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數據加載中……

很不錯的一個生成等比例高質量縮略圖的類！

import java.awt.image.BufferedImage;

import java.io.File;

import javax.imageio.ImageIO;

//生成等比例高質量縮略圖

public class ScaleImage {

private int width;

private int height;

private int scaleWidth;

double support = (double) 3.0;

double PI = (double) 3.14159265358978;

double[] contrib;

double[] normContrib;

double[] tmpContrib;

int startContrib, stopContrib;

int nDots;

int nHalfDots;

/**

* Start: Use Lanczos filter to replace the original algorithm for image

* scaling. Lanczos improves quality of the scaled image modify by :blade

public static void main(String[] args) {

ScaleImage is = new ScaleImage();

try {

is.saveImageAsJpg("F:/200712131421190.jpg", "F:/21851500.jpg", 160,

140);

} catch (Exception e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

// fromFileStr原圖片地址,saveToFileStr生成縮略圖地址,formatWideth生成圖片寬度,formatHeight高度

public void saveImageAsJpg(String fromFileStr, String saveToFileStr,

int formatWideth, int formatHeight) throws Exception {

BufferedImage srcImage;

File saveFile = new File(saveToFileStr);

File fromFile = new File(fromFileStr);

srcImage = javax.imageio.ImageIO.read(fromFile); // construct image

int imageWideth = srcImage.getWidth(null);

int imageHeight = srcImage.getHeight(null);

int changeToWideth = 0;

int changeToHeight = 0;

if (imageWideth > 0 && imageHeight > 0) {

// flag=true;

if (imageWideth / imageHeight >= formatWideth / formatHeight) {

if (imageWideth > formatWideth) {

changeToWideth = formatWideth;

changeToHeight = (imageHeight * formatWideth) / imageWideth;

} else {

changeToWideth = imageWideth;

changeToHeight = imageHeight;

}

} else {

if (imageHeight > formatHeight) {

changeToHeight = formatHeight;

changeToWideth = (imageWideth * formatHeight) / imageHeight;

} else {

changeToWideth = imageWideth;

changeToHeight = imageHeight;

}

srcImage = imageZoomOut(srcImage, changeToWideth, changeToHeight);

ImageIO.write(srcImage, "JPEG", saveFile);

}

public BufferedImage imageZoomOut(BufferedImage srcBufferImage, int w, int h) {

width = srcBufferImage.getWidth();

height = srcBufferImage.getHeight();

scaleWidth = w;

if (DetermineResultSize(w, h) == 1) {

return srcBufferImage;

}

CalContrib();

BufferedImage pbOut = HorizontalFiltering(srcBufferImage, w);

BufferedImage pbFinalOut = VerticalFiltering(pbOut, h);

return pbFinalOut;

}

/**

* 決定圖像尺寸

private int DetermineResultSize(int w, int h) {

double scaleH, scaleV;

scaleH = (double) w / (double) width;

scaleV = (double) h / (double) height;

// 需要判斷一下scaleH，scaleV，不做放大操作

if (scaleH >= 1.0 && scaleV >= 1.0) {

return 1;

}

return 0;

} // end of DetermineResultSize()

private double Lanczos(int i, int inWidth, int outWidth, double Support) {

double x;

x = (double) i * (double) outWidth / (double) inWidth;

return Math.sin(x * PI) / (x * PI) * Math.sin(x * PI / Support)

/ (x * PI / Support);

}

private void CalContrib() {

nHalfDots = (int) ((double) width * support / (double) scaleWidth);

nDots = nHalfDots * 2 + 1;

try {

contrib = new double[nDots];

normContrib = new double[nDots];

tmpContrib = new double[nDots];

} catch (Exception e) {

System.out.println("init contrib,normContrib,tmpContrib" + e);

}

int center = nHalfDots;

contrib[center] = 1.0;

double weight = 0.0;

int i = 0;

for (i = 1; i <= center; i++) {

contrib[center + i] = Lanczos(i, width, scaleWidth, support);

weight += contrib[center + i];

}

for (i = center - 1; i >= 0; i--) {

contrib[i] = contrib[center * 2 - i];

}

weight = weight * 2 + 1.0;

for (i = 0; i <= center; i++) {

normContrib[i] = contrib[i] / weight;

}

for (i = center + 1; i < nDots; i++) {

normContrib[i] = normContrib[center * 2 - i];

}

} // end of CalContrib()

// 處理邊緣

private void CalTempContrib(int start, int stop) {

double weight = 0;

int i = 0;

for (i = start; i <= stop; i++) {

weight += contrib[i];

}

for (i = start; i <= stop; i++) {

tmpContrib[i] = contrib[i] / weight;

}

} // end of CalTempContrib()

private int GetRedValue(int rgbValue) {

int temp = rgbValue & 0x00ff0000;

return temp >> 16;

}

private int GetGreenValue(int rgbValue) {

int temp = rgbValue & 0x0000ff00;

return temp >> 8;

}

private int GetBlueValue(int rgbValue) {

return rgbValue & 0x000000ff;

}

private int ComRGB(int redValue, int greenValue, int blueValue) {

return (redValue << 16) + (greenValue << 8) + blueValue;

}

// 行水平濾波

private int HorizontalFilter(BufferedImage bufImg, int startX, int stopX,

int start, int stop, int y, double[] pContrib) {

double valueRed = 0.0;

double valueGreen = 0.0;

double valueBlue = 0.0;

int valueRGB = 0;

int i, j;

for (i = startX, j = start; i <= stopX; i++, j++) {

valueRGB = bufImg.getRGB(i, y);

valueRed += GetRedValue(valueRGB) * pContrib[j];

valueGreen += GetGreenValue(valueRGB) * pContrib[j];

valueBlue += GetBlueValue(valueRGB) * pContrib[j];

}

valueRGB = ComRGB(Clip((int) valueRed), Clip((int) valueGreen),

Clip((int) valueBlue));

return valueRGB;

} // end of HorizontalFilter()

// 圖片水平濾波

private BufferedImage HorizontalFiltering(BufferedImage bufImage, int iOutW) {

int dwInW = bufImage.getWidth();

int dwInH = bufImage.getHeight();

int value = 0;

BufferedImage pbOut = new BufferedImage(iOutW, dwInH,

BufferedImage.TYPE_INT_RGB);

for (int x = 0; x < iOutW; x++) {

int startX;

int start;

int X = (int) (((double) x) * ((double) dwInW) / ((double) iOutW) + 0.5);

int y = 0;

startX = X - nHalfDots;

if (startX < 0) {

startX = 0;

start = nHalfDots - X;

} else {

start = 0;

}

int stop;

int stopX = X + nHalfDots;

if (stopX > (dwInW - 1)) {

stopX = dwInW - 1;

stop = nHalfDots + (dwInW - 1 - X);

} else {

stop = nHalfDots * 2;

}

if (start > 0 || stop < nDots - 1) {

CalTempContrib(start, stop);

for (y = 0; y < dwInH; y++) {

value = HorizontalFilter(bufImage, startX, stopX, start,

stop, y, tmpContrib);

pbOut.setRGB(x, y, value);

}

} else {

for (y = 0; y < dwInH; y++) {

value = HorizontalFilter(bufImage, startX, stopX, start,

stop, y, normContrib);

pbOut.setRGB(x, y, value);

}

return pbOut;

} // end of HorizontalFiltering()

private int VerticalFilter(BufferedImage pbInImage, int startY, int stopY,

int start, int stop, int x, double[] pContrib) {

double valueRed = 0.0;

double valueGreen = 0.0;

double valueBlue = 0.0;

int valueRGB = 0;

int i, j;

for (i = startY, j = start; i <= stopY; i++, j++) {

valueRGB = pbInImage.getRGB(x, i);

valueRed += GetRedValue(valueRGB) * pContrib[j];

valueGreen += GetGreenValue(valueRGB) * pContrib[j];

valueBlue += GetBlueValue(valueRGB) * pContrib[j];

// System.out.println(valueRed+"->"+Clip((int)valueRed)+"<-");

// System.out.println(valueGreen+"->"+Clip((int)valueGreen)+"<-");

// System.out.println(valueBlue+"->"+Clip((int)valueBlue)+"<-"+"-->");

}

valueRGB = ComRGB(Clip((int) valueRed), Clip((int) valueGreen),

Clip((int) valueBlue));

// System.out.println(valueRGB);

return valueRGB;

} // end of VerticalFilter()

private BufferedImage VerticalFiltering(BufferedImage pbImage, int iOutH) {

int iW = pbImage.getWidth();

int iH = pbImage.getHeight();

int value = 0;

BufferedImage pbOut = new BufferedImage(iW, iOutH,

BufferedImage.TYPE_INT_RGB);

for (int y = 0; y < iOutH; y++) {

int startY;

int start;

int Y = (int) (((double) y) * ((double) iH) / ((double) iOutH) + 0.5);

startY = Y - nHalfDots;

if (startY < 0) {

startY = 0;

start = nHalfDots - Y;

} else {

start = 0;

}

int stop;

int stopY = Y + nHalfDots;

if (stopY > (int) (iH - 1)) {

stopY = iH - 1;

stop = nHalfDots + (iH - 1 - Y);

} else {

stop = nHalfDots * 2;

}

if (start > 0 || stop < nDots - 1) {

CalTempContrib(start, stop);

for (int x = 0; x < iW; x++) {

value = VerticalFilter(pbImage, startY, stopY, start, stop,

x, tmpContrib);

pbOut.setRGB(x, y, value);

}

} else {

for (int x = 0; x < iW; x++) {

value = VerticalFilter(pbImage, startY, stopY, start, stop,

x, normContrib);

pbOut.setRGB(x, y, value);

}

return pbOut;

} // end of VerticalFiltering()

int Clip(int x) {

if (x < 0)

return 0;

if (x > 255)

return 255;

return x;

}

posted on 2007-12-13 21:57 davma 閱讀(1355) 評論(3) 編輯收藏

# re: 很不錯的一個生成等比例高質量縮略圖的類！ 2008-01-26 13:12 臭臭熊

# re: 很不錯的一個生成等比例高質量縮略圖的類！ 2008-05-21 19:47 ys

# re: 很不錯的一個生成等比例高質量縮略圖的類！[未登錄] 2010-09-06 15:18 ddd

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很不錯的一個生成等比例高質量縮略圖的類！

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