Interface PrintIterator

  • All Known Implementing Classes:
    AbstractIterator

    public interface PrintIterator
    Splits a Print into multiple PrintPieces, according to the space available on the graphics device. PrintIterators are created by Print.iterator(Device, GC), and are initialized with the graphics device passed to that method.
    • Method Summary

      All Methods Instance Methods Abstract Methods 
      Modifier and Type Method Description
      PrintIterator copy()
      Returns a copy of this PrintIterator, with all relevant internal states.
      boolean hasNext()
      Identifies whether any PrintPieces remain.
      org.eclipse.swt.graphics.Point minimumSize()
      Returns the minimum size PrintPiece that this Print should be broken into.
      PrintPiece next​(int width, int height)
      Returns the next PrintPiece for the Print.
      org.eclipse.swt.graphics.Point preferredSize()
      Returns the smallest size PrintPiece that this Print would be broken into if print space was unlimited.
    • Method Detail

      • hasNext

        boolean hasNext()
        Identifies whether any PrintPieces remain.
        Returns:
        whether any PrintPieces remain.
      • next

        PrintPiece next​(int width,
                        int height)
        Returns the next PrintPiece for the Print.

        If all of the remaining contents of the Print will fit in the given space, the returned PrintPiece will include all remaining contents, and subsequent calls to hasNext() will return false.

        If some, but not all of the remaining contents will fit in the given space, the returned PrintPiece will contain as much of the contents as possible, and subsequent calls to hasNext() will return true.

        If there is insufficient space for any of the remaining contents in the given space, null is returned, and subsequent calls to hasNext() will return true.

        If subsequent calls to PrintIterator#hasNext() return true, this PrintIterator cannot fit any more in the given print area. Future calls to this method should provide a fresh print area. At the top level, each returned PrintPiece contains an entire page.

        Note: PrintIterator classes should call PaperClips.next(PrintIterator, int, int) instead of calling this method directly, to gain automatic results checking to ensure all Print classes are well-behaved.

        Parameters:
        width - the width available on the graphics device for this iteration.
        height - the height available on the graphics device for this iteration.
        Returns:
        a PrintPiece that paints the next part of the Print, or null if the print area is too small. The size of the returned PrintPiece must NOT exceed the width and height indicated.
      • minimumSize

        org.eclipse.swt.graphics.Point minimumSize()
        Returns the minimum size PrintPiece that this Print should be broken into.

        Note that the size calculated by this method is a "preferred minimum," or the smallest size that the Print should normally be broken into. For a TextPrint, this is the size of the widest individual word, in pixels.

        This is distinct from the "absolute minimum," which is the smallest size that a Print could possibly be broken into. For a TextPrint, this is the size of the widest individual letter, in pixels.

        Returns:
        a Point indicating the minimum size PrintPiece this PrintIterator should be broken into.
      • preferredSize

        org.eclipse.swt.graphics.Point preferredSize()
        Returns the smallest size PrintPiece that this Print would be broken into if print space was unlimited.

        For a TextPrint, this is the size of the widest line (or the whole TextPrint, if there are no line breaks), in pixels.

        Returns:
        a Point indicating the smallest size PrintPiece that this Print would be broken into if print space was unlimited.
      • copy

        PrintIterator copy()
        Returns a copy of this PrintIterator, with all relevant internal states. This method allows a containing iterator to "back up" the current state of its child iterators before invoking next(int, int) on them. The containing iterator can then safely attempt iterating its child(ren) in a variety of ways before selecting which way is the most appropriate.
        Returns:
        a deep clone of the target with all relevant internal states.