Question

I am using the Cairo.Matrix dll in my monoandroid application to load the some System.Drawing.Drawing2D.Matix Class Methods it works fine at build time but at run time the Matrix class from Cairo.Matrix gives an error “System.NullReferenceException: Object reference not set to an instance of an object.”
when I intialize the Cairo.Matrix Class error is “Exception in loading dicom filelibcairo-2.dll.”

This below code I am trying……….

using System; 

using System.Drawing; 

using Medsynaptic.Common;

using Medsynaptic.Imaging1.Mathematics; 

**using Matrix = Cairo.Matrix;**

public class SpatialTransform : ISpatialTransform 

    { 

private Cairo.Matrix _cumulativeTransform; 

        private Cairo.Matrix _transform; 

public PointF ConvertToDestination(PointF sourcePoint) 

        { 

            double x = 0.0, y = 0.0;         

            this.CumulativeTransform.TransformPoint(ref x, ref y);      

            PointF point = new PointF((float)x, (float)y); 

            return point; 
        } 

Here it show Null Ref Exception:Object reference not set to an instance of an object

public Cairo.Matrix CumulativeTransform       
    {        

        get 

        {      

            Calculate(); 

            return _cumulativeTransform; 

        } 

    } 

 protected virtual void Calculate() 

    { 

        if (!this.RecalculationRequired) 

            return; 

ERROR @ if condition:- Object reference not set to an instance of an object

        if (_cumulativeTransform == null) 

            _cumulativeTransform = new Cairo.Matrix(); 


       // _cumulativeTransform.Reset(); 

        _cumulativeTransform.InitIdentity(); 
} 

} 

this is android debugger show an output with error Error In loading libcairo-2.dll

On Create Call

Picture box OnAttachedToWindow.

 display.Height 430

  firstRowHeight 43

  pictureBox.DisplayHeight 301

Displaying image /mnt/sdcard/Images/Series1/1.2.840.113619.2.22.287.1.20040913.195606.dcm

Request garbage collector to initiate.

Presentation Image created.

 Calling invalidate in Render Mode

Renderer will take care of it.

 Calling DrawSceneGraph

Error In loading

libcairo-2.dll

 Picture box on draw called

 Displayed medsynaptic.medsynapse/desktopexecutable.Activity1: +1m10s925ms

Answer 1

Unfortunately, the inclusion of Mono.Cairo.dll was a mistake; it can’t work, as it depends upon the native libcairo.so, which Android doesn’t provide. Mono.Cairo.dll will be removed in the next release.