CS001248 - Blinking flashing increasing brightness of backlight in WRT

From Forum Nokia Wiki

ID	CS001248;	Creation date	November 24, 2008
Platform	S60 3rd Edition, FP2, S60 5th Edition	Tested on devices	Nokia E90 Communicator (v.210.34.75 and later), Nokia 5800 XpressMusic
Category	Web Runtime (WRT)	Subcategory	Hardware

Keywords (APIs, classes, methods, functions): x-systeminfo-widget, SystemInfo.lightblink(), SystemInfo.lighton()

Overview

This code snippet demonstrates how to control the backlight of a device by using the SystemInfo Service API of the Web Runtime version 1.0.

The API is supported from S60 3rd Edition, Feature Pack 2 onwards. It is also supported in select S60 3rd Edition, Feature Pack 1 devices or their newest firmware versions (for example, Nokia E90 Communicator, from v.210.34.75 onwards).

Source

Embed the SystemInfo widget into the document:

<body>
    <embed type="application/x-systeminfo-widget" hidden="yes" />
</body>

Add three buttons to control the backlight:

<input type="button" onclick="lightOn();" value="Light on" />
<input type="button" onclick="blink();" value="Blink" />
<input type="button" onclick="lightOff();" value="Light off" />

The JavaScript code:

var sysInfo = null;
 
window.onload = init;
 
var SMOOTH = true;
 
function init() {
    // Obtain the SystemInfo object
    try {
        sysInfo = document.embeds[0];
    } catch (ex) {
        alert("SystemInfo object cannot be found.");
        return;
    }
}
 
// Switches the display light on
function lightOn() {
    if (sysInfo == undefined) {
        alert("SystemInfo object is undefined.");
        return;
    }
 
    // Reset the backlight state to default
    resetLight();
 
    sysInfo.lighton(sysInfo.lighttargetsystem, sysInfo.lightinfiniteduration,
        sysInfo.lightmaxintensity, SMOOTH);
}
 
// Starts blinking the display 
function blink() {
    if (sysInfo == undefined) {
        alert("SystemInfo object is undefined.");
        return;
    }
 
    // Reset the backlight state to default
    resetLight();
 
    sysInfo.lightblink(sysInfo.lighttargetsystem,
        sysInfo.lightinfiniteduration, sysInfo.lightdefaultcycletime,
        sysInfo.lightdefaultcycletime, sysInfo.lightmaxintensity);
}
 
// Switches the display light off
function lightOff() {
    if (sysInfo == undefined) {
        alert("SystemInfo object is undefined.");
        return;
    }
 
    sysInfo.lightoff(sysInfo.lighttargetsystem, sysInfo.lightinfiniteduration,
        SMOOTH);
}
 
// Sets the backlight of the display to default value
function resetLight() {
    if (sysInfo == undefined) {
        alert("SystemInfo object is undefined.");
        return;
    }
 
    sysInfo.lighton(sysInfo.lighttargetsystem, sysInfo.lightinfiniteduration,
        sysInfo.lightdefaultintensity, SMOOTH);
}

Postconditions

Different possibilities to control the backlight are demonstrated.

Supplementary material

For a complete example that makes use of the SystemInfo Service API to control the backlight, see Blinking_flashing_increasing_brightness_of_backlight_in_WRT.zip

Community: Wiki