c# - 旋转图像导致内存不足异常

Question

当我在服务器上旋转图像时。它会导致内存不足异常。

    /// <summary>
    /// Rotates the specified img.
    /// </summary>
    /// <param name="img">The img.</param>
    /// <param name="rotationAngle">The rotation angle.</param>
    /// <returns></returns>
    public static Bitmap Rotate(Image img, float rotationAngle)
    {
        //create an empty Bitmap image
        Bitmap bmp = new Bitmap(img.Width, img.Height);

        //turn the Bitmap into a Graphics object
        using (Graphics gfx = Graphics.FromImage(bmp))
        {
            //now we set the rotation point to the center of our image
            gfx.TranslateTransform((float) bmp.Width/2, (float) bmp.Height/2);

            //now rotate the image
            gfx.RotateTransform(rotationAngle);

            gfx.TranslateTransform(-(float) bmp.Width/2, -(float) bmp.Height/2);

            //set the InterpolationMode to HighQualityBicubic so to ensure a high
            //quality image once it is transformed to the specified size
            gfx.SmoothingMode = SmoothingMode.HighQuality;
            gfx.InterpolationMode = InterpolationMode.HighQualityBicubic;
            gfx.CompositingQuality = CompositingQuality.HighQuality;
            gfx.PixelOffsetMode = PixelOffsetMode.HighQuality;

            //now draw our new image onto the graphics object
            gfx.DrawImage(img, new Point(0, 0));
        }

        //return the image
        return bmp;
    }

异常发生在这一行:gfx.DrawImage(img, new Point(0, 0));我在互联网上搜索了一下，发现有很多人遇到了类似的问题，但都没有解决方案。

有解决办法吗？或者除了 GDI+ 之外还有其他库可以用来旋转我的图像吗？也许 WPF 中有什么东西？

堆栈跟踪:

[OutOfMemoryException: Out of memory.]
   System.Drawing.Graphics.CheckErrorStatus(Int32 status) +1588745
   System.Drawing.Graphics.DrawImage(Image image, Int32 x, Int32 y) +227
   System.Drawing.Graphics.DrawImage(Image image, Point point) +26
   Chucksoft.Core.Drawing.ImageResizer.Rotate(Image img, Single rotationAngle) in C:\Projects\ChucksoftCore\Branches\2.5.0\Source\Chucksoft.Core\Drawing\ImageResizer.cs:245
   Chucksoft.Core.Drawing.ImageResizer.Rotate(Byte[] b, Single angle, ImageFormat format) in C:\Projects\ChucksoftCore\Branches\2.5.0\Source\Chucksoft.Core\Drawing\ImageResizer.cs:22
   TheMemorableMoments.Domain.Services.ImageService.Rotate(IEnumerable`1 media, User user, Single angle) in C:\Projects\TheMemorableMoments\Branches\2.1.0\Source\TheMemorableMoments\Domain\Services\ImageService.cs:34
   TheMemorableMoments.Domain.Services.ImageService.RotateLeft(List`1 media, User user) in C:\Projects\TheMemorableMoments\Branches\2.1.0\Source\TheMemorableMoments\Domain\Services\ImageService.cs:69
   TheMemorableMoments.UI.Controllers.User.PhotosController.Rotate(IMediaFiles media, Action`2 resizeMethod) in C:\Projects\TheMemorableMoments\Branches\2.1.0\Source\TheMemorableMoments.UI\Controllers\User\PhotosController.cs:408
   TheMemorableMoments.UI.Controllers.User.PhotosController.RotateLeft(Media media) in C:\Projects\TheMemorableMoments\Branches\2.1.0\Source\TheMemorableMoments.UI\Controllers\User\PhotosController.cs:396
   lambda_method(Closure , ControllerBase , Object[] ) +127
   System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters) +258
   System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters) +39
   System.Web.Mvc.<>c__DisplayClassd.<InvokeActionMethodWithFilters>b__a() +125
   System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodFilter(IActionFilter filter, ActionExecutingContext preContext, Func`1 continuation) +640
   System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodWithFilters(ControllerContext controllerContext, IList`1 filters, ActionDescriptor actionDescriptor, IDictionary`2 parameters) +312
   System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext controllerContext, String actionName) +709
   System.Web.Mvc.Controller.ExecuteCore() +162
   System.Web.Mvc.<>c__DisplayClass8.<BeginProcessRequest>b__4() +58
   System.Web.Mvc.Async.<>c__DisplayClass1.<MakeVoidDelegate>b__0() +20
   System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +453
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

Answer 1

我成功了。我从来没有想过“内存不足”异常。相反，我使用了 Image 类的 RotateFlip 方法。查看 RotateFlip 代码，在 Reflector 中，它是直接调用 Native Library。这种方法的缺点是您只能以 90 度为增量旋转。对我来说效果很好。