# Format Presentation Text in .NET

> Format and style text in PowerPoint and OpenDocument presentations using Aspose.Slides for .NET. Customize fonts, colors, alignment, and more.

Source: https://docs.aspose.com/slides/net/text-formatting/
Updated: 2026-08-12


## **Overview**

This article shows how to format text in PowerPoint and OpenDocument presentations using Aspose.Slides for .NET. It covers background colors, transparency, character spacing, font properties, rotation, paragraph spacing, autofit behavior, text anchoring, tab stops, and language settings.

In the examples below, we’ll use a file named "sample.pptx", which contains a single text box on the first slide with the following text:

![Sample text](sample_text.png)

To find and highlight literal text or regular-expression matches, see [Search and Replace Text](/slides/net/search-and-replace-text/).

## **Set Text Background Color**

Use [IParagraphFormat.DefaultPortionFormat](https://reference.aspose.com/slides/net/aspose.slides/iparagraphformat/defaultportionformat/) to set the default highlight color for a paragraph, or use [IBasePortionFormat.HighlightColor](https://reference.aspose.com/slides/net/aspose.slides/ibaseportionformat/highlightcolor/) for individual text portions.

The following code example shows how to set the background color for the **entire paragraph**: 

```cs
using System.Drawing;
using Aspose.Slides;
using Aspose.Slides.Export;

using (var presentation = new Presentation("sample.pptx"))
{
    var autoShape = (IAutoShape)presentation.Slides[0].Shapes[0];
    var paragraph = autoShape.TextFrame.Paragraphs[0];

    // Set the highlight color for the entire paragraph.
    paragraph.ParagraphFormat.DefaultPortionFormat.HighlightColor.Color = Color.LightGray;

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

The result:

![The gray paragraph](gray_paragraph.png)

The code example below demonstrates how to set the background color for **text portions with a bold font**:

```cs
using System.Drawing;
using Aspose.Slides;
using Aspose.Slides.Export;

using (var presentation = new Presentation("sample.pptx"))
{
    var autoShape = (IAutoShape)presentation.Slides[0].Shapes[0];
    var paragraph = autoShape.TextFrame.Paragraphs[0];

    foreach (var portion in paragraph.Portions)
    {
        if (portion.PortionFormat.GetEffective().FontBold)
        {
            // Set the highlight color for the text portion.
            portion.PortionFormat.HighlightColor.Color = Color.LightGray;
        }
    }

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

The result:

![The gray text portions](gray_text_portions.png)

## **Align Text Paragraphs**

Use [IParagraphFormat.Alignment](https://reference.aspose.com/slides/net/aspose.slides/iparagraphformat/alignment/) to set paragraph alignment within a text frame. The value can be centered, left-aligned, right-aligned, justified, and so on.

The following code example shows how to align the paragraph to the **center**:

```cs
using Aspose.Slides;
using Aspose.Slides.Export;

using (var presentation = new Presentation("sample.pptx"))
{
    var autoShape = (IAutoShape)presentation.Slides[0].Shapes[0];
    var paragraph = autoShape.TextFrame.Paragraphs[0];

    // Set the alignment of the paragraph to center.
    paragraph.ParagraphFormat.Alignment = TextAlignment.Center;

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

The result:

![The aligned paragraph](aligned_paragraph.png)

## **Set Transparency for Text**

Text transparency is controlled through the alpha component of the color assigned to [IBasePortionFormat.FillFormat](https://reference.aspose.com/slides/net/aspose.slides/ibaseportionformat/fillformat/). In the examples below, `alpha = 50` is an ARGB alpha-channel value on the 0–255 scale, not a transparency percentage.

The code example below shows how to apply transparency to the **entire paragraph**:

```cs
using System.Drawing;
using Aspose.Slides;
using Aspose.Slides.Export;

int alpha = 50;

using (var presentation = new Presentation("sample.pptx"))
{
    var autoShape = (IAutoShape)presentation.Slides[0].Shapes[0];
    var paragraph = autoShape.TextFrame.Paragraphs[0];

    // Set the fill color of the text to transparent color.
    paragraph.ParagraphFormat.DefaultPortionFormat.FillFormat.FillType = FillType.Solid;
    paragraph.ParagraphFormat.DefaultPortionFormat.FillFormat.SolidFillColor.Color = Color.FromArgb(alpha, Color.Black);

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

The result:

![The transparent paragraph](transparent_paragraph.png)

The following code example shows how to apply transparency to **text portions with a bold font**:

```cs
using System.Drawing;
using Aspose.Slides;
using Aspose.Slides.Export;

int alpha = 50;

using (var presentation = new Presentation("sample.pptx"))
{
    var autoShape = (IAutoShape)presentation.Slides[0].Shapes[0];
    var paragraph = autoShape.TextFrame.Paragraphs[0];

    foreach (var portion in paragraph.Portions)
    {
        if (portion.PortionFormat.GetEffective().FontBold)
        {
            // Set the transparency of the text portion.
            portion.PortionFormat.FillFormat.FillType = FillType.Solid;
            portion.PortionFormat.FillFormat.SolidFillColor.Color = Color.FromArgb(alpha, Color.Black);
        }
    }

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

The result:

![The transparent text portions](transparent_text_portions.png)

## **Set Character Spacing for Text**

Use [IBasePortionFormat.Spacing](https://reference.aspose.com/slides/net/aspose.slides/ibaseportionformat/spacing/) to expand or condense spacing between characters in a text box.

The following C# code shows how to expand the character spacing in the **entire paragraph**:

```cs
using Aspose.Slides;
using Aspose.Slides.Export;

using (var presentation = new Presentation("sample.pptx"))
{
    var autoShape = (IAutoShape)presentation.Slides[0].Shapes[0];
    var paragraph = autoShape.TextFrame.Paragraphs[0];

    // Note: Use negative values to compress the character spacing.
    paragraph.ParagraphFormat.DefaultPortionFormat.Spacing = 3;  // Expand character spacing.

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

The result:

![The character spacing in the paragraph](character_spacing_in_paragraph.png)

The code example below shows how to expand the character spacing in **text portions with a bold font**:

```cs
using Aspose.Slides;
using Aspose.Slides.Export;

using (var presentation = new Presentation("sample.pptx"))
{
    var autoShape = (IAutoShape)presentation.Slides[0].Shapes[0];
    var paragraph = autoShape.TextFrame.Paragraphs[0];

    foreach (var portion in paragraph.Portions)
    {
        if (portion.PortionFormat.GetEffective().FontBold)
        {
            // Note: Use negative values to compress the character spacing.
            portion.PortionFormat.Spacing = 3;  // Expand character spacing.
        }
    }

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

The result:

![The character spacing in the text portions](character_spacing_in_text_portions.png)

### **Disable Kerning for Specific Fonts**

In some cases, text rendered by Aspose.Slides may look slightly tighter than the same text displayed in PowerPoint. This can happen because PowerPoint may ignore kerning data for certain fonts, even when the font contains valid kerning information and kerning is enabled in PowerPoint settings.

To make the rendered output closer to PowerPoint in such cases, you can disable kerning for text portions that use the affected font. Set [IBasePortionFormat.KerningMinimalSize](https://reference.aspose.com/slides/net/aspose.slides/ibaseportionformat/kerningminimalsize/) to a value significantly larger than the actual font size:

```cs
using Aspose.Slides;
using Aspose.Slides.Export;

using (var presentation = new Presentation("presentation.pptx"))
{
    var autoShape = (IAutoShape)presentation.Slides[0].Shapes[0];
    var targetFont = "Roboto";

    foreach (var paragraph in autoShape.TextFrame.Paragraphs)
    {
        foreach (var portion in paragraph.Portions)
        {
            if ((portion.PortionFormat.LatinFont != null &&
                 portion.PortionFormat.LatinFont.FontName == targetFont) ||
                (portion.PortionFormat.EastAsianFont != null &&
                 portion.PortionFormat.EastAsianFont.FontName == targetFont) ||
                (portion.PortionFormat.ComplexScriptFont != null &&
                 portion.PortionFormat.ComplexScriptFont.FontName == targetFont))
            {
                portion.PortionFormat.KerningMinimalSize = 100;
            }
        }
    }

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

This setting prevents kerning from being applied to matching text portions and can help align Aspose.Slides rendering with PowerPoint’s visual output for fonts affected by this PowerPoint-specific behavior.

## **Manage Text Font Properties**

Font properties can be set at the paragraph level through [IParagraphFormat.DefaultPortionFormat](https://reference.aspose.com/slides/net/aspose.slides/iparagraphformat/defaultportionformat/) or on individual portions through [IPortionFormat](https://reference.aspose.com/slides/net/aspose.slides/iportionformat/).

The following code sets the font and text style for the entire paragraph: it applies font size, bold, italic, dotted underline, and the Times New Roman font to all portions in the paragraph.

```cs
using Aspose.Slides;
using Aspose.Slides.Export;

using (var presentation = new Presentation("sample.pptx"))
{
    var autoShape = (IAutoShape)presentation.Slides[0].Shapes[0];
    var paragraph = autoShape.TextFrame.Paragraphs[0];

    // Set the font properties for the paragraph.
    paragraph.ParagraphFormat.DefaultPortionFormat.FontHeight = 12;
    paragraph.ParagraphFormat.DefaultPortionFormat.FontBold = NullableBool.True;
    paragraph.ParagraphFormat.DefaultPortionFormat.FontItalic = NullableBool.True;
    paragraph.ParagraphFormat.DefaultPortionFormat.FontUnderline = TextUnderlineType.Dotted;
    paragraph.ParagraphFormat.DefaultPortionFormat.LatinFont = new FontData("Times New Roman");

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

The result:

![The font properties for the paragraph](font_properties_for_paragraph.png)

The code example below applies similar properties to **text portions with a bold font**:

```cs
using Aspose.Slides;
using Aspose.Slides.Export;

using (var presentation = new Presentation("sample.pptx"))
{
    var autoShape = (IAutoShape)presentation.Slides[0].Shapes[0];
    var paragraph = autoShape.TextFrame.Paragraphs[0];

    foreach (var portion in paragraph.Portions)
    {
        if (portion.PortionFormat.GetEffective().FontBold)
        {
            // Set the font properties for the text portion.
            portion.PortionFormat.FontHeight = 13;
            portion.PortionFormat.FontItalic = NullableBool.True;
            portion.PortionFormat.FontUnderline = TextUnderlineType.Dotted;
            portion.PortionFormat.LatinFont = new FontData("Times New Roman");
        }
    }

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

The result:

![The font properties for text portions](font_properties_for_text_portions.png)

## **Set Text Rotation**

Use [ITextFrameFormat.TextVerticalType](https://reference.aspose.com/slides/net/aspose.slides/itextframeformat/textverticaltype/) to set a predefined text orientation within a shape.

The following code example sets the text orientation in the shape to `Vertical270`, which rotates the text **90 degrees counterclockwise**:

```cs
using Aspose.Slides;
using Aspose.Slides.Export;

using (var presentation = new Presentation("sample.pptx"))
{
    var autoShape = (IAutoShape)presentation.Slides[0].Shapes[0];

    autoShape.TextFrame.TextFrameFormat.TextVerticalType = TextVerticalType.Vertical270;

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

The result:

![The text rotation](text_rotation.png)

## **Set Custom Rotation for Text Frames**

Use [ITextFrameFormat.RotationAngle](https://reference.aspose.com/slides/net/aspose.slides/itextframeformat/rotationangle/) to set a custom rotation angle for an [ITextFrame](https://reference.aspose.com/slides/net/aspose.slides/itextframe/).

The code example below rotates the text frame by 3 degrees clockwise within the shape: 

```cs
using Aspose.Slides;
using Aspose.Slides.Export;

using (var presentation = new Presentation("sample.pptx"))
{
    var autoShape = (IAutoShape)presentation.Slides[0].Shapes[0];

    autoShape.TextFrame.TextFrameFormat.RotationAngle = 3;

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

The result:

![The custom text rotation](custom_text_rotation.png)

## **Set Line Spacing of Paragraphs**

Aspose.Slides provides [IParagraphFormat.SpaceAfter](https://reference.aspose.com/slides/net/aspose.slides/iparagraphformat/spaceafter/), [IParagraphFormat.SpaceBefore](https://reference.aspose.com/slides/net/aspose.slides/iparagraphformat/spacebefore/), and [IParagraphFormat.SpaceWithin](https://reference.aspose.com/slides/net/aspose.slides/iparagraphformat/spacewithin/) to control paragraph spacing. These properties are used as follows:

* Use a positive value to specify line spacing as a percentage of the line height.
* Use a negative value to specify line spacing in points.

The following code example shows how to specify the line spacing within the paragraph:

```cs
using Aspose.Slides;
using Aspose.Slides.Export;

using (var presentation = new Presentation("sample.pptx"))
{
    var autoShape = (IAutoShape)presentation.Slides[0].Shapes[0];
    var paragraph = autoShape.TextFrame.Paragraphs[0];

    paragraph.ParagraphFormat.SpaceWithin = 200;

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

The result:

![The line spacing within the paragraph](line_spacing.png)

## **Set Autofit Type for Text Frames**

[ITextFrameFormat.AutofitType](https://reference.aspose.com/slides/net/aspose.slides/itextframeformat/autofittype/) determines how text behaves when it exceeds the boundaries of its container. Use it to control whether the text shrinks, overflows, or resizes the shape automatically.

```cs
using Aspose.Slides;
using Aspose.Slides.Export;

using (var presentation = new Presentation("sample.pptx"))
{
    var autoShape = (IAutoShape)presentation.Slides[0].Shapes[0];

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

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

## **Set Anchor of Text Frames**

[ITextFrameFormat.AnchoringType](https://reference.aspose.com/slides/net/aspose.slides/itextframeformat/anchoringtype/) defines how text is positioned vertically inside a shape, for example at the top, middle, or bottom.

```cs
using Aspose.Slides;
using Aspose.Slides.Export;

using (var presentation = new Presentation("sample.pptx"))
{
    var autoShape = (IAutoShape)presentation.Slides[0].Shapes[0];

    autoShape.TextFrame.TextFrameFormat.AnchoringType = TextAnchorType.Bottom;

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

## **Set Text Tabulation**

Use [IParagraphFormat.DefaultTabSize](https://reference.aspose.com/slides/net/aspose.slides/iparagraphformat/defaulttabsize/) and [IParagraphFormat.Tabs](https://reference.aspose.com/slides/net/aspose.slides/iparagraphformat/tabs/) to configure tab stops in a paragraph.

```cs
using Aspose.Slides;
using Aspose.Slides.Export;

using (var presentation = new Presentation("sample.pptx"))
{
    var autoShape = (IAutoShape)presentation.Slides[0].Shapes[0];
    var paragraph = autoShape.TextFrame.Paragraphs[0];

    paragraph.ParagraphFormat.DefaultTabSize = 100;
    paragraph.ParagraphFormat.Tabs.Add(30, TabAlignment.Left);

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

The result:

![The paragraph tabs](paragraph_tabs.png)

## **Set Proofing Language**

Aspose.Slides provides [IBasePortionFormat.LanguageId](https://reference.aspose.com/slides/net/aspose.slides/ibaseportionformat/languageid/), which allows you to set the proofing language for a text portion. The proofing language determines the language used for spelling and grammar checks in PowerPoint.

The following code example shows how to set the proofing language for a text portion:

```cs
using Aspose.Slides;
using Aspose.Slides.Export;

using (var presentation = new Presentation("presentation.pptx"))
{
    var autoShape = (IAutoShape)presentation.Slides[0].Shapes[0];

    var paragraph = autoShape.TextFrame.Paragraphs[0];
    paragraph.Portions.Clear();

    var font = new FontData("SimSun");

    var textPortion = new Portion();
    textPortion.PortionFormat.ComplexScriptFont = font;
    textPortion.PortionFormat.EastAsianFont = font;
    textPortion.PortionFormat.LatinFont = font;

    // Set the Id of a proofing language.
    textPortion.PortionFormat.LanguageId = "zh-CN";

    textPortion.Text = "1。";
    paragraph.Portions.Add(textPortion);

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

## **Set Default Language**

Use [LoadOptions.DefaultTextLanguage](https://reference.aspose.com/slides/net/aspose.slides/loadoptions/defaulttextlanguage/) to define the default language for text created while loading or creating a presentation.

```cs
using Aspose.Slides;

var loadOptions = new LoadOptions();
loadOptions.DefaultTextLanguage = "en-US";

using (var presentation = new Presentation(loadOptions))
{
    var slide = presentation.Slides[0];

    // Add a new rectangle shape with text.
    var shape = slide.Shapes.AddAutoShape(ShapeType.Rectangle, 20, 20, 150, 50);
    shape.TextFrame.Text = "Sample text";

    // Check the first portion language.
    var portion = shape.TextFrame.Paragraphs[0].Portions[0];
    Console.WriteLine(portion.PortionFormat.LanguageId);
}
```

## **Set Default Text Style**

To apply default text formatting at the presentation level, use [IPresentation.DefaultTextStyle](https://reference.aspose.com/slides/net/aspose.slides/ipresentation/defaulttextstyle/).

The following code example shows how to set a default bold font with a 14 pt size for all text across slides in a new presentation.

```cs
using Aspose.Slides;
using Aspose.Slides.Export;

using (var presentation = new Presentation())
{
    // Get the top level paragraph format.
    var paragraphFormat = presentation.DefaultTextStyle.GetLevel(0);

    if (paragraphFormat != null)
    {
        paragraphFormat.DefaultPortionFormat.FontHeight = 14;
        paragraphFormat.DefaultPortionFormat.FontBold = NullableBool.True;
    }

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

## **Extract Text with the All-Caps Effect**

In PowerPoint, applying the **All Caps** font effect makes text appear in uppercase on the slide even when it was originally typed in lowercase. When you retrieve such a text portion with Aspose.Slides, the library returns the text exactly as it was entered. To match the displayed text, check [TextCapType](https://reference.aspose.com/slides/net/aspose.slides/textcaptype/) and convert the returned string to uppercase when the value is `All`.

Let’s say we have the following text box on the first slide of the sample2.pptx file.

![The All Caps effect](all_caps_effect.png)

The code example below shows how to extract the text with the **All Caps** effect applied:

```cs
using Aspose.Slides;

using (var presentation = new Presentation("sample2.pptx"))
{
    var autoShape = (IAutoShape)presentation.Slides[0].Shapes[0];
    var textPortion = autoShape.TextFrame.Paragraphs[0].Portions[0];

    Console.WriteLine($"Original text: {textPortion.Text}");

    var textFormat = textPortion.PortionFormat.GetEffective();
    if (textFormat.TextCapType == TextCapType.All)
    {
        var text = textPortion.Text.ToUpper();
        Console.WriteLine($"All-Caps effect: {text}");
    }
}
```

Output:

```text
Original text: Hello, Aspose!
All-Caps effect: HELLO, ASPOSE!
```

## **FAQ**

**How to modify text in a table on a slide?**

To modify text in a table on a slide, use [ITable](https://reference.aspose.com/slides/net/aspose.slides/itable/). Iterate through the cells and update each cell through [ICell.TextFrame](https://reference.aspose.com/slides/net/aspose.slides/icell/textframe/) and paragraph formatting through [IParagraph.ParagraphFormat](https://reference.aspose.com/slides/net/aspose.slides/iparagraph/paragraphformat/).

**How to apply gradient color to text in a PowerPoint slide?**

To apply a gradient color to text, use [IBasePortionFormat.FillFormat](https://reference.aspose.com/slides/net/aspose.slides/ibaseportionformat/fillformat/). Set [IFillFormat.FillType](https://reference.aspose.com/slides/net/aspose.slides/ifillformat/filltype/) to [FillType.Gradient](https://reference.aspose.com/slides/net/aspose.slides/filltype/) and configure the gradient stops, direction, and transparency.