Aspose.Slides FOSS for .NET lets you apply professional-quality visual effects to PowerPoint shapes entirely in C#, with no Microsoft Office and no API keys. This post demonstrates the fill system, 2D effects, and 3D formatting available in the library.

The Fill System

Every shape has a FillFormat that controls how its interior is painted. The five fill types cover the full range of PowerPoint’s design palette.

Solid Fill

The simplest fill, a flat color with optional transparency:

using Aspose.Slides.Foss;

using var prs = new Presentation();
var shape = prs.Slides[0].Shapes.AddAutoShape(
    ShapeType.RoundCornerRectangle, 100, 100, 400, 150
);
shape.AddTextFrame("Solid Fill");

shape.FillFormat.FillType = FillType.Solid;
shape.FillFormat.SolidFillColor.Color = Color.FromArgb(255, 30, 80, 180);

prs.Save("solid.pptx", SaveFormat.Pptx);

Linear Gradient Fill

Gradient stops let you blend from one color to another across the shape:

using Aspose.Slides.Foss;

using var prs = new Presentation();
var shape = prs.Slides[0].Shapes.AddAutoShape(
    ShapeType.Rectangle, 100, 100, 400, 150
);

var ff = shape.FillFormat;
ff.FillType = FillType.Gradient;
var gf = ff.GradientFormat;
gf.GradientShape = GradientShape.Linear;
gf.LinearGradientAngle = 90;   // top-to-bottom

gf.GradientStops.Add(0.0f, Color.FromArgb(255, 30, 80, 180));   // top: blue
gf.GradientStops.Add(1.0f, Color.FromArgb(255, 0, 200, 160));   // bottom: teal

prs.Save("gradient.pptx", SaveFormat.Pptx);

2D Visual Effects

Outer Drop Shadow

Attach a semi-transparent drop shadow to any shape:

using Aspose.Slides.Foss;

using var prs = new Presentation();
var shape = prs.Slides[0].Shapes.AddAutoShape(
    ShapeType.RoundCornerRectangle, 100, 100, 350, 150
);
shape.AddTextFrame("Drop Shadow");

shape.FillFormat.FillType = FillType.Solid;
shape.FillFormat.SolidFillColor.Color = Color.White;

var ef = shape.EffectFormat;
ef.EnableOuterShadowEffect();
ef.OuterShadowEffect.BlurRadius = 12;
ef.OuterShadowEffect.Direction = 315;   // upper-left
ef.OuterShadowEffect.Distance = 8;
ef.OuterShadowEffect.ShadowColor.Color = Color.FromArgb(100, 0, 0, 0);

prs.Save("shadow.pptx", SaveFormat.Pptx);

Glow Effect

A colored halo around the shape edge:

using Aspose.Slides.Foss;

using var prs = new Presentation();
var shape = prs.Slides[0].Shapes.AddAutoShape(
    ShapeType.Ellipse, 150, 100, 250, 250
);
shape.FillFormat.FillType = FillType.Solid;
shape.FillFormat.SolidFillColor.Color = Color.FromArgb(255, 20, 60, 140);

var ef = shape.EffectFormat;
ef.EnableGlowEffect();
ef.GlowEffect.Radius = 20;
ef.GlowEffect.Color.Color = Color.FromArgb(200, 0, 180, 255);

prs.Save("glow.pptx", SaveFormat.Pptx);

3D Formatting

Bevel and Material

The ThreeDFormat property gives any flat shape a three-dimensional appearance. Combine a bevel with a camera preset and a material for the richest result:

using Aspose.Slides.Foss;

using var prs = new Presentation();
var shape = prs.Slides[0].Shapes.AddAutoShape(
    ShapeType.Rectangle, 150, 150, 300, 130
);
shape.AddTextFrame("Metal Button");

// Blue solid fill
shape.FillFormat.FillType = FillType.Solid;
shape.FillFormat.SolidFillColor.Color = Color.FromArgb(255, 20, 70, 160);

// 3D bevel + camera + light + material
var tdf = shape.ThreeDFormat;
tdf.BevelTop.BevelType = BevelPresetType.Circle;
tdf.BevelTop.Width = 10;
tdf.BevelTop.Height = 5;
tdf.Camera.CameraType = CameraPresetType.PerspectiveAbove;
tdf.LightRig.LightType = LightRigPresetType.Balanced;
tdf.LightRig.Direction = LightingDirection.Top;
tdf.Material = MaterialPresetType.Metal;
tdf.Depth = 20;

prs.Save("metal-button.pptx", SaveFormat.Pptx);

Combining Effects on the Same Shape

Shadow and 3D formatting can coexist on a single shape, enabling polished “card” designs:

using Aspose.Slides.Foss;

using var prs = new Presentation();
var shape = prs.Slides[0].Shapes.AddAutoShape(
    ShapeType.RoundCornerRectangle, 120, 120, 360, 150
);
shape.AddTextFrame("Premium Card");

// Fill
shape.FillFormat.FillType = FillType.Solid;
shape.FillFormat.SolidFillColor.Color = Color.FromArgb(255, 30, 80, 180);

// 3D bevel
var tdf = shape.ThreeDFormat;
tdf.BevelTop.BevelType = BevelPresetType.Circle;
tdf.BevelTop.Width = 8;
tdf.Camera.CameraType = CameraPresetType.PerspectiveAbove;
tdf.Material = MaterialPresetType.Plastic;

// Drop shadow
var ef = shape.EffectFormat;
ef.EnableOuterShadowEffect();
ef.OuterShadowEffect.BlurRadius = 14;
ef.OuterShadowEffect.Direction = 270;
ef.OuterShadowEffect.Distance = 8;
ef.OuterShadowEffect.ShadowColor.Color = Color.FromArgb(70, 0, 0, 0);

prs.Save("premium-card.pptx", SaveFormat.Pptx);

Installation

dotnet add package Aspose.Slides.Foss

No Office installation, no license keys, no network calls; all processing happens locally.