我正在建立一个.dot文件来表示有向无环图。
我需要从这个graph.dot文件生成图像(使用C#),以便可以在应用程序的图片框中显示该图像。我应该使用哪个库?
在命令提示符下使用GraphViz的命令:
dot -Tpng graph.dot -o graph.png
我能够生成良好的图像,所以我知道我的.dot文件的格式是正确的。
谢谢你。
最佳答案
谢谢@marapet,让我指出了David Brown的项目。
我已在以下位置下载了示例:David Brown's Implicit Operator
该示例运行良好。
我将所需的代码复制到了我的项目中。我必须将.NET Target Framework从4.0更改为3.5,但这不是问题。
到目前为止,代码从未崩溃过。 (即使其他人已经报告了问题。)
更新
大卫·布朗(David Brown)的网站似乎已关闭,因此我用我从网站上获取的代码更新了此答案。
//Code for this Class downloaded from http://implicitoperator.com/blog/2010/4/11/graphviz-c-sample.html
public class GraphViz
{
public const string LIB_GVC = "gvc.dll";
public const string LIB_GRAPH = "graph.dll";
public const int SUCCESS = 0;
/// <summary>
/// Creates a new Graphviz context.
/// </summary>
[DllImport(LIB_GVC)]
public static extern IntPtr gvContext();
/// <summary>
/// Reads a graph from a string.
/// </summary>
[DllImport(LIB_GRAPH)]
public static extern IntPtr agmemread(string data);
/// <summary>
/// Renders a graph in memory.
/// </summary>
[DllImport(LIB_GVC)]
public static extern int gvRenderData(IntPtr gvc, IntPtr g,
string format, out IntPtr result, out int length);
/// <summary>
/// Applies a layout to a graph using the given engine.
/// </summary>
[DllImport(LIB_GVC)]
public static extern int gvLayout(IntPtr gvc, IntPtr g, string engine);
/// <summary>
/// Releases the resources used by a layout.
/// </summary>
[DllImport(LIB_GVC)]
public static extern int gvFreeLayout(IntPtr gvc, IntPtr g);
/// <summary>
/// Releases a context's resources.
/// </summary>
[DllImport(LIB_GVC)]
public static extern int gvFreeContext(IntPtr gvc);
/// <summary>
/// Releases the resources used by a graph.
/// </summary>
[DllImport(LIB_GRAPH)]
public static extern void agclose(IntPtr g);
public static Image RenderImage(string source, string layout, string format)
{
// Create a Graphviz context
IntPtr gvc = gvContext();
if (gvc == IntPtr.Zero)
throw new Exception("Failed to create Graphviz context.");
// Load the DOT data into a graph
IntPtr g = agmemread(source);
if (g == IntPtr.Zero)
throw new Exception("Failed to create graph from source. Check for syntax errors.");
// Apply a layout
if (gvLayout(gvc, g, layout) != SUCCESS)
throw new Exception("Layout failed.");
IntPtr result;
int length;
// Render the graph
if (gvRenderData(gvc, g, format, out result, out length) != SUCCESS)
throw new Exception("Render failed.");
// Create an array to hold the rendered graph
byte[] bytes = new byte[length];
// Copy the image from the IntPtr
Marshal.Copy(result, bytes, 0, length);
// Free up the resources
gvFreeLayout(gvc, g);
agclose(g);
gvFreeContext(gvc);
using (MemoryStream stream = new MemoryStream(bytes))
{
return Image.FromStream(stream);
}
}
}