graphics.drawable.Drawable;
 import android.net.Uri;
@@ -79,8 +81,27 @@ public class AdapterImage extends RecyclerView.Adapter<AdapterImage.ViewHolder>
 
         private void bindTo(EntityAttachment attachment) {
             if (attachment.available) {
-                Drawable d = BitmapDrawable.createFromPath(
+                Drawable d = null;
-                        EntityAttachment.getFile(context, attachment.id).getAbsolutePath());
+                File file = EntityAttachment.getFile(context, attachment.id);
+
+                if ("image/jpeg".equals(attachment.type) || "image/png".equals(attachment.type)) {
+                    BitmapFactory.Options options = new BitmapFactory.Options();
+                    options.inJustDecodeBounds = true;
+                    BitmapFactory.decodeFile(file.getAbsolutePath(), options);
+
+                    int scaleTo = context.getResources().getDisplayMetrics().widthPixels / 2;
+                    int factor = Math.min(options.outWidth / scaleTo, options.outWidth / scaleTo);
+                    if (factor > 1) {
+                        options.inJustDecodeBounds = false;
+                        options.inSampleSize = factor;
+                        Bitmap scaled = BitmapFactory.decodeFile(file.getAbsolutePath(), options);
+                        d = new BitmapDrawable(scaled);
+                    }
+                }
+
+                if (d == null)
+                    d = BitmapDrawable.createFromPath(file.getAbsolutePath());
+
                 if (d == null)
                     image.setImageResource(R.drawable.baseline_broken_image_24);
                 else