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139 lines
4.1 KiB
C++
139 lines
4.1 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
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*
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* The contents of this file are subject to the Netscape Public License
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* Version 1.0 (the "NPL"); you may not use this file except in
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* compliance with the NPL. You may obtain a copy of the NPL at
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* http://www.mozilla.org/NPL/
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*
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* Software distributed under the NPL is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
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* for the specific language governing rights and limitations under the
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* NPL.
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*
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* The Initial Developer of this code under the NPL is Netscape
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* Communications Corporation. Portions created by Netscape are
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* Copyright (C) 1998 Netscape Communications Corporation. All Rights
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* Reserved.
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*/
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#ifndef nsIFontMetrics_h___
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#define nsIFontMetrics_h___
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#include "nsISupports.h"
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#include "nsCoord.h"
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struct nsFont;
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class nsString;
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class nsIDeviceContext;
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// IID for the nsIFontMetrics interface
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#define NS_IFONT_METRICS_IID \
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{ 0xc74cb770, 0xa33e, 0x11d1, \
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{ 0xa8, 0x24, 0x00, 0x40, 0x95, 0x9a, 0x28, 0xc9 } }
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//----------------------------------------------------------------------
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/**
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* A native font handle
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*/
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typedef void* nsFontHandle;
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/**
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* Font metrics interface
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*/
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class nsIFontMetrics : public nsISupports
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{
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// XXX what about encoding, where do we put that? MMP
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public:
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static const nsIID& IID() { static nsIID iid = NS_IFONT_METRICS_IID; return iid; }
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/**
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* Initialize the font metrics. Call this after creating the font metrics.
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* Font metrics you get from the font cache do NOT need to be initialized
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*
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* @see nsIDeviceContext#GetMetricsFor()
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*/
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NS_IMETHOD Init(const nsFont& aFont, nsIDeviceContext *aContext) = 0;
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/**
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* Destroy this font metrics. This breaks the association between
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* the font metrics and the device context.
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*/
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NS_IMETHOD Destroy() = 0;
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/**
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* Return the font's xheight property, scaled into app-units.
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*/
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NS_IMETHOD GetXHeight(nscoord& aResult) = 0;
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/**
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* Return the font's superscript offset (the distance from the
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* baseline to where a superscript's baseline should be placed). The
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* value returned will be a positive value.
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*/
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NS_IMETHOD GetSuperscriptOffset(nscoord& aResult) = 0;
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/**
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* Return the font's subscript offset (the distance from the
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* baseline to where a subscript's baseline should be placed). The
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* value returned will be a positive value.
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*/
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NS_IMETHOD GetSubscriptOffset(nscoord& aResult) = 0;
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/**
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* Return the font's strikeout offset (the distance from the
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* baseline to where a strikeout should be placed) and size
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* Positive values are above the baseline, negative below.
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*/
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NS_IMETHOD GetStrikeout(nscoord& aOffset, nscoord& aSize) = 0;
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/**
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* Return the font's underline offset (the distance from the
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* baseline to where a underline should be placed) and size.
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* Positive values are above the baseline, negative below.
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*/
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NS_IMETHOD GetUnderline(nscoord& aOffset, nscoord& aSize) = 0;
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/**
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* Returns the height (in app units) of the font. This is ascent plus descent
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* plus any internal leading
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*/
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NS_IMETHOD GetHeight(nscoord &aHeight) = 0;
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/**
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* Returns the amount of internal leading (in app units) for the font. This
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* is computed as the "height - (ascent + descent)"
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*/
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NS_IMETHOD GetLeading(nscoord &aLeading) = 0;
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/**
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* Returns, in app units, the maximum distance characters in this font extend
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* above the base line.
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*/
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NS_IMETHOD GetMaxAscent(nscoord &aAscent) = 0;
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/**
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* Returns, in app units, the maximum distance characters in this font extend
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* below the base line.
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*/
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NS_IMETHOD GetMaxDescent(nscoord &aDescent) = 0;
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/**
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* Returns, in app units, the maximum character advance for the font
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*/
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NS_IMETHOD GetMaxAdvance(nscoord &aAdvance) = 0;
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/**
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* Returns the font associated with these metrics
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*/
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NS_IMETHOD GetFont(const nsFont *&aFont) = 0;
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/**
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* Returns the font handle associated with these metrics
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*/
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NS_IMETHOD GetFontHandle(nsFontHandle &aHandle) = 0;
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};
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#endif /* nsIFontMetrics_h___ */
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