Implement SkScalerContext_Windows::generateGlyphCount() and provide access via SkGlyphCache interface.

* This will be used by PDF font code.

Review URL: http://codereview.appspot.com/4261042

git-svn-id: http://skia.googlecode.com/svn/trunk@888 2bbb7eff-a529-9590-31e7-b0007b416f81

include/core/SkScalerContext.h

@@ -230,7 +230,7 @@ public:
     */
     SkUnichar glyphIDToChar(uint16_t glyphID);
 
-    unsigned    getGlyphCount() const { return this->generateGlyphCount(); }
+    unsigned    getGlyphCount() { return this->generateGlyphCount(); }
     void        getAdvance(SkGlyph*);
     void        getMetrics(SkGlyph*);
     void        getImage(const SkGlyph&);
@@ -245,7 +245,7 @@ protected:
     Rec         fRec;
     unsigned    fBaseGlyphCount;
 
-    virtual unsigned generateGlyphCount() const = 0;
+    virtual unsigned generateGlyphCount() = 0;
     virtual uint16_t generateCharToGlyph(SkUnichar) = 0;
     virtual void generateAdvance(SkGlyph*) = 0;
     virtual void generateMetrics(SkGlyph*) = 0;

src/core/SkGlyphCache.cpp

@@ -117,6 +117,10 @@ SkUnichar SkGlyphCache::glyphToUnichar(uint16_t glyphID) {
     return fScalerContext->glyphIDToChar(glyphID);
 }
 
+unsigned SkGlyphCache::getGlyphCount() {
+    return fScalerContext->getGlyphCount();
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 
 const SkGlyph& SkGlyphCache::getUnicharAdvance(SkUnichar charCode) {

src/core/SkGlyphCache.h

@@ -77,6 +77,10 @@ public:
     */
     SkUnichar glyphToUnichar(uint16_t);
 
+    /** Returns the number of glyphs for this strike.
+    */
+    unsigned getGlyphCount();
+
     /** Return the image associated with the glyph. If it has not been generated
         this will trigger that.
     */

src/core/SkScalerContext.cpp

@@ -645,7 +645,7 @@ public:
     SkScalerContext_Empty(const SkDescriptor* desc) : SkScalerContext(desc) {}
 
 protected:
-    virtual unsigned generateGlyphCount() const {
+    virtual unsigned generateGlyphCount() {
         return 0;
     }
     virtual uint16_t generateCharToGlyph(SkUnichar uni) {

src/ports/SkFontHost_FreeType.cpp

@@ -121,7 +121,7 @@ public:
     }
 
 protected:
-    virtual unsigned generateGlyphCount() const;
+    virtual unsigned generateGlyphCount();
     virtual uint16_t generateCharToGlyph(SkUnichar uni);
     virtual void generateAdvance(SkGlyph* glyph);
     virtual void generateMetrics(SkGlyph* glyph);
@@ -731,7 +731,7 @@ void SkScalerContext_FreeType::emboldenOutline(FT_Outline* outline) {
     FT_Outline_Embolden(outline, strength);
 }
 
-unsigned SkScalerContext_FreeType::generateGlyphCount() const {
+unsigned SkScalerContext_FreeType::generateGlyphCount() {
     return fFace->num_glyphs;
 }
 

src/ports/SkFontHost_ascender.cpp

@@ -22,7 +22,7 @@ public:
     virtual ~SkScalerContext_Ascender();
 
 protected:
-    virtual unsigned generateGlyphCount() const;
+    virtual unsigned generateGlyphCount();
     virtual uint16_t generateCharToGlyph(SkUnichar uni);
     virtual void generateMetrics(SkGlyph* glyph);
     virtual void generateImage(const SkGlyph& glyph);
@@ -102,7 +102,7 @@ SkScalerContext_Ascender::~SkScalerContext_Ascender()
     sk_free(fHandle);
 }
 
-unsigned SkScalerContext_Ascender::generateGlyphCount() const
+unsigned SkScalerContext_Ascender::generateGlyphCount()
 {
     return 1000;
 }

src/ports/SkFontHost_mac_atsui.cpp

@@ -87,7 +87,7 @@ public:
     virtual ~SkScalerContext_Mac();
 
 protected:
-    virtual unsigned generateGlyphCount() const;
+    virtual unsigned generateGlyphCount();
     virtual uint16_t generateCharToGlyph(SkUnichar uni);
     virtual void generateAdvance(SkGlyph* glyph);
     virtual void generateMetrics(SkGlyph* glyph);
@@ -184,7 +184,7 @@ SkScalerContext_Mac::~SkScalerContext_Mac() {
 
 // man, we need to consider caching this, since it is just dependent on
 // fFontID, and not on any of the other settings like matrix or flags
-unsigned SkScalerContext_Mac::generateGlyphCount() const {
+unsigned SkScalerContext_Mac::generateGlyphCount() {
     // The 'maxp' table stores the number of glyphs a offset 4, in 2 bytes
     uint16_t numGlyphs;
     if (SkFontHost::GetTableData(fRec.fFontID,

src/ports/SkFontHost_mac_coretext.cpp

@@ -314,7 +314,7 @@ public:
 
 
 protected:
-    unsigned                            generateGlyphCount(void) const;
+    unsigned                            generateGlyphCount(void);
     uint16_t                            generateCharToGlyph(SkUnichar uni);
     void                                generateAdvance(SkGlyph* glyph);
     void                                generateMetrics(SkGlyph* glyph);
@@ -373,7 +373,7 @@ SkScalerContext_Mac::~SkScalerContext_Mac(void)
     CFSafeRelease(mFont);
 }
 
-unsigned SkScalerContext_Mac::generateGlyphCount(void) const
+unsigned SkScalerContext_Mac::generateGlyphCount(void)
 {
     return(mGlyphCount);
 }

src/ports/SkFontHost_win.cpp

@@ -17,6 +17,7 @@
 #include "SkString.h"
 //#include "SkStream.h"
 
+#include "SkEndian.h"
 #include "SkFontHost.h"
 #include "SkDescriptor.h"
 #include "SkAdvancedTypefaceMetrics.h"
@@ -63,6 +64,32 @@ static inline FIXED SkScalarToFIXED(SkScalar x) {
     return SkFixedToFIXED(SkScalarToFixed(x));
 }
 
+static unsigned calculateGlyphCount(HDC hdc) {
+    // The 'maxp' table stores the number of glyphs at offset 4, in 2 bytes.
+    const DWORD maxpTag = *(DWORD*) "maxp";
+    uint16_t glyphs;
+    if (GetFontData(hdc, maxpTag, 4, &glyphs, sizeof(glyphs)) != GDI_ERROR) {
+        return SkEndian_SwapBE16(glyphs);
+    }
+    
+    // Binary search for glyph count.
+    static const MAT2 mat2 = {{0, 1}, {0, 0}, {0, 0}, {0, 1}};
+    int32_t max = SK_MaxU16 + 1;
+    int32_t min = 0;
+    GLYPHMETRICS gm;
+    while (min < max) {
+        int32_t mid = min + ((max - min) / 2);
+        if (GetGlyphOutlineW(hdc, mid, GGO_METRICS | GGO_GLYPH_INDEX, &gm, 0,
+                             NULL, &mat2) == GDI_ERROR) {
+            max = mid;
+        } else {
+            min = mid + 1;
+        }
+    }
+    SkASSERT(min == max);
+    return min;
+}
+
 static SkTypeface::Style GetFontStyle(const LOGFONT& lf) {
     int style = SkTypeface::kNormal;
     if (lf.lfWeight == FW_SEMIBOLD || lf.lfWeight == FW_DEMIBOLD || lf.lfWeight == FW_BOLD)
@@ -188,7 +215,7 @@ public:
     virtual ~SkScalerContext_Windows();
 
 protected:
-    virtual unsigned generateGlyphCount() const;
+    virtual unsigned generateGlyphCount();
     virtual uint16_t generateCharToGlyph(SkUnichar uni);
     virtual void generateAdvance(SkGlyph* glyph);
     virtual void generateMetrics(SkGlyph* glyph);
@@ -203,10 +230,12 @@ private:
     HFONT        fSavefont;
     HFONT        fFont;
     SCRIPT_CACHE fSC;
+    int          fGlyphCount;
 };
 
 SkScalerContext_Windows::SkScalerContext_Windows(const SkDescriptor* desc)
-        : SkScalerContext(desc), fDDC(0), fFont(0), fSavefont(0), fSC(0) {
+        : SkScalerContext(desc), fDDC(0), fFont(0), fSavefont(0), fSC(0)
+        , fGlyphCount(-1) {
     SkAutoMutexAcquire  ac(gFTMutex);
 
 	fScale = fRec.fTextSize / gCanonicalTextSize;
@@ -239,9 +268,11 @@ SkScalerContext_Windows::~SkScalerContext_Windows() {
     }
 }
 
-unsigned SkScalerContext_Windows::generateGlyphCount() const {
-    return 0xFFFF;
-    //    return fFace->num_glyphs;
+unsigned SkScalerContext_Windows::generateGlyphCount() {
+    if (fGlyphCount < 0) {
+        fGlyphCount = calculateGlyphCount(fDDC);
+    }
+    return fGlyphCount;
 }
 
 uint16_t SkScalerContext_Windows::generateCharToGlyph(SkUnichar uni) {