Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;

import android.graphics.ColorMatrix;
import android.graphics.ColorMatrixColorFilter;
import android.graphics.Paint;

public class Main {
    /**
     * 
     * @param paint
     */
    public static void setThreshold(Paint paint, float threshold) {
        /*
         * Elevation matrix. This will threshold the elevation with GPS altitude.
         * The factor is used to increase the brightness for a given elevation map.
         * Elevation map is prepared so that altitudes from 0-5000 meter are encoded with 0-200 pixel values.
         * Each pixel level is 25 meter. 
         * 
         * Negative sign for black threshold instead of white.
         * Threshold of to 0 to 100 translated to 0 - 200 for all pixels thresholded at 5000 meters.
         * 
         * Calibrated (visually) at 
         * KRNO - 1346 meters, threshold = 28
         * KLXV - 3027 meters, threshold = 61
         * L70  - 811  meters, threshold = 16
         * KHIE - 326  meters, threshold = 7
         *--------------------------------------------
         *       5510                    = 112  ~ 50 meters per px
         * Formula to calculate threshold is:
         * threshold = altitude / 3 (meters per foot) / 50
         * Give 2 levels margin of safety
         */
        float factor = 4.f;
        float mx[] = { factor, 0, 0, 0, -(factor) * (threshold - 5) * 2.0f, 0, factor / 1.5f, 0, 0,
                -(factor) * (threshold - 5) * 2.0f, 0, 0, factor / 2.0f, 0, -(factor) * (threshold - 5) * 2.0f, 0,
                0, 0, 1, 0 };
        ColorMatrix cm = new ColorMatrix(mx);
        paint.setColorFilter(new ColorMatrixColorFilter(cm));
    }
}