java图片添加文字/图片水印

读取要处理的图片

ClassPathResource resource = new ClassPathResource("template/clockbg.png");
BufferedImage image = ImageIO.read(resource.getInputStream());

创建画笔

Graphics2D pen = image.createGraphics();

添加文字

pen.setFont(new Font("微软雅黑", Font.PLAIN, 40));
pen.setColor(Color.black);
pen.drawString(timeContent, START_X, y);

添加网络图片

BufferedImage headImage = ImageIO.read(new URL(param.getImage()));
pen.drawImage(headImage, START_X, y - INTERVAL_Y, 100, 100, null);

获取字体行数

private int getRowNum(String content) {
    int rowNum = content.length() / FONT_NUM;
    if (content.length() % FONT_NUM != 0) {
        rowNum ++;
    }
    return rowNum;
}

文字区域换行

// 内容区域
String content = "恭喜您完成《" + param.getTrainName() + "》课程与认证。";
int rowNum = getRowNum(content);
for (int i = 0; i < rowNum; i++) {
    if (i == rowNum - 1) {
        pen.drawString(content.substring(FONT_NUM * i), START_X, y);
    } else {
        pen.drawString(content.substring(FONT_NUM * i, FONT_NUM * (i + 1)), START_X, y);
    }
    y += INTERVAL_Y;
}

docker中添加中文字体

ADD yahei.ttf /usr/share/fonts/ttf-yahei/yahei.ttf

RUN apk add fontconfig