Parent topic: Using a gICAPI web component
Web components / Using a gICAPI web component

Using image resources with the gICAPI web component

This section explains how to use image resources in a gICAPI web component.

Image resources in gICAPI web components

In some cases, web components require image resources, which can be classified as follows:

  1. Common (static) image resources, that are part of the gICAPI web component implementation. This category of image resource can be referenced with absolute URLs (retrieved automatically by the HTML viewer), or can be deployed as part of the gICAPI web component assets, when referenced with relative URLs.
  2. Private (variable) image resources, that are displayed by the program at runtime. This category of image resource can be referenced with absolute URLs (retrieved automatically by the HTML viewer), or can be provided by using the ui.Interface.filenameToURI() / FGLIMAGEPATH mechanism (as described below).

Referencing image resources in HTML

Image resources are typically referenced in HTML within the <img/> element, by setting the src attribute to a relative or absolute URL:

The following example uses an absolute URL:

<img src="http://www.4js.com/images/smiley.gif" alt="Smiley face" height= "42" width= "42" >

This example uses a relative URL:

<img src="smiley.gif" alt="Smiley face" height= "42" width= "42" >

The gICAPI web component framework can automatically retrieve image resources. If the value is not an absolute or relative URL that can be resolved by the HTML viewer, the image resources are retrieved from the Genero application using the ui.Interface.filenameToURI() / FGLIMAGEPATH mechanism.

Providing static images in gICAPI web component files

To provide common static images as assets of your gICAPI web component, provide the image files along with the main HTML file, typically in a dedicated directory. For example, if you define the following directory structure:

3DChart/3DChart.html
3DChart/images/redraw.gif
3DChart/images/fetchdata.gif

The HTML content of the web component can reference common static images as follows:

<img src="images/redraw.gif" alt="Smiley face" height= "42" width= "42" >

Providing application images from Genero programs

Some gICAPI web components display variable image resources provided at runtime. For example, a photo gallery web component displaying pictures. Such image resources are usually private to the application.

To use image resources that are not static images part of the gICAPI web component assets:
  1. Reference absolute URLs directly in the HTML content (in "src" attributes of image elements) with http:, https: or file: shemes, to be retrieved automatically by the HTML viewer, or:
  2. Reference image resources in the HTML content with the URI returned from the ui.Interface.filenameToURI() method, to provide image files from the platform where the application executes (can be a server or mobile device):
    • When running the application on a server behind the GAS, the filenameToURI() method will convert the local file path to a URL that will make the image file available through the GAS.
    • When using a direct connection to the front-end (typical GDC desktop configuration with application running on a server), the file name will be returned as is and the images will then be transmitted through the FGLIMAGEPATH mechanism, as described in Providing the image resource.
    • When running apps on mobile devices, the filenameToURI() method will build the complete path to the local file, according to the list of directories defined in the FGLIMAGEPATH environment variable. The image resource is then directly read from the device file system.

    Try Example 5: Application images in gICAPI web component, to see this method in practice.

Parent topic: Using a gICAPI web component