Java图片缩放类

在网上找了两个图片的缩放类，在这里分享一下：

 

package manager.util; import java.util.Calendar; import java.io.File; import java.awt.image.BufferedImage; import java.awt.Image; import java.awt.image.AffineTransformOp; import javax.imageio.ImageIO; import java.awt.geom.AffineTransform; public class UploadImg { String fromFileStr; String saveToFileStr; String sysimgfile; int width; int height; String suffix; /** * @param fromFileStr * 原始图片完整路径 * @param saveToFileStr * 缩略图片保存路径 * @param sysimgfilenNow * 处理后的图片文件名前缀 * */ public UploadImg(String fromFileStr, String saveToFileStr, String sysimgfile,String suffix,int width,int height) { this.fromFileStr = fromFileStr; this.saveToFileStr = saveToFileStr; this.sysimgfile = sysimgfile; this.width=width; this.height=height; this.suffix=suffix; } public boolean createThumbnail() throws Exception { // fileExtNmae是图片的格式 gif JPG 或png // String fileExtNmae=""; double Ratio = 0.0; File F = new File(fromFileStr); if (!F.isFile()) throw new Exception(F + " is not image file error in CreateThumbnail!"); File ThF = new File(saveToFileStr, sysimgfile +"."+suffix); BufferedImage Bi = ImageIO.read(F); Image Itemp = Bi.getScaledInstance(width, height, Bi.SCALE_SMOOTH); if ((Bi.getHeight() > width) || (Bi.getWidth() > height)) { if (Bi.getHeight() > Bi.getWidth()) Ratio = (double)width / Bi.getHeight(); else Ratio = (double)height / Bi.getWidth(); } AffineTransformOp op = new AffineTransformOp(AffineTransform .getScaleInstance(Ratio, Ratio), null); Itemp = op.filter(Bi, null); try { ImageIO.write((BufferedImage) Itemp, suffix, ThF); } catch (Exception ex) { throw new Exception(" ImageIo.write error in CreatThum.: " + ex.getMessage()); } return (true); } public static void main(String[] args) { UploadImg UI; boolean ss = false; try { UI = new UploadImg("d://FairyTaleVector040.png", "d://temp", "ps_low1","png",650,650); ss = UI.createThumbnail(); if (ss) { System.out.println("Success"); } else { System.out.println("Error"); } } catch (Exception e) { System.out.print(e.toString()); } } }

 

 

这个类，可以对jpg、png、gif三种图片缩放，缩放按等比例缩放

 

 

 

package manager.util; import java.awt.Graphics2D; import java.awt.RenderingHints; import java.awt.geom.AffineTransform; import java.awt.image.BufferedImage; import java.awt.image.ColorModel; import java.awt.image.WritableRaster; import java.io.File; import javax.imageio.ImageIO; public class Thumbnail { /** * 生成缩略图 * fromFileStr:原图片路径 * saveToFileStr:缩略图路径 * width:缩略图的宽 * height:缩略图的高 */ public static void saveImageAsJpg(String fromFileStr, String saveToFileStr, int width, int height,boolean equalProportion) throws Exception { BufferedImage srcImage; String imgType="JPEG"; if(fromFileStr.toLowerCase().endsWith(".png")){ imgType="PNG"; } File fromFile=new File(fromFileStr); File saveFile=new File(saveToFileStr); srcImage=ImageIO.read(fromFile); if(width>0||height>0){ srcImage=resize(srcImage,width,height,equalProportion); } ImageIO.write(srcImage,imgType,saveFile); } /** * 将原图片的BufferedImage对象生成缩略图 * source：原图片的BufferedImage对象 * targetW:缩略图的宽 * targetH:缩略图的高 */ public static BufferedImage resize(BufferedImage source,int targetW,int targetH,boolean equalProportion){ int type=source.getType(); BufferedImage target=null; double sx=(double)targetW/source.getWidth(); double sy=(double)targetH/source.getHeight(); //这里想实现在targetW，targetH范围内实现等比例的缩放 //如果不需要等比例的缩放则下面的if else语句注释调即可 if(equalProportion){ if(sx>sy){ sx=sy; targetW=(int)(sx*source.getWidth()); }else{ sy=sx; targetH=(int)(sx*source.getHeight()); } } if(type==BufferedImage.TYPE_CUSTOM){ ColorModel cm=source.getColorModel(); WritableRaster raster=cm.createCompatibleWritableRaster(targetW,targetH); boolean alphaPremultiplied=cm.isAlphaPremultiplied(); target=new BufferedImage(cm,raster,alphaPremultiplied,null); }else{ target=new BufferedImage(targetW,targetH,type); Graphics2D g=target.createGraphics(); g.setRenderingHint(RenderingHints.KEY_RENDERING,RenderingHints.VALUE_RENDER_QUALITY); g.drawRenderedImage(source,AffineTransform.getScaleInstance(sx,sy)); g.dispose(); } return target; } public static void main(String[] args){ try{ Thumbnail.saveImageAsJpg("D://FairyTaleVector040.png", "D://temp//test.png", 480, 480,true); }catch(Exception e){ e.printStackTrace(); } } }

 

这个类只能对jpg图片缩放，但是提供了两种缩放方式：等比例和不等比例