高像素清晰缩略图生成(java)

高像素清晰缩略图生成(java) 在公司实习的时候还是练了不少代码的，觉得这个类算得上写的比较通用吧，其中也借鉴了别人的算法，贴出来大家共享共同进步。 package com.modules.image; import com.modules.basicObject; import java.net.*; import java.io.*; import java.awt.image.*; import java.awt.*; import com.sun.image.codec.jpeg.*; import javax.imageio.ImageIO; import javax.imageio.stream.*; import com.book.db.dbOperator; import java.sql.ResultSet; import java.util.*; import javax.imageio.stream.*; import javax.imageio.*; /** *

Title: Image Process

*

Copyright: Copyright (c) 2006

* * @Johbin,Wang * @version 1.0 */ public class imager extends basicObject { private Image org_image = null; private BufferedImage bfd_image = null; private BufferedImage tag = null; private String imageName = ""; private String sourceFileURI =""; private String desFileURI = ""; private String imageType = "jpeg";//defaultf format private String str_uri=null; public imager() { } public boolean setImage(String m_id,String type) { try{ str_uri = getAppPath() + "files/images/"; imageType = type; imageName = m_id + "." + imageType; str_uri += imageName; sourceFileURI = str_uri; File _file = new File(str_uri); org_image = javax.imageio.ImageIO.read(_file); return true; } catch(Exception e) { this.AddError("set image", e.getMessage()+"
"+imageName+"
"+str_uri+"
"); return false; } } //generate resized image, and put it under images/thumb directory //add record into database //return image id if successfully public String resize(int width,int height,String pos){ try { if(org_image!=null) { BufferedImage temp = null; desFileURI = getAppPath() + "files/images/thumb/"+"SM"+imageName.substring(2); //destination image URI int _width = org_image.getWidth(null); int _height = org_image.getHeight(null); FileOutputStream out=new FileOutputStream(desFileURI); JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out); if(_width<=width&&_height<=height) { if(_width==width&&_height==height) { FileInputStream fileis = new FileInputStream(sourceFileURI); FileOutputStream fileos = new FileOutputStream(desFileURI); int count; byte[] buffer = new byte[100]; while(-1 != (count = fileis.read(buffer))){ fileos.write(buffer); fileos.flush(); } fileis.close(); fileos.close(); } else { tag = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB); tag.getGraphics().drawImage(org_image,(width-_width)/2,(height-_height)/2,_width,_height,null); //encoder.encode(tag); //out.close(); ImageIO.write(temp,imageType,new File(desFileURI)); } } else if(_width>width&&_height<=height) { //scale the source image tag = new BufferedImage(_width,height,BufferedImage.TYPE_INT_RGB); tag.getGraphics().drawImage(org_image,0,(height-_height)/2,_width,_height,null); //clip image if(pos.equalsIgnoreCase("TL")||pos.equalsIgnoreCase("ML")||pos.equalsIgnoreCase("BL")) { temp = tag.getSubimage(0,0, width,height); } else if(pos.equalsIgnoreCase("TM")||pos.equalsIgnoreCase("MM")||pos.equalsIgnoreCase("BM")) { temp = tag.getSubimage((_width-width)/2,0, width,height); } else { temp = tag.getSubimage(_width-width,0, width,height); } encoder.encode(temp); //out.close(); //ImageIO.write(temp,imageType,new File(desFileURI)); } else if(_height>height&&_width<=width) { //scale the source image tag = new BufferedImage(width,_height,BufferedImage.TYPE_INT_RGB); tag.getGraphics().drawImage(org_image,(width-_width)/2,0,_width,_height,null); //clip image if(pos.equalsIgnoreCase("TL")||pos.equalsIgnoreCase("TM")||pos.equalsIgnoreCase("TR")) { temp = tag.getSubimage(0,0, width,height); } else if(pos.equalsIgnoreCase("ML")||pos.equalsIgnoreCase("MM")||pos.equalsIgnoreCase("MR")) { temp = tag.getSubimage(0,(_height-height)/2, width,height); } else { temp = tag.getSubimage(0,_height-height, width,height); } encoder.encode(temp); //out.close(); ImageIO.write(temp,imageType,new File(desFileURI)); } else { if(_width==_height) { if(_width>width)// just scale source image, no clipping. { tag = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB); tag.getGraphics().drawImage(org_image,0,0,width,height,null); encoder.encode(tag); //out.close(); //ImageIO.write(tag,imageType,new File(desFileURI)); } } else if(_width>_height) { if(imageType.equals("gif")||imageType.equals("GIF")){ //scale the source image tag = new BufferedImage(Math.round((float)_width/_height*height),height,BufferedImage.TYPE_INT_RGB); tag.getGraphics().drawImage(org_image,0,0,Math.round((float)_width /_height*height),height,null); this.AddError("width","width= "+Math.round((float)_width/_height*height)+"height="+height); //clip image if(pos.equalsIgnoreCase("TL")||pos.equalsIgnoreCase("ML")||pos.equalsIgnoreCase("BL")) { temp = tag.getSubimage(0,0, width,height); } else if(pos.equalsIgnoreCase("TM")||pos.equalsIgnoreCase("MM")||pos.equalsIgnoreCase("BM")) { temp = tag.getSubimage(Math.round(((float)_width/_height*height-width)/2),0, width,height); } else { temp = tag.getSubimage(Math.round(((float)_width/_height*height-width)),0, width,height); } encoder.encode(temp); //out.close(); //ImageIO.write(temp,imageType,new File(desFileURI)); } else{ ///////scale the image with a high quality////////// tag = new BufferedImage(_width,_height,BufferedImage.TYPE_INT_RGB); tag.getGraphics().drawImage(org_image,0,0,_width,_height,null); BufferedImage rtBf = null; ImageScale is = new ImageScale(); rtBf = is.imageZoomOut(tag,Math.round((float)_width/_height*height),height); //this.AddError("width","scale width= "+Math.round((float)_width/_height*height)+" "+"height="+ height); //clip image if(pos.equalsIgnoreCase("TL")||pos.equalsIgnoreCase("ML")||pos.equalsIgnoreCase("BL")) { temp = rtBf.getSubimage(0,0, width,height); } else if(pos.equalsIgnoreCase("TM")||pos.equalsIgnoreCase("MM")||pos.equalsIgnoreCase("BM")) { temp = rtBf.getSubimage(Math.round(((float)_width/_height*height-width)/2),0, width,height); } else { temp = rtBf.getSubimage(Math.round(((float)_width/_height*height-width)),0, width,height); } ImageIO.write(temp,imageType,new File(desFileURI)); } } else { if(imageType.equals("gif")||imageType.equals("GIF")){ //scale the source image tag = new BufferedImage(width,Math.round((float)_height/_width*width),BufferedImage.TYPE_INT_RGB); tag.getGraphics().drawImage(org_image,0,0,width,Math.round((float)_height/_width*width),null); //clip image if(pos.equalsIgnoreCase("TL")||pos.equalsIgnoreCase("TM")||pos.equalsIgnoreCase("TR")) { temp = tag.getSubimage(0,0, width,height); } else if(pos.equalsIgnoreCase("ML")||pos.equalsIgnoreCase("MM")||pos.equalsIgnoreCase("MR")) { temp = tag.getSubimage(0,Math.round(((float)_height/_width*width-height)/2), width,height); } else { temp = tag.getSubimage(0,Math.round((float)_height/_width*width-height), width,height); } encoder.encode(temp); // out.close(); //ImageIO.write(temp,imageType,new File(desFileURI)); } else{ ///////scale the image with a high quality////////// tag = new BufferedImage(_width,_height,BufferedImage.TYPE_INT_RGB); tag.getGraphics().drawImage(org_image,0,0,_width,_height,null); BufferedImage rtBf = null; ImageScale is = new ImageScale(); rtBf = is.imageZoomOut(tag,width,Math.round((float)_height/_width*width)); //clip image if(pos.equalsIgnoreCase("TL")||pos.equalsIgnoreCase("TM")||pos.equalsIgnoreCase("TR")) { temp = rtBf.getSubimage(0,0, width,height); } else if(pos.equalsIgnoreCase("ML")||pos.equalsIgnoreCase("MM")||pos.equalsIgnoreCase("MR")) { temp = rtBf.getSubimage(0,Math.round(((float)_height/_width*width-height)/2), width,height); } else { temp = rtBf.getSubimage(0,Math.round((float)_height/_width*width-height), width,height); } // encoder.encode(temp); //out.close(); ImageIO.write(temp,imageType,new File(desFileURI)); } } } out.close(); return "SM"+imageName.substring(2,9); } else{ this.AddError("Error","the image format is illegal"); return "fail"; } }catch(Exception e) { this.AddError("Scale Image Fail", e.toString()+" "); return "fail"; } } ////inner class for filter and scale image with a high quality. 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; //Use Lanczos filter to replace the original algorithm for image scaling. Lanczos improves quality of the scaled image 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; } /** * ?????? * */ private int DetermineResultSize(int w, int h) { double scaleH, scaleV; scaleH = (double) w / (double) width; scaleV = (double) h / (double) height; //??????scaleH?scaleV??????? 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[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() //???? 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; } //????? 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() //?????? 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; } } }