sizerequirements.java

gcc的组建

   * @param offsets will hold the offset values for each component
   * @param spans will hold the span values for each component
   * @param forward whether the components should be placed in the forward
   *     direction (left-right or top-bottom) or reverse direction
   *     (right-left or bottom-top)
   */
  public static void calculateTiledPositions(int allocated,
                                             SizeRequirements total,
                                             SizeRequirements[] children,
                                             int[] offsets, int[] spans,
                                             boolean forward)
  {
    int span = 0;
    if (forward)
      {
        int offset = 0;
        for (int i = 0; i < children.length; i++)
          {
            offsets[i] = offset;
            spans[i] = children[i].preferred;
            span += spans[i];
            offset += children[i].preferred;
          }
      }
    else
      {
        int offset = allocated;
        for (int i = 0; i < children.length; i++)
          {
            offset -= children[i].preferred;
            offsets[i] = offset;
            span += spans[i];
            spans[i] = children[i].preferred;
          }
      }
    // Adjust spans so that we exactly fill the allocated region. If
    if (span > allocated)
      adjustSmaller(allocated, children, spans, span);
    else if (span < allocated)
      adjustGreater(allocated, children, spans, span);

    // Adjust offsets.
    if (forward)
      {
        int offset = 0;
        for (int i = 0; i < children.length; i++)
          {
            offsets[i] = offset;
            offset += spans[i];
          }
      }
    else
      {
        int offset = allocated;
        for (int i = 0; i < children.length; i++)
          {
            offset -= spans[i];
            offsets[i] = offset;
          }
      }
  }

  private static void adjustSmaller(int allocated, SizeRequirements[] children,
                                    int[] spans, int span)
  {
    // Sum up (prefSize - minSize) over all children
    int sumDelta = 0;
    for (int i = 0; i < children.length; i++)
      sumDelta += children[i].preferred - children[i].minimum;

    // If we have sumDelta == 0, then all components have prefSize == maxSize
    // and we can't do anything about it.
    if (sumDelta == 0)
      return;

    // Adjust all sizes according to their preferred and minimum sizes.
    for (int i = 0; i < children.length; i++)
      {
        double factor = ((double) (children[i].preferred - children[i].minimum))
                        / ((double) sumDelta);
        // In case we have a sumDelta of 0, the factor should also be 0.
        if (Double.isNaN(factor))
          factor = 0;
        spans[i] -= factor * (span - allocated);
      }
  }

  private static void adjustGreater(int allocated, SizeRequirements[] children,
                                    int[] spans, int span)
  {
    // Sum up (maxSize - prefSize) over all children
    long sumDelta = 0;
    for (int i = 0; i < children.length; i++)
      {
        sumDelta += children[i].maximum - children[i].preferred;
      }

    // If we have sumDelta == 0, then all components have prefSize == maxSize
    // and we can't do anything about it.
    if (sumDelta == 0)
      return;

    // Adjust all sizes according to their preferred and minimum sizes.
    for (int i = 0; i < children.length; i++)
      {
        double factor = ((double) (children[i].maximum - children[i].preferred))
                        / ((double) sumDelta);
        spans[i] += factor * (allocated - span);
      }
  }

  /**
   * Calculate the offsets and spans of the components, when they should
   * be placed end-to-end.
   *
   * You must specify the amount of allocated space in
   * <code>allocated</code>, the total size requirements of the set of
   * components in <code>total</code> (this can be calculated using
   * {@link #getTiledSizeRequirements} and the size requirements of the
   * components in <code>children</code>.
   *
   * The calculated offset and span values for each component are then
   * stored in the arrays <code>offsets</code> and <code>spans</code>.
   *
   * The components are tiled in the forward direction, beginning with
   * an offset of 0.
   * 
   * @param allocated the amount of allocated space
   * @param total the total size requirements of the components
   * @param children the size requirement of each component
   * @param offsets will hold the offset values for each component
   * @param spans will hold the span values for each component
   */
  public static void calculateAlignedPositions(int allocated,
                                               SizeRequirements total,
                                               SizeRequirements[] children,
                                               int[] offsets, int[] spans)
  {
    calculateAlignedPositions(allocated, total, children, offsets, spans,
                              true);
  }

  /**
   * Calculate the offsets and spans of the components, when they should
   * be placed end-to-end.
   *
   * You must specify the amount of allocated space in
   * <code>allocated</code>, the total size requirements of the set of
   * components in <code>total</code> (this can be calculated using
   * {@link #getTiledSizeRequirements} and the size requirements of the
   * components in <code>children</code>.
   *
   * The calculated offset and span values for each component are then
   * stored in the arrays <code>offsets</code> and <code>spans</code>.
   *
   * Depending on the value of <code>forward</code> the components are
   * placed in the forward direction (left-right or top-bottom), where
   * the offsets begin with 0, or in the reverse direction
   * (right-left or bottom-top).
   *
   * @param allocated the amount of allocated space
   * @param total the total size requirements of the components
   * @param children the size requirement of each component
   * @param spans will hold the span values for each component
   * @param forward whether the components should be placed in the forward
   *     direction (left-right or top-bottom) or reverse direction
   *     (right-left or bottom-top)
   */
  public static void calculateAlignedPositions(int allocated,
                                               SizeRequirements total,
                                               SizeRequirements[] children,
                                               int[] offset, int[] spans,
                                               boolean forward)
  {
    // First we compute the position of the baseline.
    float baseline = allocated * total.alignment;

    // Now we can layout the components along the baseline.
    for (int i = 0; i < children.length; i++)
      {
        float align = children[i].alignment;
        // Try to fit the component into the available space.
        int[] spanAndOffset = new int[2];
        if (align < .5F || baseline == 0)
          adjustFromRight(children[i], baseline, allocated, spanAndOffset);
        else
          adjustFromLeft(children[i], baseline, allocated, spanAndOffset);
        spans[i] = spanAndOffset[0];
        offset[i] = spanAndOffset[1];
      }
  }

  /**
   * Adjusts the span and offset of a component for the aligned layout.
   *
   * @param reqs
   * @param baseline
   * @param allocated
   * @param spanAndOffset
   */
  private static void adjustFromRight(SizeRequirements reqs, float baseline,
                                      int allocated, int[] spanAndOffset)
  {
    float right = allocated - baseline;
    // If the resulting span exceeds the maximum of the component, then adjust
    // accordingly.
    float maxRight = ((float) reqs.maximum) * (1.F - reqs.alignment);
    if (right / (1.F - reqs.alignment) > reqs.maximum)
      right = maxRight;
    // If we have not enough space on the left side, then adjust accordingly.
    if (right / (1.F - reqs.alignment) * reqs.alignment > allocated - baseline)
      right = ((float) (allocated - baseline))
             / reqs.alignment * (1.F - reqs.alignment);

    spanAndOffset[0] = (int) (right / (1.F - reqs.alignment));
    spanAndOffset[1] = (int) (baseline - spanAndOffset[0] * reqs.alignment);
  }

  /**
   * Adjusts the span and offset of a component for the aligned layout.
   *
   * @param reqs
   * @param baseline
   * @param allocated
   * @param spanAndOffset
   */
  private static void adjustFromLeft(SizeRequirements reqs, float baseline,
                                     int allocated, int[] spanAndOffset)
  {
    float left = baseline;
    // If the resulting span exceeds the maximum of the component, then adjust
    // accordingly.
    float maxLeft = ((float) reqs.maximum) * reqs.alignment;
    if (left / reqs.alignment > reqs.maximum)
      left = maxLeft;
    // If we have not enough space on the right side, then adjust accordingly.
    if (left / reqs.alignment * (1.F - reqs.alignment) > allocated - baseline)
      left = ((float) (allocated - baseline))
             / (1.F - reqs.alignment) * reqs.alignment;

    spanAndOffset[0] = (int) (left / reqs.alignment);
    spanAndOffset[1] = (int) (baseline - spanAndOffset[0] * reqs.alignment);
  }

  /**
   * Returns an array of new preferred sizes for the children based on
   * <code>delta</code>. <code>delta</code> specifies a change in the
   * allocated space. The sizes of the children will be shortened or
   * lengthened to accomodate the new allocation.
   *
   * @param delta the change of the size of the total allocation for
   *     the components
   * @param children the size requirements of each component
   *
   * @return the new preferred sizes for each component
   */
  public static int[] adjustSizes(int delta, SizeRequirements[] children)
  {
    return null; // TODO
  }
}