OS X Issue

[alexgoldstone]

I am using .Net Core 2.0 on OS X 10.12.6

Per the instructions, my .csproj file contains:

<PackageReference Include="runtime.osx.10.10-x64.CoreCompat.System.Drawing" Version="5.4.0-r8" />

I have also tried with version 1 of the above runtime with same results.

My code looks like:

using (System.IO.Stream picStream = ImageFactory.BuildImage("AB123", 60, 307, 20, 10, ImageFormatType.Png))
            {
                byte[] image = new byte[picStream.Length];
                picStream.Read(image, 0, (int)picStream.Length);
                var uri = Convert.ToBase64String(image);
            }

I get the following error:

fail: Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware[0]
      An unhandled exception has occurred while executing the request
System.NotImplementedException: The requested feature is not implemented [GDI+ status: NotImplemented]
   at System.Drawing.GDIPlus.CheckStatus(Status status)
   at System.Drawing.Bitmap..ctor(Int32 width, Int32 height, PixelFormat format)
   at CaptchaGen.NetCore.ImageFactory.BuildImage(String captchaCode, Int32 imageHeight, Int32 imageWidth, Int32 fontSize, Int32 distortion, ImageFormatType imgType)
   at api.Controllers.CaptchaController.<Create>d__3.MoveNext() in /api/Controllers/CaptchaController.cs:line 53

My interpretation of the above is that the OS X runtime does not implement GDIPlus.CheckStatus which is used by this library rendering the library incompatible with OS X.

Any assistance you can provide will be gratefully received.

[alexgoldstone]

Also raised a ticket here: https://github.com/CoreCompat/System.Drawing/issues/12#issuecomment-347760325

Two suggestions were:

1. The official https://www.nuget.org/packages/System.Drawing.Common/ is out. give it a try.

2. You (or CaptchaGen) trying to create an image in a format which is not supported by (your copy of) libgdiplus, the native library backing System.Drawing.Common and CoreCompat.System.Drawing.

I have installed the latest System.Drawing.Common but now the error I get is:

'System.TypeInitializationException: The type initializer for 'System.Drawing.GDIPlus' threw an exception. ---> System.DllNotFoundException: Unable to load DLL 'gdiplus': The specified module or one of its dependencies could not be found.
 (Exception from HRESULT: 0x8007007E)
   at System.Drawing.GDIPlus.GdiplusStartup(UInt64& token, GdiplusStartupInput& input, GdiplusStartupOutput& output)
   at System.Drawing.GDIPlus..cctor()
   --- End of inner exception stack trace ---
   at System.Drawing.GDIPlus.GdipCreateBitmapFromScan0(Int32 width, Int32 height, Int32 stride, PixelFormat format, IntPtr scan0, IntPtr& bmp)
   at System.Drawing.Bitmap..ctor(Int32 width, Int32 height, PixelFormat format)
   at CaptchaGen.NetCore.ImageFactory.BuildImage(String captchaCode, Int32 imageHeight, Int32 imageWidth, Int32 fontSize, Int32 distortion, ImageFormatType imgType)
   at api.Controllers.CaptchaController.Create() in /api/Controllers/CaptchaController.cs:line 55'

Is this a problem with the above dependency or does CaptchaGen.NetCore need to be updated to use the above dependency instead?

[alexgoldstone]

It seems with the new System.Drawing.Common dependency, you have to install mono-libgdiplus manually. I have now done this and get the following error:

System.NotImplementedException: The requested feature is not implemented [GDI+ status: NotImplemented]
   at System.Drawing.GDIPlus.CheckStatus(Status status)
   at System.Drawing.Bitmap..ctor(Int32 width, Int32 height, PixelFormat format)
   at CaptchaGen.NetCore.ImageFactory.BuildImage(String captchaCode, Int32 imageHeight, Int32 imageWidth, Int32 fontSize, Int32 distortion, ImageFormatType imgType)
   at api.Controllers.CaptchaController.Create() in /api/Controllers/CaptchaController.cs:line 55

So i have now confirmed that I get the same error whether I use runtime.osx.10.10-x64.CoreCompat.System.Drawing or the new System.Drawing.Common once I have mono-libgdiplus installed.

[alexgoldstone]

Format64bppArgb is not an implemented format for OS X.

Using Format32bppArgb should work.

[the-mighty-mo]

I know this issue is ancient, but this issue (still) exists on all non-Windows systems.

Switching from Format64bppArgb to Format32bppArgb (ImageFactory.cs lines 57, 59) fixes the issue. This has been tested on OS X, Windows 10, Ubuntu, and Raspberry Pi OS.

Edit: I should also point out that almost all monitors can't display more than 32-bit color anyways.

[Michael-List]

@the-mighty-mo I can confirm your problem, same when using docker image (mcr.microsoft.com/dotnet/aspnet:5.0) @yangzhongke I made a pull request to fix this issue. Please see: https://github.com/yangzhongke/CaptchaGen.NetCore/pull/3