mirror of
https://github.com/Stirling-Tools/Stirling-PDF.git
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100 lines
4.2 KiB
Java
100 lines
4.2 KiB
Java
package stirling.software.SPDF.controller.api;
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import java.io.ByteArrayInputStream;
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import java.io.ByteArrayOutputStream;
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import java.io.IOException;
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import org.slf4j.Logger;
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import org.slf4j.LoggerFactory;
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import org.springframework.http.ResponseEntity;
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import org.springframework.web.bind.annotation.PostMapping;
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import org.springframework.web.bind.annotation.RequestParam;
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import org.springframework.web.bind.annotation.RestController;
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import org.springframework.web.multipart.MultipartFile;
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import com.itextpdf.kernel.geom.PageSize;
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import com.itextpdf.kernel.geom.Rectangle;
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import com.itextpdf.kernel.pdf.PdfDocument;
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import com.itextpdf.kernel.pdf.PdfPage;
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import com.itextpdf.kernel.pdf.PdfReader;
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import com.itextpdf.kernel.pdf.PdfWriter;
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import com.itextpdf.kernel.pdf.canvas.PdfCanvas;
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import com.itextpdf.kernel.pdf.xobject.PdfFormXObject;
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import io.swagger.v3.oas.annotations.Operation;
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import io.swagger.v3.oas.annotations.Parameter;
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import io.swagger.v3.oas.annotations.media.Schema;
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import stirling.software.SPDF.utils.WebResponseUtils;
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@RestController
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public class MultiPageLayoutController {
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private static final Logger logger = LoggerFactory.getLogger(MultiPageLayoutController.class);
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@PostMapping(value = "/multi-page-layout", consumes = "multipart/form-data")
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@Operation(summary = "Merge multiple pages of a PDF document into a single page", description = "This operation takes an input PDF file and the number of pages to merge into a single sheet in the output PDF file.")
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public ResponseEntity<byte[]> mergeMultiplePagesIntoOne(
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@Parameter(description = "The input PDF file", required = true) @RequestParam("fileInput") MultipartFile file,
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@Parameter(description = "The number of pages to fit onto a single sheet in the output PDF. Acceptable values are 2, 3, 4, 9, 16.", required = true, schema = @Schema(type = "integer", allowableValues = {
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"2", "3", "4", "9", "16" })) @RequestParam("pagesPerSheet") int pagesPerSheet)
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throws IOException {
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if (pagesPerSheet != 2 && pagesPerSheet != 3
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&& pagesPerSheet != (int) Math.sqrt(pagesPerSheet) * Math.sqrt(pagesPerSheet)) {
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throw new IllegalArgumentException("pagesPerSheet must be 2, 3 or a perfect square");
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}
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int cols = pagesPerSheet == 2 || pagesPerSheet == 3 ? pagesPerSheet : (int) Math.sqrt(pagesPerSheet);
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int rows = pagesPerSheet == 2 || pagesPerSheet == 3 ? 1 : (int) Math.sqrt(pagesPerSheet);
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byte[] bytes = file.getBytes();
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PdfReader reader = new PdfReader(new ByteArrayInputStream(bytes));
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PdfDocument pdfDoc = new PdfDocument(reader);
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ByteArrayOutputStream baos = new ByteArrayOutputStream();
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PdfWriter writer = new PdfWriter(baos);
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PdfDocument outputPdf = new PdfDocument(writer);
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PageSize pageSize = new PageSize(PageSize.A4.rotate());
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int totalPages = pdfDoc.getNumberOfPages();
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float cellWidth = pageSize.getWidth() / cols;
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float cellHeight = pageSize.getHeight() / rows;
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for (int i = 1; i <= totalPages; i += pagesPerSheet) {
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PdfPage page = outputPdf.addNewPage(pageSize);
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PdfCanvas pdfCanvas = new PdfCanvas(page);
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for (int row = 0; row < rows; row++) {
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for (int col = 0; col < cols; col++) {
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int index = i + row * cols + col;
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if (index <= totalPages) {
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// Get the page and calculate scaling factors
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Rectangle rect = pdfDoc.getPage(index).getPageSize();
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float scaleWidth = cellWidth / rect.getWidth();
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float scaleHeight = cellHeight / rect.getHeight();
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float scale = Math.min(scaleWidth, scaleHeight);
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PdfFormXObject formXObject = pdfDoc.getPage(index).copyAsFormXObject(outputPdf);
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float x = col * cellWidth + (cellWidth - rect.getWidth() * scale) / 2;
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float y = (rows - 1 - row) * cellHeight + (cellHeight - rect.getHeight() * scale) / 2;
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// Save the graphics state, apply the transformations, add the object, and then
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// restore the graphics state
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pdfCanvas.saveState();
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pdfCanvas.concatMatrix(scale, 0, 0, scale, x, y);
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pdfCanvas.addXObject(formXObject, 0, 0);
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pdfCanvas.restoreState();
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}
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}
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}
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}
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outputPdf.close();
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byte[] pdfContent = baos.toByteArray();
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pdfDoc.close();
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return WebResponseUtils.bytesToWebResponse(pdfContent, file.getOriginalFilename().replaceFirst("[.][^.]+$", "") + "_layoutChanged.pdf");
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}
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}
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