Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;
// Use of this source code is governed by a BSD-style license that can be

import android.graphics.Color;

public class Main {
    private static final float CONTRAST_LIGHT_ITEM_THRESHOLD = 3f;

    /**
     * Check whether lighter or darker foreground elements (i.e. text, drawables etc.)
     * should be used depending on the given background color.
     * @param backgroundColor The background color value which is being queried.
     * @return Whether light colored elements should be used.
     */
    public static boolean shoudUseLightForegroundOnBackground(int backgroundColor) {
        return getContrastForColor(backgroundColor) >= CONTRAST_LIGHT_ITEM_THRESHOLD;
    }

    /** Calculates the contrast between the given color and white, using the algorithm provided by
     * the WCAG v2 in http://www.w3.org/TR/WCAG20/#contrast-ratiodef.
     */
    private static float getContrastForColor(int color) {
        float bgR = Color.red(color) / 255f;
        float bgG = Color.green(color) / 255f;
        float bgB = Color.blue(color) / 255f;
        bgR = (bgR < 0.03928f) ? bgR / 12.92f : (float) Math.pow((bgR + 0.055f) / 1.055f, 2.4f);
        bgG = (bgG < 0.03928f) ? bgG / 12.92f : (float) Math.pow((bgG + 0.055f) / 1.055f, 2.4f);
        bgB = (bgB < 0.03928f) ? bgB / 12.92f : (float) Math.pow((bgB + 0.055f) / 1.055f, 2.4f);
        float bgL = 0.2126f * bgR + 0.7152f * bgG + 0.0722f * bgB;
        return Math.abs((1.05f) / (bgL + 0.05f));
    }
}