跳到主要内容

添加、删除水印

对指定页面添加水印，包括文本水印或图片水印。

  • 文本水印可以设置字体、大小、旋转，位置等属性。
  • 图片水印可以设置缩放、旋转、透明度和位置等属性。

接口说明​

接口名描述
addWatermark(info: WatermarkInfo, startIndex: number, endIndex: number, oddPages: boolean, evenPages: boolean): void插入水印到PDF文档。如果插入的是图片，支持的图片格式参考ImageFormat，文本字符无限制。
removeWatermark(): boolean删除PDF文档水印。

addWatermark方法属于耗时业务，需要遍历每一页去添加水印，添加页面较多时建议放到线程里去处理。

示例代码​

添加、删除文本水印​

添加文本水印

  1. 调用loadDocument方法，加载PDF文档。
  2. 实例化文本水印TextWatermarkInfo类，并设置相关属性，包括字体、大小、旋转，位置等。
  3. 调用addWatermark，添加文本水印。
  4. 保存PDF文档到应用沙箱。

删除文本水印

  1. 调用loadDocument方法，加载PDF文档。
  2. 调用removeWatermark，删除文本水印。
  3. 保存PDF文档到应用沙箱。
import { pdfService } from '@kit.PDFKit';
import { hilog } from '@kit.PerformanceAnalysisKit';
import { Font } from '@kit.ArkUI';

@Entry
@Component
struct PdfPage {
  private pdfDocument: pdfService.PdfDocument = new pdfService.PdfDocument();
  private context = this.getUIContext().getHostContext() as Context;

  build() {
    Column() {
      Button('addTextWatermark').onClick(async () => {
        // 确保沙箱目录有input.pdf文档
        let filePath = this.context.filesDir + '/input.pdf';
        let res = this.pdfDocument.loadDocument(filePath);
        if (res === pdfService.ParseResult.PARSE_SUCCESS) {
          let wminfo: pdfService.TextWatermarkInfo = new pdfService.TextWatermarkInfo();
          wminfo.watermarkType = pdfService.WatermarkType.WATERMARK_TEXT;
          wminfo.content = 'This is Watermark';
          wminfo.textSize = 30;
          wminfo.textColor = 200;
          wminfo.fontInfo = new pdfService.FontInfo();
          // 确保字体路径存在
          let font: Font = new Font()
          wminfo.fontInfo.fontPath = font.getFontByName('HarmonyOS Sans').path;
          wminfo.opacity = 0.5;
          wminfo.isOnTop = true;
          wminfo.rotation = 45;
          wminfo.scale = 1.5;
          wminfo.opacity = 0.5;
          wminfo.verticalAlignment = pdfService.WatermarkAlignment.WATERMARK_ALIGNMENT_TOP;
          wminfo.horizontalAlignment = pdfService.WatermarkAlignment.WATERMARK_ALIGNMENT_LEFT;
          wminfo.horizontalSpace = 1.0;
          wminfo.verticalSpace = 1.0;
          this.pdfDocument.addWatermark(wminfo, 0, 5, true, true);
          let outPdfPath = this.context.filesDir + '/testTextWatermark.pdf';
          let result = this.pdfDocument.saveDocument(outPdfPath);
          hilog.info(0x0000, 'PdfPage', 'addTextWatermark %{public}s!', result ? 'success' : 'fail');
        }
        this.pdfDocument.releaseDocument();
      })
      Button('removeTextWatermark').onClick(async () => {
        let filePath = this.context.filesDir + '/testTextWatermark.pdf';
        let res = this.pdfDocument.loadDocument(filePath);
        if (res === pdfService.ParseResult.PARSE_SUCCESS && this.pdfDocument.hasWatermark()) {
          let removeResult = this.pdfDocument.removeWatermark();
          if (removeResult) {
            let outPdfPath = this.context.filesDir + '/removeWatermark.pdf';
            let result = this.pdfDocument.saveDocument(outPdfPath);
            hilog.info(0x0000, 'PdfPage', 'removeWatermark %{public}s!', result ? 'success' : 'fail');
          }
        }
        this.pdfDocument.releaseDocument();
      })
    }
  }
}

添加、删除图片水印​

添加图片水印

  1. 调用loadDocument方法加载PDF文档。
  2. 实例化图片水印ImageWatermarkInfo类，并设置相关属性，包括缩放、旋转、透明度和位置等。
  3. 调用addWatermark添加图片水印。
  4. 保存PDF文档到应用沙箱。

删除图片水印

  1. 调用loadDocument方法加载PDF文档。
  2. 调用removeWatermark删除图片水印。
  3. 保存PDF文档到应用沙箱。
import { pdfService } from '@kit.PDFKit';
import { hilog } from '@kit.PerformanceAnalysisKit';

@Entry
@Component
struct PdfPage {
  private pdfDocument: pdfService.PdfDocument = new pdfService.PdfDocument();
  private context = this.getUIContext().getHostContext() as Context;

  build() {
    Column() {
      Button('addImageWatermark').onClick(async () => {
        let filePath = this.context.filesDir + '/input.pdf';
        let res = this.pdfDocument.loadDocument(filePath);
        if (res === pdfService.ParseResult.PARSE_SUCCESS) {
          let wminfo: pdfService.ImageWatermarkInfo = new pdfService.ImageWatermarkInfo();
          wminfo.watermarkType = pdfService.WatermarkType.WATERMARK_IMAGE;
          // 确保沙箱目录有img.jpg文档
          wminfo.imagePath = this.context.filesDir + '/img.jpg';
          wminfo.opacity = 0.5;
          wminfo.isOnTop = true;
          wminfo.rotation = 45;
          wminfo.scale = 0.5;
          wminfo.opacity = 0.5;
          wminfo.verticalAlignment = pdfService.WatermarkAlignment.WATERMARK_ALIGNMENT_TOP;
          wminfo.horizontalAlignment = pdfService.WatermarkAlignment.WATERMARK_ALIGNMENT_LEFT;
          wminfo.horizontalSpace = 1.0;
          wminfo.verticalSpace = 1.0;
          this.pdfDocument.addWatermark(wminfo, 0, 5, true, true);
          let outPdfPath = this.context.filesDir + '/testImageWatermark.pdf';
          let result = this.pdfDocument.saveDocument(outPdfPath);
          hilog.info(0x0000, 'PdfPage', 'addImageWatermark %{public}s!', result ? 'success' : 'fail');
        }
        this.pdfDocument.releaseDocument();
      })
      Button('removeImageWatermark').onClick(async () => {
        let filePath = this.context.filesDir + '/testImageWatermark.pdf';
        let res = this.pdfDocument.loadDocument(filePath);
        if (res === pdfService.ParseResult.PARSE_SUCCESS && this.pdfDocument.hasWatermark()) {
          let removeResult = this.pdfDocument.removeWatermark();
          if (removeResult) {
            let outPdfPath = this.context.filesDir + '/removeImageWatermark.pdf';
            let result = this.pdfDocument.saveDocument(outPdfPath);
            hilog.info(0x0000, 'PdfPage', 'removeImageWatermark %{public}s!', result ? 'success' : 'fail');
          }
        }
        this.pdfDocument.releaseDocument();
      })
    }
  }
}