background-color:transparent；

1：启动快捷方式，并打开图片
 
2：双击右下角的层
 
 
3：右键选择左侧工具栏的图标，选择魔棒工具
 
 
4：点击图片，如下图所示
 
 
5：点击Delete键，效果如图所示。
 

项目中遇到一个需要把背景图改为透明的需求，因为我这里图片可能会比较复杂所以会出现有些背景留着图片没了的问题。所以根据网络上的资源学习了一下我项目可以用的。
 
package file;

import javax.imageio.ImageIO;
import javax.swing.*;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.*;

/**
 * 描述 The type Tm img.
 *
 * @author Jack Que
 * @created 2021 -07-08 10:25:10
 */
public class tmImg {


    /**
     * 描述 The entry point of application.
     *
     * @param args the input arguments
     * @author Jack Que
     * @created 2021 -07-08 10:25:10
     */
    public static void main(String[] args) {
        try {
//            changeImgColor("D:\\IEC202105181050.JPG");
            changeImgColor("D:\\IEC202105181050.JPG");
            changeImgColor("D:\\201709160000.png");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * 将背景替换为透明
     *
     * @param imgBytes the img bytes
     * @return
     * @throws IOException the io exception
     * @author Jack Que
     * @created 2021 -07-08 10:25:10 Change img color.
     */
    public static void changeImgColor(String path) throws IOException {

        File file = new File(path);
        String fileName = file.getName();
        BufferedImage bi =  ImageIO.read(file);
        Image image = (Image) bi;
        //将原图片的二进制转化为ImageIcon
        ImageIcon imageIcon = new ImageIcon(image);
        int width = imageIcon.getIconWidth();
        int height = imageIcon.getIconHeight();
//
        //图片缓冲流
        BufferedImage bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_4BYTE_ABGR);
        Graphics2D graphics2D = (Graphics2D) bufferedImage.getGraphics();
        graphics2D.drawImage(imageIcon.getImage(), 0, 0, imageIcon.getImageObserver());

        int alpha = 255;

		//这个背景底色的选择，我这里选择的是比较偏的位置，可以修改位置。背景色选择不知道有没有别的更优的方式（比如先过滤一遍获取颜色次数最多的，但是因为感觉做起来会比较复杂没去实现），如果有可以评论。
        int RGB=bufferedImage.getRGB(width-1, height-1);

        for(int i = bufferedImage.getMinX(); i < width; i++) {
            for(int j = bufferedImage.getMinY(); j < height; j++) {

                int rgb = bufferedImage.getRGB(i, j);

                int r = (rgb & 0xff0000) >>16;
                int g = (rgb & 0xff00) >> 8;
                int b = (rgb & 0xff);
                int R = (RGB & 0xff0000) >>16;
                int G = (RGB & 0xff00) >> 8;
                int B = (RGB & 0xff);
                //a为色差范围值，渐变色边缘处理，数值需要具体测试，50左右的效果比较可以
                int a = 45;
                if(Math.abs(R-r) < a && Math.abs(G-g) < a && Math.abs(B-b) < a ) {
                    alpha = 0;
                } else {
                    alpha = 255;
                }
                rgb = (alpha << 24)|(rgb & 0x00ffffff);
                bufferedImage.setRGB(i,j,rgb);
            }
        }

//        graphics2D.drawImage(bufferedImage, 0, 0, imageIcon.getImageObserver());

        //新建字节输出流，用来存放替换完背景的图片
//        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();

        String[] split = fileName.split("\\.");
        fileName = split[0]+"(已转换)."+split[1];
        ImageIO.write(bufferedImage, "png", new File("D:\\"+fileName));
    }

    public static String convertRgbStr(int color) {
        int red = (color & 0xff0000) >> 16;// 获取color(RGB)中R位
        int green = (color & 0x00ff00) >> 8;// 获取color(RGB)中G位
        int blue = (color & 0x0000ff);// 获取color(RGB)中B位
        return red + "," + green + "," + blue;
    }
}

 
css 文本背景色透明
 
Introduction:
 
 
 介绍： 
 
 
In web development, there are numerous ways by which we can style our websites or web pages. You can make use of lots of properties for creating attractive and responsive websites.
 
 
 在Web开发中，我们可以通过多种方式来设计网站或网页的样式。 您可以利用许多属性来创建吸引人的响应式网站。 
 
 
Styling is very important for any website or web page. If your web page or website is not styled properly then there are chances that the audience would not like to go through your website or web page and if you have created a website or web page with good styling, then there are chances that your website or web page will draw a lot of attention.
 
 
 样式对于任何网站或网页都非常重要。 如果您的网页或网站的样式设置不正确，则有可能观众不希望浏览您的网站或网页，并且如果您创建的网站或网页的样式良好，则很有可能您的网站或网站网页将引起很多关注。 
 
 
Trivia:
 
 
 琐事： 
 
 
Styling goes hand in hand while developing a web page or a website. You should dedicate as much time as you can while styling your website or web page. If you are just a beginner then you might face some problems when it comes to styling as initially, no one is aware of so many properties. So to be a good professional developer, you will need to learn as many properties as possible. When you have an abundance of knowledge about various properties then you will be able to style websites or web pages very swiftly and easily.
 
 
 在开发网页或网站时，样式是齐头并进的。 在设计网站或网页的样式时，您应该花费尽可能多的时间。 如果您只是一个初学者，那么像最初一样在样式方面可能会遇到一些问题，没有人知道这么多的属性。 因此，要成为一名优秀的专业开发人员，您将需要学习尽可能多的属性。 如果您对各种属性有足够的了解，那么您将能够非常轻松快捷地对网站或网页进行样式设置。 
 
 
Here, in this article, we are going to discuss one aspect of styling the websites or web pages. From this article, you will learn how you can make the background of an image or a text as transparent.
 
 
 在本文中，我们将在这里讨论网站或网页样式的一方面。 从本文中，您将学习如何使图像或文本的背景透明。 
 
 
So, let us move on with the next section.
 
 
 因此，让我们继续下一节。 
 
 
Briefing:
 
 
 简报： 
 
 
For setting the background of an image or a text as transparent you will have to make use of a certain property. This property is known as opacity. To achieve what you desire your opacity is the most crucial property at play. Before, we learn how we can set the background as transparent using this property. First, let us get familiar with the opacity property.
 
 
 要将图像或文本的背景设置为透明，必须使用某些属性。 此属性称为不透明度 。 要实现您所希望的不透明度，是最关键的属性。 在此之前，我们学习了如何使用此属性将背景设置为透明。 首先，让我们熟悉opacity属性。 
 
 
Property:
 
 
 属性： 
 
 
The opacity is a property that would help in making any element as transparent or opaque or slightly translucent. You can make us of opacity property on any element. The scale of opacity property ranges from 0 to 1, where 0 is defined as completely transparent and 1 is defined as completely opaque.
 
 
 不透明度是一种有助于使任何元素透明或不透明或稍微半透明的属性。 您可以使我们在任何元素上都具有不透明度属性。 不透明度属性的范围为0到1 ，其中0定义为完全透明，而1定义为完全不透明。 
 
 
Now that we are familiar with the opacity property, let us discuss the solution now.
 
 
 现在我们熟悉了opacity属性，让我们现在讨论解决方案。 
 
 
Syntax:
 
 
 句法： 
 
 
element{
	opacity : value;
}


 
Example:
 
 
 例： 
 
 
<!DOCTYPE html>

<html>

<head>
    <style>
        div {
            background-color: #f40;
            font-size: 40px;
            text-align: center;
            opacity: 0.5;
            color: #fff;
        }
    </style>
</head>

<body>
    <div>This is IncludeHelp</div>
</body>

</html>


 
Output
 
 
 输出量 
 
 
  

    
  
 
 
In the above example, the opacity is set to 0.5.
 
 
 在上面的示例中， 不透明度设置为0.5 。 
 
 

  
翻译自: https://www.includehelp.com/code-snippets/how-to-set-the-background-of-a-text-or-an-image-as-transparent-using-css.aspx
 
 
css 文本背景色透明