Android 墨水屏黑白红色阶算法和抖动算法, 拿过去直接用, 有问题直接下面问
色阶法
一张图像，我们可以把它划分为几个大的颜色域，图像上的每个像素点根据颜色跟这几个色域的趋近程度，被划分到这些颜色域中去。这种方法比较适用于颜色不多的图像，例如亮色或者三色的形状或者文字图像。以黑白红三色墨水屏为例，处理图像的时候我们希望把它处理成黑白红三色，因此对于一张图像来说，我们可以把图像的所有颜色划分三个大的颜色区域：黑色区域，白色区域，红色区域。
抖动法
对于那些颜色比较多，或者渐变区域比较多的图像，上面的色阶法并不太合适，很多时候图像里面的渐变区域的像素可能跟所有颜色域都很接近，如果用色阶法的画就会让图像丢失很多图像细节。很多摄像头拍摄的图片，通过混合颜色的方法来绘画阴影和过度区域，这些图像中，渐变区域占了大部分
对于人眼来说，很容易把特别小的颜色混淆了，比如两种颜色红和蓝并列，如果把它缩小到足够小的手，在人眼看来会变成一种由红和蓝混合而成的颜色。人眼的缺陷意味着我们可以通过欺骗人眼，利用“混合”的方法来获取更多可以表现的颜色，抖动算法就是采用了这一种现象。
package com.example.cinreadedp.ImageProcess;
import android.graphics.Bitmap;
import android.graphics.Color;
public class EPaperPicture
{
private static int srcW, srcH; // Width and height of source image
private static int dstW, dstH; // Width and height of destination image
private static Bitmap srcBmp; // Bitmap of source image
private static Bitmap dstBmp; // Bitmap of destination image
private static int[] curPal; // Current palette
private static int[][] palettes = new int[][] // Palettes
{
new int[] { Color.BLACK, Color.WHITE }, //1黑白
new int[] { Color.BLACK, Color.WHITE, Color.RED }, //2黑白红
new int[] { Color.BLACK, Color.WHITE, Color.GRAY }, //3黑白灰
new int[] { Color.BLACK, Color.WHITE, Color.GRAY, Color.RED }, //4黑白灰红
new int[] { Color.BLACK, Color.WHITE }, //5黑白
new int[] { Color.BLACK, Color.WHITE, Color.YELLOW }, //6黑白黄
new int[] {}, //7
new int[] { 0xff000000, 0xffffffff, 0xff00ff00, 0xff0000ff, 0xffff0000, 0xffffff00,0xffff8000}, //8RGB 全彩
};
// Return the square error of {r, g, b},
// that means how far them are from standard color stdCol
//---------------------------------------------------------
private static double getErr(double r, double g, double b, int stdCol)
{
r -= Color.red (stdCol);
g -= Color.green(stdCol);
b -= Color.blue (stdCol);
return r*r + g*g + b*b;
}
// Return the index of current palette color which is
// nearest to the {r, g, b}
//---------------------------------------------------------
private static int getNear(double r, double g, double b)
{
int ind = 0;
double err = getErr(r, g, b, curPal[0]);
for (int i = 1; i < curPal.length; i++)
{
double cur = getErr(r, g, b, curPal[i]);
if (cur < err) { err = cur; ind = i; }
}
return ind;
}
// Return the index of current palette color which is
// nearest to the color clr
//---------------------------------------------------------
private static int getNear(int clr)
{
return getNear(Color.red(clr), Color.green(clr), Color.blue(clr));
}
// Adding of color {r, g, b} into e color array with
// weight k. Here every r, g or b channel takes one cell
// in e color array and can have any integer value.
//---------------------------------------------------------
private static void addVal(double[] e, int i, double r, double g, double b, double k)
{
int index = i * 3;
e[index ] = (r * k) / 16 + e[index ];
e[index + 1] = (g * k) / 16 + e[index + 1];
e[index + 2] = (b * k) / 16 + e[index + 2];
}
// Returns a color from the current palette
// which is nearest to source bitmap pixel at (x, y), or
// returns default color if (x, y) is out of the bitmap
//---------------------------------------------------------
private static int nearColor(int x, int y)
{
if ((x >= srcW) || (y >= srcH)) return curPal[(x + y) % 2 == 0 ? 1 : 0];
return curPal[getNear(srcBmp.getPixel(x, y))];
}
//originalImage 原始图片
//isLvl 1 色阶算法 0 抖动算法
//width 输出文件宽度
//height 输出文件高度
//index_t 可以选择6种数据格式 palettes
public static Bitmap createIndexedImage(Bitmap originalImage,boolean isLvl,int width,int height,int index_t)
{
//EPaperDisplay epd = EPaperDisplay.getDisplays()[EPaperDisplay.epdInd];
srcBmp = originalImage;
dstBmp = Bitmap.createBitmap(width,height, srcBmp.getConfig());
int palInd = index_t;
// if (!isRed) palInd = palInd & 0xE;
curPal = palettes[palInd];
dstW = dstBmp.getWidth();
dstH = dstBmp.getHeight();
srcW = srcBmp.getWidth();
srcH = srcBmp.getHeight();
int[] srcArr = new int[srcW * srcH];
int[] dstArr = new int[dstW * dstH];
int index = 0;
srcBmp.getPixels(srcArr, 0, srcW, 0, 0, srcW, srcH);
if (isLvl) //色阶算法
{
for (int y = 0; y < dstH; y++)
for (int x = 0; x < dstW; x++)
dstArr[index++] = nearColor(x, y);
}
else //抖动算法
{
int aInd = 0;
int bInd = 1;
double[][] errArr = new double[2][];
errArr[0] = new double[3*dstW];
errArr[1] = new double[3*dstW];
for (int i = 0; i < dstW; i++)
{
errArr[bInd][3*i ] = 0;
errArr[bInd][3*i + 1] = 0;
errArr[bInd][3*i + 2] = 0;
}
for (int j = 0; j < dstH; j++)
{
if (j >= srcH)
{
for (int i = 0; i < dstW; i++, index++)
dstArr[index] = curPal[(i + j) % 2 == 0 ? 1 : 0];
continue;
}
aInd = ((bInd = aInd) + 1) & 1;
for (int i = 0; i < dstW; i++)
{
errArr[bInd][3*i ] = 0;
errArr[bInd][3*i + 1] = 0;
errArr[bInd][3*i + 2] = 0;
}
for (int i = 0; i < dstW; i++)
{
if (i >= srcW)
{
dstArr[index++] = curPal[(i + j) % 2 == 0 ? 1 : 0];
continue;
}
int srcPix = srcArr[j * srcW + i];
double r = Color.red (srcPix) + errArr[aInd][3*i ];
double g = Color.green(srcPix) + errArr[aInd][3*i + 1];
double b = Color.blue (srcPix) + errArr[aInd][3*i + 2];
int colVal = curPal[getNear(r, g, b)];
dstArr[index++] = colVal;
r -= Color.red (colVal);
g -= Color.green(colVal);
b -= Color.blue (colVal);
if (i == 0)
{
addVal(errArr[bInd], (i ), r, g, b, 7.0);
addVal(errArr[bInd], (i + 1), r, g, b, 2.0);
addVal(errArr[aInd], (i + 1), r, g, b, 7.0);
}
else if (i == dstW - 1)
{
addVal(errArr[bInd], (i - 1), r, g, b, 7.0);
addVal(errArr[bInd], (i ), r, g, b, 9.0);
}
else
{
addVal(errArr[bInd], (i - 1), r, g, b, 3.0);
addVal(errArr[bInd], (i ), r, g, b, 5.0);
addVal(errArr[bInd], (i + 1), r, g, b, 1.0);
addVal(errArr[aInd], (i + 1), r, g, b, 7.0);
}
}
}
}
// Put converted pixels into destination image bitmap
//-----------------------------------------------------
dstBmp.setPixels(dstArr, 0, dstW, 0, 0, dstW, dstH);
return dstBmp;
}
// Returns the index of color in palette
//-----------------------------------------------------
public int getVal(int color)
{
int r = Color.red(color);
int b = Color.blue(color);
if((r == 0xFF) && (b == 0xFF)) return 1;
if((r == 0x7F) && (b == 0x7F)) return 2;
if((r == 0xFF) && (b == 0x00)) return 3;
return 0;
}
// Returns the index of color in palette just for 5.65f e-Paper
//-----------------------------------------------------
public int getVal_7color(int color)
{
int r = Color.red(color);
int g = Color.green(color);
int b = Color.blue(color);
if((r == 0x00) && (g == 0x00) && (b == 0x00)) return 0;
if((r == 0xFF) && (g == 0xFF) && (b == 0xFF)) return 1;
if((r == 0x00) && (g == 0xFF) && (b == 0x00)) return 2;
if((r == 0x00) && (g == 0x00) && (b == 0xFF)) return 3;
if((r == 0xFF) && (g == 0x00) && (b == 0x00)) return 4;
if((r == 0xFF) && (g == 0xFF) && (b == 0x00)) return 5;
if((r == 0xFF) && (g == 0x80) && (b == 0x00)) return 6;
return 7;
}
}
