Package com.itextpdf.kernel.colors.gradients

Class AbstractLinearGradientBuilder

java.lang.Object
com.itextpdf.kernel.colors.gradients.AbstractGradientBuilder<Point>
com.itextpdf.kernel.colors.gradients.AbstractLinearGradientBuilder
All Implemented Interfaces:
IGradientBuilder
Direct Known Subclasses:
LinearGradientBuilder, StrategyBasedLinearGradientBuilder
public abstract class AbstractLinearGradientBuilder extends AbstractGradientBuilder<Point>
Base class for linear gradient builders implementations.

Color transitions for linear gradients are defined by a series of color stops along a gradient vector. A gradient normal defines how the colors in a vector are painted to the surface. For a linear gradient, a normal is a line perpendicular to the vector.

Contains the main logic that works with stop colors and creation of the resulted pdf color object.

  • Field Details

  • Constructor Details

    • AbstractLinearGradientBuilder

      public AbstractLinearGradientBuilder()

  • Method Details

    • addColorStop

      @Deprecated public AbstractLinearGradientBuilder addColorStop (GradientColorStop gradientColorStop)
      Deprecated.
      use AbstractGradientBuilder.addStopColor(GradientColorStop) instead
      Adds the new color stop to the end (more info).

      Note: if the previously added color stop's offset would have grater offset than the added one, then the new offset would be normalized to be equal to the previous one. (Comparison made between relative on coordinates vector offsets. If any of them has the absolute offset, then the absolute value would converted to relative first.)

      Parameters:
      gradientColorStop - the gradient stop color to add
      Returns:
      the current builder instance

    • setSpreadMethod

      @Deprecated public AbstractLinearGradientBuilder setSpreadMethod (GradientSpreadMethod gradientSpreadMethod)
      Deprecated.
      use AbstractGradientBuilder.setSpread(GradientSpreadMethod) instead
      Set the spread method to use for the gradient
      Parameters:
      gradientSpreadMethod - the gradient spread method to set
      Returns:
      the current builder instance

    • getColorStops

      @Deprecated public List<GradientColorStop> getColorStops()
      Deprecated.
      use AbstractGradientBuilder.getStopColors() instead
      Get the copy of current color stops list. Note that the stop colors are not copied here
      Returns:
      the copy of current stop colors list

    • getSpreadMethod

      @Deprecated public GradientSpreadMethod getSpreadMethod()
      Deprecated.
      use AbstractGradientBuilder.getSpread() instead
      Get the current spread method
      Returns:
      the current spread method

    • getGradientVector

      @Deprecated protected abstract Point[] getGradientVector (Rectangle targetBoundingBox, AffineTransform contextTransform)
      Deprecated.
      use AbstractGradientBuilder.getGradientVectorWithTransform(Rectangle, AffineTransform)
      Returns the base gradient vector in gradient vector space. This vector would be set as shading coordinates vector and its length would be used to translate all color stops absolute offsets into the relatives.
      Parameters:
      targetBoundingBox - the rectangle to be covered by constructed color in current space
      contextTransform - the current canvas transformation
      Returns:
      the array of exactly two elements specifying the gradient coordinates vector

    • getCurrentSpaceToGradientVectorSpaceTransformation

      @Deprecated protected AffineTransform getCurrentSpaceToGradientVectorSpaceTransformation (Rectangle targetBoundingBox, AffineTransform contextTransform)
      Deprecated.
      use AbstractGradientBuilder.getGradientVectorWithTransform(Rectangle, AffineTransform)
      Returns the current space to gradient vector space transformations that should be applied to the shading color. The transformation should be invertible as the current target bounding box coordinates should be transformed into the resulted shading space coordinates.
      Parameters:
      targetBoundingBox - the rectangle to be covered by constructed color in current space
      contextTransform - the current canvas transformation
      Returns:
      the additional transformation to be concatenated to the current for resulted shading or null if no additional transformation is specified

    • evaluateCoveringDomain

      protected static double[] evaluateCoveringDomain (Point[] coords, Rectangle toCover)
      Evaluates the minimal domain that covers the box with vector normals. The domain corresponding to the initial vector is [0, 1].
      Parameters:
      coords - the array of exactly two elements that describe the base vector (corresponding to [0,1] domain, that need to be adjusted to cover the box
      toCover - the box that needs to be covered
      Returns:
      the array of two elements in ascending order specifying the calculated covering domain

    • createCoordinatesForNewDomain

      protected static Point[] createCoordinatesForNewDomain (double[] newDomain, Point[] baseVector)
      Expand the base vector to cover the new domain
      Parameters:
      newDomain - the array of exactly two elements that specifies the domain that should be covered by the created vector
      baseVector - the array of exactly two elements that specifies the base vector which corresponds to [0, 1] domain
      Returns:
      the array of two

    • computeCoveringDomain

      protected double[] computeCoveringDomain (Point[] coords, Rectangle toCover)
      Computes the minimal domain that covers the box with vector normals. The domain corresponding to the initial vector is [0, 1].
      Specified by:
      computeCoveringDomain in class AbstractGradientBuilder<Point>
      Parameters:
      coords - the array of exactly two elements that describe the base vector (corresponding to [0,1] domain, that need to be adjusted to cover the box
      toCover - the box that needs to be covered
      Returns:
      the array of two elements in ascending order specifying the calculated covering domain

    • createCoordsForNewDomain

      protected Point[] createCoordsForNewDomain (double[] newDomain, Point[] baseVector)
      Expand the base vector to cover the new domain
      Specified by:
      createCoordsForNewDomain in class AbstractGradientBuilder<Point>
      Parameters:
      newDomain - the array of exactly two elements that specifies the domain that should be covered by the created vector
      baseVector - the array of exactly two elements that specifies the base vector which corresponds to [0, 1] domain
      Returns:
      the array of two

    • createCoveringCoordinates

      protected Point[] createCoveringCoordinates (Rectangle targetBoundingBox)
      Creates some gradient vector which would cover the target bounding box.
      Specified by:
      createCoveringCoordinates in class AbstractGradientBuilder<Point>
      Parameters:
      targetBoundingBox - the bounding box to cover
      Returns:
      constructed gradient vector

    • getBaseVectorLength

      protected double getBaseVectorLength (Point[] coordinates)
      Evaluates base vector length for future color stops spreading.
      Specified by:
      getBaseVectorLength in class AbstractGradientBuilder<Point>
      Parameters:
      coordinates - the base vector
      Returns:
      base vector length

    • createCoordsDictEntry

      protected PdfArray createCoordsDictEntry (Point[] coordinates)
      Converts gradient vector into pdf coordinates array for shading.
      Specified by:
      createCoordsDictEntry in class AbstractGradientBuilder<Point>
      Parameters:
      coordinates - vector to convert
      Returns:
      constructed pdf array

    • createPdfShading

      protected AbstractPdfShading createPdfShading (PdfColorSpace colorSpace, PdfArray coordinates, PdfArray coordinatesDomain, IPdfFunction stopsFunction)
      Creates the gradient shading object.
      Specified by:
      createPdfShading in class AbstractGradientBuilder<Point>
      Parameters:
      colorSpace - colorspace to use
      coordinates - gradient coordinates
      coordinatesDomain - gradient coordinates domain
      stopsFunction - color stops function
      Returns:
      constructed gradient shading