HelpButton.fxml

<?xml version="1.0" encoding="UTF-8"?>

<?import javafx.geometry.Rectangle2D?>
<?import javafx.scene.control.Button?>
<?import javafx.scene.image.Image?>
<?import javafx.scene.image.ImageView?>

<Button mnemonicParsing="false" onAction="#onActionButtonHelpHemiPhoto" style="-fx-padding: 3; -fx-background-radius: 20;" xmlns="http://javafx.com/javafx/8.0.65" xmlns:fx="http://javafx.com/fxml/1" fx:controller="fr.amap.lidar.amapvox.gui.HelpButtonController">
   <graphic>
      <ImageView fitHeight="15.0" fitWidth="15.0" pickOnBounds="true" preserveRatio="true">
         <image>
            <Image url="@icons/help.png" />
         </image>
         <viewport>
            <Rectangle2D />
         </viewport>
      </ImageView>
   </graphic>
</Button>