Java实现图片转字符输出示例demo

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前面几篇博文介绍了使用jdk来对图片做一些有意思的转换，接下来我们再介绍一个有意思的玩法，直接根据图片，输出一个二维字符数组，实现用字符来实现绘画的场景

各位小伙伴可能都有看到过一些有趣的注释，比如大佛，美女之类的，通关本文，相信你也很可以很简单的实现类似的场景

关键实现，在前面的文章中其实也说到了，下面是超链

接下来我们需要做的就是将之前转成字符图片输出的地方稍微改一下，根据当前色颜色，来选择合适的替换字符保存下来

所以关键的实现在于，如何根据颜色来选择字符

java复制代码// 这个字符来自于github搜索结果，下面将最后一个从原来的点号改成了空格，即白色时，不输出字符
private static final String DEFAULT_CHAR_SET = "$@B%8&WM#*oahkbdpqwmZO0QLCJUYXzcvunxrjft/\\|()1{}[]?-_+~<>i!lI;:,\\\"^`' ";

/**
 * 基于颜色的灰度值，获取对应的字符
 * @param g
 * @return
 */
public static char toChar(Color g) {
    double gray = 0.299 * g.getRed() + 0.578 * g.getGreen() + 0.114 * g.getBlue();
    return DEFAULT_CHAR_SET.charAt((int) (gray / 255 * DEFAULT_CHAR_SET.length()));
}

接下来我们针对之前的方法，稍微改造一下

java复制代码Color getAverage(BufferedImage image, int x, int y, int w, int h) {
    int red = 0;
    int green = 0;
    int blue = 0;

    int size = 0;
    for (int i = y; (i < h + y) && (i < image.getHeight()); i++) {
        for (int j = x; (j < w + x) && (j < image.getWidth()); j++) {
            int color = image.getRGB(j, i);
            red += ((color & 0xff0000) >> 16);
            green += ((color & 0xff00) >> 8);
            blue += (color & 0x0000ff);
            ++size;
        }
    }

    red = Math.round(red / (float) size);
    green = Math.round(green / (float) size);
    blue = Math.round(blue / (float) size);
    return new Color(red, green, blue);
}

private void parseChars(BufferedImage img) {
    int w = img.getWidth(), h = img.getHeight();
    // 这个size可用来控制精度，越小则越像原图
    int size = 4;
    List<List<String>> list = new ArrayList<>();
    for (int y = 0; y < h; y += size) {
        List<String> line = new ArrayList<>();
        for (int x = 0; x < w; x += size) {
            Color avgColor = getAverage(img, x, y, size, size);
            line.add(String.valueOf(toChar(avgColor)));
        }
        list.add(line);
    }

    System.out.println("---------------------- 开始 ------------------------");
    for (List<String> line: list) {
        for (String s: line) {
            System.out.print(s + " ");
        }
        System.out.println();
    }
    System.out.println("---------------------- 结束 ------------------------");
}

注意上面的实现，需要重点注意的是原图的遍历方式，一层一层的遍历，即外部是y轴，内部循环是x轴

接下来看一下测试case

java复制代码@Test
public void testChars() throws Exception{
    String file = "http://pic.dphydh.com/pic/newspic/2017-12-13/505831-1.png";
    BufferedImage img = ImageLoadUtil.getImageByPath(file);
    // 缩放一下图片为300x300，方便对输出字符截图
    img = GraphicUtil.scaleImg(300,300, img);
    parseChars(img);
    System.out.println("---over------");
}

实际输出如下(实际输出结果与皮神还是很像的)

text复制代码---------------------- 开始 ------------------------
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---------------------- 结束 ------------------------

虽说上面这个是输出了字符图，从结果上看也比价像，但是需要注意的是，若图片的背景非白色，主角不是那么突出的场景，通过上面的方式输出的结果可能就不太友好了，解决办法当然就是识别背景，识别主体，针对主体元素进行转换（这个过程后面有机会再介绍）

接下来我们借助开源项目 github.com/liuyueyi/qu… 来迅速的实现字符图输出

以一个冰雪女王的转换图来验证下效果

1
2

java复制代码String file = "http://5b0988e595225.cdn.sohucs.com/images/20200410/76499041d3b144b58d6ed83f307df8a3.jpeg";
BufferedImage res = ImgPixelWrapper.build().setSourceImg(file).setBlockSize(4).setPixelType(PixelStyleEnum.CHAR_BLACK).build().asBufferedImg();

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