bug 99010 - font changes. r=shanjian@netscape.com, sr=waterson@netscape.com

gfx/public/nsFont.h

@@ -49,6 +49,20 @@
 // Enumerator callback function. Return PR_FALSE to stop
 typedef PRBool (*nsFontFamilyEnumFunc)(const nsString& aFamily, PRBool aGeneric, void *aData);
 
+// IDs for generic fonts
+// NOTE: 0, 1 are reserved for the special IDs of the default variable
+// and fixed fonts in the presentation context, see nsIPresContext.h
+const PRUint8 kGenericFont_NONE         = 0x00;
+// Special
+const PRUint8 kGenericFont_moz_variable = 0x00; // for the default variable width font
+const PRUint8 kGenericFont_moz_fixed    = 0x01; // our special "use the user's fixed font"
+// CSS
+const PRUint8 kGenericFont_serif        = 0x02;
+const PRUint8 kGenericFont_sans_serif   = 0x04;
+const PRUint8 kGenericFont_monospace    = 0x08;
+const PRUint8 kGenericFont_cursive      = 0x10;
+const PRUint8 kGenericFont_fantasy      = 0x20;
+
 // Font structure.
 struct NS_GFX nsFont {
   // The family name of the font
@@ -67,20 +81,29 @@ struct NS_GFX nsFont {
   // line-through). The decorations can be binary or'd together.
   PRUint8 decorations;
 
-  // The size of the font, in nscoord units
+  // The logical size of the font, in nscoord units
   nscoord size;
 
+  // The aspect-value (ie., the ratio actualsize:actualxheight) that any
+  // actual physical font created from this font structure must have when
+  // rendering or measuring a string. A value of 0 means no adjustment
+  // needs to be done.
+  float sizeAdjust;
+
   // Initialize the font struct with an iso-latin1 name
   nsFont(const char* aName, PRUint8 aStyle, PRUint8 aVariant,
-         PRUint16 aWeight, PRUint8 aDecoration, nscoord aSize);
+         PRUint16 aWeight, PRUint8 aDecoration, nscoord aSize,
+         float aSizeAdjust=0.0f);
 
   // Initialize the font struct with a (potentially) unicode name
   nsFont(const nsString& aName, PRUint8 aStyle, PRUint8 aVariant,
-         PRUint16 aWeight, PRUint8 aDecoration, nscoord aSize);
+         PRUint16 aWeight, PRUint8 aDecoration, nscoord aSize,
+         float aSizeAdjust=0.0f);
 
   // Make a copy of the given font
   nsFont(const nsFont& aFont);
 
+  nsFont();
   ~nsFont();
 
   PRBool operator==(const nsFont& aOther) const {
@@ -93,10 +116,13 @@ struct NS_GFX nsFont {
 
   // Utility method to interpret name string
   // enumerates all families specified by this font only
-  // returns PR_TRUE if completed, PF_FALSE if stopped
+  // returns PR_TRUE if completed, PR_FALSE if stopped
   // enclosing quotes will be removed, and whitespace compressed (as needed)
   PRBool EnumerateFamilies(nsFontFamilyEnumFunc aFunc, void* aData) const;
   void GetFirstFamily(nsString& aFamily) const;
+
+  // Utility method to return the ID of a generic font
+  static void GetGenericID(const nsString& aGeneric, PRUint8* aID);
 };
 
 #define NS_FONT_STYLE_NORMAL              0

gfx/public/nsIRenderingContext.h

@@ -57,6 +57,7 @@ struct nsFont;
 struct nsPoint;
 struct nsPathPoint;
 struct nsRect;
+struct nsTextDimensions;
 #ifdef MOZ_MATHML
 struct nsBoundingMetrics;
 #endif
@@ -579,65 +580,76 @@ public:
   NS_IMETHOD GetWidth(const PRUnichar *aString, PRUint32 aLength,
                       nscoord &aWidth, PRInt32 *aFontID = nsnull) = 0;
 
+  /**
+   * Returns the dimensions of a string, i.e., the overall extent of a string
+   * whose rendering may involve switching between different fonts that have
+   * different metrics.
+   * @param aString string to measure
+   * @param aLength number of characters in string
+   * @param aFontID an optional out parameter used to store a
+   *        font identifier that can be passed into the DrawString()
+   *        methods to speed measurements
+   * @return aDimensions struct that contains the extent of the string (see below)
+   */
+  NS_IMETHOD GetTextDimensions(const char* aString, PRUint32 aLength,
+                               nsTextDimensions& aDimensions) = 0;
+  NS_IMETHOD GetTextDimensions(const PRUnichar* aString, PRUint32 aLength,
+                               nsTextDimensions& aDimensions, PRInt32* aFontID = nsnull) = 0;
+
 #ifdef _WIN32
   /**
    * Given an available width and an array of break points,
-   * returns the width (in app units) of the text that fit and
+   * returns the dimensions (in app units) of the text that fit and
    * the number of characters that fit. The number of characters
    * corresponds to an entry in the break array.
-   * If no font has been Set, the results are undefined.
+   * If no font has been set, the results are undefined.
-   * @param aString 8-bit character string to measure
+   * @param aString, string to measure
-   * @param aLength number of characters in string
+   * @param aLength, number of characters in string
-   * @param aAvailWidth the available space in which the text must fit
+   * @param aAvailWidth, the available space in which the text must fit
-   * @param aBreaks array of places to break. Specified as offsets from the
+   * @param aBreaks, array of places to break. Specified as offsets from the
    *          start of the string
-   * @param aNumBreaks the number of entries in the break array. The last
+   * @param aNumBreaks, the number of entries in the break array. The last
    *          entry in the break array must equal the length of the string
-   * @param aWidth out parameter for width
+   * @param aDimensions, out parameter for the dimensions, the ascent and descent
-   * @param aNumCharsFit the number of characters that fit in the available space
+   *           of the last word are left out to allow possible line-breaking before
-   * @param aFontID an optional out parameter used to store a
+   *           the last word. However, the width of the last word is included.
+   * @param aNumCharsFit, the number of characters that fit in the available space
+   * @param aLastWordDimensions, dimensions of the last word, the width field,
+   *             dimensions.width, should be -1 for an unknown width. But the 
+   *             ascent and descent are expected to be known.
+   * @param aFontID, an optional out parameter used to store a
    *        font identifier that can be passed into the DrawString()
    *        methods to speed rendering
    * @return error status
    */
-  NS_IMETHOD GetWidth(const char *aString,
+  NS_IMETHOD GetTextDimensions(const char*       aString,
-                      PRInt32     aLength,
+                               PRInt32           aLength,
-                      PRInt32     aAvailWidth,
+                               PRInt32           aAvailWidth,
-                      PRInt32*    aBreaks,
+                               PRInt32*          aBreaks,
-                      PRInt32     aNumBreaks,
+                               PRInt32           aNumBreaks,
-                      nscoord&    aWidth,
+                               nsTextDimensions& aDimensions,
-                      PRInt32&    aNumCharsFit,
+                               PRInt32&          aNumCharsFit,
-                      PRInt32*    aFontID = nsnull) = 0;
+                               nsTextDimensions& aLastWordDimensions,
+                               PRInt32*          aFontID = nsnull) = 0;
 
-  /**
+  NS_IMETHOD GetTextDimensions(const PRUnichar*  aString,
-   * Given an available width and an array of break points,
+                               PRInt32           aLength,
-   * returns the width (in app units) of the text that fit and
+                               PRInt32           aAvailWidth,
-   * the number of characters that fit. The number of characters
+                               PRInt32*          aBreaks,
-   * corresponds to an entry in the break array.
+                               PRInt32           aNumBreaks,
-   * If no font has been Set, the results are undefined.
+                               nsTextDimensions& aDimensions,
-   * @param aString Unicode string to measure
+                               PRInt32&          aNumCharsFit,
-   * @param aLength number of characters in string
+                               nsTextDimensions& aLastWordDimensions,
-   * @param aAvailWidth the available space in which the text must fit
+                               PRInt32*          aFontID = nsnull) = 0;
-   * @param aBreaks array of places to break. Specified as offsets from the
-   *          start of the string
-   * @param aNumBreaks the number of entries in the break array. The last
-   *          entry in the break array must equal the length of the string
-   * @param aWidth out parameter for width
-   * @param aNumCharsFit the number of characters that fit in the available space
-   * @param aFontID an optional out parameter used to store a
-   *        font identifier that can be passed into the DrawString()
-   *        methods to speed rendering
-   * @return error status
-   */
-  NS_IMETHOD GetWidth(const PRUnichar *aString,
-                      PRInt32          aLength,
-                      PRInt32          aAvailWidth,
-                      PRInt32*         aBreaks,
-                      PRInt32          aNumBreaks,
-                      nscoord&         aWidth,
-                      PRInt32&         aNumCharsFit,
-                      PRInt32*         aFontID = nsnull) = 0;
 #endif
+  /*
+   * XXX Buggy APIs: the DrawString() APIs are not implemented according
+   * to their signature. Indeed aX and aY are not interpreted as the
+   * coordinates of the baseline.
+   * XXX TODO: replace the buggy DrawString() APIs with the newer DrawString2()
+   * APIs and fix callers. The newer APIs are the ones to use in conjunction
+   * with GetTextDimensions().
+   */
 
   /**
    * Draw a string in the RenderingContext
@@ -651,6 +663,15 @@ public:
                         nscoord aX, nscoord aY,
                         const nscoord* aSpacing = nsnull) = 0;
 
+  /** 
+   * Same as above, with the difference that the implementation is
+   * correctly intepreting aX and aY as the horizontal and vertical
+   * starting point of the baseline
+   */
+  NS_IMETHOD DrawString2(const char *aString, PRUint32 aLength,
+                        nscoord aX, nscoord aY,
+                        const nscoord* aSpacing = nsnull) = 0;
+
   /**
    * Draw a string in the RenderingContext
    * @param aString A PRUnichar of the string
@@ -666,6 +687,10 @@ public:
                         nscoord aX, nscoord aY,
                         PRInt32 aFontID = -1,
                         const nscoord* aSpacing = nsnull) = 0;
+  NS_IMETHOD DrawString2(const PRUnichar *aString, PRUint32 aLength,
+                        nscoord aX, nscoord aY,
+                        PRInt32 aFontID = -1,
+                        const nscoord* aSpacing = nsnull) = 0;
 
   /**
    * Draw a string in the RenderingContext
@@ -860,6 +885,40 @@ public:
 //stop using it.
 #define NS_COPYBITS_TO_BACK_BUFFER          0x0008
 
+/* Struct used to represent the overall extent of a string
+   whose rendering may involve switching between different
+   fonts that have different metrics.
+*/
+struct nsTextDimensions {
+  // max ascent amongst all the fonts needed to represent the string
+  nscoord ascent;
+
+  // max descent amongst all the fonts needed to represent the string
+  nscoord descent;
+
+  // width of the string
+  nscoord width;
+
+
+  nsTextDimensions()
+  {
+    Clear();
+  }
+
+  /* Set all member data to zero */
+  void 
+  Clear() {
+    ascent = descent = width = 0;
+  }
+
+  /* Sum with another dimension */
+  void 
+  Combine(const nsTextDimensions& aOther) {
+    if (ascent < aOther.ascent) ascent = aOther.ascent;
+    if (descent < aOther.descent) descent = aOther.descent;   
+    width += aOther.width;
+  }
+};
 
 #ifdef MOZ_MATHML
 /* Struct used for accurate measurements of a string in order

gfx/src/nsFont.cpp

@@ -40,7 +40,8 @@
 #include "nsString.h"
 
 nsFont::nsFont(const char* aName, PRUint8 aStyle, PRUint8 aVariant,
-               PRUint16 aWeight, PRUint8 aDecoration, nscoord aSize)
+               PRUint16 aWeight, PRUint8 aDecoration, nscoord aSize,
+               float aSizeAdjust)
 {
   name.AssignWithConversion(aName);
   style = aStyle;
@@ -48,10 +49,12 @@ nsFont::nsFont(const char* aName, PRUint8 aStyle, PRUint8 aVariant,
   weight = aWeight;
   decorations = aDecoration;
   size = aSize;
+  sizeAdjust = aSizeAdjust;
 }
 
 nsFont::nsFont(const nsString& aName, PRUint8 aStyle, PRUint8 aVariant,
-               PRUint16 aWeight, PRUint8 aDecoration, nscoord aSize)
+               PRUint16 aWeight, PRUint8 aDecoration, nscoord aSize,
+               float aSizeAdjust)
   : name(aName)
 {
   style = aStyle;
@@ -59,6 +62,7 @@ nsFont::nsFont(const nsString& aName, PRUint8 aStyle, PRUint8 aVariant,
   weight = aWeight;
   decorations = aDecoration;
   size = aSize;
+  sizeAdjust = aSizeAdjust;
 }
 
 nsFont::nsFont(const nsFont& aOther)
@@ -69,6 +73,11 @@ nsFont::nsFont(const nsFont& aOther)
   weight = aOther.weight;
   decorations = aOther.decorations;
   size = aOther.size;
+  sizeAdjust = aOther.sizeAdjust;
+}
+
+nsFont::nsFont()
+{
 }
 
 nsFont::~nsFont()
@@ -82,6 +91,7 @@ PRBool nsFont::Equals(const nsFont& aOther) const
       (weight == aOther.weight) &&
       (decorations == aOther.decorations) &&
       (size == aOther.size) &&
+      (sizeAdjust == aOther.sizeAdjust) &&
       name.EqualsIgnoreCase(aOther.name)) {
     return PR_TRUE;
   }
@@ -96,18 +106,15 @@ nsFont& nsFont::operator=(const nsFont& aOther)
   weight = aOther.weight;
   decorations = aOther.decorations;
   size = aOther.size;
+  sizeAdjust = aOther.sizeAdjust;
   return *this;
 }
 
-
 static PRBool IsGenericFontFamily(const nsString& aFamily)
 {
-  return PRBool(aFamily.EqualsIgnoreCase("serif") ||
+  PRUint8 generic;
-                aFamily.EqualsIgnoreCase("sans-serif") ||
+  nsFont::GetGenericID(aFamily, &generic);
-                aFamily.EqualsIgnoreCase("cursive") ||
+  return generic != kGenericFont_NONE;
-                aFamily.EqualsIgnoreCase("fantasy") ||
-                aFamily.EqualsIgnoreCase("monospace") ||
-                aFamily.EqualsIgnoreCase("-moz-fixed"));  // our special "use the user's fixed font"
 }
 
 const PRUnichar kNullCh       = PRUnichar('\0');
@@ -190,3 +197,14 @@ void nsFont::GetFirstFamily(nsString& aFamily) const
   EnumerateFamilies(FontEnumCallback, &aFamily);
 }
 
+/*static*/
+void nsFont::GetGenericID(const nsString& aGeneric, PRUint8* aID)
+{
+  *aID = kGenericFont_NONE;
+  if (aGeneric.EqualsIgnoreCase("-moz-fixed"))      *aID = kGenericFont_moz_fixed;
+  else if (aGeneric.EqualsIgnoreCase("serif"))      *aID = kGenericFont_serif;
+  else if (aGeneric.EqualsIgnoreCase("sans-serif")) *aID = kGenericFont_sans_serif;
+  else if (aGeneric.EqualsIgnoreCase("cursive"))    *aID = kGenericFont_cursive;
+  else if (aGeneric.EqualsIgnoreCase("fantasy"))    *aID = kGenericFont_fantasy;
+  else if (aGeneric.EqualsIgnoreCase("monospace"))  *aID = kGenericFont_monospace;
+}