package com.bcxin.survey.utils;


import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Transparency;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;

import org.apache.commons.lang.StringUtils;

public class ImageUtil {

	/**
     * 按指定高度 等比例缩放图片
     * 
     * @param imageFile
     * @param newPath
     * @param newWidth 新图的宽度
     * @throws IOException
     */
    public static void zoomImageScale(File imageFile, String newPath, int newWidth) throws IOException {
         if(!imageFile.canRead())
             return;
        BufferedImage bufferedImage = ImageIO.read(imageFile);
        if (null == bufferedImage) 
            return;
        
        int originalWidth = bufferedImage.getWidth();
        int originalHeight = bufferedImage.getHeight();
        double scale = (double)originalWidth / (double)newWidth;    // 缩放的比例
        
        int newHeight =  (int)(originalHeight / scale);

        zoomImageUtils(imageFile, newPath, bufferedImage, newWidth, newHeight);
    }
    
    private static void zoomImageUtils(File imageFile, String newPath, BufferedImage bufferedImage, int width, int height)
            throws IOException{
        
         String suffix = StringUtils.substringAfterLast(imageFile.getName(), ".");
        
         // 处理 png 背景变黑的问题
        if(suffix != null && (suffix.trim().toLowerCase().endsWith("png") || suffix.trim().toLowerCase().endsWith("gif"))){
            BufferedImage to= new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); 
            Graphics2D g2d = to.createGraphics(); 
            to = g2d.getDeviceConfiguration().createCompatibleImage(width, height, Transparency.TRANSLUCENT); 
            g2d.dispose(); 
            
            g2d = to.createGraphics(); 
            Image from = bufferedImage.getScaledInstance(width, height, Image.SCALE_AREA_AVERAGING); 
            g2d.drawImage(from, 0, 0, null);
            g2d.dispose(); 
            
            ImageIO.write(to, suffix, new File(newPath));
        }else{
            // 高质量压缩，其实对清晰度而言没有太多的帮助
            BufferedImage newImage = new BufferedImage(width, height, bufferedImage.getType());
            Graphics g = newImage.getGraphics();
            g.drawImage(bufferedImage, 0, 0, width, height, null);
            g.dispose();
            ImageIO.write(newImage, suffix, new File(newPath));
        }
    }
    
    public static int[] getImagePixels(File imageFile){
    	BufferedImage bi ;
		try {
			bi = ImageIO.read(imageFile);
			int width = bi.getWidth();
	    	int height = bi.getHeight();
	    	int ints[]  = {width,height}; 
	    	return ints;
		} catch (IOException e) {
			e.printStackTrace();
		}
    	return new int[]{0,0};
    }
}