Working Solution for Worksheet Resizing

It has been observed that Excel worksheets embedded as OLE objects in a PowerPoint presentation through Aspose components are resized to an unidentified scale after the first activation. This behavior creates a noticeable visual difference in the presentation between the pre- and post-activation states of the OLE object. We have investigated this issue in detail and provided a solution, which is covered in this article.

Background

In the article Manage OLE, we explained how to add an OLE frame to a PowerPoint presentation using Aspose.Slides for Java. To address the object preview issue, we assigned an image of the selected worksheet area to the OLE object frame. In the output presentation, when you double-click the OLE object frame displaying the worksheet image, the Excel workbook is activated. End users can make any desired changes to the actual Excel workbook and then return to the slide by clicking outside the activated Excel workbook. The size of the OLE object frame will change when the user returns to the slide. The resizing factor will vary depending on the size of the OLE object frame and the embedded Excel workbook.

Cause of Resizing

Since the Excel workbook has its own window size, it tries to retain its original size upon first activation. On the other hand, the OLE object frame has its own size. According to Microsoft, when the Excel workbook is activated, Excel and PowerPoint negotiate the size to ensure it maintains the correct proportions as part of the embedding process. The resizing occurs based on the differences between the Excel window size and the OLE object frame’s size and position.

Working Solution

There are two possible solutions to avoid the resizing effect.

Scale the OLE frame size in the PowerPoint presentation to match the height and width of the desired number of rows and columns in the OLE frame.
Keep the OLE frame size constant and scale the size of the participating rows and columns to fit within the selected OLE frame size.

Scale the OLE Frame Size

In this approach, we will learn how to set the OLE frame size of the embedded Excel workbook to match the cumulative size of the participating rows and columns in the Excel worksheet.

Suppose we have a template Excel sheet and want to add it to a presentation as an OLE frame. In this scenario, the size of the OLE object frame will first be calculated based on the cumulative row heights and column widths of the participating rows and columns in the workbook. Then, we will set the size of the OLE frame to this calculated value. To avoid the red “EMBEDDED OLE OBJECT” message for the OLE frame in PowerPoint, we will also capture an image of the desired portions of the rows and columns in the workbook and set it as the OLE frame image.

int startRow = 0, rowCount = 10;
int startColumn = 0, columnCount = 13;
int worksheetIndex = 0;

int imageResolution = 96;

com.aspose.cells.Workbook workbook = new com.aspose.cells.Workbook( "sample.xlsx");
com.aspose.cells.Worksheet worksheet = workbook.getWorksheets().get(worksheetIndex);

// Set the displayed size when the workbook file is used as an OLE object in PowerPoint.
int lastRow = startRow + rowCount - 1;
int lastColumn = startColumn + columnCount - 1;
workbook.getWorksheets().setOleSize(startRow, lastRow, startColumn, lastColumn);

com.aspose.cells.Range cellRange = worksheet.getCells().createRange(startRow, startColumn, rowCount, columnCount);
InputStream imageStream = CreateOleImage(cellRange, imageResolution);

// Get the width and height of the OLE image in points.
Image image = ImageIO.read(imageStream);
float imageWidth = image.getWidth(null) * 72f / imageResolution;
float imageHeight = image.getHeight(null) * 72f / imageResolution;

// We need to use the modified workbook.
ByteArrayOutputStream oleStream = new ByteArrayOutputStream();
workbook.save(oleStream, com.aspose.cells.SaveFormat.XLSX);
workbook.dispose();

Presentation presentation = new Presentation();
ISlide slide = presentation.getSlides().get_Item(0);

// Add the OLE image to the presentation resources.
imageStream.reset();
IPPImage oleImage = presentation.getImages().addImage(imageStream);
imageStream.close();

// Create the OLE object frame.
IOleEmbeddedDataInfo dataInfo = new OleEmbeddedDataInfo(oleStream.toByteArray(), "xlsx");
IOleObjectFrame oleFrame = slide.getShapes().addOleObjectFrame(10, 10, imageWidth, imageHeight, dataInfo);
oleFrame.getSubstitutePictureFormat().getPicture().setImage(oleImage);
oleFrame.setObjectIcon(false);
oleStream.close();

presentation.save("output.pptx", SaveFormat.Pptx);
presentation.dispose();

static InputStream CreateOleImage(com.aspose.cells.Range cellRange, int imageResolution) throws Exception {
    com.aspose.cells.PageSetup pageSetup = cellRange.getWorksheet().getPageSetup();
    pageSetup.setPrintArea(cellRange.getAddress());
    pageSetup.setLeftMargin(0);
    pageSetup.setRightMargin(0);
    pageSetup.setTopMargin(0);
    pageSetup.setBottomMargin(0);
    pageSetup.clearHeaderFooter();

    com.aspose.cells.ImageOrPrintOptions imageOptions = new com.aspose.cells.ImageOrPrintOptions();
    imageOptions.setImageType(com.aspose.cells.ImageType.PNG);
    imageOptions.setVerticalResolution(imageResolution);
    imageOptions.setHorizontalResolution(imageResolution);
    imageOptions.setOnePagePerSheet(true);
    imageOptions.setOnlyArea(true);

    com.aspose.cells.SheetRender sheetRender = new com.aspose.cells.SheetRender(cellRange.getWorksheet(), imageOptions);
    ByteArrayOutputStream imageStream = new ByteArrayOutputStream();

    sheetRender.toImage(0, imageStream);
    return new ByteArrayInputStream(imageStream.toByteArray());
}

Scale the Cell Range Size

In this approach, we will learn how to scale the heights of the participating rows and the width of the participating columns to match a custom OLE frame size.

Suppose we have a template Excel sheet and want to add it to a presentation as an OLE frame. In this scenario, we will set the size of the OLE frame and scale the size of the rows and columns that participate in the OLE frame area. We will then save the workbook to a stream to apply the changes and convert it to a byte array for adding it to the OLE frame. To avoid the red “EMBEDDED OLE OBJECT” message for the OLE frame in PowerPoint, we will also capture an image of the desired portions of the rows and columns in the workbook and set it as the OLE frame image.

int startRow = 0, rowCount = 10;
int startColumn = 0, columnCount = 13;
int worksheetIndex = 0;

int imageResolution = 96;
float frameWidth = 400, frameHeight = 100;

com.aspose.cells.Workbook workbook = new com.aspose.cells.Workbook("sample.xlsx");
com.aspose.cells.Worksheet worksheet = workbook.getWorksheets().get(worksheetIndex);

// Set the displayed size when the workbook file is used as an OLE object in PowerPoint.
int lastRow = startRow + rowCount - 1;
int lastColumn = startColumn + columnCount - 1;
workbook.getWorksheets().setOleSize(startRow, lastRow, startColumn, lastColumn);

// Scale the cell range to fit the frame size.
com.aspose.cells.Range cellRange = worksheet.getCells().createRange(startRow, startColumn, rowCount, columnCount);
ScaleCellRange(cellRange, frameWidth, frameHeight);

InputStream imageStream = CreateOleImage(cellRange, imageResolution);

// We need to use the modified workbook.
ByteArrayOutputStream oleStream = new ByteArrayOutputStream();
workbook.save(oleStream, com.aspose.cells.SaveFormat.XLSX);
workbook.dispose();

Presentation presentation = new Presentation();
ISlide slide = presentation.getSlides().get_Item(0);

// Add the OLE image to the presentation resources.
IPPImage oleImage = presentation.getImages().addImage(imageStream);
imageStream.close();

// Create the OLE object frame.
IOleEmbeddedDataInfo dataInfo = new OleEmbeddedDataInfo(oleStream.toByteArray(), "xlsx");
IOleObjectFrame oleFrame = slide.getShapes().addOleObjectFrame(10, 10, frameWidth, frameHeight, dataInfo);
oleFrame.getSubstitutePictureFormat().getPicture().setImage(oleImage);
oleFrame.setObjectIcon(false);
oleStream.close();

presentation.save("output.pptx", SaveFormat.Pptx);
presentation.dispose();

/**
 * @param width     The expected width of the cell range in points.
 * @param height    The expected height of the cell range in points.
 */
static void ScaleCellRange(com.aspose.cells.Range cellRange, float width, float height) {
    double rangeWidth = cellRange.getWidth();
    double rangeHeight = cellRange.getHeight();

    for (int i = 0; i < cellRange.getColumnCount(); i++) {
        int columnIndex = cellRange.getFirstColumn() + i;
        double columnWidth = cellRange.getWorksheet()
                .getCells()
                .getColumnWidth(columnIndex, false, com.aspose.cells.CellsUnitType.POINT);

        double newColumnWidth = columnWidth * width / rangeWidth;
        double widthInInches = newColumnWidth / 72.0;
        cellRange.getWorksheet()
                .getCells()
                .setColumnWidthInch(columnIndex, widthInInches);
    }

    for (int i = 0; i < cellRange.getRowCount(); i++) {
        int rowIndex = cellRange.getFirstRow() + i;
        double rowHeight = cellRange.getWorksheet()
                .getCells()
                .getRowHeight(rowIndex, false, com.aspose.cells.CellsUnitType.POINT);

        double newRowHeight = rowHeight * height / rangeHeight;
        double heightInInches = newRowHeight / 72.0;
        cellRange.getWorksheet()
                .getCells()
                .setRowHeightInch(rowIndex, heightInInches);
    }
}

static InputStream CreateOleImage(com.aspose.cells.Range cellRange, int imageResolution) throws Exception {
    com.aspose.cells.PageSetup pageSetup = cellRange.getWorksheet().getPageSetup();
    pageSetup.setPrintArea(cellRange.getAddress());
    pageSetup.setLeftMargin(0);
    pageSetup.setRightMargin(0);
    pageSetup.setTopMargin(0);
    pageSetup.setBottomMargin(0);
    pageSetup.clearHeaderFooter();

    com.aspose.cells.ImageOrPrintOptions imageOptions = new com.aspose.cells.ImageOrPrintOptions();
    imageOptions.setImageType(com.aspose.cells.ImageType.PNG);
    imageOptions.setVerticalResolution(imageResolution);
    imageOptions.setHorizontalResolution(imageResolution);
    imageOptions.setOnePagePerSheet(true);
    imageOptions.setOnlyArea(true);

    com.aspose.cells.SheetRender sheetRender = new com.aspose.cells.SheetRender(cellRange.getWorksheet(), imageOptions);
    ByteArrayOutputStream imageStream = new ByteArrayOutputStream();

    sheetRender.toImage(0, imageStream);
    return new ByteArrayInputStream(imageStream.toByteArray());
}

Conclusion

There are two approaches to fix the worksheet resizing issue. The selection of the appropriate approach depends on the specific requirements and use case. Both approaches work the same way, whether the presentations are created from a template or from scratch. Additionally, there is no limit on the size of the OLE object frame in this solution.

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