使用POI在Excel里插入圖片，如何使插入的圖片使用固定的大小？先介紹原有的兩種方式：
一種是指定開始和結尾單元格，然后從頭畫到尾，相當於平鋪
還有一種就是僅指定開始的單元格，圖片的大小跟這個單元格的長寬有關，可以放大縮小固定的倍數，相當於左對齊
第一種效果如下：
第二種效果如下：
第一種方法的關鍵代碼如下：
1 private void pictureToSheet(Sheet finalSheet, Row row, Cell cell, int pictureIdx) { 2 Drawing patriarch = finalSheet.createDrawingPatriarch(); 3 ExcelPositionRange excelPositionRange = ExcelTransferUtils.getMergedRegionPositionRange(finalSheet, row.getRowNum(), cell.getColumnIndex()); 4 ClientAnchor anchor = patriarch.createAnchor(0, 0, 1023, 255, 5 excelPositionRange.getFirstCol(), 6 excelPositionRange.getFirstRow(), 7 excelPositionRange.getLastCol(), 8 excelPositionRange.getLastRow() 9 ); 10 patriarch.createPicture(anchor, pictureIdx); 11 }
注：代碼中的excelPositionRange，是俺自定義的一個類型。里邊只有四個變量和get/set方法，四個變量分別是單元格的開始、結尾單元格的橫縱坐標。這個大家可以根據需要來改。
PS：其中1023和255指的是每個單元格被切分的份數，指定的是最后的單元格的最右下角的一個點，其方法的源代碼在本文最后的附錄里。
第二種方法的關鍵代碼如下：
1 private void pictureToSheet(Sheet finalSheet, Row row, Cell cell, int pictureIdx) { 2 Drawing patriarch = finalSheet.createDrawingPatriarch(); 3 ExcelPositionRange excelPositionRange = ExcelTransferUtils.getMergedRegionPositionRange(finalSheet, row.getRowNum(), cell.getColumnIndex()); 4 5 CreationHelper helper = finalSheet.getWorkbook().getCreationHelper(); 6 ClientAnchor anchor = helper.createClientAnchor(); 7 8 // 圖片插入坐標 9 anchor.setCol1(excelPositionRange.getFirstCol()); 10 anchor.setRow1(excelPositionRange.getFirstRow()); 11 12 // 使用固定的長寬比例系數 13 double a = 5.9; 14 double b = 1; 15 16 // 插入圖片 17 Picture pict = patriarch.createPicture(anchor, pictureIdx); 18 pict.resize(a,b); 19 }
進階方法：
在第二種方法的基礎上，可以計算出不同的系數，達到生成圖片都是同一個長寬的功能，從而輸出固定大小的圖片
1 private void pictureToSheet(Sheet finalSheet, Row row, Cell cell, int pictureIdx) { 2 Drawing patriarch = finalSheet.createDrawingPatriarch(); 3 ExcelPositionRange excelPositionRange = ExcelTransferUtils.getMergedRegionPositionRange(finalSheet, row.getRowNum(), cell.getColumnIndex()); 4 5 CreationHelper helper = finalSheet.getWorkbook().getCreationHelper(); 6 ClientAnchor anchor = helper.createClientAnchor(); 7 8 // 圖片插入坐標 9 anchor.setCol1(excelPositionRange.getFirstCol()); 10 anchor.setRow1(excelPositionRange.getFirstRow()); 11 12 // 指定我想要的長寬 13 double standardWidth = 112; 14 double standardHeight = 41; 15 16 // 計算單元格的長寬 17 double cellWidth = finalSheet.getColumnWidthInPixels(cell.getColumnIndex()); 18 double cellHeight = cell.getRow().getHeightInPoints()/72*96; 19 20 // 計算需要的長寬比例的系數 21 double a = standardWidth / cellWidth; 22 double b = standardHeight / cellHeight; 23 24 // 插入圖片 25 Picture pict = patriarch.createPicture(anchor, pictureIdx); 26 pict.resize(a,b); 27 }
PS：這里參考了POI獲取單元格長寬的的方法：http://www.cnblogs.com/acm-bingzi/p/poiWidth.html
附錄一
一般插入圖片的樣例代碼：
1 // 插入 PNG 圖片至 Excel 2 String fileName = strAppRootPath + "images/" + "bxlogo.png"; 3 4 InputStream is = new FileInputStream(fileName); 5 byte[] bytes = IOUtils.toByteArray(is); 6 7 int pictureIdx = workbook.addPicture(bytes, Workbook.PICTURE_TYPE_PNG); 8 9 CreationHelper helper = workbook.getCreationHelper(); 10 Drawing drawing = sheet.createDrawingPatriarch(); 11 ClientAnchor anchor = helper.createClientAnchor(); 12 13 // 圖片插入坐標 14 anchor.setCol1(0); 15 anchor.setRow1(1); 16 // 插入圖片 17 Picture pict = drawing.createPicture(anchor, pictureIdx); 18 pict.resize();
附錄二
patriarch.createAnchor的源代碼跟蹤
1 /** 2 * Creates a new client anchor and sets the top-left and bottom-right 3 * coordinates of the anchor. 4 * 5 * Note: Microsoft Excel seems to sometimes disallow 6 * higher y1 than y2 or higher x1 than x2, you might need to 7 * reverse them and draw shapes vertically or horizontally flipped! 8 * 9 * @param dx1 the x coordinate within the first cell. 10 * @param dy1 the y coordinate within the first cell. 11 * @param dx2 the x coordinate within the second cell. 12 * @param dy2 the y coordinate within the second cell. 13 * @param col1 the column (0 based) of the first cell. 14 * @param row1 the row (0 based) of the first cell. 15 * @param col2 the column (0 based) of the second cell. 16 * @param row2 the row (0 based) of the second cell. 17 */ 18 public HSSFClientAnchor(int dx1, int dy1, int dx2, int dy2, short col1, int row1, short col2, int row2) { 19 super(dx1, dy1, dx2, dy2); 20 21 checkRange(dx1, 0, 1023, "dx1"); 22 checkRange(dx2, 0, 1023, "dx2"); 23 checkRange(dy1, 0, 255, "dy1"); 24 checkRange(dy2, 0, 255, "dy2"); 25 checkRange(col1, 0, MAX_COL, "col1"); 26 checkRange(col2, 0, MAX_COL, "col2"); 27 checkRange(row1, 0, MAX_ROW, "row1"); 28 checkRange(row2, 0, MAX_ROW, "row2"); 29 30 setCol1((short) Math.min(col1, col2)); 31 setCol2((short) Math.max(col1, col2)); 32 setRow1(Math.min(row1, row2)); 33 setRow2(Math.max(row1, row2)); 34 35 if (col1 > col2){ 36 _isHorizontallyFlipped = true; 37 } 38 if (row1 > row2){ 39 _isVerticallyFlipped = true; 40 } 41 }
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