Implement onCountGlyphs and onGetUPEM on Windows.

src/ports/SkFontHost_win.cpp

Index: src/ports/SkFontHost_win.cpp
===================================================================
--- src/ports/SkFontHost_win.cpp	(revision 10083)
+++ src/ports/SkFontHost_win.cpp	(working copy)
@@ -15,6 +15,7 @@
 #include "SkFontHost.h"
 #include "SkGlyph.h"
 #include "SkMaskGamma.h"
+#include "SkOTTable_maxp.h"
 #include "SkOTUtils.h"
 #include "SkPath.h"
 #include "SkStream.h"
@@ -140,12 +141,22 @@
     return SkFixedToFIXED(SkScalarToFixed(x));
 }
 
-static unsigned calculateOutlineGlyphCount(HDC hdc) {
+static unsigned calculateGlyphCount(HDC hdc, const LOGFONT& lf) {
+    TEXTMETRIC textMetric;
+    if (0 == GetTextMetrics(hdc, &textMetric)) {
+        call_ensure_accessible(lf);
+        if (0 == GetTextMetrics(hdc, &textMetric)) {
+            textMetric.tmPitchAndFamily = TMPF_TRUETYPE;

[vandebo (ex-Chrome), 2013/07/15 17:32:56]

Maybe put this on line 146 to make it more obvious what's going on?  It would
also avoid the if on 148.

[bungeman-skia, 2013/07/15 18:21:36]

Done. I dislike unneeded stores, but I suppose I dislike unneeded compares and
branches more. 

+        }
+    }
+
+    if (!(textMetric.tmPitchAndFamily & TMPF_VECTOR)) {
+        return textMetric.tmLastChar;
+    }
+
     // The 'maxp' table stores the number of glyphs at offset 4, in 2 bytes.
-    const DWORD maxpTag =
-        SkEndian_SwapBE32(SkSetFourByteTag('m', 'a', 'x', 'p'));
     uint16_t glyphs;
-    if (GetFontData(hdc, maxpTag, 4, &glyphs, sizeof(glyphs)) != GDI_ERROR) {
+    if (GDI_ERROR != GetFontData(hdc, SkOTTableMaximumProfile::TAG, 4, &glyphs, sizeof(glyphs))) {
         return SkEndian_SwapBE16(glyphs);
     }
 
@@ -167,6 +178,29 @@
     return min;
 }
 
+static unsigned calculateUPEM(HDC hdc, const LOGFONT& lf) {
+    TEXTMETRIC textMetric;

[vandebo (ex-Chrome), 2013/07/15 17:32:56]

If you pull this out into a helper function you could do:

TEXTMETRIC textMetric;
if (get_text_metric(hdc, &textMetrics) && !(textMetric.tmPitchAndFamily ...

[bungeman-skia, 2013/07/15 18:21:36]

This doesn't want to be in a helper, it wants to be in the LogFontTypeface (and
it almost is). I was trying to avoid that this time around.

+    if (0 == GetTextMetrics(hdc, &textMetric)) {
+        call_ensure_accessible(lf);
+        if (0 == GetTextMetrics(hdc, &textMetric)) {
+            textMetric.tmPitchAndFamily = TMPF_TRUETYPE;
+        }
+    }
+
+    if (!(textMetric.tmPitchAndFamily & TMPF_VECTOR)) {
+        return textMetric.tmMaxCharWidth;
+    }
+
+    OUTLINETEXTMETRIC otm;
+    unsigned int otmRet = GetOutlineTextMetrics(hdc, sizeof(otm), &otm);
+    if (0 == otmRet) {
+        call_ensure_accessible(lf);
+        otmRet = GetOutlineTextMetrics(hdc, sizeof(otm), &otm);
+    }
+
+    return (0 == otmRet) ? 0 : otm.otmEMSquare;
+}
+
 class LogFontTypeface : public SkTypeface {
 public:
     LogFontTypeface(SkTypeface::Style style, SkFontID fontID, const LOGFONT& lf, bool serializeAsStream = false) :
@@ -228,6 +262,8 @@
                                 SkAdvancedTypefaceMetrics::PerGlyphInfo,
                                 const uint32_t*, uint32_t) const SK_OVERRIDE;
     virtual void onGetFontDescriptor(SkFontDescriptor*, bool*) const SK_OVERRIDE;
+    virtual int onCountGlyphs() const SK_OVERRIDE;
+    virtual int onGetUPEM() const SK_OVERRIDE;
 };
 
 class FontMemResourceTypeface : public LogFontTypeface {
@@ -724,10 +760,8 @@
 
 unsigned SkScalerContext_Windows::generateGlyphCount() {
     if (fGlyphCount < 0) {
-        if (fType == SkScalerContext_Windows::kBitmap_Type) {
-           return fTM.tmLastChar;
-        }
-        fGlyphCount = calculateOutlineGlyphCount(fDDC);
+        fGlyphCount = calculateGlyphCount(
+                          fDDC, static_cast<const LogFontTypeface*>(this->getTypeface())->fLogFont);
     }
     return fGlyphCount;
 }
@@ -1446,7 +1480,7 @@
     if (!GetOutlineTextMetrics(hdc, sizeof(otm), &otm)) {
         goto Error;
     }
-    glyphCount = calculateOutlineGlyphCount(hdc);
+    glyphCount = calculateGlyphCount(hdc, fLogFont);
 
     info = new SkAdvancedTypefaceMetrics;
     info->fEmSize = otm.otmEMSquare;
@@ -1684,6 +1718,34 @@
     return stream;
 }
 
+int LogFontTypeface::onCountGlyphs() const {
+    HDC hdc = ::CreateCompatibleDC(NULL);
+    HFONT font = CreateFontIndirect(&fLogFont);
+    HFONT savefont = (HFONT)SelectObject(hdc, font);
+
+    unsigned int glyphCount = calculateGlyphCount(hdc, fLogFont);
+
+    SelectObject(hdc, savefont);
+    DeleteObject(font);
+    DeleteDC(hdc);
+
+    return glyphCount;
+}
+
+int LogFontTypeface::onGetUPEM() const {
+    HDC hdc = ::CreateCompatibleDC(NULL);
+    HFONT font = CreateFontIndirect(&fLogFont);
+    HFONT savefont = (HFONT)SelectObject(hdc, font);
+
+    unsigned int upem = calculateUPEM(hdc, fLogFont);
+
+    SelectObject(hdc, savefont);
+    DeleteObject(font);
+    DeleteDC(hdc);
+
+    return upem;
+}
+
 SkScalerContext* LogFontTypeface::onCreateScalerContext(const SkDescriptor* desc) const {
     SkScalerContext_Windows* ctx = SkNEW_ARGS(SkScalerContext_Windows,
                                                 (const_cast<LogFontTypeface*>(this), desc));