pjs/layout/generic/nsLeafFrame.h

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 1998
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

/* base class for rendering objects that do not have child lists */

#ifndef nsLeafFrame_h___
#define nsLeafFrame_h___

#include "nsFrame.h"
#include "nsDisplayList.h"

/**
 * Abstract class that provides simple fixed-size layout for leaf objects
 * (e.g. images, form elements, etc.). Deriviations provide the implementation
 * of the GetDesiredSize method. The rendering method knows how to render
 * borders and backgrounds.
 */
class nsLeafFrame : public nsFrame {
public:
  NS_DECL_FRAMEARENA_HELPERS

  // nsIFrame replacements
  NS_IMETHOD BuildDisplayList(nsDisplayListBuilder*   aBuilder,
                              const nsRect&           aDirtyRect,
                              const nsDisplayListSet& aLists) {
    DO_GLOBAL_REFLOW_COUNT_DSP("nsLeafFrame");
    return DisplayBorderBackgroundOutline(aBuilder, aLists);
  }

  /**
   * Both GetMinWidth and GetPrefWidth will return whatever GetIntrinsicWidth
   * returns.
   */
  virtual nscoord GetMinWidth(nsIRenderingContext *aRenderingContext);
  virtual nscoord GetPrefWidth(nsIRenderingContext *aRenderingContext);

  /**
   * Our auto size is just intrinsic width and intrinsic height.
   */
  virtual nsSize ComputeAutoSize(nsIRenderingContext *aRenderingContext,
                                 nsSize aCBSize, nscoord aAvailableWidth,
                                 nsSize aMargin, nsSize aBorder,
                                 nsSize aPadding, PRBool aShrinkWrap);

  /**
   * Reflow our frame.  This will use the computed width plus borderpadding for
   * the desired width, and use the return value of GetIntrinsicHeight plus
   * borderpadding for the desired height.  Ascent will be set to the height,
   * and descent will be set to 0.
   */
  NS_IMETHOD Reflow(nsPresContext*      aPresContext,
                    nsHTMLReflowMetrics& aDesiredSize,
                    const nsHTMLReflowState& aReflowState,
                    nsReflowStatus&      aStatus);
  
  /**
   * This method does most of the work that Reflow() above need done.
   */
  NS_IMETHOD DoReflow(nsPresContext*      aPresContext,
                      nsHTMLReflowMetrics& aDesiredSize,
                      const nsHTMLReflowState& aReflowState,
                      nsReflowStatus&      aStatus);

  virtual PRBool IsFrameOfType(PRUint32 aFlags) const
  {
    // We don't actually contain a block, but we do always want a
    // computed width, so tell a little white lie here.
    return nsFrame::IsFrameOfType(aFlags & ~(nsIFrame::eReplacedContainsBlock));
  }

protected:
  nsLeafFrame(nsStyleContext* aContext) : nsFrame(aContext) {}
  virtual ~nsLeafFrame();

  /**
   * Return the intrinsic width of the frame's content area. Note that this
   * should not include borders or padding and should not depend on the applied
   * styles.
   */
  virtual nscoord GetIntrinsicWidth() = 0;

  /**
   * Return the intrinsic height of the frame's content area.  This should not
   * include border or padding.  This will only matter if the specified height
   * is auto.  Note that subclasses must either implement this or override
   * Reflow and ComputeAutoSize; the default Reflow and ComputeAutoSize impls
   * call this method.
   */
  virtual nscoord GetIntrinsicHeight();

  /**
   * Subroutine to add in borders and padding
   */
  void AddBordersAndPadding(const nsHTMLReflowState& aReflowState,
                            nsHTMLReflowMetrics& aDesiredSize);

  /**
   * Set aDesiredSize to be the available size
   */
  void SizeToAvailSize(const nsHTMLReflowState& aReflowState,
                       nsHTMLReflowMetrics& aDesiredSize);
};

#endif /* nsLeafFrame_h___ */