gecko/mobile/android/base/gfx/BitmapUtils.java

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/* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
2012-05-21 04:12:37 -07:00
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
package org.mozilla.gecko.gfx;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Color;
import android.util.Base64;
import android.util.Log;
public final class BitmapUtils {
private static final String LOGTAG = "GeckoBitmapUtils";
public static int getDominantColor(Bitmap source) {
return getDominantColor(source, true);
}
public static int getDominantColor(Bitmap source, boolean applyThreshold) {
int[] colors = new int[37];
int[] sat = new int[11];
int[] val = new int[11];
int maxH = 0;
int maxS = 0;
int maxV = 0;
if (source == null)
return Color.argb(255,255,255,255);
for (int row = 0; row < source.getHeight(); row++) {
for (int col = 0; col < source.getWidth(); col++) {
int c = source.getPixel(col, row);
if (Color.alpha(c) < 128)
continue;
float[] hsv = new float[3];
Color.colorToHSV(c, hsv);
// arbitrarily chosen values for "white" and "black"
if (applyThreshold && hsv[1] <= 0.35f && hsv[2] <= 0.35f)
continue;
int h = Math.round(hsv[0] / 10.0f);
int s = Math.round(hsv[1] * 10.0f);
int v = Math.round(hsv[2] * 10.0f);
colors[h]++;
sat[s]++;
val[v]++;
// we only care about the most unique non white or black hue - if threshold is applied
// we also store its saturation and value params to match the color better
if (colors[h] > colors[maxH]) {
maxH = h;
maxS = s;
maxV = v;
}
}
}
float[] hsv = new float[3];
hsv[0] = maxH*10.0f;
hsv[1] = (float)maxS/10.0f;
hsv[2] = (float)maxV/10.0f;
return Color.HSVToColor(hsv);
}
/**
* Decodes a bitmap from a Base64 data URI.
*
* @param dataURI a Base64-encoded data URI string
* @return the decoded bitmap, or null if the data URI is invalid
*/
public static Bitmap getBitmapFromDataURI(String dataURI) {
String base64 = dataURI.substring(dataURI.indexOf(',') + 1);
try {
byte[] raw = Base64.decode(base64, Base64.DEFAULT);
return BitmapFactory.decodeByteArray(raw, 0, raw.length);
} catch (Exception e) {
Log.e(LOGTAG, "exception decoding bitmap from data URI: " + dataURI, e);
}
return null;
}
}