The Tor Browser: comparison gfx/src/nsFontMetrics.h

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+:72527134a68d
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+* License, v. 2.0. If a copy of the MPL was not distributed with this
+* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#ifndef NSFONTMETRICS__H__
+#define NSFONTMETRICS__H__
+#include <stdint.h>                     // for uint32_t
+#include <sys/types.h>                  // for int32_t
+#include "gfxFont.h"                    // for gfxFont, gfxFontGroup
+#include "mozilla/Assertions.h"         // for MOZ_ASSERT_HELPER2
+#include "nsAutoPtr.h"                  // for nsRefPtr
+#include "nsCOMPtr.h"                   // for nsCOMPtr
+#include "nsCoord.h"                    // for nscoord
+#include "nsError.h"                    // for nsresult
+#include "nsFont.h"                     // for nsFont
+#include "nsISupports.h"                // for NS_INLINE_DECL_REFCOUNTING
+#include "nscore.h"                     // for char16_t
+class gfxUserFontSet;
+class gfxTextPerfMetrics;
+class nsDeviceContext;
+class nsIAtom;
+class nsRenderingContext;
+struct nsBoundingMetrics;
+/**
+* Font metrics
+*
+* This class may be somewhat misnamed. A better name might be
+* nsFontList. The style system uses the nsFont struct for various
+* font properties, one of which is font-family, which can contain a
+* *list* of font names. The nsFont struct is "realized" by asking the
+* device context to cough up an nsFontMetrics object, which contains
+* a list of real font handles, one for each font mentioned in
+* font-family (and for each fallback when we fall off the end of that
+* list).
+*
+* The style system needs to have access to certain metrics, such as
+* the em height (for the CSS "em" unit), and we use the first Western
+* font's metrics for that purpose. The platform-specific
+* implementations are expected to select non-Western fonts that "fit"
+* reasonably well with the Western font that is loaded at Init time.
+*/
+class nsFontMetrics MOZ_FINAL
+{
+public:
+nsFontMetrics();
+NS_INLINE_DECL_REFCOUNTING(nsFontMetrics)
+/**
+* Initialize the font metrics. Call this after creating the font metrics.
+* Font metrics you get from the font cache do NOT need to be initialized
+*
+* @see nsDeviceContext#GetMetricsFor()
+*/
+nsresult Init(const nsFont& aFont, nsIAtom* aLanguage,
+nsDeviceContext *aContext,
+gfxUserFontSet *aUserFontSet,
+gfxTextPerfMetrics *aTextPerf);
+/**
+* Destroy this font metrics. This breaks the association between
+* the font metrics and the device context.
+*/
+void Destroy();
+/**
+* Return the font's x-height.
+*/
+nscoord XHeight();
+/**
+* Return the font's superscript offset (the distance from the
+* baseline to where a superscript's baseline should be placed).
+* The value returned will be positive.
+*/
+nscoord SuperscriptOffset();
+/**
+* Return the font's subscript offset (the distance from the
+* baseline to where a subscript's baseline should be placed).
+* The value returned will be positive.
+*/
+nscoord SubscriptOffset();
+/**
+* Return the font's strikeout offset (the distance from the
+* baseline to where a strikeout should be placed) and size.
+* Positive values are above the baseline, negative below.
+*/
+void GetStrikeout(nscoord& aOffset, nscoord& aSize);
+/**
+* Return the font's underline offset (the distance from the
+* baseline to where a underline should be placed) and size.
+* Positive values are above the baseline, negative below.
+*/
+void GetUnderline(nscoord& aOffset, nscoord& aSize);
+/**
+* Returns the amount of internal leading for the font.
+* This is normally the difference between the max ascent
+* and the em ascent.
+*/
+nscoord InternalLeading();
+/**
+* Returns the amount of external leading for the font.
+* em ascent(?) plus external leading is the font designer's
+* recommended line-height for this font.
+*/
+nscoord ExternalLeading();
+/**
+* Returns the height of the em square.
+* This is em ascent plus em descent.
+*/
+nscoord EmHeight();
+/**
+* Returns the ascent part of the em square.
+*/
+nscoord EmAscent();
+/**
+* Returns the descent part of the em square.
+*/
+nscoord EmDescent();
+/**
+* Returns the height of the bounding box.
+* This is max ascent plus max descent.
+*/
+nscoord MaxHeight();
+/**
+* Returns the maximum distance characters in this font extend
+* above the base line.
+*/
+nscoord MaxAscent();
+/**
+* Returns the maximum distance characters in this font extend
+* below the base line.
+*/
+nscoord MaxDescent();
+/**
+* Returns the maximum character advance for the font.
+*/
+nscoord MaxAdvance();
+/**
+* Returns the average character width
+*/
+nscoord AveCharWidth();
+/**
+* Returns the often needed width of the space character
+*/
+nscoord SpaceWidth();
+/**
+* Returns the font associated with these metrics. The return value
+* is only defined after Init() has been called.
+*/
+const nsFont &Font() { return mFont; }
+/**
+* Returns the language associated with these metrics
+*/
+nsIAtom* Language() { return mLanguage; }
+int32_t GetMaxStringLength();
+// Get the width for this string.  aWidth will be updated with the
+// width in points, not twips.  Callers must convert it if they
+// want it in another format.
+nscoord GetWidth(const char* aString, uint32_t aLength,
+nsRenderingContext *aContext);
+nscoord GetWidth(const char16_t* aString, uint32_t aLength,
+nsRenderingContext *aContext);
+// Draw a string using this font handle on the surface passed in.
+void DrawString(const char *aString, uint32_t aLength,
+nscoord aX, nscoord aY,
+nsRenderingContext *aContext);
+void DrawString(const char16_t* aString, uint32_t aLength,
+nscoord aX, nscoord aY,
+nsRenderingContext *aContext,
+nsRenderingContext *aTextRunConstructionContext);
+nsBoundingMetrics GetBoundingMetrics(const char16_t *aString,
+uint32_t aLength,
+nsRenderingContext *aContext);
+// Returns the LOOSE_INK_EXTENTS bounds of the text for determing the
+// overflow area of the string.
+nsBoundingMetrics GetInkBoundsForVisualOverflow(const char16_t *aString,
+uint32_t aLength,
+nsRenderingContext *aContext);
+void SetTextRunRTL(bool aIsRTL) { mTextRunRTL = aIsRTL; }
+bool GetTextRunRTL() { return mTextRunRTL; }
+gfxFontGroup* GetThebesFontGroup() { return mFontGroup; }
+gfxUserFontSet* GetUserFontSet() { return mFontGroup->GetUserFontSet(); }
+int32_t AppUnitsPerDevPixel() { return mP2A; }
+private:
+// Private destructor, to discourage deletion outside of Release():
+~nsFontMetrics();
+const gfxFont::Metrics& GetMetrics() const;
+nsFont mFont;
+nsRefPtr<gfxFontGroup> mFontGroup;
+nsCOMPtr<nsIAtom> mLanguage;
+nsDeviceContext *mDeviceContext;
+int32_t mP2A;
+bool mTextRunRTL;
+};
+#endif /* NSFONTMETRICS__H__ */

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comparison: gfx/src/nsFontMetrics.h

gfx/src/nsFontMetrics.h