Codechange: Replace magic numbers by constants.

src/fontcache.cpp

@@ -440,7 +440,7 @@ void FreeTypeFontCache::SetFontSize(FontSize fs, FT_Face face, int pixels)
 			/* Font height is minimum height plus the difference between the default
 			 * height for this font size and the small size. */
 			int diff = scaled_height - ScaleFontTrad(_default_font_height[FS_SMALL]);
-			pixels = Clamp(std::min<uint>(head->Lowest_Rec_PPEM, 20u) + diff, scaled_height, MAX_FONT_SIZE);
+			pixels = Clamp(std::min<uint>(head->Lowest_Rec_PPEM, MAX_FONT_MIN_REC_SIZE) + diff, scaled_height, MAX_FONT_SIZE);
 		}
 	} else {
 		pixels = ScaleFontTrad(pixels);
@@ -608,7 +608,7 @@ const Sprite *FreeTypeFontCache::InternalGetGlyph(GlyphID key, bool aa)
 	uint height = std::max(1U, (uint)slot->bitmap.rows  + (this->fs == FS_NORMAL));
 
 	/* Limit glyph size to prevent overflows later on. */
-	if (width > 256 || height > 256) usererror("Font glyph is too large");
+	if (width > MAX_GLYPH_DIM || height > MAX_GLYPH_DIM) usererror("Font glyph is too large");
 
 	/* FreeType has rendered the glyph, now we allocate a sprite and copy the image into it */
 	SpriteLoader::Sprite sprite;

src/fontcache_internal.h

@@ -22,6 +22,9 @@ static const byte SHADOW_COLOUR = 2;
 /** Font cache for fonts that are based on a TrueType font. */
 class TrueTypeFontCache : public FontCache {
 protected:
+	static constexpr int MAX_GLYPH_DIM = 256;          ///< Maximum glyph dimensions.
+	static constexpr uint MAX_FONT_MIN_REC_SIZE = 20u; ///< Upper limit for the recommended font size in case a font file contains nonsensical values.
+
 	int req_size;  ///< Requested font size.
 	int used_size; ///< Used font size.
 

src/os/windows/font_win32.cpp

@@ -414,7 +414,7 @@ void Win32FontCache::SetFontSize(FontSize fs, int pixels)
 			/* Font height is minimum height plus the difference between the default
 			 * height for this font size and the small size. */
 			int diff = scaled_height - ScaleFontTrad(this->GetDefaultFontHeight(FS_SMALL));
-			pixels = Clamp(std::min(otm->otmusMinimumPPEM, 20u) + diff, scaled_height, MAX_FONT_SIZE);
+			pixels = Clamp(std::min(otm->otmusMinimumPPEM, MAX_FONT_MIN_REC_SIZE) + diff, scaled_height, MAX_FONT_SIZE);
 
 			SelectObject(dc, old);
 			DeleteObject(temp);
@@ -489,7 +489,7 @@ void Win32FontCache::ClearFontCache()
 	uint height = std::max(1U, (uint)gm.gmBlackBoxY + (this->fs == FS_NORMAL));
 
 	/* Limit glyph size to prevent overflows later on. */
-	if (width > 256 || height > 256) usererror("Font glyph is too large");
+	if (width > MAX_GLYPH_DIM || height > MAX_GLYPH_DIM) usererror("Font glyph is too large");
 
 	/* GDI has rendered the glyph, now we allocate a sprite and copy the image into it. */
 	SpriteLoader::Sprite sprite;