From ac0eb346b746b1dd2b3698d8b03dbba9d584ef36 Mon Sep 17 00:00:00 2001
From: Olaf Wintermann <olaf.wintermann@gmail.com>
Date: Sat, 16 Aug 2025 13:47:52 +0200
Subject: [PATCH] add nfont FontTextExtents functions

---
 application/nfont.c | 76 +++++++++++++++++++++++++++++++++++++++++++++
 application/nfont.h | 14 +++++++++
 2 files changed, 90 insertions(+)

diff --git a/application/nfont.c b/application/nfont.c
index cce3666..ab8c921 100644
--- a/application/nfont.c
+++ b/application/nfont.c
@@ -281,3 +281,79 @@ void FontDrawString32(
     }
 
 }
+
+void FontTextExtents8(
+        Display *dpy,
+        NFont *font,
+        const FcChar8 *string,
+        int len,
+        XGlyphInfo *extents)
+{
+    FcChar32 static_buffer[128];
+    FcChar32 *buf = static_buffer;
+    if(len >= 128) {
+        buf = calloc(len, sizeof(FcChar32));
+    }
+    
+    // convert string from utf8 to utf32
+    int c = 0;
+    for(int i=0;i<len;) {
+        int n = FcUtf8ToUcs4(string+i, &buf[c++], len-i);
+        i += n;
+    }
+    
+    FontTextExtents32(dpy, font, buf, c, extents);
+    
+    if(buf != static_buffer) {
+        free(buf);
+    }
+}
+
+void FontTextExtents32(
+        Display *dpy,
+        NFont *font,
+        const FcChar32 *string,
+        int len,
+        XGlyphInfo *extents)
+{
+    XGlyphInfo ret = { 0 };
+    
+    XftFont *currentFont = FontDefault(font);
+    int pos = 0;
+    for(int i=0;i<len;i++) {
+        XftFont *cFont = FindFont(font, string[i]);
+        if(cFont != currentFont && i > pos) {
+            const FcChar32 *segStr = string+pos;
+            int segLen = i-pos;
+            
+            // get extents of string segment
+            XGlyphInfo ext;
+            XftTextExtents32(dpy, currentFont, segStr, segLen, &ext);
+            
+            if(ext.height > ret.height) {
+                ret.height = ext.height;
+            }
+            ret.width += ext.width;
+            ret.xOff += ext.xOff;
+            
+            pos = i;
+        }
+        currentFont = cFont;
+    }
+    
+    if(pos < len) {
+        const FcChar32 *segStr = string+pos;
+        int segLen = len-pos;
+        // get extents of string segment
+        XGlyphInfo ext;
+        XftTextExtents32(dpy, currentFont, segStr, segLen, &ext);
+
+        if(ext.height > ret.height) {
+            ret.height = ext.height;
+        }
+        ret.width += ext.width;
+        ret.xOff += ext.xOff;
+    }
+    
+    *extents = ret;
+}
diff --git a/application/nfont.h b/application/nfont.h
index cbefd86..65c720b 100644
--- a/application/nfont.h
+++ b/application/nfont.h
@@ -81,6 +81,20 @@ void FontDrawString32(
         const FcChar32 *string,
         int len);
 
+void FontTextExtents8(
+        Display *dpy,
+        NFont *font,
+        const FcChar8 *string,
+        int len,
+        XGlyphInfo *extents);
+
+void FontTextExtents32(
+        Display *dpy,
+        NFont *font,
+        const FcChar32 *string,
+        int len,
+        XGlyphInfo *extents);
+
 #ifdef __cplusplus
 }
 #endif
-- 
2.47.3