/// <summary>
/// When in the svg element
/// <c>overflow</c>
/// is
/// <c>visible</c>
/// the corresponding formXObject
/// should have a BBox (form XObject’s bounding box; see PDF 32000-1:2008 - 8.10.2 Form Dictionaries)
/// that should cover the entire svg space (page in pdf) in order to be able to show parts of the element which are outside the current element viewPort.
/// </summary>
/// <remarks>
/// When in the svg element
/// <c>overflow</c>
/// is
/// <c>visible</c>
/// the corresponding formXObject
/// should have a BBox (form XObject’s bounding box; see PDF 32000-1:2008 - 8.10.2 Form Dictionaries)
/// that should cover the entire svg space (page in pdf) in order to be able to show parts of the element which are outside the current element viewPort.
/// To do this, we get the inverse matrix of all the current transformation matrix changes and apply it to the root viewPort.
/// This allows you to get the root rectangle in the final coordinate system.
/// </remarks>
/// <param name="context">current context to get canvases and view ports</param>
/// <param name="stream">stream to write a BBox</param>
private static void WriteBBoxAccordingToVisibleOverflow(SvgDrawContext context, PdfStream stream)
{
IList <PdfCanvas> canvases = new List <PdfCanvas>();
int canvasesSize = context.Size();
for (int i = 0; i < canvasesSize; i++)
{
canvases.Add(context.PopCanvas());
}
AffineTransform transform = new AffineTransform();
for (int i = canvases.Count - 1; i >= 0; i--)
{
PdfCanvas canvas = canvases[i];
Matrix matrix = canvas.GetGraphicsState().GetCtm();
transform.Concatenate(new AffineTransform(matrix.Get(0), matrix.Get(1), matrix.Get(3), matrix.Get(4), matrix
.Get(6), matrix.Get(7)));
context.PushCanvas(canvas);
}
try {
transform = transform.CreateInverse();
}
catch (NoninvertibleTransformException) {
// Case with zero determiner (see PDF 32000-1:2008 - 8.3.4 Transformation Matrices - NOTE 3)
// for example with a, b, c, d in cm equal to 0
stream.Put(PdfName.BBox, new PdfArray(new Rectangle(0, 0, 0, 0)));
ILog logger = LogManager.GetLogger(typeof(AbstractBranchSvgNodeRenderer));
logger.Warn(SvgLogMessageConstant.UNABLE_TO_GET_INVERSE_MATRIX_DUE_TO_ZERO_DETERMINANT);
return;
}
Point[] points = context.GetRootViewPort().ToPointsArray();
transform.Transform(points, 0, points, 0, points.Length);
Rectangle bbox = Rectangle.CalculateBBox(JavaUtil.ArraysAsList(points));
stream.Put(PdfName.BBox, new PdfArray(bbox));
}