Stencil Drawing – C# code and Stencil Maker

Online Stencil Maker

If you need to turn your photos or images into stencils, use our free online tool! It creates image stencils and allows you to vectorize them for scalable and clear vector graphics. Stencil Maker supports many image formats, including JPEG, JPG, PJP, PJPEG, PNG, BMP, ICO, GIF, TIFF, WEBP, XBM, SVG, and more.

What is an image stencil?

Image stenciling is a process that turns an ordinary picture or photo into an outline image that can be used as a stencil for graffiti-like effects. There are several basic steps for turning a photo or image into a stencil:

• Convert a photo or image to grayscale, this step is optional, as you can reduce the number of colors to quantize instead.
• Quantize image colors to simplify the image, after that you can download the result or vectorize it and get the stencil shape lines.
• There are three options for drawing stencils. The first is “None” when all the vectorized shapes are filled, the second is “Auto” when the shapes are not filled and the borders have the “original” color, and the last is “MonoСolor” when the shapes are also not filled, but the borders have the predefined color.
  

How to use Image Vectorizer?

1. First, load the raster image from a local file system in JPEG, JPG, PJP, PJPEG, WEBP, PNG, BMP, ICO, GIF, TIFF, XBM or other bitmap format. You will see three windows - Source Image, Quantized Image and Vectorized Image - with the preview of initial, color-quantized and vectorized images.
2. Image Vectorizer converts Image to vector with default settings and you can download vectorized Image as an SVG file. But for getting a better result, you can handle the quantization and vectorization processes with two settings sidebars. Click “Quantize” button to apply quantization settings, click “Vectorize” button to apply vectorization settings and convert Image to SVG.
3. Click the “Download” button to get the resultant.

Image Vectorizer converts raster bitmap images into vector artwork constructed from outlines. The vectorization algorithm includes the next steps: color quantization, contour tracing, trace smoothing, trace simplification, and building SVG path elements from the traces. Apply custom settings to get the best Image vectorization result.

Quantization Options

Color quantization is a process of selecting the limited number of colors to use in an image. It is applied when the color information of an image is to be reduced. Color quantization is a very complex process involving a number of factors. This can be implemented using different algorithms. Each of the algorithms determines which colors from the larger set of colors remain in the new image and how the discarded colors are mapped to the remaining ones.

• colors - desired palette size;
• method - histogram methods that implement various color quantization algorithms;
• minHueCols - is a parameter that works with color gradients;
• scale - or scaling factor - configurable for finer or coarser sampling of colors;
• grayscale - you can convert the image to grayscale by clicking the checkbox.

Vectorization Options

• threshold - is responsible for setting the number of pixels to mark the contour;
• severity - affects contours’ smoothing and determines the extent of the region considered by query point the Nearest Neighbor approach;
• line-width - affects lines’ width for marking the contours;
• stencil - turns an ordinary image or photo into an outline image that can be used as a stencil for graffiti-like effects;
• trace paths - you can view the points in a curve that are responsible for building path segments.

Vector graphics are the best for creating logos, icons, page layouts, maps, graphs, line arts, illustrations, technical drawings and more. It is not the most suitable format for continuous-tone images with blends of color or editing photographs. However, vectorizing photos can result in impressive artistic effects that can be interesting and useful.

How to Make Stencil in C#

Aspose.SVG for the .NET API provides classes and methods that allow you to implement the image vectorization process and work with stenciling options.

	// Initialize an instance of the ImageVectorizer class
	var vectorizer = new ImageVectorizer
    {
		//optionally set configuration
        Configuration =
        {
			//optionally set path builder
            PathBuilder = new BezierPathBuilder {
			//optionally set trace smoother
            TraceSmoother = new ImageTraceSmoother(1),
                ErrorThreshold = 30,
                MaxIterations = 30
            },
            ColorsLimit = 10,
            LineWidth = 1,
            // set stencil effect configuration
            Stencil = new StencilConfiguration { Type = StencilType.MonoColor, Color = Aspose.Svg.Drawing.Color.FromRgb(0,0,255) }
        }
    };
    // Vectorize image from the specified file
	using var document = vectorizer.Vectorize(InputFolder + "image.png");
    // Save vectorized image as SVG file 
	document.Save(OutputFolder + "image.svg");

Steps to Make Stencil in C#

Aspose.SVG for .NET API offers a high-speed C# library that you can use for different SVG parsing tasks. The ImageVectorization Namespace includes classes and interfaces for implementing the image vectorization process with stenciling options. To make stencil from PNG image, you should follow a few steps:

1. Initialize an instance of the ImageVectorizer class. Use one of ImageVectorizer() constructors and specify configuration properties.
   • PathBuilder property gets or sets the SVG path segments builder.
   • ColorsLimit property gets or sets the maximum number of colors used to quantize an image.
   • Stencil property gets or sets stencil effect configuration. By default, no stencil effect is applied.
2. Vectorize an image from the specified file. The Vectorize() method takes the path to the image file and returns an SVGDocument.
3. Save the vectorized image to SVG. Use the Save() method and pass to it the output path.

In the documentation chapter Vectorization – Basic Overview , you will find image vectorization info, a description of the image vectorization process and vectorization options, learn how to vectorize raster images such as PNG, JPG, BMP, TIFF, GIF, ICO into an SVG document.

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