The purpose of the Gauge widget is to provide an application developer with means of advancing and declining values in a circulare, graphical fashion. The application developer supplies a background image for the gauge as well as an image of the center of the gauge. Two such images can be seen below, as an exmaple, but they are not a part of the LinearGauge widget and it is purely up to the application developer to provide the graphics.
The widget supports a customizable easing equation for animating between set gauge-values. An animations length is determined by a configurable duration. A developer can ask the LinearGauge widget for the position of it's gauge level. The shape of the needle and the shadow of the needle is embedded inside the Gauge class and can be changed to suit the application
This widget was created and tested using TouchGFX version 4.2
The following exemplifies, in code, how to set up a Gauge widget. Once set up, the level of the gauge can be controlled by calling setValue(). Setting a value outside range of the configured minimum and maximum values will set the value to the limit.
// Set the background and center bitmaps
gauge.setBitmaps(Bitmap(BITMAP_GAUGE_BACKGROUND_ID), Bitmap(BITMAP_GAUGE_NEEDLE_PIN_ID));
// Set the value range to 0-30 and the corresponding degrees to 240-480
gauge.setLimits(0, 30, 240, 480);
// Place the gauge on the screen
gauge.setXY(100,85);
// Set the formula for moving the needle
gauge.setEasingEquation(EasingEquations::linearEaseNone);
// Set the speed of the needle movement
gauge.setAnimationDuration(20);
// Set current value to 20
gauge.setValue(20);
// Add widget
add(gauge);