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  • Java-生成缩略图工具类

    import java.awt.Color;
    import java.awt.Graphics2D;
    import java.awt.Image;
    import java.awt.RenderingHints;
    import java.awt.image.BufferedImage;
    import java.io.File;
    
    public class ThumbnailGenerator {
    
        public void transform(String originalFile, String thumbnailFile, int thumbWidth, int thumbHeight, int quality) throws Exception 
        {
            Image image = javax.imageio.ImageIO.read(new File(originalFile));
    
            double thumbRatio = (double)thumbWidth / (double)thumbHeight;
            int imageWidth    = image.getWidth(null);
            int imageHeight   = image.getHeight(null);
            double imageRatio = (double)imageWidth / (double)imageHeight;
            if (thumbRatio < imageRatio) 
            {
                thumbHeight = (int)(thumbWidth / imageRatio);
            } 
            else 
            {
                thumbWidth = (int)(thumbHeight * imageRatio);
            }
    
            if(imageWidth < thumbWidth && imageHeight < thumbHeight)
            {
                thumbWidth = imageWidth;
                thumbHeight = imageHeight;
            }
            else if(imageWidth < thumbWidth)
                thumbWidth = imageWidth;
            else if(imageHeight < thumbHeight)
                thumbHeight = imageHeight;
    
            BufferedImage thumbImage = new BufferedImage(thumbWidth, thumbHeight, BufferedImage.TYPE_INT_RGB);
            Graphics2D graphics2D = thumbImage.createGraphics();
            graphics2D.setBackground(Color.WHITE);
            graphics2D.setPaint(Color.WHITE); 
            graphics2D.fillRect(0, 0, thumbWidth, thumbHeight);
            graphics2D.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
            graphics2D.drawImage(image, 0, 0, thumbWidth, thumbHeight, null);
    
            javax.imageio.ImageIO.write(thumbImage, "JPG", new File(thumbnailFile));
        }
    }
    
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  • 原文地址:https://www.cnblogs.com/bilaisheng/p/10210968.html
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