Format Presentation Text in C++

Overview

This article shows how to format text in PowerPoint and OpenDocument presentations using Aspose.Slides for C++. It covers highlighting, 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:

Highlight Text

Use the ITextFrame.HighlightText method when you need to highlight text that matches a specific sample within a text frame. The method applies a highlight color to matching text fragments and can be used with ITextSearchOptions to control how the search is performed, for example, to match only whole words.

The code example below highlights all occurrences of the characters “try” and then highlights only the full word “to”.

auto presentation = System::MakeObject<Presentation>(u"sample.pptx");

// Get the first shape from the first slide.
auto shape = System::ExplicitCast<IAutoShape>(presentation->get_Slide(0)->get_Shape(0));

// Highlight the word "try" in the shape.
shape->get_TextFrame()->HighlightText(u"try", System::Drawing::Color::get_LightBlue());

auto searchOptions = System::MakeObject<TextSearchOptions>();
searchOptions->set_WholeWordsOnly(true);

// Highlight the word "to" in the shape.
shape->get_TextFrame()->HighlightText(u"to", System::Drawing::Color::get_Violet(), searchOptions, nullptr);

presentation->Save(u"highlighted_text.pptx", SaveFormat::Pptx);
presentation->Dispose();

The result:

Highlight Text Using Regular Expressions

The ITextFrame.HighlightRegex method highlights text matches found by a regular expression. In C++, this API is exposed on ITextFrame.

The code example below highlights all words that contain seven or more characters:

auto presentation = System::MakeObject<Presentation>(u"sample.pptx");
auto shape = System::ExplicitCast<IAutoShape>(presentation->get_Slide(0)->get_Shape(0));

auto regex = System::MakeObject<System::Text::RegularExpressions::Regex>(u"\\b[^\\s]{7,}\\b");

// Highlight all words with seven or more characters.
shape->get_TextFrame()->HighlightRegex(regex, System::Drawing::Color::get_Yellow(), nullptr);

presentation->Save(u"highlighted_text_using_regex.pptx", SaveFormat::Pptx);
presentation->Dispose();

The result:

Set Text Background Color

Use IParagraphFormat.DefaultPortionFormat to set the default highlight color for a paragraph, or use IPortionFormat.HighlightColor for individual text portions.

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

auto presentation = System::MakeObject<Presentation>(u"sample.pptx");

auto autoShape = System::ExplicitCast<IAutoShape>(presentation->get_Slide(0)->get_Shape(0));
auto paragraph = autoShape->get_TextFrame()->get_Paragraph(0);

// Set the highlight color for the entire paragraph.
paragraph->get_ParagraphFormat()->get_DefaultPortionFormat()->get_HighlightColor()->set_Color(System::Drawing::Color::get_LightGray());

presentation->Save(u"gray_paragraph.pptx", SaveFormat::Pptx);
presentation->Dispose();

The result:

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

auto presentation = System::MakeObject<Presentation>(u"sample.pptx");

auto autoShape = System::ExplicitCast<IAutoShape>(presentation->get_Slide(0)->get_Shape(0));
auto paragraph = autoShape->get_TextFrame()->get_Paragraph(0);
auto portions = paragraph->get_Portions();
int portionCount = portions->get_Count();

for (int portionIndex = 0; portionIndex < portionCount; portionIndex++)
{
    auto portion = portions->idx_get(portionIndex);
    if (portion->get_PortionFormat()->GetEffective()->get_FontBold())
    {
        // Set the highlight color for the text portion.
        portion->get_PortionFormat()->get_HighlightColor()->set_Color(System::Drawing::Color::get_LightGray());
    }
}

presentation->Save(u"gray_text_portions.pptx", SaveFormat::Pptx);
presentation->Dispose();

The result:

Align Text Paragraphs

Use 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:

auto presentation = System::MakeObject<Presentation>(u"sample.pptx");

auto autoShape = System::ExplicitCast<IAutoShape>(presentation->get_Slide(0)->get_Shape(0));
auto paragraph = autoShape->get_TextFrame()->get_Paragraph(0);

// Set the alignment of the paragraph to center.
paragraph->get_ParagraphFormat()->set_Alignment(TextAlignment::Center);

presentation->Save(u"aligned_paragraph.pptx", SaveFormat::Pptx);
presentation->Dispose();

The result:

Set Transparency for Text

Text transparency is controlled through the alpha component of the color assigned to IPortionFormat.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:

int alpha = 50;

auto presentation = System::MakeObject<Presentation>(u"sample.pptx");

auto autoShape = System::ExplicitCast<IAutoShape>(presentation->get_Slide(0)->get_Shape(0));
auto paragraph = autoShape->get_TextFrame()->get_Paragraph(0);
auto defaultPortionFormat = paragraph->get_ParagraphFormat()->get_DefaultPortionFormat();

// Set the fill color of the text to transparent color.
defaultPortionFormat->get_FillFormat()->set_FillType(FillType::Solid);
auto transparentColor = System::Drawing::Color::FromArgb(alpha, System::Drawing::Color::get_Black());
defaultPortionFormat->get_FillFormat()->get_SolidFillColor()->set_Color(transparentColor);

presentation->Save(u"transparent_paragraph.pptx", SaveFormat::Pptx);
presentation->Dispose();

The result:

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

int alpha = 50;

auto presentation = System::MakeObject<Presentation>(u"sample.pptx");

auto autoShape = System::ExplicitCast<IAutoShape>(presentation->get_Slide(0)->get_Shape(0));
auto paragraph = autoShape->get_TextFrame()->get_Paragraph(0);
auto portions = paragraph->get_Portions();
int portionCount = portions->get_Count();

for (int portionIndex = 0; portionIndex < portionCount; portionIndex++)
{
    auto portion = portions->idx_get(portionIndex);
    if (portion->get_PortionFormat()->GetEffective()->get_FontBold())
    {
        // Set the transparency of the text portion.
        portion->get_PortionFormat()->get_FillFormat()->set_FillType(FillType::Solid);
        auto transparentColor = System::Drawing::Color::FromArgb(alpha, System::Drawing::Color::get_Black());
        portion->get_PortionFormat()->get_FillFormat()->get_SolidFillColor()->set_Color(transparentColor);
    }
}

presentation->Save(u"transparent_text_portions.pptx", SaveFormat::Pptx);
presentation->Dispose();

The result:

Set Character Spacing for Text

Use 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:

auto presentation = System::MakeObject<Presentation>(u"sample.pptx");

auto autoShape = System::ExplicitCast<IAutoShape>(presentation->get_Slide(0)->get_Shape(0));
auto paragraph = autoShape->get_TextFrame()->get_Paragraph(0);

// Note: Use negative values to compress the character spacing.
paragraph->get_ParagraphFormat()->get_DefaultPortionFormat()->set_Spacing(3.0f);

presentation->Save(u"character_spacing_in_paragraph.pptx", SaveFormat::Pptx);
presentation->Dispose();

The result:

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

auto presentation = System::MakeObject<Presentation>(u"sample.pptx");

auto autoShape = System::ExplicitCast<IAutoShape>(presentation->get_Slide(0)->get_Shape(0));
auto paragraph = autoShape->get_TextFrame()->get_Paragraph(0);
auto portions = paragraph->get_Portions();
int portionCount = portions->get_Count();

for (int portionIndex = 0; portionIndex < portionCount; portionIndex++)
{
    auto portion = portions->idx_get(portionIndex);
    if (portion->get_PortionFormat()->GetEffective()->get_FontBold())
    {
        // Note: Use negative values to compress the character spacing.
        portion->get_PortionFormat()->set_Spacing(3.0f);
    }
}

presentation->Save(u"character_spacing_in_text_portions.pptx", SaveFormat::Pptx);
presentation->Dispose();

The result:

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 IPortionFormat.KerningMinimalSize to a value significantly larger than the actual font size:

auto presentation = System::MakeObject<Presentation>(u"presentation.pptx");

auto autoShape = System::ExplicitCast<IAutoShape>(presentation->get_Slide(0)->get_Shape(0));
System::String targetFont = u"Roboto";
auto paragraphs = autoShape->get_TextFrame()->get_Paragraphs();
int paragraphCount = paragraphs->get_Count();

for (int paragraphIndex = 0; paragraphIndex < paragraphCount; paragraphIndex++)
{
    auto paragraph = paragraphs->idx_get(paragraphIndex);
    auto portions = paragraph->get_Portions();
    int portionCount = portions->get_Count();

    for (int portionIndex = 0; portionIndex < portionCount; portionIndex++)
    {
        auto portion = portions->idx_get(portionIndex);
        auto portionFormat = portion->get_PortionFormat();
        auto latinFont = portionFormat->get_LatinFont();
        auto eastAsianFont = portionFormat->get_EastAsianFont();
        auto complexScriptFont = portionFormat->get_ComplexScriptFont();

        bool isLatinFont = latinFont != nullptr && latinFont->get_FontName() == targetFont;
        bool isEastAsianFont = eastAsianFont != nullptr && eastAsianFont->get_FontName() == targetFont;
        bool isComplexScriptFont = complexScriptFont != nullptr && complexScriptFont->get_FontName() == targetFont;

        if (isLatinFont || isEastAsianFont || isComplexScriptFont)
        {
            portionFormat->set_KerningMinimalSize(100.0f);
        }
    }
}

presentation->Save(u"output.pptx", SaveFormat::Pptx);
presentation->Dispose();

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 or on individual portions through 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.

auto presentation = System::MakeObject<Presentation>(u"sample.pptx");

auto autoShape = System::ExplicitCast<IAutoShape>(presentation->get_Slide(0)->get_Shape(0));
auto paragraph = autoShape->get_TextFrame()->get_Paragraph(0);
auto defaultPortionFormat = paragraph->get_ParagraphFormat()->get_DefaultPortionFormat();

// Set the font properties for the paragraph.
defaultPortionFormat->set_FontHeight(12.0f);
defaultPortionFormat->set_FontBold(NullableBool::True);
defaultPortionFormat->set_FontItalic(NullableBool::True);
defaultPortionFormat->set_FontUnderline(TextUnderlineType::Dotted);
defaultPortionFormat->set_LatinFont(System::MakeObject<FontData>(u"Times New Roman"));

presentation->Save(u"font_properties_for_paragraph.pptx", SaveFormat::Pptx);
presentation->Dispose();

The result:

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

auto presentation = System::MakeObject<Presentation>(u"sample.pptx");

auto autoShape = System::ExplicitCast<IAutoShape>(presentation->get_Slide(0)->get_Shape(0));
auto paragraph = autoShape->get_TextFrame()->get_Paragraph(0);
auto portions = paragraph->get_Portions();
int portionCount = portions->get_Count();

for (int portionIndex = 0; portionIndex < portionCount; portionIndex++)
{
    auto portion = portions->idx_get(portionIndex);
    if (portion->get_PortionFormat()->GetEffective()->get_FontBold())
    {
        // Set the font properties for the text portion.
        portion->get_PortionFormat()->set_FontHeight(13.0f);
        portion->get_PortionFormat()->set_FontItalic(NullableBool::True);
        portion->get_PortionFormat()->set_FontUnderline(TextUnderlineType::Dotted);
        portion->get_PortionFormat()->set_LatinFont(System::MakeObject<FontData>(u"Times New Roman"));
    }
}

presentation->Save(u"font_properties_for_text_portions.pptx", SaveFormat::Pptx);
presentation->Dispose();

The result:

Set Text Rotation

Use 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:

auto presentation = System::MakeObject<Presentation>(u"sample.pptx");

auto autoShape = System::ExplicitCast<IAutoShape>(presentation->get_Slide(0)->get_Shape(0));

autoShape->get_TextFrame()->get_TextFrameFormat()->set_TextVerticalType(TextVerticalType::Vertical270);

presentation->Save(u"text_rotation.pptx", SaveFormat::Pptx);
presentation->Dispose();

The result:

Set Custom Rotation for Text Frames

Use ITextFrameFormat.RotationAngle to set a custom rotation angle for an ITextFrame.

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

auto presentation = System::MakeObject<Presentation>(u"sample.pptx");

auto autoShape = System::ExplicitCast<IAutoShape>(presentation->get_Slide(0)->get_Shape(0));

autoShape->get_TextFrame()->get_TextFrameFormat()->set_RotationAngle(3.0f);

presentation->Save(u"custom_text_rotation.pptx", SaveFormat::Pptx);
presentation->Dispose();

The result:

Set Line Spacing of Paragraphs

Aspose.Slides provides IParagraphFormat.SpaceAfter, IParagraphFormat.SpaceBefore, and 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:

auto presentation = System::MakeObject<Presentation>(u"sample.pptx");

auto autoShape = System::ExplicitCast<IAutoShape>(presentation->get_Slide(0)->get_Shape(0));
auto paragraph = autoShape->get_TextFrame()->get_Paragraph(0);

paragraph->get_ParagraphFormat()->set_SpaceWithin(200.0f);

presentation->Save(u"line_spacing.pptx", SaveFormat::Pptx);
presentation->Dispose();

The result:

Set Autofit Type for Text Frames

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.

auto presentation = System::MakeObject<Presentation>(u"sample.pptx");

auto autoShape = System::ExplicitCast<IAutoShape>(presentation->get_Slide(0)->get_Shape(0));

autoShape->get_TextFrame()->get_TextFrameFormat()->set_AutofitType(TextAutofitType::Shape);

presentation->Save(u"autofit_type.pptx", SaveFormat::Pptx);
presentation->Dispose();

Set Anchor of Text Frames

ITextFrameFormat.AnchoringType defines how text is positioned vertically inside a shape, for example at the top, middle, or bottom.

auto presentation = System::MakeObject<Presentation>(u"sample.pptx");

auto autoShape = System::ExplicitCast<IAutoShape>(presentation->get_Slide(0)->get_Shape(0));

autoShape->get_TextFrame()->get_TextFrameFormat()->set_AnchoringType(TextAnchorType::Bottom);

presentation->Save(u"text_anchor.pptx", SaveFormat::Pptx);
presentation->Dispose();

Set Text Tabulation

Use IParagraphFormat.DefaultTabSize and IParagraphFormat.Tabs to configure tab stops in a paragraph.

auto presentation = System::MakeObject<Presentation>(u"sample.pptx");

auto autoShape = System::ExplicitCast<IAutoShape>(presentation->get_Slide(0)->get_Shape(0));
auto paragraph = autoShape->get_TextFrame()->get_Paragraph(0);

paragraph->get_ParagraphFormat()->set_DefaultTabSize(100.0f);
paragraph->get_ParagraphFormat()->get_Tabs()->Add(30.0f, TabAlignment::Left);

presentation->Save(u"paragraph_tabs.pptx", SaveFormat::Pptx);
presentation->Dispose();

The result:

Set Proofing Language

Aspose.Slides provides IPortionFormat.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:

auto presentation = System::MakeObject<Presentation>(u"presentation.pptx");

auto autoShape = System::ExplicitCast<IAutoShape>(presentation->get_Slide(0)->get_Shape(0));

auto paragraph = autoShape->get_TextFrame()->get_Paragraph(0);
paragraph->get_Portions()->Clear();

auto font = System::MakeObject<FontData>(u"SimSun");

auto textPortion = System::MakeObject<Portion>();
textPortion->get_PortionFormat()->set_ComplexScriptFont(font);
textPortion->get_PortionFormat()->set_EastAsianFont(font);
textPortion->get_PortionFormat()->set_LatinFont(font);

// Set the Id of a proofing language.
textPortion->get_PortionFormat()->set_LanguageId(u"zh-CN");

textPortion->set_Text(u"1.");
paragraph->get_Portions()->Add(textPortion);

presentation->Save(u"proofing_language.pptx", SaveFormat::Pptx);
presentation->Dispose();

Set Default Language

Use ILoadOptions.DefaultTextLanguage to define the default language for text created while loading or creating a presentation.

auto loadOptions = System::MakeObject<LoadOptions>();
loadOptions->set_DefaultTextLanguage(u"en-US");

auto presentation = System::MakeObject<Presentation>(loadOptions);
auto slide = presentation->get_Slide(0);

// Add a new rectangle shape with text.
auto shape = slide->get_Shapes()->AddAutoShape(ShapeType::Rectangle, 20.0f, 20.0f, 150.0f, 50.0f);
shape->get_TextFrame()->set_Text(u"Sample text");

// Check the first portion language.
auto portion = shape->get_TextFrame()->get_Paragraph(0)->get_Portion(0);
System::Console::WriteLine(portion->get_PortionFormat()->get_LanguageId());

presentation->Dispose();

Set Default Text Style

To apply default text formatting at the presentation level, use 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.

auto presentation = System::MakeObject<Presentation>();

// Get the top level paragraph format.
auto paragraphFormat = presentation->get_DefaultTextStyle()->GetLevel(0);

if (paragraphFormat != nullptr)
{
    paragraphFormat->get_DefaultPortionFormat()->set_FontHeight(14.0f);
    paragraphFormat->get_DefaultPortionFormat()->set_FontBold(NullableBool::True);
}

presentation->Save(u"default_text_style.pptx", SaveFormat::Pptx);
presentation->Dispose();

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

auto presentation = System::MakeObject<Presentation>(u"sample2.pptx");

auto autoShape = System::ExplicitCast<IAutoShape>(presentation->get_Slide(0)->get_Shape(0));
auto textPortion = autoShape->get_TextFrame()->get_Paragraph(0)->get_Portion(0);

System::Console::WriteLine(u"Original text: " + textPortion->get_Text());

auto textFormat = textPortion->get_PortionFormat()->GetEffective();
if (textFormat->get_TextCapType() == TextCapType::All)
{
    auto text = textPortion->get_Text().ToUpper();
    System::Console::WriteLine(u"All-Caps effect: " + text);
}

presentation->Dispose();

Output:

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. Iterate through the cells and update each cell through ICell.TextFrame and paragraph formatting through IParagraph.ParagraphFormat.

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

To apply a gradient color to text, use IPortionFormat.FillFormat. Set IFillFormat.FillType to FillType.Gradient and configure the gradient stops, direction, and transparency.