JAVA 生成高品质缩略图(转)
ScaleImage.javaimport java.awt.image.BufferedImage;import java.io.File;import javax.imageio.ImageIO;//生成等比例高质量缩略图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("d:/firefox.jpg", "d:/test.jpg", 768, 680); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } } // fromFileStr原图片地址,saveToFileStr生成缩略图地址,formatWideth生成图片宽度,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; } /** *//** * 决定图像尺寸 */ private int DetermineResultSize(int w, int h) { double scaleH, scaleV; scaleH = (double) w / (double) width; scaleV = (double) h / (double) height; // 需要判断一下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; normContrib = new double; tmpContrib = new double; } catch (Exception e) { System.out.println("init contrib,normContrib,tmpContrib" + e); } int center = nHalfDots; contrib = 1.0; double weight = 0.0; int i = 0; for (i = 1; i <= center; i++) { contrib = Lanczos(i, width, scaleWidth, support); weight += contrib; } for (i = center - 1; i >= 0; i--) { contrib = contrib; } weight = weight * 2 + 1.0; for (i = 0; i <= center; i++) { normContrib = contrib / weight; } for (i = center + 1; i < nDots; i++) { normContrib = normContrib; } } // end of CalContrib() // 处理边缘 private void CalTempContrib(int start, int stop) { double weight = 0; int i = 0; for (i = start; i <= stop; i++) { weight += contrib; } for (i = start; i <= stop; i++) { tmpContrib = contrib / 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; } // 行水平滤波 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; valueGreen += GetGreenValue(valueRGB) * pContrib; valueBlue += GetBlueValue(valueRGB) * pContrib; } valueRGB = ComRGB(Clip((int) valueRed), Clip((int) valueGreen), Clip((int) valueBlue)); return valueRGB; } // end of HorizontalFilter() // 图片水平滤波 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; valueGreen += GetGreenValue(valueRGB) * pContrib; valueBlue += GetBlueValue(valueRGB) * pContrib; // 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; }}
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ImageScale.java
import java.awt.image.BufferedImage;public class ImageScale {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 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;}/** * 决定图像尺寸 * */private int DetermineResultSize(int w, int h) {double scaleH, scaleV;scaleH = (double) w / (double) width;scaleV = (double) h / (double) height;//需要判断一下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);} // end of Lanczos()//// Assumption: same horizontal and vertical scaling factor//private void CalContrib() {nHalfDots = (int) ((double) width * support / (double) scaleWidth);nDots = nHalfDots * 2 + 1;try {contrib = new double;normContrib = new double;tmpContrib = new double;} catch (Exception e) {System.out.println("init contrib,normContrib,tmpContrib" + e);}int center = nHalfDots;contrib = 1.0;double weight = 0.0;int i = 0;for (i = 1; i <= center; i++) {contrib = Lanczos(i, width, scaleWidth, support);weight += contrib;}for (i = center - 1; i >= 0; i--) {contrib = contrib;}weight = weight * 2 + 1.0;for (i = 0; i <= center; i++) {normContrib = contrib / weight;}for (i = center + 1; i < nDots; i++) {normContrib = normContrib;}} // end of CalContrib()//处理边缘private void CalTempContrib(int start, int stop) {double weight = 0;int i = 0;for (i = start; i <= stop; i++) {weight += contrib;}for (i = start; i <= stop; i++) {tmpContrib = contrib / 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;}//行水平滤波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;valueGreen += GetGreenValue(valueRGB) * pContrib;valueBlue += GetBlueValue(valueRGB) * pContrib;}valueRGB = ComRGB(Clip((int) valueRed), Clip((int) valueGreen),Clip((int) valueBlue));return valueRGB;} // end of HorizontalFilter()//图片水平滤波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;valueGreen += GetGreenValue(valueRGB) * pContrib;valueBlue += GetBlueValue(valueRGB) * pContrib;// 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;}/** * End: * Use Lanczos filter to replace the original algorithm for image scaling. Lanczos improves quality of the scaled image * modify by :blade * */}
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