title: zoom in and zoom out in ng2-pdf-viewer
body: <p>am using ng2-pdf-viewer to show pdf files in my app.</p>
  
  <pre><code>&lt;pdf-viewer [src]="pdfSrc"
            [page]="page"
            [zoom]="1.1"
            style="width: 100%;"
  </code></pre>
  
  <blockquote>
    <p></p>
  </blockquote>
  
  <p>I want to add zoom in and zoom out buttons. How can i implement this in ng2-pdf-viewer.</p>
  
  <p>Suggestion about any other better library that i can use with angular 4 for pdf files will be highly appreciated</p>