Enhance Your Presentations with AutoFit in C#

Overview

By default, when you add a textbox, Microsoft PowerPoint uses the Resize shape to fit text setting for the textbox—it automatically resizes the textbox to ensure its text always fits into it.

• When the text in the textbox becomes longer or bigger, PowerPoint automatically enlarges the textbox—increasing its height—to allow it to hold more text.
• When the text in the textbox becomes shorter or smaller, PowerPoint automatically reduces the textbox—decreasing its height—to clear redundant space.

In PowerPoint, these are the four important parameters or options that control the autofit behavior for a textbox:

• Do not Autofit
• Shrink text on overflow
• Resize shape to fit text
• Wrap text in shape

Aspose.Slides for .NET provides similar options—properties under the TextFrameFormat class—that allow you to control the autofit behavior for textboxes in presentations.

Resize Shape to Fit Text

If you want the text in a box to always fit into that box after changes are made to the text, you have to use the Resize shape to fit text option. To specify this setting, set the AutofitType property from the TextFrameFormat class to Shape.

This C# code shows how to specify that text must always fit into its box in a PowerPoint presentation:

using (Presentation presentation = new Presentation())
{
    ISlide slide = presentation.Slides[0];
    IAutoShape autoShape = slide.Shapes.AddAutoShape(ShapeType.Rectangle, 30, 30, 350, 100);

    Portion portion = new Portion("lorem ipsum...");
    portion.PortionFormat.FillFormat.SolidFillColor.Color = Color.Black;
    portion.PortionFormat.FillFormat.FillType = FillType.Solid;
    autoShape.TextFrame.Paragraphs[0].Portions.Add(portion);

    ITextFrameFormat textFrameFormat = autoShape.TextFrame.TextFrameFormat;
    textFrameFormat.AutofitType = TextAutofitType.Shape;

    presentation.Save("output_presentation.pptx", SaveFormat.Pptx);
}

If the text becomes longer or bigger, the textbox will be automatically resized (increased in height) to ensure all the text fits into it. If the text becomes shorter, the reverse occurs.

Do Not Autofit

If you want a textbox or shape to retain its dimensions no matter the changes made to the text it contains, you have to use the Do not Autofit option. To specify this setting, set the AutofitType property from the TextFrameFormat class to None.

This C# code shows how to specify that a textbox must always retain its dimensions in a PowerPoint presentation:

using (Presentation presentation = new Presentation())
{
    ISlide slide = presentation.Slides[0];
    IAutoShape autoShape = slide.Shapes.AddAutoShape(ShapeType.Rectangle, 30, 30, 350, 100);

    Portion portion = new Portion("lorem ipsum...");
    portion.PortionFormat.FillFormat.SolidFillColor.Color = Color.Black;
    portion.PortionFormat.FillFormat.FillType = FillType.Solid;
    autoShape.TextFrame.Paragraphs[0].Portions.Add(portion);

    ITextFrameFormat textFrameFormat = autoShape.TextFrame.TextFrameFormat;
    textFrameFormat.AutofitType = TextAutofitType.None;

    presentation.Save("output_presentation.pptx", SaveFormat.Pptx);
}

When the text becomes too long for its box, it spills out.

Shrink Text on Overflow

If the text becomes too long for its box, through the Shrink text on overflow option, you can specify that the text’s size and spacing must be reduced to make it fit into its box. To specify this setting, set the AutofitType property from the TextFrameFormat class to Normal.

This C# code shows how to specify that text must be shrunk on overflow in a PowerPoint presentation:

using (Presentation presentation = new Presentation())
{
    ISlide slide = presentation.Slides[0];
    IAutoShape autoShape = slide.Shapes.AddAutoShape(ShapeType.Rectangle, 30, 30, 350, 100);

    Portion portion = new Portion("lorem ipsum...");
    portion.PortionFormat.FillFormat.SolidFillColor.Color = Color.Black;
    portion.PortionFormat.FillFormat.FillType = FillType.Solid;
    autoShape.TextFrame.Paragraphs[0].Portions.Add(portion);

    ITextFrameFormat textFrameFormat = autoShape.TextFrame.TextFrameFormat;
    textFrameFormat.AutofitType = TextAutofitType.Normal;

    presentation.Save("output_presentation.pptx", SaveFormat.Pptx);
}

Info

When the Shrink text on overflow option is used, the setting is applied only when the text becomes too long for its box.

Wrap Text

If you want the text in a shape to be wrapped inside that shape when the text goes beyond the shape’s border (width only), you have to use the Wrap text in shape parameter. To specify this setting, you have to set the WrapText property from the TextFrameFormat class to NullableBool.True.

This C# code shows how to use the Wrap Text setting in a PowerPoint presentation:

using (Presentation presentation = new Presentation())
{
    ISlide slide = presentation.Slides[0];
    IAutoShape autoShape = slide.Shapes.AddAutoShape(ShapeType.Rectangle, 30, 30, 350, 100);

    Portion portion = new Portion("lorem ipsum...");
    portion.PortionFormat.FillFormat.SolidFillColor.Color = Color.Black;
    portion.PortionFormat.FillFormat.FillType = FillType.Solid;
    autoShape.TextFrame.Paragraphs[0].Portions.Add(portion);

    ITextFrameFormat textFrameFormat = autoShape.TextFrame.TextFrameFormat;
    textFrameFormat.WrapText = NullableBool.True;

    presentation.Save("output_presentation.pptx", SaveFormat.Pptx);
}

Note

If you set the WrapText property to NullableBool.False for a shape, when the text inside the shape becomes longer than the shape’s width, the text extends beyond the shape’s borders along a single line.