package cn.ksource.core.util;
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import java.awt.image.BufferedImage;
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import java.io.File;
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import javax.imageio.ImageIO;
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//生成等比例高质量缩略图
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public class ScaleImage {
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private int width;
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private int height;
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private int scaleWidth;
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double support = (double) 3.0;
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double PI = (double) 3.14159265358978;
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double[] contrib;
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double[] normContrib;
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double[] tmpContrib;
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int startContrib, stopContrib;
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int nDots;
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int nHalfDots;
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/*public static void main(String[] args) {
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ScaleImage is = new ScaleImage();
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try {
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is.saveImageAsJpg("E:/14.jpg", "E:/14.jpg", 10, 10);
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} catch (Exception e) {
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e.printStackTrace();
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}
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}*/
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public void saveImageAsJpg(String fromFileStr, String saveToFileStr, int formatWideth, int formatHeight) throws Exception {
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File file=this.saveImageAsJpg(fromFileStr, saveToFileStr, formatWideth, formatHeight, false);
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/*System.out.println(file.getPath());*/
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}
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// fromFileStr原图片地址,saveToFileStr生成缩略图地址,formatWideth生成图片宽度,formatHeight高度,equal强制生成的缩略图宽、高等与提供的宽高,默认为false;
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public File saveImageAsJpg(String fromFileStr, String saveToFileStr, int formatWideth, int formatHeight, boolean equal) throws Exception {
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BufferedImage srcImage;
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File saveFile = new File(saveToFileStr);
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File fromFile = new File(fromFileStr);
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srcImage = javax.imageio.ImageIO.read(fromFile); // construct image
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int imageWideth = srcImage.getWidth(null);
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int imageHeight = srcImage.getHeight(null);
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int changeToWideth = 0;
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int changeToHeight = 0;
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if (imageWideth > 0 && imageHeight > 0) {
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if (!equal) {
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// flag=true;
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if (imageWideth / imageHeight >= formatWideth / formatHeight) {
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if (imageWideth > formatWideth) {
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changeToWideth = formatWideth;
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changeToHeight = (imageHeight * formatWideth) / imageWideth;
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// 保证生成的缩略图的高度不高于给定高
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changeToHeight = (changeToHeight > formatHeight) ? formatHeight : changeToHeight;
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}else if (imageHeight > formatHeight) {
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changeToHeight = formatHeight;
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changeToWideth = (imageWideth * formatHeight) / imageHeight;
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} else {
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changeToWideth = imageWideth;
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changeToHeight = imageHeight;
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}
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} else {
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if (imageHeight > formatHeight) {
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changeToHeight = formatHeight;
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changeToWideth = (imageWideth * formatHeight) / imageHeight;
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// 保证生成的缩略图的宽度不高于给定宽
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changeToWideth = (changeToWideth > formatWideth) ? formatWideth : changeToWideth;
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}else if (imageWideth > formatWideth) {
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changeToWideth = formatWideth;
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changeToHeight = (imageHeight * formatWideth) / imageWideth;
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// 保证生成的缩略图的高度不高于给定高
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changeToHeight = (changeToHeight > formatHeight) ? formatHeight : changeToHeight;
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} else {
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changeToWideth = imageWideth;
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changeToHeight = imageHeight;
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}
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}
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} else {
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changeToWideth = formatWideth;
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changeToHeight = formatHeight;
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}
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}
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srcImage = imageZoomOut(srcImage, changeToWideth, changeToHeight);
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ImageIO.write(srcImage, "JPEG", saveFile);
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return saveFile;
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}
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public BufferedImage imageZoomOut(BufferedImage srcBufferImage, int w, int h) {
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width = srcBufferImage.getWidth();
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height = srcBufferImage.getHeight();
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scaleWidth = w;
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if (DetermineResultSize(w, h) == 1) {
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return srcBufferImage;
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}
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CalContrib();
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BufferedImage pbOut = HorizontalFiltering(srcBufferImage, w);
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BufferedImage pbFinalOut = VerticalFiltering(pbOut, h);
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return pbFinalOut;
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}
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/** */
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/**
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* 决定图像尺寸
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*/
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private int DetermineResultSize(int w, int h) {
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double scaleH, scaleV;
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scaleH = (double) w / (double) width;
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scaleV = (double) h / (double) height;
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// 需要判断一下scaleH，scaleV，不做放大操作
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if (scaleH >= 1.0 && scaleV >= 1.0) {
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return 1;
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}
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return 0;
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} // end of DetermineResultSize()
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private double Lanczos(int i, int inWidth, int outWidth, double Support) {
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double x;
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x = (double) i * (double) outWidth / (double) inWidth;
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return Math.sin(x * PI) / (x * PI) * Math.sin(x * PI / Support) / (x * PI / Support);
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}
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private void CalContrib() {
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nHalfDots = (int) ((double) width * support / (double) scaleWidth);
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nDots = nHalfDots * 2 + 1;
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try {
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contrib = new double[nDots];
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normContrib = new double[nDots];
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tmpContrib = new double[nDots];
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} catch (Exception e) {
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System.out.println("init contrib,normContrib,tmpContrib" + e);
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}
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int center = nHalfDots;
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contrib[center] = 1.0;
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double weight = 0.0;
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int i = 0;
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for (i = 1; i <= center; i++) {
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contrib[center + i] = Lanczos(i, width, scaleWidth, support);
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weight += contrib[center + i];
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}
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for (i = center - 1; i >= 0; i--) {
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contrib[i] = contrib[center * 2 - i];
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}
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weight = weight * 2 + 1.0;
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for (i = 0; i <= center; i++) {
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normContrib[i] = contrib[i] / weight;
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}
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for (i = center + 1; i < nDots; i++) {
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normContrib[i] = normContrib[center * 2 - i];
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}
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} // end of CalContrib()
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// 处理边缘
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private void CalTempContrib(int start, int stop) {
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double weight = 0;
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int i = 0;
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for (i = start; i <= stop; i++) {
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weight += contrib[i];
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}
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for (i = start; i <= stop; i++) {
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tmpContrib[i] = contrib[i] / weight;
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}
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} // end of CalTempContrib()
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private int GetRedValue(int rgbValue) {
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int temp = rgbValue & 0x00ff0000;
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return temp >> 16;
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}
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private int GetGreenValue(int rgbValue) {
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int temp = rgbValue & 0x0000ff00;
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return temp >> 8;
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}
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private int GetBlueValue(int rgbValue) {
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return rgbValue & 0x000000ff;
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}
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private int ComRGB(int redValue, int greenValue, int blueValue) {
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return (redValue << 16) + (greenValue << 8) + blueValue;
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}
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// 行水平滤波
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private int HorizontalFilter(BufferedImage bufImg, int startX, int stopX, int start, int stop, int y, double[] pContrib) {
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double valueRed = 0.0;
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double valueGreen = 0.0;
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double valueBlue = 0.0;
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int valueRGB = 0;
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int i, j;
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for (i = startX, j = start; i <= stopX; i++, j++) {
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valueRGB = bufImg.getRGB(i, y);
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valueRed += GetRedValue(valueRGB) * pContrib[j];
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valueGreen += GetGreenValue(valueRGB) * pContrib[j];
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valueBlue += GetBlueValue(valueRGB) * pContrib[j];
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}
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valueRGB = ComRGB(Clip((int) valueRed), Clip((int) valueGreen), Clip((int) valueBlue));
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return valueRGB;
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} // end of HorizontalFilter()
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// 图片水平滤波
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private BufferedImage HorizontalFiltering(BufferedImage bufImage, int iOutW) {
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int dwInW = bufImage.getWidth();
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int dwInH = bufImage.getHeight();
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int value = 0;
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BufferedImage pbOut = new BufferedImage(iOutW, dwInH, BufferedImage.TYPE_INT_RGB);
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for (int x = 0; x < iOutW; x++) {
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int startX;
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int start;
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int X = (int) (((double) x) * ((double) dwInW) / ((double) iOutW) + 0.5);
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int y = 0;
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startX = X - nHalfDots;
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if (startX < 0) {
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startX = 0;
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start = nHalfDots - X;
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} else {
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start = 0;
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}
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int stop;
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int stopX = X + nHalfDots;
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if (stopX > (dwInW - 1)) {
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stopX = dwInW - 1;
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stop = nHalfDots + (dwInW - 1 - X);
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} else {
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stop = nHalfDots * 2;
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}
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if (start > 0 || stop < nDots - 1) {
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CalTempContrib(start, stop);
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for (y = 0; y < dwInH; y++) {
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value = HorizontalFilter(bufImage, startX, stopX, start, stop, y, tmpContrib);
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pbOut.setRGB(x, y, value);
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}
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} else {
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for (y = 0; y < dwInH; y++) {
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value = HorizontalFilter(bufImage, startX, stopX, start, stop, y, normContrib);
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pbOut.setRGB(x, y, value);
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}
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}
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}
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return pbOut;
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} // end of HorizontalFiltering()
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private int VerticalFilter(BufferedImage pbInImage, int startY, int stopY, int start, int stop, int x, double[] pContrib) {
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double valueRed = 0.0;
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double valueGreen = 0.0;
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double valueBlue = 0.0;
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int valueRGB = 0;
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int i, j;
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for (i = startY, j = start; i <= stopY; i++, j++) {
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valueRGB = pbInImage.getRGB(x, i);
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valueRed += GetRedValue(valueRGB) * pContrib[j];
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valueGreen += GetGreenValue(valueRGB) * pContrib[j];
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valueBlue += GetBlueValue(valueRGB) * pContrib[j];
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// System.out.println(valueRed+"->"+Clip((int)valueRed)+"<-");
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//
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// System.out.println(valueGreen+"->"+Clip((int)valueGreen)+"<-");
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// System.out.println(valueBlue+"->"+Clip((int)valueBlue)+"<-"+"-->");
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}
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valueRGB = ComRGB(Clip((int) valueRed), Clip((int) valueGreen), Clip((int) valueBlue));
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// System.out.println(valueRGB);
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return valueRGB;
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} // end of VerticalFilter()
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private BufferedImage VerticalFiltering(BufferedImage pbImage, int iOutH) {
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int iW = pbImage.getWidth();
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int iH = pbImage.getHeight();
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int value = 0;
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BufferedImage pbOut = new BufferedImage(iW, iOutH, BufferedImage.TYPE_INT_RGB);
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for (int y = 0; y < iOutH; y++) {
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int startY;
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int start;
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int Y = (int) (((double) y) * ((double) iH) / ((double) iOutH) + 0.5);
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startY = Y - nHalfDots;
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if (startY < 0) {
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startY = 0;
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start = nHalfDots - Y;
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} else {
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start = 0;
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}
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int stop;
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int stopY = Y + nHalfDots;
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if (stopY > (int) (iH - 1)) {
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stopY = iH - 1;
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stop = nHalfDots + (iH - 1 - Y);
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} else {
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stop = nHalfDots * 2;
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}
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if (start > 0 || stop < nDots - 1) {
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CalTempContrib(start, stop);
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for (int x = 0; x < iW; x++) {
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value = VerticalFilter(pbImage, startY, stopY, start, stop, x, tmpContrib);
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pbOut.setRGB(x, y, value);
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}
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} else {
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for (int x = 0; x < iW; x++) {
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value = VerticalFilter(pbImage, startY, stopY, start, stop, x, normContrib);
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pbOut.setRGB(x, y, value);
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}
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}
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}
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return pbOut;
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} // end of VerticalFiltering()
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int Clip(int x) {
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if (x < 0)
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return 0;
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if (x > 255)
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return 255;
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return x;
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}
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}
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