Prev - Next Buttons Support

Needs to have a twig variable for buttons. Added a todo for twig variable

@joshi.rohit100 and @navneet0693, as per #2 added the one's mentioned in todo, Please check this :)

+++ b/src/Plugin/Field/FieldFormatter/ImagefieldSlideshowFieldFormatter.php
@@ -95,6 +95,7 @@ class ImagefieldSlideshowFieldFormatter extends ImageFormatterBase implements Co
       'imagefield_slideshow_style_pause' => '1',
+      'imagefield_slideshow_prev_next' => TRUE,
     ) + parent::defaultSettings();

shouldn't this be false or will affect the exiting installation.

+++ b/src/Plugin/Field/FieldFormatter/ImagefieldSlideshowFieldFormatter.php
@@ -197,6 +204,11 @@ class ImagefieldSlideshowFieldFormatter extends ImageFormatterBase implements Co
+    if ($image_prev_next) {
+      $summary[] .= t('Prev & Next :' . $image_prev_next);
+    }

shouldn't this be more verbose instead of 0 or 1 like 'Yes/No' ?

Also how about some theming/css for new buttons.

screenshot is looking good to me. Just a question, not with screenshot but what if we have only one image ? :)

Yes thats true that button will be of no use for one image button showing buttons when they are of no use is kind of a bad UX. But then again, choice is of maintainer :)

1. Yup guys we should have FALSE by default and we should not show prev and next if we have only one image, i have added a piece of check please have a check of this.
2. @navneet0693 was not able to apply this patch seems image is missing, please change in the latest patch now

root@karthik:/var/www/d83/modules/imagefield_slideshow# git apply -v prev_next_buttons-2781361-8.patch
Checking patch css/imagefield_slideshow.css...
Checking patch imagefield_slideshow.libraries.yml...
Checking patch imagefield_slideshow.module...
Checking patch img/next.png...
error: cannot apply binary patch to 'img/next.png' without full index line
error: img/next.png: patch does not apply
Checking patch img/previous.png...
error: cannot apply binary patch to 'img/previous.png' without full index line
error: img/previous.png: patch does not apply
Checking patch js/imagefield_slideshow.js...
Checking patch src/Plugin/Field/FieldFormatter/ImagefieldSlideshowFieldFormatter.php...
Checking patch templates/imagefield-slideshow.html.twig...

@joshi.rohit100, i have committed with the changes mentioned and @navneet0693 you can create one more ticket if you need to work on styling part.
thank you guys..