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我正在使用我发现的代码将 SVG 文件光栅化为图像文件。该链接是http://www.experts-exchange.com/Programming/Languages/C_Sharp/Q_24547525.html。我的代码看起来相同，但我遇到了访问冲突：

“试图读取或写入受保护的内存。这通常表明其他内存已损坏。”`

为了消除显而易见的问题：我使用 Gimp 目录中的 svg 文件，所以我有一个已知的好文件。我使用 e: 作为保存到文件的位置，这样库就不会遇到任何安全/权限问题。我正在以管理员权限运行 Visual Studio，以防出现问题。我的盒子是 64 位的，我将 Local.testsettings 设置为“在 64 位机器上的 64 坑进程中运行测试”。

有任何想法吗？

我的代码是：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;
using System.ComponentModel;

namespace TA.Rasterizer
{
    /// <summary>
    /// Takes SVG image file type and converts to PNG image file type. 
    /// Gimp must be installed. Gimp dll location must be in the web.config
    /// file key "ThreatAnalyzer-DllDirectoryForGimp".
    /// <summary>
    /// http://msdn.microsoft.com/en-us/magazine/cc164123.aspx
    /// http://www.experts-exchange.com/Programming/Languages/C_Sharp/Q_24547525.html
    /// </summary>    /// </summary>
    public static class Rasterizer
    {
        // C:\Windows\System32
        [DllImport("kernel32.dll", SetLastError = true)]
        static extern bool SetDllDirectory(string pathname);

        [DllImport("libgobject-2.0-0.dll", SetLastError = true)]
        static extern void g_type_init();

        [DllImport("librsvg-2-2.dll", SetLastError = true)]
        static extern IntPtr rsvg_pixbuf_from_file_at_size(string file_name, int width, int height, out IntPtr error);

        [DllImport("libgdk_pixbuf-2.0-0.dll", CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Auto)]
        static extern bool gdk_pixbuf_save(IntPtr pixbuf, string filename, string type, out IntPtr error, __arglist);
        //static extern bool gdk_pixbuf_save_to_buffer(

        /// <summary>
        /// Get location of Gimp installed Dlls from web.config appsettings key/value.
        /// Key name is found in this.webConfigFileAppSettingsGimp
        /// </summary>
        /// <returns></returns>
        private static string GetGimpDllLocationFromConfigurationFile(bool webapp, string nonDefaultConfigFileName)
        {
            // connect to config file
            Configuration rasterizerConfiguration = new TA.Rasterizer.Configuration(webapp, nonDefaultConfigFileName);

            // grab config setting
            return rasterizerConfiguration.Get("ThreatAnalyzer-DllDirectoryForGimp");
        }

        /// <summary>
        /// http://msdn.microsoft.com/en-us/magazine/cc164123.aspx
        /// You must check that file exists after call in order to check success. 
        /// </summary>
        /// <param name="inputFileName">SVG file to be converted</param>
        /// <param name="outputFileName">PNG file as final product</param>
        /// <returns></returns>
        public static void SvgToPng(string inputFileName, string outputFileName, bool webapp, string nonDefaultConfigFileName)
        {
            string gimpDllLocation = GetGimpDllLocationFromConfigurationFile(webapp, nonDefaultConfigFileName);

            bool rasterizeSuccess = ExternRaster.RasterizeSvg(inputFileName, outputFileName, gimpDllLocation);

            if (!rasterizeSuccess)
            {
                Int32 err = System.Runtime.InteropServices.Marshal.GetLastWin32Error();
                throw new Win32Exception(err);
            }
        }

    /// <summary>
    /// http://msdn.microsoft.com/en-us/magazine/cc164123.aspx
    /// http://www.experts-exchange.com/Programming/Languages/C_Sharp/Q_24547525.html
    /// </summary>
    internal sealed class ExternRaster
    {

        public static bool RasterizeSvg(string inputFileName, string outputFileName, string gimpDllLocation)
        {
            bool callSuccessful = SetDllDirectory(gimpDllLocation);
            if (!callSuccessful)
            {
                throw new Exception("Could not set DLL directory");
            }
            g_type_init();
            IntPtr error1;
            IntPtr result = rsvg_pixbuf_from_file_at_size(@"E:\green.svg", -1, -1, out error1);
            if (error1 != IntPtr.Zero)
            {
                throw new Exception(Marshal.ReadInt32(error1).ToString());
            }

            IntPtr error2;
            callSuccessful = gdk_pixbuf_save(result, @"E:\green.jpg", "jpg", out error2, __arglist(null));
            if (!callSuccessful)
            {
                throw new Exception(error2.ToInt32().ToString());
            }

            return true;
        }

    }



    }
}

我从 MSTest 单元测试中访问代码：

    /// <summary>
    ///A test for RasterizeSvg
    ///</summary>
    [TestMethod()]
    public void RasterizeSvgTest()
    {
        // arrange
        string svgFileNameInAppDirectory = "1kijvsrewxxr3mdvlwitjvyu-pie.svg";

        string currentClassLibDirectory = Environment.CurrentDirectory.Replace(@"\bin\debug\","");
        string pathToAppData = Setup.GetDataPath(); 
        string inputFileName = Path.Combine(pathToAppData, svgFileNameInAppDirectory);
        string outputFileName = Path.Combine(pathToAppData, svgFileNameInAppDirectory.Replace("svg","png"));
        bool webapp = false; 
        string nonDefaultConfigFileName = string.Empty; 

        // act
        Rasterizer.SvgToPng(inputFileName, outputFileName, webapp, nonDefaultConfigFileName);

        // assert
        bool fileExists = File.Exists(outputFileName);
        Assert.IsTrue(fileExists);

        // cleanup
        if (fileExists)
        {
            File.Delete(outputFileName);
        }
    }
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1 回答 1

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的文档rsvg_pixbuf_from_file_at_size说

如果发生错误，则设置错误并返回 NULL。

对我来说，这可能意味着，当成功时，您的error1变量不会设置为有效指针。您应该改为测试返回值result。

我认为@GojiraDemonstah 所说的“jpg”与“jpeg”也很重要。

此外，rsvg_pixbuf_from_file_at_size分配一个新的GdkPixbuf并且您没有任何代码可以释放它。为此，您还应该拥有

[DllImport("libgobject-2.0-0.dll", SetLastError = true)]
static extern void g_object_unref(IntPtr obj);

在你的进口和

g_object_unref(result);

调用gdk_pixbuf_save后避免泄漏内存。

于 2013-06-17T13:24:35.933 回答