gecko/layout/generic/nsFontInflationData.h
L. David Baron be1535321a Build font data structure by walking the necessary text. (Bug 706193, patch 3) r=roc
Compute the amount of text in the scope of an nsFontInflationData
object.  This walks the text that's inside of the block formatting
context at which this object is rooted, excluding the text that's inside
any nested BFC.  Using the amount of text, the font sizes of the text,
and the line threshold preference, we compute whether to enable font
size inflation within that block formatting context.
2012-04-16 15:32:12 -07:00

103 lines
3.6 KiB
C++

/* vim: set shiftwidth=2 tabstop=8 autoindent cindent expandtab: */
/* ***** 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 the font size inflation manager.
*
* The Initial Developer of the Original Code is the Mozilla Foundation.
* Portions created by the Initial Developer are Copyright (C) 2012
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* L. David Baron <dbaron@dbaron.org>, Mozilla Corporation (original author)
*
* Alternatively, the contents of this file may be used under the terms of
* either 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 ***** */
/* Per-block-formatting-context manager of font size inflation for pan and zoom UI. */
#ifndef nsFontInflationData_h_
#define nsFontInflationData_h_
#include "nsIFrame.h"
#include "nsLayoutUtils.h"
#include "nsBlockFrame.h"
struct nsHTMLReflowState;
class nsFontInflationData
{
public:
static nsFontInflationData* FindFontInflationDataFor(const nsIFrame *aFrame);
static void
UpdateFontInflationDataWidthFor(const nsHTMLReflowState& aReflowState);
static void MarkFontInflationDataTextDirty(nsIFrame *aFrame);
bool InflationEnabled() {
if (mTextDirty) {
ScanText();
}
return mInflationEnabled;
}
private:
nsFontInflationData(nsIFrame* aBFCFrame);
nsFontInflationData(const nsFontInflationData&) MOZ_DELETE;
void operator=(const nsFontInflationData&) MOZ_DELETE;
void UpdateWidth(const nsHTMLReflowState &aReflowState);
enum SearchDirection { eFromStart, eFromEnd };
static nsIFrame* FindEdgeInflatableFrameIn(nsIFrame *aFrame,
SearchDirection aDirection);
void MarkTextDirty() { mTextDirty = true; }
void ScanText();
// Scan text in the subtree rooted at aFrame. Increment mTextAmount
// by multiplying the number of characters found by the font size
// (yielding the width that would be occupied by the characters if
// they were all em squares). But stop scanning if mTextAmount
// crosses mTextThreshold.
void ScanTextIn(nsIFrame *aFrame);
static const nsIFrame* FlowRootFor(const nsIFrame *aFrame)
{
while (!(aFrame->GetStateBits() & NS_FRAME_FONT_INFLATION_FLOW_ROOT)) {
aFrame = aFrame->GetParent();
}
return aFrame;
}
nsIFrame *mBFCFrame;
nscoord mTextAmount, mTextThreshold;
bool mInflationEnabled; // for this BFC
bool mTextDirty;
};
#endif /* !defined(nsFontInflationData_h_) */