System.Drawing.Graphics.DrawImage C# (CSharp) Method

        public void DrawImage(Image image, PointF [] destPoints, RectangleF srcRect, GraphicsUnit srcUnit)
        {
            if (image == null)
                throw new ArgumentNullException ("image");
            if (destPoints == null)
                throw new ArgumentNullException ("destPoints");

            if (destPoints.Length < 3)
                throw new ArgumentException ("Destination points must be an array with a length of 3 or 4. " +
                                             "A length of 3 defines a parallelogram with the upper-left, upper-right, " +
                                             "and lower-left corners. A length of 4 defines a quadrilateral with the " +
                                             "fourth element of the array specifying the lower-right coordinate.");

            // Windows throws a Not Implemented error if the points are more than 3
            if (destPoints.Length > 3)
                throw new NotImplementedException ();

            var srcRect1 = srcRect;

            // If the source units are not the same we need to convert them
            // The reason we check for Pixel here is that our graphics already has the Pixel's baked into the model view transform
            if (srcUnit != graphicsUnit && srcUnit != GraphicsUnit.Pixel)
            {
                ConversionHelpers.GraphicsUnitConversion (srcUnit, graphicsUnit, image.HorizontalResolution, image.VerticalResolution,  ref srcRect1);
            }

            // Obtain the subImage
            var subImage = image.NativeCGImage.WithImageInRect (srcRect1.ToCGRect ());

            // If we do not have anything to draw then we exit here
            if (subImage.Width == 0 || subImage.Height == 0)
                return;

            // create our rectangle.  Offset is 0 because the CreateGeometricTransform bakes our x,y offset in there.
            var rect = new RectangleF (0,0, destPoints [1].X - destPoints [0].X, destPoints [2].Y - destPoints [0].Y);

            // We need to flip our Y axis so the image appears right side up
            var geoTransform = new CGAffineTransform (1, 0, 0, -1, 0, rect.Height);

            // Make sure we scale the image in case the source rectangle
            // overruns our subimage bounds (width and/or height)
            float scaleX = subImage.Width/srcRect1.Width;
            float scaleY = subImage.Height/srcRect1.Height;
            geoTransform.Scale (scaleX, scaleY);

            //var geott = GeomUtilities.CreateGeometricTransform (rect, destPoints);
            geoTransform.Multiply (GeomUtilities.CreateGeometricTransform (rect, destPoints));

            // Apply our transform to the context
            context.ConcatCTM (geoTransform);

            // now we draw our image.
            context.DrawImage(rect.ToCGRect (), subImage);

            // Now we revert our image transform from the context
            var revert = CGAffineTransform.CGAffineTransformInvert (geoTransform);
            context.ConcatCTM (revert);
        }

 public void _drawTabHeader(Graphics nGraphics, Font nFont, Rectangle nRectangle)
 {
     int width_ = nRectangle.Height - 2;
     switch (mSideTabStatus)
     {
         case SideTabStatus_.mNormal_:
             ControlPaint.DrawBorder3D(nGraphics, nRectangle, Border3DStyle.RaisedInner);
             nGraphics.DrawImage(mSideTabImage, nRectangle.X + 1, nRectangle.Y + 1, width_, width_);
             nGraphics.DrawString(mSideTabName, nFont, SystemBrushes.ControlText, new PointF(nRectangle.X + width_ + 2, nRectangle.Y + 2));
             break;
         case SideTabStatus_.mSelected_:
             ControlPaint.DrawBorder3D(nGraphics, nRectangle, Border3DStyle.Sunken);
             nGraphics.DrawImage(mSideTabImage, nRectangle.X + 1, nRectangle.Y + 1, width_, width_);
             nGraphics.DrawString(mSideTabName, nFont, SystemBrushes.ControlText, new PointF(nRectangle.X + width_ + 2, nRectangle.Y + 2));
             break;
         case SideTabStatus_.mDragged_:
             ControlPaint.DrawBorder3D(nGraphics, nRectangle, Border3DStyle.RaisedInner);
             nRectangle.X += 1;
             nRectangle.Y += 1;
             nRectangle.Width -= 2;
             nRectangle.Height -= 2;
             nGraphics.FillRectangle(SystemBrushes.ControlDarkDark, nRectangle);
             nGraphics.DrawString(mSideTabName, nFont, SystemBrushes.HighlightText, new PointF(nRectangle.X + width_ , nRectangle.Y));
             break;
     }
 }