Copying graphics

Sometimes, you may want to reuse a set of graphic elements multiple times, e.g. a “sprite”, or just a collection of paths. You can achieve this by using the DrawGraphics method, which lets you draw the contents of a Graphics object on another Graphics object.

The first step is to create a Graphics object to hold the image that will be copied; you can do this by invoking the parameterless Graphics constructor. Then you can draw on this new object as normal. Finally, you invoke the DrawGraphics method on the original Graphics object that you obtained from the page, passing the new Graphics as an argument, together with a Point or two doubles that determine where the origin of the copied Graphics will be placed.

The following example shows how this method can be used.

using VectSharp;
using VectSharp.SVG;

Page page = new Page(100, 100);
Graphics graphics = page.Graphics;

// Create a new Graphics object to contain the symbol.
Graphics symbol = new Graphics();

// Draw something on this graphics object.
symbol.FillPath(new GraphicsPath().Arc(5, 5, 5, 0, 2 * Math.PI), Colour.FromRgb(0, 158, 115));
symbol.FillPath(new GraphicsPath().Arc(2, 2, 2, 0, 2 * Math.PI), Colour.FromRgb(0, 114, 178));
symbol.FillPath(new GraphicsPath().Arc(8, 2, 2, 0, 2 * Math.PI), Colour.FromRgb(86, 180, 233));
symbol.FillPath(new GraphicsPath().Arc(2, 8, 2, 0, 2 * Math.PI), Colour.FromRgb(230, 159, 0));
symbol.FillPath(new GraphicsPath().Arc(8, 8, 2, 0, 2 * Math.PI), Colour.FromRgb(213, 94, 0));

// Copy the symbol multiple times on the page.
for (int i = 0; i < 10; i++)
{
    for (int j = 0; j < 10; j++)
    {
        graphics.DrawGraphics(i * 10, j * 10, symbol);
    }
}

page.SaveAsSVG("DrawGraphics.svg");

The DrawGraphics method also has another overload, which accepts an additional parameter; this is used to apply filters to the image, and is described in the next section.