ggo_optim.patch

diff --git a/src/fontcache.cpp b/src/fontcache.cpp
index 3756a7452..86526a3bc 100644
--- a/src/fontcache.cpp
+++ b/src/fontcache.cpp
@@ -719,6 +724,7 @@ class Win32FontCache : public TrueTypeFontCache {
 	HFONT font = NULL;  ///< The font face associated with this font.
 	HDC dc = NULL;
 	HGDIOBJ old_font;
+	SIZE glyph_size;
 
 	void SetFontSize(FontSize fs, int pixels);
 	virtual const void *InternalGetFontTable(uint32 tag, size_t &length);
@@ -800,6 +806,8 @@ void Win32FontCache::SetFontSize(FontSize fs, int pixels)
 	this->ascender = otm->otmTextMetrics.tmAscent;
 	this->descender = otm->otmTextMetrics.tmDescent;
 	this->height = this->ascender + this->descender;
+	this->glyph_size.cx = otm->otmTextMetrics.tmMaxCharWidth;
+	this->glyph_size.cy = otm->otmTextMetrics.tmHeight;
 
 	DEBUG(freetype, 2, "Loaded font '%s' with size %d", FS2OTTD((LPTSTR)((BYTE *)otm + (ptrdiff_t)otm->otmpFullName)), pixels);
 }
@@ -820,11 +828,20 @@ void Win32FontCache::ClearFontCache()
 	/* First query size of needed glyph memory, then allocate the memory and query again. */
 	GLYPHMETRICS gm;
 	MAT2 mat = { {0, 1}, {0, 0}, {0, 0}, {0, 1} };
-	DWORD ret = GetGlyphOutline(this->dc, key, GGO_GLYPH_INDEX | (aa ? GGO_GRAY8_BITMAP : GGO_BITMAP), &gm, 0, NULL, &mat);
-	if (ret == GDI_ERROR) usererror("Unable to render font glyph");
 
-	byte *bmp = AllocaM(byte, ret);
-	GetGlyphOutline(this->dc, key, GGO_GLYPH_INDEX | (aa ? GGO_GRAY8_BITMAP : GGO_BITMAP), &gm, ret, bmp, &mat);
+	/* Make a guess for the needed memory size. */
+	DWORD ret = this->glyph_size.cy * Align(aa ? this->glyph_size.cx : max(this->glyph_size.cx / 8l, 1l), 4); // Bitmap data is DWORD-aligned rows.
+	byte *bmp = bmp = AllocaM(byte, ret);
+	ret = GetGlyphOutline(this->dc, key, GGO_GLYPH_INDEX | (aa ? GGO_GRAY8_BITMAP : GGO_BITMAP), &gm, ret, bmp, &mat);
+
+	if (ret == GDI_ERROR) {
+		/* No dice with the guess. First query size of needed glyph memory,
+		 * then allocate the memory and query again. */
+		ret = GetGlyphOutline(this->dc, key, GGO_GLYPH_INDEX | (aa ? GGO_GRAY8_BITMAP : GGO_BITMAP), &gm, 0, NULL, &mat);
+		if (ret == GDI_ERROR) usererror("Unable to render font glyph");
+		bmp = AllocaM(byte, ret);
+		GetGlyphOutline(this->dc, key, GGO_GLYPH_INDEX | (aa ? GGO_GRAY8_BITMAP : GGO_BITMAP), &gm, ret, bmp, &mat);
+	}
 
 	/* Add 1 pixel for the shadow on the medium font. Our sprite must be at least 1x1 pixel. */
 	uint width = max(1U, (uint)gm.gmBlackBoxX + (this->fs == FS_NORMAL));