标签:java efault can array tde icon 测试 data 缩小
网上找到的,略微地改动了一番
大致能满足这样的需求:
当图片长度或宽度超过一个正方形边长时,等比缩小,使图片能够放入正方形内。缩放后尽可能保持图片原先的质量。
import com.sun.image.codec.jpeg.JPEGImageEncoder; import com.sun.image.codec.jpeg.JPEGCodec; import com.sun.image.codec.jpeg.JPEGEncodeParam; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.awt.Color; import java.awt.Graphics; import java.awt.Image; import java.awt.image.BufferedImage; import java.awt.image.Kernel; import java.awt.image.ConvolveOp; import javax.swing.ImageIcon; public class ImageUtil { public static void resize(File originalFile, File resizedFile, int newWidth, float quality) throws IOException { if (quality > 1) { throw new IllegalArgumentException("Quality has to be between 0 and 1"); } ImageIcon ii = new ImageIcon(originalFile.getCanonicalPath()); Image i = ii.getImage(); Image resizedImage = null; // No necessary to resized small image, just copy it. --Deolin if (i.getWidth(null) <= newWidth && i.getHeight(null) <= newWidth) { int byteread = 0; @SuppressWarnings("resource") InputStream in = new FileInputStream(originalFile); @SuppressWarnings("resource") OutputStream out = new FileOutputStream(resizedFile); byte[] buffer = new byte[1024]; while ((byteread = in.read(buffer)) != -1) { out.write(buffer, 0, byteread); } return; } int iWidth = i.getWidth(null); int iHeight = i.getHeight(null); if (iWidth > iHeight) { resizedImage = i.getScaledInstance(newWidth, (newWidth * iHeight) / iWidth, Image.SCALE_SMOOTH); } else { resizedImage = i.getScaledInstance((newWidth * iWidth) / iHeight, newWidth, Image.SCALE_SMOOTH); } // This code ensures that all the pixels in the image are loaded. Image temp = new ImageIcon(resizedImage).getImage(); // Create the buffered image. BufferedImage bufferedImage = new BufferedImage(temp.getWidth(null), temp.getHeight(null), BufferedImage.TYPE_INT_RGB); // Copy image to buffered image. Graphics g = bufferedImage.createGraphics(); // Clear background and paint the image. g.setColor(Color.WHITE); g.fillRect(0, 0, temp.getWidth(null), temp.getHeight(null)); g.drawImage(temp, 0, 0, null); g.dispose(); // Soften. float softenFactor = 0.05f; float[] softenArray = { 0, softenFactor, 0, softenFactor, 1 - (softenFactor * 4), softenFactor, 0, softenFactor, 0 }; Kernel kernel = new Kernel(3, 3, softenArray); ConvolveOp cOp = new ConvolveOp(kernel, ConvolveOp.EDGE_NO_OP, null); bufferedImage = cOp.filter(bufferedImage, null); // Write the jpeg to a file. FileOutputStream out = new FileOutputStream(resizedFile); // Encodes image as a JPEG data stream JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out); JPEGEncodeParam param = encoder.getDefaultJPEGEncodeParam(bufferedImage); param.setQuality(quality, true); encoder.setJPEGEncodeParam(param); encoder.encode(bufferedImage); } public static void main(String[] args) throws IOException { File originalImage = new File("C:\\1.bmp"); resize(originalImage, new File("C:\\thumb_1.bmp"), 250, 1f); } }
示例中关键参数是newWidth 250,代表了将图片宽或高较长的那边缩放到250,另一边等比例缩放,达到能够放入250*250的正方形中的效果;
如果图片宽高相等,则会缩放到250*250的大小。
如果图片宽高都小于250,那么它原本就能够放入正方形,则会复制自身
测试效果
标签:java efault can array tde icon 测试 data 缩小
原文地址:http://www.cnblogs.com/deolin/p/6905556.html