Scale text to match 'm' size

Fixes bug 12304

5 files changed, 65 insertions, 1 deletions

diff --git a/splash/SplashFTFont.cc b/splash/SplashFTFont.cc
index 0241df01..28e48d79 100644
--- a/splash/SplashFTFont.cc
+++ b/splash/SplashFTFont.cc
@@ -42,7 +42,7 @@ SplashFTFont::SplashFTFont(SplashFTFontFile *fontFileA, SplashCoord *matA,
   SplashFont(fontFileA, matA, textMatA, fontFileA->engine->aa)
 {
   FT_Face face;
-  double size, div;
+  double div;
   int x, y;
 
   face = fontFileA->face;
@@ -239,6 +239,59 @@ GBool SplashFTFont::makeGlyph(int c, int xFrac, int yFrac,
   return gTrue;
 }
 
+double SplashFTFont::getGlyphAdvance(int c)
+{
+  SplashFTFontFile *ff;
+  FT_Vector offset;
+  FT_UInt gid;
+  FT_Matrix identityMatrix;
+
+  ff = (SplashFTFontFile *)fontFile;
+
+  // init the matrix
+  identityMatrix.xx = 65536; // 1 in 16.16 format
+  identityMatrix.xy = 0;
+  identityMatrix.yx = 0;
+  identityMatrix.yy = 65536; // 1 in 16.16 format
+
+  // init the offset
+  offset.x = 0;
+  offset.y = 0;
+
+  FT_Set_Transform(ff->face, &identityMatrix, &offset);
+
+  if (ff->codeToGID && c < ff->codeToGIDLen) {
+    gid = (FT_UInt)ff->codeToGID[c];
+  } else {
+    gid = (FT_UInt)c;
+  }
+  if (ff->trueType && gid == 0) {
+    // skip the TrueType notdef glyph
+    return -1;
+  }
+
+  // if we have the FT2 bytecode interpreter, autohinting won't be used
+#ifdef TT_CONFIG_OPTION_BYTECODE_INTERPRETER
+  if (FT_Load_Glyph(ff->face, gid,
+		    aa ? FT_LOAD_NO_BITMAP : FT_LOAD_DEFAULT)) {
+    return -1;
+  }
+#else
+  // FT2's autohinting doesn't always work very well (especially with
+  // font subsets), so turn it off if anti-aliasing is enabled; if
+  // anti-aliasing is disabled, this seems to be a tossup - some fonts
+  // look better with hinting, some without, so leave hinting on
+  if (FT_Load_Glyph(ff->face, gid,
+		    aa ? FT_LOAD_NO_HINTING | FT_LOAD_NO_BITMAP
+                       : FT_LOAD_DEFAULT)) {
+    return -1;
+  }
+#endif
+
+  // 64.0 is 1 in 26.6 format
+  return ff->face->glyph->metrics.horiAdvance / 64.0 / size;
+}
+
 struct SplashFTFontPath {
   SplashPath *path;
   SplashCoord textScale;
diff --git a/splash/SplashFTFont.h b/splash/SplashFTFont.h
index 70c01d38..4e220263 100644
--- a/splash/SplashFTFont.h
+++ b/splash/SplashFTFont.h
@@ -43,12 +43,16 @@ public:
   // Return the path for a glyph.
   virtual SplashPath *getGlyphPath(int c);
 
+  // Return the advance of a glyph. (in 0..1 range)
+  virtual double getGlyphAdvance(int c);
+
 private:
 
   FT_Size sizeObj;
   FT_Matrix matrix;
   FT_Matrix textMatrix;
   SplashCoord textScale;
+  double size;
 };
 
 #endif // HAVE_FREETYPE_FREETYPE_H || HAVE_FREETYPE_H
diff --git a/splash/SplashFont.h b/splash/SplashFont.h
index 3af9412a..f59b3a1e 100644
--- a/splash/SplashFont.h
+++ b/splash/SplashFont.h
@@ -75,6 +75,10 @@ public:
   // Return the path for a glyph.
   virtual SplashPath *getGlyphPath(int c) = 0;
 
+  // Return the advance of a glyph. (in 0..1 range)
+  // < 0 means not known
+  virtual double getGlyphAdvance(int c) { return -1; }
+
   // Return the font transform matrix.
   SplashCoord *getMatrix() { return mat; }
 
diff --git a/splash/SplashFontFile.cc b/splash/SplashFontFile.cc
index 1c70d3c8..80c99ae0 100644
--- a/splash/SplashFontFile.cc
+++ b/splash/SplashFontFile.cc
@@ -34,6 +34,7 @@ SplashFontFile::SplashFontFile(SplashFontFileID *idA, SplashFontSrc *srcA) {
   src = srcA;
   src->ref();
   refCnt = 0;
+  doAdjustMatrix = gFalse;
 }
 
 SplashFontFile::~SplashFontFile() {
diff --git a/splash/SplashFontFile.h b/splash/SplashFontFile.h
index 1e4639eb..e04e28cd 100644
--- a/splash/SplashFontFile.h
+++ b/splash/SplashFontFile.h
@@ -62,6 +62,8 @@ public:
   // the SplashFontFile object.
   void decRefCnt();
 
+  GBool doAdjustMatrix;
+
 protected:
 
   SplashFontFile(SplashFontFileID *idA, SplashFontSrc *srcA);