Manage Presentation Backgrounds in C#

Overview

Solid colors, gradients, and images are commonly used for slide backgrounds. You can set the background for a normal slide (a single slide) or a master slide (applies to multiple slides at once).

Set a Solid Color Background for a Normal Slide

Aspose.Slides allows you to set a solid color as the background for a specific slide in a presentation—even if the presentation uses a master slide. The change applies only to the selected slide.

1. Create an instance of the Presentation class.
2. Set the slide’s BackgroundType to OwnBackground.
3. Set the slide background FillType to Solid.
4. Use the SolidFillColor property on FillFormat to specify the solid background color.
5. Save the modified presentation.

The following C# example shows how to set a blue solid color as the background for a normal slide:

// Create an instance of the Presentation class.
using (Presentation presentation = new Presentation())
{
    ISlide slide = presentation.Slides[0];

    // Set the background color of the slide to blue.
    slide.Background.Type = BackgroundType.OwnBackground;
    slide.Background.FillFormat.FillType = FillType.Solid;
    slide.Background.FillFormat.SolidFillColor.Color = Color.Blue;

    // Save the presentation to disk.
    presentation.Save("SolidColorBackground.pptx", SaveFormat.Pptx);
}

Set a Solid Color Background for the Master Slide

Aspose.Slides allows you to set a solid color as the background for the master slide in a presentation. The master slide acts as a template that controls formatting for all slides, so when you choose a solid color for the master slide’s background, it applies to every slide.

1. Create an instance of the Presentation class.
2. Set the master slide’s BackgroundType (via masters) to OwnBackground.
3. Set the master slide background FillType to Solid.
4. Use the SolidFillColor to specify the solid background color.
5. Save the modified presentation.

The following C# example shows how to set a solid color (forest green) as the background for a master slide:

// Create an instance of the Presentation class.
using (Presentation presentation = new Presentation())
{
    IMasterSlide masterSlide = presentation.Masters[0];

    // Set the background color for the Master slide to Forest Green.
    masterSlide.Background.Type = BackgroundType.OwnBackground;
    masterSlide.Background.FillFormat.FillType = FillType.Solid;
    masterSlide.Background.FillFormat.SolidFillColor.Color = Color.ForestGreen;

    // Save the presentation to disk.
    presentation.Save("MasterSlideBackground.pptx", SaveFormat.Pptx);
}

Set a Gradient Background for a Slide

A gradient is a graphical effect created by a gradual change in color. When used as a slide background, gradients can make presentations look more artistic and professional. Aspose.Slides allows you to set a gradient color as the background for slides.

1. Create an instance of the Presentation class.
2. Set the slide’s BackgroundType to OwnBackground.
3. Set the slide background FillType to Gradient.
4. Use the GradientFormat property on FillFormat to configure your preferred gradient settings.
5. Save the modified presentation.

The following C# example shows how to set a gradient color as the background for a slide:

// Create an instance of the Presentation class.
using (Presentation presentation = new Presentation())
{
    ISlide slide = presentation.Slides[0];

    // Apply a gradient effect to the background.
    slide.Background.Type = BackgroundType.OwnBackground;
    slide.Background.FillFormat.FillType = FillType.Gradient;
    slide.Background.FillFormat.GradientFormat.TileFlip = TileFlip.FlipBoth;

    // Save the presentation to disk.
    presentation.Save("GradientBackground.pptx", SaveFormat.Pptx);
}

Set an Image as a Slide Background

In addition to solid and gradient fills, Aspose.Slides allows you to use images as slide backgrounds.

1. Create an instance of the Presentation class.
2. Set the slide’s BackgroundType to OwnBackground.
3. Set the slide background FillType to Picture.
4. Load the image you want to use as the slide background.
5. Add the image to the presentation’s image collection.
6. Use the PictureFillFormat property on FillFormat to assign the image as the background.
7. Save the modified presentation.

The following C# example shows how to set an image as the background for a slide:

// Create an instance of the Presentation class.
using (Presentation presentation = new Presentation())
{
    ISlide slide = presentation.Slides[0];

    // Set background image properties.
    slide.Background.Type = BackgroundType.OwnBackground;
    slide.Background.FillFormat.FillType = FillType.Picture;
    slide.Background.FillFormat.PictureFillFormat.PictureFillMode = PictureFillMode.Stretch;

    // Load the image.
    IImage image = Images.FromFile("Tulips.jpg");
    // Add the image to the presentation's image collection.
    IPPImage ppImage = presentation.Images.AddImage(image);
    image.Dispose();

    slide.Background.FillFormat.PictureFillFormat.Picture.Image = ppImage;

    // Save the presentation to disk.
    presentation.Save("ImageAsBackground.pptx", SaveFormat.Pptx);
}

The following code sample shows how to set the background fill type to a tiled picture and modify the tiling properties:

using (Presentation presentation = new Presentation())
{
    ISlide firstSlide = presentation.Slides[0];

    IBackground background = firstSlide.Background;

    background.Type = BackgroundType.OwnBackground;
    background.FillFormat.FillType = FillType.Picture;

    IPPImage ppImage;
    using (IImage newImage = Aspose.Slides.Images.FromFile("image.png"))
        ppImage = presentation.Images.AddImage(newImage);

    // Set the image used for the background fill.
    IPictureFillFormat backPictureFillFormat = background.FillFormat.PictureFillFormat;
    backPictureFillFormat.Picture.Image = ppImage;

    // Set the picture fill mode to Tile and adjust the tile properties.
    backPictureFillFormat.PictureFillMode = PictureFillMode.Tile;
    backPictureFillFormat.TileOffsetX = 15f;
    backPictureFillFormat.TileOffsetY = 15f;
    backPictureFillFormat.TileScaleX = 46f;
    backPictureFillFormat.TileScaleY = 87f;
    backPictureFillFormat.TileAlignment = RectangleAlignment.Center;
    backPictureFillFormat.TileFlip = TileFlip.FlipY;

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

Read more: Tile Picture As Texture.

Change the Background Image Transparency

You may want to adjust the transparency of a slide’s background image to make the contents of the slide stand out. The following C# code shows you how to change the transparency for a slide background image:

var transparencyValue = 30; // For example.

// Get the collection of picture transform operations.
var imageTransform = slide.Background.FillFormat.PictureFillFormat.Picture.ImageTransform;

// Find an existing fixed-percentage transparency effect.
var transparencyOperation = null as IAlphaModulateFixed;
foreach (var operation in imageTransform)
{
    if (operation is IAlphaModulateFixed alphaModulateFixed)
    {
        transparencyOperation = alphaModulateFixed;
        break;
    }
}

// Set the new transparency value.
if (transparencyOperation == null)
{
    imageTransform.AddAlphaModulateFixedEffect(100 - transparencyValue);
}
else
{
    transparencyOperation.Amount = (100 - transparencyValue);
}

Get the Slide Background Value

Aspose.Slides provides the IBackgroundEffectiveData interface for retrieving a slide’s effective background values. This interface exposes the effective FillFormat and EffectFormat.

Using the BaseSlide class’s background property, you can obtain the effective background for a slide.

The following C# example shows how to get a slide’s effective background value:

// Create an instance of the Presentation class.
using (Presentation presentation = new Presentation("Sample.pptx"))
{
    ISlide slide = presentation.Slides[0];  

    // Retrieve the effective background, taking into account master, layout, and theme.
    IBackgroundEffectiveData effBackground = slide.Background.GetEffective();

    if (effBackground.FillFormat.FillType == FillType.Solid)
        Console.WriteLine("Fill color: " + effBackground.FillFormat.SolidFillColor);
    else
        Console.WriteLine("Fill type: " + effBackground.FillFormat.FillType);
}