A method and system for maintaining the validity of a virtual merge preview of multiple PDF files with electronic signatures

Abstract

The present application relates to electronic file management technical field, especially a kind of maintenance electronic signature effectiveness multi-PDF file virtual merging preview method, comprising the following steps: the unique identification list of multiple signed electronic signature PDF files is sorted;Metadata of PDF file is obtained in turn and the setting and identification of slice are carried out;Initialization preview view is carried out by creating virtual scroll container and generating global page mapping table, and placeholder is created in virtual scroll container;Virtual scroll container is monitored and initiates on-demand request;Preview effect diagram is generated by virtual merging;The data of non-active slice is released from memory.The present application also discloses a kind of maintenance electronic signature effectiveness multi-PDF file virtual merging preview system.The present application can be overall consulted to multiple signed PDF, improve the experience of user, while strictly abide by electronic signature management specification, maintain the legal effectiveness of electronic signature.

Claims

1. A method for virtual merging and previewing multiple PDF files to maintain the validity of electronic signatures, characterized in that, Includes the following steps: S1. Receive a list of unique identifiers for multiple signed electronically stamped PDF files to be previewed, and sort the list of unique identifiers according to business rules to obtain a sorted list; S2. According to the sorting list, the metadata of the PDF files are obtained sequentially to set and identify the PDFs as segments; S3. Obtain the sorted list and the metadata to initialize the preview view by creating a virtual scrolling container and generating a global page number mapping table, and create a placeholder in the virtual scrolling container; S4. Monitor the virtual scrolling container and calculate the visible area and cache area through the scroll bar position and the global page number mapping table, so as to initiate on-demand requests based on the fragments corresponding to the visible area and the cache area; S5. Extract the requested page data of the requested segment from the PDF file according to the on-demand request, render the page data as an image data stream, and fill the image data stream into the corresponding placeholders to generate a preview effect image through virtual merging; S6. Release the data of inactive segments from memory while preserving their placeholder structure.

2. The method for virtual merging and previewing multiple PDF files to maintain the validity of electronic signatures according to claim 1, characterized in that: In step S1, the unique identifier list includes an ID array, and the business rules include document number, archiving order, and timestamp.

3. The method for virtual merging and previewing multiple PDF files to maintain the validity of electronic signatures according to claim 1, characterized in that: In step S2, the metadata includes the total number of pages in the file, the file size, and the electronic signature verification status; according to the size of the PDF file and a preset strategy, the size of each segment of the PDF file is set and identified.

4. The method for virtual merging and previewing multiple PDF files to maintain the validity of electronic signatures according to claim 1, characterized in that: In step S3, multiple PDF files are virtually merged, and the total height of the merged document is calculated to create the virtual scrolling container. A mapping relationship is established based on the page number of each PDF file to map the global page number to the source file ID and its local page number, thereby generating the global page number mapping table; In the virtual scrolling container, a placeholder is created for each page, and the absolute positioning of the placeholder is set to the corresponding vertical position to simulate the skeleton structure of a long document, thereby obtaining a virtual long document.

5. The method for virtual merging and previewing multiple PDF files to maintain the validity of electronic signatures according to claim 4, characterized in that: In step S4, the pull-down scroll event and pull-up scroll event of the virtual scroll container are monitored, and the current scroll bar position is calculated in real time to determine the range of global page numbers covered by the visible area in the current virtual long document. Based on the global page number of the visible area, the global page number mapping table is queried to determine the fragments of the source file required to be displayed in the visible area and the adjacent cache area. The PDF file ID, the corresponding fragment index required by the visible area and the cache area are used to generate request parameters for on-demand requests.

6. The method for virtual merging and previewing multiple PDF files to maintain the validity of electronic signatures according to claim 5, characterized in that: In step S5, after rendering the page data into an image data stream, it is checked whether the image data stream cache exists in memory. If the cache exists, the data of the image data stream is extracted from the cache. When the cache does not exist, receive the data from the image data stream; After the cache check is completed, the image data stream is filled into the placeholder of the corresponding page number to generate a preview image by virtually merging the image data stream.

7. The method for virtual merging and previewing multiple PDF files to maintain the validity of electronic signatures according to claim 1, characterized in that: In step S6, by monitoring the user's scroll position, rendered content that is far from the current visible area is marked as an inactive fragment, and the data of the inactive fragment is released from memory using the LRU algorithm.

8. A virtual merging and previewing system for multiple PDF files to maintain the validity of electronic signatures, used to implement the virtual merging and previewing method for multiple PDF files to maintain the validity of electronic signatures as described in claim 1, characterized in that, include: The backend module is used for managing the PDF files, extracting the metadata of the PDF files, and processing the fragmented data of the PDF files. The front-end module is used to generate preview images using a virtual scrolling container; The cache management module is used for managing memory usage and cache release. The status synchronization module is used for data transmission and status synchronization between the backend module and the frontend module.

9. A virtual merging and previewing system for multiple PDF files to maintain the validity of electronic signatures according to claim 8, characterized in that: The status synchronization module establishes a dual-channel synchronization mechanism, which includes a request-response channel and a status synchronization channel. The request-response channel is used for the transmission of PDF files, metadata, and fragmented data between the backend module and the frontend module. The status synchronization channel is used for synchronizing status information between the backend module and the frontend module.

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