How to Optimize SVG – C# Examples

Why Optimize SVG?

The SVG format is very flexible, but it also has some drawbacks. One of them is that the format is not very efficient. This means that SVG images can be slow to load, and they can also be slow to render. This is a problem for web developers because it can affect the user experience. It can also affect the SEO of a website because search engines can penalize slow websites. Optimizing SVGs for performance reasons is a very common task. Aspose.SVG for .NET API provides the SVGOptimizer class to help with that task. This tool compresses the SVG document by applying various heuristics to optimize paths and remove unused or useless elements and attributes.

Aspose.SVG offers Free Online SVG Optimizer. Optimize SVG files to make your website faster and better! You can use a set of options that allow you to flexibly control the compression and simplification level and achieve the desired result. With the SVG Optimizer, you will optimize SVG easily within minutes. Try our forceful application for free now!

Optimize SVG in C#

To optimize SVG documents, use the following code snippet:

 1using Aspose.Svg;
 2using System.IO;
 3using Aspose.Svg.Toolkit.Optimizers;
 4...
 5
 6	// Initialize an SVG document from a file
 7    using (var document = new SVGDocument(Path.Combine(DataDir, "source.svg")))
 8    {
 9        var options = new SVGOptimizationOptions();
10        // Set float precision
11        options.PathOptimizationOptions.FloatPrecision = 2;
12        // Optimize document
13        SVGOptimizer.Optimize(document, options);
14        // Save document to a file
15        document.Save(Path.Combine(DataDir, "optimized.svg"));
16    }

The current section describes supported scenarios of SVG file optimization. Let’s look at the steps to optimize SVG.

Initialize an SVG document from a file using one of the SVGDocument() constructors.
Create a new SVGOptimizationOptions object. Use the SVGOptimizationOptions() constructor.
Use the PathOptimizationOptions property of the SVGOptimizationOptions class to optimize SVG paths.
Call the Optimize() method to optimize SVG document.
Save the optimized SVG document to a file.

SVG Optimization Options

Aspose.SVG for .NET API offers a set of optimization options that allow to reduce SVG code by removing empty elements, attributes with empty values, unused stroke and fill attributes, elements that are not visible during rendering, empty containers, empty text elements, line indents and breaks, and more.
Aspose.SVG C# library supports the following SVG elements optimization options SVGOptimizationOptions:

The CollapseGroups property collapses excess groups.

Original SVG

1<svg xmlns="http://www.w3.org/2000/svg">
2    <g>
3        <g attr1="val1">
4            <path d="..."/>
5        </g>
6    </g>
7</svg>

Optimized SVG

1<svg xmlns="http://www.w3.org/2000/svg">
2    <g>
3        <g attr1="val1">
4           <path d="..."/>
5        </g>
6    </g>
7</svg>

RemoveDescriptions – Removes only editors content or empty elements

Original SVG

1<svg xmlns="http://www.w3.org/2000/svg">
2    <desc>Created with ...</desc>
3    <desc>Custom description</desc>
4    <path d="...">
5</svg>

Optimized SVG

1<svg xmlns="http://www.w3.org/2000/svg">
2    <desc>Custom description</desc>
3    <path d="...">
4</svg>

RemoveEmptyAttributes – Removes attributes with empty values

Original SVG

1<svg xmlns="http://www.w3.org/2000/svg">
2    <path attr1=" attr2 =" d="M..."/>
3</svg>"

Optimized SVG

1<svg xmlns="http://www.w3.org/2000/svg">
2    <path d="M..."/>
3</svg>"

RemoveEmptyContainers – Removes empty containers

Original SVG

1<svg xmlns="http://www.w3.org/2000/svg">
2    <pattern/>
3    <g>
4        <marker>
5            <a/>
6        </marker>
7    </g>
8    <path d="M..."/>
9</svg>

Optimized SVG

1<svg xmlns="http://www.w3.org/2000/svg">
2    <path d="M..."/>
3</svg>

RemoveEmptyText – Removes empty ‘Text’ elements

Original SVG

1<svg xmlns="http://www.w3.org/2000/svg">
2    <g>
3        <text></text>
4        <tspan></tspan>
5        <tref>...</tref>
6    </g>
7</svg>

Optimized SVG

1<svg xmlns="http://www.w3.org/2000/svg">
2    <g></g>
3</svg>

RemoveHiddenElements – Removes elements that are not visible during rendering

Original SVG

 1<svg xmlns="http://www.w3.org/2000/svg">
 2    <style>
 3      .a { display: block; opacity: 0.5; }
 4    </style>
 5    <g>
 6        <rect display="none"  width="1" height="1" />
 7        <rect display="none" class="a" width="1" height="1" />
 8        <rect opacity="0"  width="1" height="1" />
 9        <rect opacity="0" class="a" width="1" height="1" />
10        <rect x="1" y="1" width="0" height="1" fill="blue" />
11        <g visibility="hidden">
12             <rect x="1" y="1" width="1" height="1" fill="red" />
13        </g>
14        <circle cx="10" cy="10" r="0">
15        </circle>
16        <ellipse rx="0"/>
17        <image width="0"/>
18        <path d="M 10 10 L 0"/>
19    </g>
20</svg>

Optimized SVG

1<svg xmlns="http://www.w3.org/2000/svg">
2    <style>.a { display: block; opacity: 0.5; }</style>
3    <g>
4        <rect display="none" class="a" width="1" height="1"/>
5        <rect opacity="0" class="a" width="1" height="1"/>
6    </g>
7</svg>

RemoveMetadata – Removes metadata

Original SVG

1<svg xmlns="http://www.w3.org/2000/svg">
2    <metadata>...</metadata>
3    <path d="..."/>
4</svg>

Optimized SVG

1<svg xmlns="http://www.w3.org/2000/svg">
2    <path d="..."/>
3</svg>

RemoveUnusedNamespaces – Removes the declaration of unused namespaces from the SVG element that are not used in elements or attributes

Original SVG

1<svg xmlns="http://www.w3.org/2000/svg" xmlns:test="http://test1.com/" xmlns:test2="http://test2.com/">
2    <g test:attr="val">
3        <g>
4            test
5        </g>
6    </g>
7</svg>

Optimized SVG

1<svg xmlns="http://www.w3.org/2000/svg" xmlns:test="http://test1.com/">
2    <g test:attr="val">
3        <g>
4            test
5        </g>
6    </g>
7</svg>

RemoveUnusedDefs – Removes the content of defs that are not displayed directly without identifiers

Original SVG

1<svg xmlns="http://www.w3.org/2000/svg">
2    <defs>
3        <path d="M..."/>
4        <g>
5            <path d="M..." id="test"/>
6        </g>
7    </defs>
8</svg>

Optimized SVG

1<svg xmlns="http://www.w3.org/2000/svg">
2    <defs>
3        <path d="M..." id="test"/>
4    </defs>
5</svg>

RemoveUselessStrokeAndFill – Removes unused stroke and fill attributes

Original SVG

 1<svg xmlns="http://www.w3.org/2000/svg">
 2    <defs>
 3        <g id="test">
 4            <rect stroke-dashoffset="5" width="10" height="10"/>
 5        </g>
 6    </defs>
 7    <circle fill="red" stroke-width="6" stroke-dashoffset="5" cx="6" cy="6" r="5"/>
 8    <circle fill="red" stroke="#000" stroke-width="6" stroke-dashoffset="5" stroke-opacity="0" cx="6" cy="6" r="5"/>
 9    <circle fill="red" stroke="#000" stroke-width="0" stroke-dashoffset="5" cx="6" cy="6" r="5"/>
10    <circle fill="red" stroke="#000" stroke-width="6" stroke-dashoffset="5" cx="6" cy="6" r="5"/>
11    <g stroke="#000" stroke-width="6">
12        <circle fill="red" stroke="red" stroke-width="0" stroke-dashoffset="5" cx="6" cy="6" r="5"/>
13        <circle fill="red" stroke-dashoffset="5" cx="6" cy="6" r="5"/>
14    </g>
15    <g stroke="#000">
16        <circle fill="red" stroke-width="0" stroke-dashoffset="5" cx="6" cy="6" r="5"/>
17        <circle fill="red" stroke="none" stroke-dashoffset="5" cx="6" cy="6" r="5"/>
18    </g>
19</svg>

Optimized SVG

 1<svg xmlns="http://www.w3.org/2000/svg">
 2    <defs>
 3        <g id="test">
 4            <rect stroke-dashoffset="5" width="10" height="10"/>
 5        </g>
 6    </defs>
 7    <circle fill="red" cx="6" cy="6" r="5"/>
 8    <circle fill="red" cx="6" cy="6" r="5"/>
 9    <circle fill="red" cx="6" cy="6" r="5"/>
10    <circle fill="red" stroke="#000" stroke-width="6" stroke-dashoffset="5" cx="6" cy="6" r="5"/>
11    <g stroke="#000" stroke-width="6">
12        <circle fill="red" cx="6" cy="6" r="5" stroke="none"/>
13        <circle fill="red" stroke-dashoffset="5" cx="6" cy="6" r="5"/>
14    </g>
15    <g stroke="#000">
16        <circle fill="red" cx="6" cy="6" r="5" stroke="none"/>
17        <circle fill="red" cx="6" cy="6" r="5" stroke="none"/>
18    </g>
19</svg>

CleanListOfValues – Rounds to 3 decimal places of list numeric values in attributes

Original SVG

1<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 500.2132 500.213823642" enable-background="new 0 0 500.224551535 500.213262">
2    test
3</svg>

Optimized SVG

1<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 500.213 500.214" enable-background="new 0 0 500.225 500.213">
2    test
3</svg>

RemoveIndentsAndLineBreaks – Removes line indents and breaks

Original SVG

1<svg xmlns="http://www.w3.org/2000/svg">
2    <g>
3        <ellipse rx="1"/>
4        <ellipse ry="1"/>
5    </g>
6</svg>

Optimized SVG

1<svg xmlns="http://www.w3.org/2000/svg"><g><ellipse rx="1"/><ellipse ry="1"/></g></svg>

Path Optimization Options

SVGOptimizationOptions contains PathOptimizationOptions which supports next optimization options:

ApplyTransforms – Applies transformations to the Path segments

Original path

1<path d="M32 4a4 4 0 0 0-4-4H8a4 4 0 0 1-4 4v28a4 4 0 0 1 4 4h20a4 4 0 0 0 4-4V4z" fill="#888" transform="matrix(1 0 0 -1 0 36)"/>

Optimized path

1<path d="M32 32a4 4 0 0 1-4 4H8a4 4 0 0 0-4-4V4a4 4 0 0 0 4-4h20a4 4 0 0 1 4 4v28z" fill="#888"/>

ArcBuildingThreshold – Sets the threshold error for replacing Bezier segments with arc segments

Original path

1<path d="M.49 8.8c-.3-.75-.44-1.55-.44-2.35 0-3.54 2.88-6.43 6.43-6.43 3.53 0 6.42 2.88 6.42 6.43 0 .8-.15 1.6-.43 2.35"/>

Optimized path

ArcBuildingThreshold = 1

1<path d="M.49 8.8C.19 8.05.05 7.25.05 6.45.05 2.91 2.93.02 6.48.02c3.53 0 6.42 2.88 6.42 6.43 0 .8-.15 1.6-.43 2.35"/>

ArcBuildingThreshold = 4

1<path d="M.49 8.8A6.438 6.438 0 0 1 6.48.02c3.53 0 6.42 2.88 6.42 6.43 0 .8-.15 1.6-.43 2.35"/>

ArcBuildingTolerance – Sets the percentage of radius for replacing Bezier segments with arc segments

Original path

1<path d="M41.008 0.102c1.891 0.387 3.393 1.841 3.849 3.705"/>

Optimized path

ArcBuildingTolerance = 0

1<path d="M41.008.102c1.89.387 3.393 1.84 3.85 3.705"/>

ArcBuildingTolerance = 0.5f

1<path d="M41.008.102a5.006 5.006 0 0 1 3.85 3.705"/>

FloatPrecision – Sets the float-precision floating-point value to a specified number of fractional digits

Original path

1<p><path d="M33.02783,1.965459 C33.097408,2.035034 38.04136,6.978988 38.04136,6.978988 C38.04136,6.978988 38.00943,4.03467 38.00943,4.03467 L34,0.02523956 L34,0 L13,0 L13,2 L33.06237,2 Z"></path></p>

Optimized path

FloatPrecision = 2

1<path d="m33.03 1.97 5.01 5-.03-2.94-4.01-4V0H13v2h20.06z"/>

FloatPrecision = 3

1<path d="M33.028 1.965 38.04 6.98l-.03-2.945L34 .025V0H13v2h20.062z"/>

RemoveSpaceAfterFlags – Removes extra space after ‘arcto’ command flags

Original path

1<path d="m100 200 200 200H100V300c0-200 150-200 150-100s150 100 150 0q0-150 200 100t400 0a150 150 0 1 0 150-150z"/>

Optimized path

1<path d="m100 200 200 200H100V300c0-200 150-200 150-100s150 100 150 0q0-150 200 100t400 0a150 150 0 10150-150z"/>

You can download the complete examples and data files from GitHub. About downloading from GitHub and running examples, you find out from the How to Run the Examples section.

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