/**
* Transforms the given Rectangle into the image coordinate system which is [0,1]x[0,1] by default
*/
private Rectangle TransformIntersection(Matrix imageCTM, Rectangle rect)
{
AffineTransform t = new AffineTransform(imageCTM[Matrix.I11], imageCTM[Matrix.I12],
imageCTM[Matrix.I21], imageCTM[Matrix.I22],
imageCTM[Matrix.I31], imageCTM[Matrix.I32]);
Point2D p1;
Point2D p2;
Point2D p3;
Point2D p4;
try
{
p1 = t.InverseTransform(new Point(rect.Left, rect.Bottom), null);
p2 = t.InverseTransform(new Point(rect.Left, rect.Top), null);
p3 = t.InverseTransform(new Point(rect.Right, rect.Bottom), null);
p4 = t.InverseTransform(new Point(rect.Right, rect.Top), null);
}
catch (InvalidOperationException e)
{
throw new SystemException(e.Message, e);
}
return(GetRectangle(p1, p2, p3, p4));
}
/// <summary>
/// Builds the
/// <see cref="iText.Kernel.Colors.Color"/>
/// object representing the linear gradient with specified configuration
/// that fills the target bounding box.
/// </summary>
/// <param name="targetBoundingBox">the bounding box to be filled in current space</param>
/// <param name="contextTransform">
/// the transformation from the base coordinates space into
/// the current space. The
/// <see langword="null"/>
/// value is valid and can be used
/// if there is no transformation from base coordinates to current space
/// specified, or it is equal to identity transformation.
/// </param>
/// <param name="document">
/// the
/// <see cref="iText.Kernel.Pdf.PdfDocument"/>
/// for which the linear gradient would be built.
/// </param>
/// <returns>
/// the constructed
/// <see cref="iText.Kernel.Colors.Color"/>
/// or
/// <see langword="null"/>
/// if no color to be applied
/// or base gradient vector has been specified
/// </returns>
public virtual Color BuildColor(Rectangle targetBoundingBox, AffineTransform contextTransform, PdfDocument
document)
{
// TODO: DEVSIX-4136 the document argument would be required for opaque gradients (as we would need to create a mask form xObject)
Point[] baseCoordinatesVector = GetGradientVector(targetBoundingBox, contextTransform);
if (baseCoordinatesVector == null || this.stops.IsEmpty())
{
// Can not create gradient color with 0 stops or null coordinates vector
return(null);
}
// evaluate actual coordinates and transformation
AffineTransform shadingTransform = new AffineTransform();
if (contextTransform != null)
{
shadingTransform.Concatenate(contextTransform);
}
AffineTransform gradientTransformation = GetCurrentSpaceToGradientVectorSpaceTransformation(targetBoundingBox
, contextTransform);
if (gradientTransformation != null)
{
try {
if (targetBoundingBox != null)
{
targetBoundingBox = Rectangle.CalculateBBox(JavaUtil.ArraysAsList(gradientTransformation.InverseTransform(
new Point(targetBoundingBox.GetLeft(), targetBoundingBox.GetBottom()), null), gradientTransformation.InverseTransform
(new Point(targetBoundingBox.GetLeft(), targetBoundingBox.GetTop()), null), gradientTransformation.InverseTransform
(new Point(targetBoundingBox.GetRight(), targetBoundingBox.GetBottom()), null), gradientTransformation
.InverseTransform(new Point(targetBoundingBox.GetRight(), targetBoundingBox.GetTop()), null)));
}
shadingTransform.Concatenate(gradientTransformation);
}
catch (NoninvertibleTransformException) {
LogManager.GetLogger(GetType()).Error(iText.IO.LogMessageConstant.UNABLE_TO_INVERT_GRADIENT_TRANSFORMATION
);
}
}
PdfShading.Axial axial = CreateAxialShading(baseCoordinatesVector, this.stops, this.spreadMethod, targetBoundingBox
);
if (axial == null)
{
return(null);
}
PdfPattern.Shading shading = new PdfPattern.Shading(axial);
if (!shadingTransform.IsIdentity())
{
double[] matrix = new double[6];
shadingTransform.GetMatrix(matrix);
shading.SetMatrix(new PdfArray(matrix));
}
return(new PatternColor(shading));
}