Support for image preview & drag and drop

src/components/Widgets/ImageControl.js

@@ -4,13 +4,70 @@ export default class ImageControl extends React.Component {
   constructor(props) {
     super(props);
     this.handleChange = this.handleChange.bind(this);
+    this.handleFileInputRef = this.handleFileInputRef.bind(this);
+    this.handleClick = this.handleClick.bind(this);
+    this.handleDragEnter = this.handleDragEnter.bind(this);
+    this.handleDragOver = this.handleDragOver.bind(this);
+  }
+
+  handleFileInputRef(el) {
+    this._fileInput = el;
+  }
+
+  handleClick(e) {
+    this._fileInput.click();
+  }
+
+  handleDragEnter(e) {
+    e.stopPropagation();
+    e.preventDefault();
+  }
+
+  handleDragOver(e) {
+    e.stopPropagation();
+    e.preventDefault();
   }
 
   handleChange(e) {
-    this.props.onChange(e.target.value);
+    e.stopPropagation();
+    e.preventDefault();
+    const fileList = e.dataTransfer ? e.dataTransfer.files : e.target.files;
+    const files = [...fileList];
+    const imageType = /^image\//;
+
+    // Iterate to list of files and return the first image on the list
+    const file = files.find((currentFile) => {
+      if (imageType.test(currentFile.type)) {
+        return currentFile;
+      }
+    });
+
+    this.props.onChange(file);
   }
 
   render() {
-    return <input type="file" onChange={this.handleChange}/>;
+    return (
+      <div
+          onClick={this.handleClick}
+          onDragEnter={this.handleDragEnter}
+          onDragOver={this.handleDragOver}
+          onDrop={this.handleChange}
+      >
+        Click or drop image here.
+        <input
+            type="file"
+            accept="image/*"
+            onChange={this.handleChange}
+            style={styles.input}
+            ref={this.handleFileInputRef}
+        />
+      </div>
+    );
   }
 }
+
+const styles = {
+  input: {
+    display: 'none'
+  }
+};

src/components/Widgets/ImagePreview.js

@@ -3,11 +3,15 @@ import React from 'react';
 export default class ImagePreview extends React.Component {
   constructor(props) {
     super(props);
+    this.handleImageLoaded = this.handleImageLoaded.bind(this);
+  }
+
+  handleImageLoaded() {
+    window.URL.revokeObjectURL(this.props);
   }
 
   render() {
     const { value } = this.props;
-
+    return value ? <img src={window.URL.createObjectURL(value)} onLoad={this.handleImageLoaded} /> : null;
-    return value ? <img src={value}/> : null;
   }
 }