How to modify the dragging effect when using HTML5 drag-and-drop?

Question

I am using angularJS for my web appliaction, and I need to write a component that contains dragging operation. When I tried to accomplish the goal, I found it hard to control the dragging effect around the pointer, since it was not a real element but an image cut (I assume). For now the dragging image is a copy of the element being drag and contains the hover effect, and even have white background from its parent. (I cut two image and display below)

So how can I modify the dragging effct with css or js?

I add a class "is-dragging" for the element being dragged when dragstart event is trigger, and change the style of the element being drag. But the dragging image just remain the same.

html

<div ng-if="current == -1" class="form-library">
    <div ng-repeat="(key, item) in formMap"
         class="form-type-items"
         ng-class="{'is-dragging': dragInfo.type == 'add' && key == dragInfo.data.type}"
         draggable="true"
         ng-dragstart="onDragStart($event, key)"
         ng-dragend="onDragEnd($event)">
         <div class="form-type-icon">
             <i class="{{'iconfont icon-'+item.icon}}"></i>
         </div>
         <span class="form-type-name">{{ item.name }}</span>
    </div>
</div>

scss

&:hover {
    .form-type-name {
        color: $brand-color-1;
    }
    .form-type-icon {
        .iconfont {
            color: $brand-color-1;
        }
    }
}
&.is-dragging {
   opacity: 0.36;
   background-color: transparent;
   .form-type-name {
       color: $gray-2;
   }
   .form-type-icon {
       .iconfont {
           color: $gray-2;
       }
   }
}

Answer 1

It looks like styles are applied after the dragging starts so the dragging visual copy is a shallow copy of the element from the instance when the dragging just started. As a work around you can try to first apply styles, and then set draggable attribute on the element, and remove it after an element is been released

<div ng-if="current == -1" class="form-library">
    <div ng-repeat="(key, item) in formMap"
            class="form-type-items"
            ng-class="{'is-dragging': dragInfo.type == 'add' && key == dragInfo.data.type}"
            draggable="true"
            on-mousedown="onMouseDown($event, key)"
            on-mouseup="onMouseUp($event)">
            <div class="form-type-icon">
                <i class="{{'iconfont icon-'+item.icon}}"></i>
            </div>
            <span class="form-type-name">{{ item.name }}</span>
    </div>
</div>


<script>
function onMouseDown(e) {
    // set variable that will apply necessary class to TRUE

    // then add draggable attribute
    e.target.setAttribute('draggable', true)
}


function onMouseUp(e) {
    // set variable for drabble class to FALSE

    // then remove draggable attribute
    e.target.setAttribute('draggable', false)
}

</script>