Working Solution for Worksheet Resizing

Background

In the article Manage OLE, we explained how to add an OLE frame to a PowerPoint presentation using Aspose.Slides for .NET. 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 in the PowerPoint presentation to match the total height and width of the selected rows and columns.
  • Keep the OLE frame size constant and scale the selected rows and columns to fit within it.

Scale the OLE Frame Size

This approach sets the OLE frame size to match the total height and width of the selected rows and columns in the embedded Excel worksheet.

The example loads an existing Excel workbook and selects the first 10 rows and 13 columns of its first worksheet using zero-based indices. WorksheetCollection.SetOleSize defines the displayed range. The preview is rendered at 96 DPI, and its pixel dimensions are converted to points using 72 points per inch. ShapeCollection.AddOleObjectFrame embeds the modified workbook in a frame with those dimensions. The preview is assigned through OleObjectFrame.SubstitutePictureFormat to replace the “EMBEDDED OLE OBJECT” placeholder in the saved presentation.

using System.Drawing;
using Aspose.Slides;
using Aspose.Slides.DOM.Ole;
using Aspose.Slides.Export;

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

int imageResolution = 96;

using var workbook = new Aspose.Cells.Workbook("sample.xlsx");
var worksheet = workbook.Worksheets[worksheetIndex];

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

var cellRange = worksheet.Cells.CreateRange(startRow, startColumn, rowCount, columnCount);
var imageStream = CreateOleImage(cellRange, imageResolution);

// Get the width and height of the OLE image in points.
using var image = Image.FromStream(imageStream);
var imageWidth = image.Width * 72 / imageResolution;
var imageHeight = image.Height * 72 / imageResolution;

// We need to use the modified workbook.
using var oleStream = new MemoryStream();
workbook.Save(oleStream, Aspose.Cells.SaveFormat.Xlsx);

using var presentation = new Presentation();
var slide = presentation.Slides.First();

// Add the OLE image to the presentation resources.
imageStream.Seek(0, SeekOrigin.Begin);
var oleImage = presentation.Images.AddImage(imageStream);

// Create the OLE object frame.
var dataInfo = new OleEmbeddedDataInfo(oleStream.ToArray(), "xlsx");
var oleFrame = slide.Shapes.AddOleObjectFrame(10, 10, imageWidth, imageHeight, dataInfo);
oleFrame.SubstitutePictureFormat.Picture.Image = oleImage;
oleFrame.IsObjectIcon = false;

presentation.Save("output.pptx", SaveFormat.Pptx);

The preview helper sets PageSetup.PrintArea to the selected range and removes margins, headers, and footers. With ImageOrPrintOptions.OnlyArea enabled, SheetRender.ToImage renders the range as a PNG image. The helper rewinds the image stream before returning it for use in the presentation.

static MemoryStream CreateOleImage(Aspose.Cells.Range cellRange, int imageResolution)
{
    var pageSetup = cellRange.Worksheet.PageSetup;
    pageSetup.PrintArea = cellRange.Address;
    pageSetup.LeftMargin = 0;
    pageSetup.RightMargin = 0;
    pageSetup.TopMargin = 0;
    pageSetup.BottomMargin = 0;
    pageSetup.ClearHeaderFooter();

    var imageOptions = new Aspose.Cells.Rendering.ImageOrPrintOptions
    {
        ImageType = Aspose.Cells.Drawing.ImageType.Png,
        VerticalResolution = imageResolution,
        HorizontalResolution = imageResolution,
        OnePagePerSheet = true,
        OnlyArea = true
    };

    var sheetRender = new Aspose.Cells.Rendering.SheetRender(cellRange.Worksheet, imageOptions);
    var imageStream = new MemoryStream();

    sheetRender.ToImage(0, imageStream);
    imageStream.Seek(0, SeekOrigin.Begin);

    return imageStream;
}

Scale the Cell Range Size

This approach scales the heights of the selected rows and the widths of the selected columns to match a custom OLE frame size.

The example loads an existing Excel workbook and selects the first 10 rows and 13 columns of its first worksheet using zero-based indices. WorksheetCollection.SetOleSize defines the displayed range, and the helper below scales that range to fit a frame 400 points wide and 100 points high. After saving the modified workbook to a stream, ShapeCollection.AddOleObjectFrame embeds it at the specified size. A preview rendered at 96 DPI is assigned through OleObjectFrame.SubstitutePictureFormat, so the saved presentation displays the selected cells instead of the default placeholder.

using Aspose.Slides;
using Aspose.Slides.DOM.Ole;
using Aspose.Slides.Export;

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

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

using var workbook = new Aspose.Cells.Workbook("sample.xlsx");
var worksheet = workbook.Worksheets[worksheetIndex];

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

// Scale the cell range to fit the frame size.
var cellRange = worksheet.Cells.CreateRange(startRow, startColumn, rowCount, columnCount);
ScaleCellRange(cellRange, frameWidth, frameHeight);

var imageStream = CreateOleImage(cellRange, imageResolution);

// We need to use the modified workbook.
using var oleStream = new MemoryStream();
workbook.Save(oleStream, Aspose.Cells.SaveFormat.Xlsx);

using var presentation = new Presentation();
var slide = presentation.Slides.First();

// Add the OLE image to the presentation resources.
var oleImage = presentation.Images.AddImage(imageStream);

// Create the OLE object frame.
var dataInfo = new OleEmbeddedDataInfo(oleStream.ToArray(), "xlsx");
var oleFrame = slide.Shapes.AddOleObjectFrame(10, 10, frameWidth, frameHeight, dataInfo);
oleFrame.SubstitutePictureFormat.Picture.Image = oleImage;
oleFrame.IsObjectIcon = false;

presentation.Save("output.pptx", SaveFormat.Pptx);

The scaling helper calculates separate width and height ratios for the selected range, preserving the relative widths of its columns and the relative heights of its rows. It converts the calculated dimensions from points to inches before applying them with Cells.SetColumnWidthInch and Cells.SetRowHeightInch. The selected range must have nonzero width and height.

/// <param name="width">The expected width of the cell range in points.</param>
/// <param name="height">The expected height of the cell range in points.</param>
static void ScaleCellRange(Aspose.Cells.Range cellRange, float width, float height)
{
    var rangeWidth = cellRange.Width;
    var rangeHeight = cellRange.Height;

    for (int i = 0; i < cellRange.ColumnCount; i++)
    {
        var columnIndex = cellRange.FirstColumn + i;
        var columnWidth = cellRange.Worksheet.Cells.GetColumnWidth(columnIndex, false, Aspose.Cells.CellsUnitType.Point);

        var newColumnWidth = columnWidth * width / rangeWidth;
        var widthInInches = newColumnWidth / 72;
        cellRange.Worksheet.Cells.SetColumnWidthInch(columnIndex, widthInInches);
    }

    for (int i = 0; i < cellRange.RowCount; i++)
    {
        var rowIndex = cellRange.FirstRow + i;
        var rowHeight = cellRange.Worksheet.Cells.GetRowHeight(rowIndex, false, Aspose.Cells.CellsUnitType.Point);

        var newRowHeight = rowHeight * height / rangeHeight;
        var heightInInches = newRowHeight / 72;
        cellRange.Worksheet.Cells.SetRowHeightInch(rowIndex, heightInInches);
    }
}

This preview helper renders the resized range using SheetRender.ToImage. It limits PageSetup.PrintArea to that range, removes margins, headers, and footers, and returns a PNG stream positioned at its beginning.

static Stream CreateOleImage(Aspose.Cells.Range cellRange, int imageResolution)
{
    var pageSetup = cellRange.Worksheet.PageSetup;
    pageSetup.PrintArea = cellRange.Address;
    pageSetup.LeftMargin = 0;
    pageSetup.RightMargin = 0;
    pageSetup.TopMargin = 0;
    pageSetup.BottomMargin = 0;
    pageSetup.ClearHeaderFooter();

    var imageOptions = new Aspose.Cells.Rendering.ImageOrPrintOptions
    {
        ImageType = Aspose.Cells.Drawing.ImageType.Png,
        VerticalResolution = imageResolution,
        HorizontalResolution = imageResolution,
        OnePagePerSheet = true,
        OnlyArea = true
    };

    var sheetRender = new Aspose.Cells.Rendering.SheetRender(cellRange.Worksheet, imageOptions);
    var imageStream = new MemoryStream();

    sheetRender.ToImage(0, imageStream);
    imageStream.Seek(0, SeekOrigin.Begin);

    return imageStream;
}

Approach A resizes the OLE frame to an unchanged range; approach B scales the range to a fixed 400 by 100 point frame.

The sample uses approach B: it keeps a 400 × 100-point OLE frame and scales the selected range to fit. Approach A is the separate alternative. Convert 96-DPI preview pixels to slide points using 72 ÷ 96.

Conclusion

FAQ

Why does an embedded Excel worksheet change size when first activated in PowerPoint?

This happens because Excel tries to maintain the original window size when activated, while the OLE object frame in PowerPoint has its own dimensions. PowerPoint and Excel negotiate the size to maintain the aspect ratio, which can cause the resizing.

Is it possible to prevent this resizing issue entirely?

Yes. By scaling the OLE frame to fit the Excel cell range size or scaling the cell range to fit the desired OLE frame size, you can prevent unwanted resizing.

Which scaling method should I use, OLE frame scaling or cell range scaling?

Select OLE frame scaling if you want to maintain the original Excel row and column sizes. Select cell range scaling if you want a fixed size for the OLE frame in your presentation.

Will these solutions work if my presentation is based on a template?

Yes. Both solutions work for presentations created from templates and from scratch.

Is there a limit to the size of the OLE frame when using these methods?

No. You can make the OLE object frame any size as long as you set the scale appropriately.

Is there a way to avoid the “EMBEDDED OLE OBJECT” placeholder text in PowerPoint?

Yes. By taking a snapshot of the target Excel cell range and setting it as the OLE frame’s placeholder image, you can display a custom preview image in place of the default placeholder.

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