Pdf Charts and Drawings

Fix #4129. Fix #4168. Html Writer, which all the Pdf writers use, defines its charts and drawings (henceforth I will just use charts for this discussion) using position:absolute and z-index. Browsers handle this correctly, but none of the Pdf writers do, and I can't think of an alternative method of styling them. The result is that the charts take up too much or too little room on the Pdf.

I suggested in the two discussions that treating the areas covered by the charts as merged cells might mitigate the problem. I think there are too many unknowns to do so automatically (and see next paragraph). However, adding to Spreadsheet new methods `mergeChartCellsForPdf` and `mergeDrawingCellsForPdf` allows the end user to do this if desired. The new methods are exercised for charts in samples/Chart/32_Chart_read_write_PDF, the results of which are much improved as a result. New samples/Pdf/21f_Drawing_mpdf does likewise for drawings.

The new methods alter the spreadsheet they are working on, which could be a problem if you still wish to work with the spreadsheet after writing it to Pdf. In that case, making a copy of the spreadsheet, then calling the new methods on the copy, and writing the copy to Pdf is probably best.

Author: oleibman

samples/Chart/32_Chart_read_write_PDF.php

@@ -37,6 +37,9 @@
     $reader->setIncludeCharts(true);
     $spreadsheet = $reader->load($inputFileName);
 
+    $helper->log('Merge chart cells (needed only for Pdf)');
+    $spreadsheet->mergeChartCellsForPdf();
+
     $helper->log('Iterate worksheets looking at the charts');
     foreach ($spreadsheet->getWorksheetIterator() as $worksheet) {
         $sheetName = $worksheet->getTitle();

samples/Pdf/21f_Drawing_mpdf.php

@@ -0,0 +1,50 @@
+<?php
+
+use PhpOffice\PhpSpreadsheet\Spreadsheet;
+use PhpOffice\PhpSpreadsheet\Worksheet\Drawing;
+use PhpOffice\PhpSpreadsheet\Writer\Pdf\Mpdf;
+
+require __DIR__ . '/../Header.php';
+require_once __DIR__ . '/Mpdf2.php';
+
+$spreadsheet = new Spreadsheet();
+$sheet = $spreadsheet->getActiveSheet();
+
+$sheet->getCell('A1')->setValue('A1');
+$sheet->getCell('B1')->setValue('B');
+$sheet->getCell('C1')->setValue('C');
+$sheet->getCell('D1')->setValue('D');
+$sheet->getCell('E1')->setValue('E');
+$sheet->getCell('F1')->setValue('F');
+$sheet->getCell('G1')->setValue('G');
+$sheet->getCell('A2')->setValue('A2');
+$sheet->getCell('A3')->setValue('A3');
+$sheet->getCell('A4')->setValue('A4');
+$sheet->getCell('A5')->setValue('A5');
+$sheet->getCell('A6')->setValue('A6');
+$sheet->getCell('A7')->setValue('A7');
+$sheet->getCell('A8')->setValue('A8');
+
+$helper->log('Add drawing to worksheet');
+$drawing = new Drawing();
+$drawing->setName('Blue Square');
+$path = __DIR__ . DIRECTORY_SEPARATOR . '..' . DIRECTORY_SEPARATOR . 'images/blue_square.png';
+$drawing->setPath($path);
+$drawing->setResizeProportional(false);
+$drawing->setWidth(320);
+$drawing->setCoordinates('B2');
+$drawing->setCoordinates2('G6');
+$drawing->setWorksheet($sheet, true);
+
+$helper->log('Merge drawing cells for Pdf');
+$spreadsheet->mergeDrawingCellsForPdf();
+
+$helper->log('Write to Mpdf');
+$writer = new Mpdf($spreadsheet);
+$filename = $helper->getFileName(__FILE__, 'pdf');
+$writer->save($filename);
+$helper->log("Saved $filename");
+if (PHP_SAPI !== 'cli') {
+    echo '<a href="/download.php?type=pdf&name=' . basename($filename) . '">Download ' . basename($filename) . '</a><br />';
+}
+$spreadsheet->disconnectWorksheets();

src/PhpSpreadsheet/Spreadsheet.php

@@ -1610,4 +1610,52 @@ public function setValueBinder(?IValueBinder $valueBinder): self
 
         return $this;
     }
+
+    /**
+     * All the PDF writers treat charts as if they occupy a single cell.
+     * This will be better most of the time.
+     * It is not needed for any other output type.
+     * It changes the contents of the spreadsheet, so you might
+     * be better off cloning the spreadsheet and then using
+     * this method on, and then writing, the clone.
+     */
+    public function mergeChartCellsForPdf(): void
+    {
+        foreach ($this->workSheetCollection as $worksheet) {
+            foreach ($worksheet->getChartCollection() as $chart) {
+                $br = $chart->getBottomRightCell();
+                $tl = $chart->getTopLeftCell();
+                if ($br !== '' && $br !== $tl) {
+                    if (!$worksheet->cellExists($br)) {
+                        $worksheet->getCell($br)->setValue(' ');
+                    }
+                    $worksheet->mergeCells("$tl:$br");
+                }
+            }
+        }
+    }
+
+    /**
+     * All the PDF writers do better with drawings than charts.
+     * This will be better some of the time.
+     * It is not needed for any other output type.
+     * It changes the contents of the spreadsheet, so you might
+     * be better off cloning the spreadsheet and then using
+     * this method on, and then writing, the clone.
+     */
+    public function mergeDrawingCellsForPdf(): void
+    {
+        foreach ($this->workSheetCollection as $worksheet) {
+            foreach ($worksheet->getDrawingCollection() as $drawing) {
+                $br = $drawing->getCoordinates2();
+                $tl = $drawing->getCoordinates();
+                if ($br !== '' && $br !== $tl) {
+                    if (!$worksheet->cellExists($br)) {
+                        $worksheet->getCell($br)->setValue(' ');
+                    }
+                    $worksheet->mergeCells("$tl:$br");
+                }
+            }
+        }
+    }
 }