Book Image

Mastering OpenLayers 3

By : Gábor Farkas
Book Image

Mastering OpenLayers 3

By: Gábor Farkas

Overview of this book

OpenLayers 3 allows you to create stunning web mapping and WebGIS applications. It uses modern, cutting edge browser technologies. It is written with Closure Library, enabling you to build browser-independent applications without painful debugging ceremonies, which even have some limited fallback options for older browsers. With this guide, you will be introduced to the world of advanced web mapping and WebGIS. First, you will be introduced to the advanced features and functionalities available in OpenLayers 3. Next, you will be taken through the key points of creating custom applications with OpenLayers 3. You will then learn how to create the web mapping application of yours (or your company's) dream with this open source, expense-free, yet very powerful library. We’ll also show you how to make amazing looking thematic maps and create great effects with canvas manipulation. By the end of this book, you will have a strong command of web mapping and will be well on your way to creating amazing applications using OpenLayers 3.
Table of Contents (17 chapters)
Mastering OpenLayers 3
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface
Index

Mapping interactions to controls


In this example, called ch05_select, we fill the gap between interactions and controls, and create a simple feature selecting the control. As we need to inform the user about the control's status, we create some CSS rules for active controls. Activated controls will have a nice orange color, which won't change, if we hover over them. We also extend the ol-unselectable class to our controls:

.layertree,.toolbar .ol-unselectable {
[…]
.toolbar .ol-control button.active {
    background-color: rgba(234,129,8,1);
}
.toolbar .ol-control button.active:hover {
    background-color: rgba(234,129,8,1);
}

Creating the control

Next, we can go on and build a custom control that has only one job: managing the underlying interaction. Firstly, we set up the control's properties and GUI elements based on the supplied options:

ol.control.Interaction = function (opt_options) {
    var options = opt_options || {};
    var controlDiv = document.createElement('div');
    controlDiv...