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An Open Source JavaFX PDF Viewer
/*
* ===========================================
* Java Pdf Extraction Decoding Access Library
* ===========================================
*
* Project Info: http://www.idrsolutions.com
* Help section for developers at http://www.idrsolutions.com/support/
*
* (C) Copyright 1997-2015 IDRsolutions and Contributors.
*
* This file is part of JPedal/JPDF2HTML5
*
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* ---------------
* D3.java
* ---------------
*/
package com.idrsolutions.image.png;
/**
* Class performs dithering in 24 bit images
*/
public class D3 {
public final int r;
public final int g;
public final int b;
public final int rgb;
public D3(int r,int g, int b){
this.r = r;
this.g = g;
this.b = b;
this.rgb = (r << 16) | (g << 8) | b;
}
private static int diff(int r, int g, int b, D3 pal) {
int Rdiff = r - pal.r;
int Gdiff = g - pal.g;
int Bdiff = b - pal.b;
return Rdiff * Rdiff + Gdiff * Gdiff + Bdiff * Bdiff;
}
public static int[] findClosest(int argb, D3[] palette) {
D3 closest = palette[0];
D3 n;
int r = (argb>> 16) & 0xff;
int g = (argb >> 8) & 0xff;
int b = argb & 0xff;
int cDiff = diff(r,g,b,closest);
int nDiff;
int found = 0;
for (int i = 1; i < 256; i++) {
n = palette[i];
nDiff = diff(r,g,b,n);
if (nDiff < cDiff) {
closest = n;
found = i;
cDiff = nDiff;
}
}
return new int[]{closest.rgb, found};
}
public static byte[] process(byte[] colorPalette, int[][] image, int h, int w) {
int p = 0;
D3[] palette = new D3[256];
for (int i = 0; i < 256; i++) {
int r = colorPalette[p++] & 0xff;
int g = colorPalette[p++] & 0xff;
int b = colorPalette[p++] & 0xff;
palette[i] = new D3(r, g, b);
}
byte[] indexedPixels = new byte[h * w];
p = 0;
for (int y = 0; y < h; y++) {
for (int x = 0; x < w; x++) {
final int argb = image[y][x];
// byte bb = wu.findMatch(argb);
// indexedPixels[p++] = bb;
// int nextArgb = palette[bb&0xff].rgb;
int[] obj = findClosest(argb, palette);
int nextArgb = obj[0];
indexedPixels[p++] = (byte) obj[1];
int r = (argb >> 16) & 0xff;
int g = (argb >> 8) & 0xff;
int b = argb & 0xff;
int nr = (nextArgb >> 16) & 0xff;
int ng = (nextArgb >> 8) & 0xff;
int nb = nextArgb & 0xff;
int errR = r - nr;
int errG = g - ng;
int errB = b - nb;
if (x + 1 < w) {
int update = applyFloyd(image[y][x + 1], errR, errG, errB, 7);
image[y][x + 1] = update;
if (y + 1 < h) {
update = applyFloyd(image[y + 1][x + 1], errR, errG, errB, 1);
image[y + 1][x + 1] = update;
}
}
if (y + 1 < h) {
int update = applyFloyd(image[y + 1][x], errR, errG, errB, 5);
image[y + 1][x] = update;
if (x - 1 >= 0) {
update = applyFloyd(image[y + 1][x - 1], errR, errG, errB, 3);
image[y + 1][x - 1] = update;
}
}
}
}
return indexedPixels;
}
private static int applyFloyd(final int argb, final int errR, final int errG, final int errB, final int mul) {
int r = (argb >> 16) & 0xff;
int g = (argb >> 8) & 0xff;
int b = argb & 0xff;
r += errR * mul / 16;
g += errG * mul / 16;
b += errB * mul / 16;
if (r < 0) {
r = 0;
} else if (r > 0xff) {
r = 0xff;
}
if (g < 0) {
g = 0;
} else if (g > 0xff) {
g = 0xff;
}
if (b < 0) {
b = 0;
} else if (b > 0xff) {
b = 0xff;
}
return (r << 16) | (g << 8) | b;
}
}