Format Presentation Text in Python

Overview

This article shows how to format text in PowerPoint and OpenDocument presentations using Aspose.Slides for Python via .NET. 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 TextFrame.highlight_text 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 TextSearchOptions 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”.

import aspose.pydrawing as draw
import aspose.slides as slides

with slides.Presentation("sample.pptx") as presentation:
    # Get the first shape from the first slide.
    shape = presentation.slides[0].shapes[0]

    # Highlight the word "try" in the shape.
    shape.text_frame.highlight_text("try", draw.Color.light_blue)

    search_options = slides.TextSearchOptions()
    search_options.whole_words_only = True

    # Highlight the word "to" in the shape.
    shape.text_frame.highlight_text("to", draw.Color.violet, search_options, None)

    presentation.save("highlighted_text.pptx", slides.export.SaveFormat.PPTX)

The result:

Highlight Text Using Regular Expressions

The TextFrame.highlight_regex method highlights text matches found by a regular expression. In Python, this API is exposed on TextFrame.

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

import aspose.pydrawing as draw
import aspose.slides as slides

with slides.Presentation("sample.pptx") as presentation:
    shape = presentation.slides[0].shapes[0]

    regex = r"\b[^\s]{7,}\b"

    # Highlight all words with seven or more characters.
    shape.text_frame.highlight_regex(regex, draw.Color.yellow, None)

    presentation.save("highlighted_text_using_regex.pptx", slides.export.SaveFormat.PPTX)

The result:

Set Text Background Color

Use ParagraphFormat.default_portion_format to set the default highlight color for a paragraph, or use PortionFormat.highlight_color for individual text portions.

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

import aspose.pydrawing as draw
import aspose.slides as slides

with slides.Presentation("sample.pptx") as presentation:
    auto_shape = presentation.slides[0].shapes[0]
    paragraph = auto_shape.text_frame.paragraphs[0]

    # Set the highlight color for the entire paragraph.
    paragraph.paragraph_format.default_portion_format.highlight_color.color = draw.Color.light_gray

    presentation.save("gray_paragraph.pptx", slides.export.SaveFormat.PPTX)

The result:

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

import aspose.pydrawing as draw
import aspose.slides as slides

with slides.Presentation("sample.pptx") as presentation:
    auto_shape = presentation.slides[0].shapes[0]
    paragraph = auto_shape.text_frame.paragraphs[0]

    for portion in paragraph.portions:
        if portion.portion_format.get_effective().font_bold:
            # Set the highlight color for the text portion.
            portion.portion_format.highlight_color.color = draw.Color.light_gray

    presentation.save("gray_text_portions.pptx", slides.export.SaveFormat.PPTX)

The result:

Align Text Paragraphs

Use ParagraphFormat.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:

import aspose.slides as slides

with slides.Presentation("sample.pptx") as presentation:
    auto_shape = presentation.slides[0].shapes[0]
    paragraph = auto_shape.text_frame.paragraphs[0]

    # Set the alignment of the paragraph to center.
    paragraph.paragraph_format.alignment = slides.TextAlignment.CENTER

    presentation.save("aligned_paragraph.pptx", slides.export.SaveFormat.PPTX)

The result:

Set Transparency for Text

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

import aspose.pydrawing as draw
import aspose.slides as slides

alpha = 50

with slides.Presentation("sample.pptx") as presentation:
    auto_shape = presentation.slides[0].shapes[0]
    paragraph = auto_shape.text_frame.paragraphs[0]

    # Set the fill color of the text to transparent color.
    paragraph.paragraph_format.default_portion_format.fill_format.fill_type = slides.FillType.SOLID
    paragraph.paragraph_format.default_portion_format.fill_format.solid_fill_color.color = draw.Color.from_argb(alpha, draw.Color.black)

    presentation.save("transparent_paragraph.pptx", slides.export.SaveFormat.PPTX)

The result:

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

import aspose.pydrawing as draw
import aspose.slides as slides

alpha = 50

with slides.Presentation("sample.pptx") as presentation:
    auto_shape = presentation.slides[0].shapes[0]
    paragraph = auto_shape.text_frame.paragraphs[0]

    for portion in paragraph.portions:
        if portion.portion_format.get_effective().font_bold:
            # Set the transparency of the text portion.
            portion.portion_format.fill_format.fill_type = slides.FillType.SOLID
            portion.portion_format.fill_format.solid_fill_color.color = draw.Color.from_argb(alpha, draw.Color.black)

    presentation.save("transparent_text_portions.pptx", slides.export.SaveFormat.PPTX)

The result:

Set Character Spacing for Text

Use BasePortionFormat.spacing to expand or condense spacing between characters in a text box.

The following Python code shows how to expand the character spacing in the entire paragraph:

import aspose.slides as slides

with slides.Presentation("sample.pptx") as presentation:
    auto_shape = presentation.slides[0].shapes[0]
    paragraph = auto_shape.text_frame.paragraphs[0]

    # Note: Use negative values to compress the character spacing.
    paragraph.paragraph_format.default_portion_format.spacing = 3  # Expand character spacing.

    presentation.save("character_spacing_in_paragraph.pptx", slides.export.SaveFormat.PPTX)

The result:

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

import aspose.slides as slides

with slides.Presentation("sample.pptx") as presentation:
    auto_shape = presentation.slides[0].shapes[0]
    paragraph = auto_shape.text_frame.paragraphs[0]

    for portion in paragraph.portions:
        if portion.portion_format.get_effective().font_bold:
            # Note: Use negative values to compress the character spacing.
            portion.portion_format.spacing = 3  # Expand character spacing.

    presentation.save("character_spacing_in_text_portions.pptx", slides.export.SaveFormat.PPTX)

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 PortionFormat.kerning_minimal_size to a value significantly larger than the actual font size:

import aspose.slides as slides

with slides.Presentation("presentation.pptx") as presentation:
    auto_shape = presentation.slides[0].shapes[0]
    target_font = "Roboto"

    for paragraph in auto_shape.text_frame.paragraphs:
        for portion in paragraph.portions:
            latin_font = portion.portion_format.latin_font
            east_asian_font = portion.portion_format.east_asian_font
            complex_script_font = portion.portion_format.complex_script_font

            if ((latin_font is not None and latin_font.font_name == target_font) or
                    (east_asian_font is not None and east_asian_font.font_name == target_font) or
                    (complex_script_font is not None and complex_script_font.font_name == target_font)):
                portion.portion_format.kerning_minimal_size = 100

    presentation.save("output.pptx", slides.export.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 ParagraphFormat.default_portion_format or on individual portions through PortionFormat.

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.

import aspose.slides as slides

with slides.Presentation("sample.pptx") as presentation:
    auto_shape = presentation.slides[0].shapes[0]
    paragraph = auto_shape.text_frame.paragraphs[0]

    # Set the font properties for the paragraph.
    paragraph.paragraph_format.default_portion_format.font_height = 12
    paragraph.paragraph_format.default_portion_format.font_bold = slides.NullableBool.TRUE
    paragraph.paragraph_format.default_portion_format.font_italic = slides.NullableBool.TRUE
    paragraph.paragraph_format.default_portion_format.font_underline = slides.TextUnderlineType.DOTTED
    paragraph.paragraph_format.default_portion_format.latin_font = slides.FontData("Times New Roman")

    presentation.save("font_properties_for_paragraph.pptx", slides.export.SaveFormat.PPTX)

The result:

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

import aspose.slides as slides

with slides.Presentation("sample.pptx") as presentation:
    auto_shape = presentation.slides[0].shapes[0]
    paragraph = auto_shape.text_frame.paragraphs[0]

    for portion in paragraph.portions:
        if portion.portion_format.get_effective().font_bold:
            # Set the font properties for the text portion.
            portion.portion_format.font_height = 13
            portion.portion_format.font_italic = slides.NullableBool.TRUE
            portion.portion_format.font_underline = slides.TextUnderlineType.DOTTED
            portion.portion_format.latin_font = slides.FontData("Times New Roman")

    presentation.save("font_properties_for_text_portions.pptx", slides.export.SaveFormat.PPTX)

The result:

Set Text Rotation

Use TextFrameFormat.text_vertical_type 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:

import aspose.slides as slides

with slides.Presentation("sample.pptx") as presentation:
    auto_shape = presentation.slides[0].shapes[0]

    auto_shape.text_frame.text_frame_format.text_vertical_type = slides.TextVerticalType.VERTICAL270

    presentation.save("text_rotation.pptx", slides.export.SaveFormat.PPTX)

The result:

Set Custom Rotation for Text Frames

Use TextFrameFormat.rotation_angle to set a custom rotation angle for a TextFrame.

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

import aspose.slides as slides

with slides.Presentation("sample.pptx") as presentation:
    auto_shape = presentation.slides[0].shapes[0]

    auto_shape.text_frame.text_frame_format.rotation_angle = 3

    presentation.save("custom_text_rotation.pptx", slides.export.SaveFormat.PPTX)

The result:

Set Line Spacing of Paragraphs

Aspose.Slides provides ParagraphFormat.space_after, ParagraphFormat.space_before, and ParagraphFormat.space_within 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:

import aspose.slides as slides

with slides.Presentation("sample.pptx") as presentation:
    auto_shape = presentation.slides[0].shapes[0]
    paragraph = auto_shape.text_frame.paragraphs[0]

    paragraph.paragraph_format.space_within = 200

    presentation.save("line_spacing.pptx", slides.export.SaveFormat.PPTX)

The result:

Set Autofit Type for Text Frames

TextFrameFormat.autofit_type 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.

import aspose.slides as slides

with slides.Presentation("sample.pptx") as presentation:
    auto_shape = presentation.slides[0].shapes[0]

    auto_shape.text_frame.text_frame_format.autofit_type = slides.TextAutofitType.SHAPE

    presentation.save("autofit_type.pptx", slides.export.SaveFormat.PPTX)

Set Anchor of Text Frames

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

import aspose.slides as slides

with slides.Presentation("sample.pptx") as presentation:
    auto_shape = presentation.slides[0].shapes[0]

    auto_shape.text_frame.text_frame_format.anchoring_type = slides.TextAnchorType.BOTTOM

    presentation.save("text_anchor.pptx", slides.export.SaveFormat.PPTX)

Set Text Tabulation

Use ParagraphFormat.default_tab_size and ParagraphFormat.tabs to configure tab stops in a paragraph.

import aspose.slides as slides

with slides.Presentation("sample.pptx") as presentation:
    auto_shape = presentation.slides[0].shapes[0]
    paragraph = auto_shape.text_frame.paragraphs[0]

    paragraph.paragraph_format.default_tab_size = 100
    paragraph.paragraph_format.tabs.add(30, slides.TabAlignment.LEFT)

    presentation.save("paragraph_tabs.pptx", slides.export.SaveFormat.PPTX)

The result:

Set Proofing Language

Aspose.Slides provides PortionFormat.language_id, 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:

import aspose.slides as slides

with slides.Presentation("presentation.pptx") as presentation:
    auto_shape = presentation.slides[0].shapes[0]

    paragraph = auto_shape.text_frame.paragraphs[0]
    paragraph.portions.clear()

    font = slides.FontData("SimSun")

    text_portion = slides.Portion()
    text_portion.portion_format.complex_script_font = font
    text_portion.portion_format.east_asian_font = font
    text_portion.portion_format.latin_font = font

    # Set the Id of a proofing language.
    text_portion.portion_format.language_id = "zh-CN"

    text_portion.text = "1."
    paragraph.portions.add(text_portion)

    presentation.save("proofing_language.pptx", slides.export.SaveFormat.PPTX)

Set Default Language

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

import aspose.slides as slides

load_options = slides.LoadOptions()
load_options.default_text_language = "en-US"

with slides.Presentation(load_options) as presentation:
    slide = presentation.slides[0]

    # Add a new rectangle shape with text.
    shape = slide.shapes.add_auto_shape(slides.ShapeType.RECTANGLE, 20, 20, 150, 50)
    shape.text_frame.text = "Sample text"

    # Check the first portion language.
    portion = shape.text_frame.paragraphs[0].portions[0]
    print(portion.portion_format.language_id)

Set Default Text Style

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

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.

import aspose.slides as slides

with slides.Presentation() as presentation:
    # Get the top level paragraph format.
    paragraph_format = presentation.default_text_style.get_level(0)

    if paragraph_format is not None:
        paragraph_format.default_portion_format.font_height = 14
        paragraph_format.default_portion_format.font_bold = slides.NullableBool.TRUE

    presentation.save("default_text_style.pptx", slides.export.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 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:

import aspose.slides as slides

with slides.Presentation("sample2.pptx") as presentation:
    auto_shape = presentation.slides[0].shapes[0]
    text_portion = auto_shape.text_frame.paragraphs[0].portions[0]

    print("Original text:", text_portion.text)

    text_format = text_portion.portion_format.get_effective()
    if text_format.text_cap_type == slides.TextCapType.ALL:
        text = text_portion.text.upper()
        print("All-Caps effect:", text)

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 Table. Iterate through the cells and update each cell through Cell.text_frame and paragraph formatting through Paragraph.paragraph_format.

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

To apply a gradient color to text, use PortionFormat.fill_format. Set FillFormat.fill_type to FillType.GRADIENT and configure the gradient stops, direction, and transparency.