From eeae4512ae6b5286aff600d82e612fc10fef5a76 Mon Sep 17 00:00:00 2001
From: PeterN <peter@fuzzle.org>
Date: Sat, 23 Feb 2019 16:07:25 +0000
Subject: [PATCH] Fix #7003: Freetype fonts were scaled by both GUI and Font
 zoom levels. (#7267)

---
 src/fontcache.cpp | 14 ++++++--------
 src/zoom_func.h   | 20 ++++++++++++++++++++
 2 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/src/fontcache.cpp b/src/fontcache.cpp
index 9b732ce1ed..604cc7374e 100644
--- a/src/fontcache.cpp
+++ b/src/fontcache.cpp
@@ -184,12 +184,12 @@ uint SpriteFontCache::GetGlyphWidth(GlyphID key)
 {
 	SpriteID sprite = this->GetUnicodeGlyph(key);
 	if (sprite == 0) sprite = this->GetUnicodeGlyph('?');
-	return SpriteExists(sprite) ? GetSprite(sprite, ST_FONT)->width + ScaleGUITrad(this->fs != FS_NORMAL ? 1 : 0) : 0;
+	return SpriteExists(sprite) ? GetSprite(sprite, ST_FONT)->width + ScaleFontTrad(this->fs != FS_NORMAL ? 1 : 0) : 0;
 }
 
 int SpriteFontCache::GetHeight() const
 {
-	return this->height * (1 << (ZOOM_LVL_OUT_4X - _font_zoom));
+	return ScaleFontTrad(this->height);
 }
 
 bool SpriteFontCache::GetDrawGlyphShadow()
@@ -282,21 +282,19 @@ void FreeTypeFontCache::SetFontSize(FontSize fs, FT_Face face, int pixels)
 {
 	if (pixels == 0) {
 		/* Try to determine a good height based on the minimal height recommended by the font. */
-		int scaled_height = ScaleGUITrad(_default_font_height[this->fs]);
+		int scaled_height = ScaleFontTrad(_default_font_height[this->fs]);
 		pixels = scaled_height;
 
 		TT_Header *head = (TT_Header *)FT_Get_Sfnt_Table(this->face, ft_sfnt_head);
 		if (head != NULL) {
 			/* Font height is minimum height plus the difference between the default
 			 * height for this font size and the small size. */
-			int diff = scaled_height - ScaleGUITrad(_default_font_height[FS_SMALL]);
+			int diff = scaled_height - ScaleFontTrad(_default_font_height[FS_SMALL]);
 			pixels = Clamp(min(head->Lowest_Rec_PPEM, 20) + diff, scaled_height, MAX_FONT_SIZE);
 		}
+	} else {
+		pixels = ScaleFontTrad(pixels);
 	}
-
-	/* Apply user-specified font zoom. */
-	pixels *= (1 << (ZOOM_LVL_OUT_4X - _font_zoom));
-
 	this->used_size = pixels;
 
 	FT_Error err = FT_Set_Pixel_Sizes(this->face, 0, pixels);
diff --git a/src/zoom_func.h b/src/zoom_func.h
index da266e35c6..0e8fa8c9ef 100644
--- a/src/zoom_func.h
+++ b/src/zoom_func.h
@@ -84,4 +84,24 @@ static inline int ScaleGUITrad(int value)
 	return UnScaleGUI(value * ZOOM_LVL_BASE);
 }
 
+/**
+ * Short-hand to apply font zoom level.
+ * @param value Pixel amount at #ZOOM_LVL_BEGIN (full zoom in).
+ * @return Pixel amount at #ZOOM_LVL_FONT (current interface size).
+ */
+static inline int UnScaleFont(int value)
+{
+	return UnScaleByZoom(value, ZOOM_LVL_FONT);
+}
+
+/**
+ * Scale traditional pixel dimensions to Font zoom level.
+ * @param value Pixel amount at #ZOOM_LVL_BASE (traditional "normal" interface size).
+ * @return Pixel amount at #ZOOM_LVL_FONT (current interface size).
+ */
+static inline int ScaleFontTrad(int value)
+{
+	return UnScaleFont(value * ZOOM_LVL_BASE);
+}
+
 #endif /* ZOOM_FUNC_H */