Fossil Forum

Small CSS-only feature that helps when scrolling through a long diff, and one forgets which file is looked at. - Both bright/dark mode CSS added. - Slight transparency in filename background, to know if we are at top of diff or somewhere inbetween (where text behind shows through) - Now this is hardcoded in --webpage mode, but could be further flag-gated if would bother someone (don't think worth the effort, but your call)

Index: src/diffcmd.c
==================================================================
--- src/diffcmd.c
+++ src/diffcmd.c
@@ -148,10 +148,30 @@
            DIFF_WEBPAGE|DIFF_TCL))==0
   ){
     blob_appendf(pOut, "Index: %s\n%.66c\n", zFile, '=');
   }
 }
+
+void diff_print_file_intro(
+  DiffConfig *pCfg,       /* Diff configuration */
+  Blob *pOut              /* Write to this blob, or stdout if this is NULL */
+){
+  u64 diffFlags = pCfg->diffFlags;
+  if( diffFlags & DIFF_WEBPAGE ){
+    blob_appendf(pOut,"<div>\n");
+  }
+}
+
+void diff_print_file_outro(
+  DiffConfig *pCfg,       /* Diff configuration */
+  Blob *pOut              /* Write to this blob, or stdout if this is NULL */
+){
+  u64 diffFlags = pCfg->diffFlags;
+  if( diffFlags & DIFF_WEBPAGE ){
+    blob_appendf(pOut,"</div>\n");
+  }
+}

 /*
 ** Print the +++/--- filename lines or whatever filename information
 ** is appropriate for the output format.
 **
@@ -158,11 +178,11 @@
 */
 void diff_print_filenames(
   const char *zLeft,      /* Name of the left file */
   const char *zRight,     /* Name of the right file */
   DiffConfig *pCfg,       /* Diff configuration */
-  Blob *pOut              /* Write to this blob, or stdout of this is NULL */
+  Blob *pOut              /* Write to this blob, or stdout if this is NULL */
 ){
   u64 diffFlags = pCfg->diffFlags;
   /* Standardize on /dev/null, regardless of platform. */
   if( pCfg->diffFlags & DIFF_FILE_ADDED ) zLeft = "/dev/null";
   if( pCfg->diffFlags & DIFF_FILE_DELETED ) zRight = "/dev/null";
@@ -231,10 +251,13 @@
 @ body {
 @    background-color: white;
 @ }
 @ h1 {
 @   font-size: 150%;
+@   background-color: #ffffffe0;
+@   position: sticky;
+@   top: 0em;
 @ }
 @
 @ table.diff {
 @   width: 100%;
 @   border-spacing: 0;
@@ -316,10 +339,13 @@
 @   background-color: #c0c0ff;
 @   text-decoration: none;
 @   font-weight: bold;
 @ }
 @ @media (prefers-color-scheme: dark) {
+@   h1 {
+@     background-color: #353535e0;
+@   }
 @   body {
 @     background-color: #353535;
 @     color: #ffffff;
 @   }
 @   td.diffln ins {
@@ -361,10 +387,13 @@
 @    background-color: #353535;
 @    color: #ffffff;
 @ }
 @ h1 {
 @   font-size: 150%;
+@   background-color: #353535e0;
+@   position: sticky;
+@   top: 0em;
 @ }
 @
 @ table.diff {
 @   width: 100%;
 @   border-spacing: 0;
@@ -600,12 +629,14 @@
         if( pCfg->diffFlags & DIFF_NUMSTAT ){
           if( !(pCfg->diffFlags & DIFF_BRIEF) ){
             blob_appendf(pOut, "%s %s\n", blob_str(&out), zName);
           }
         }else{
+          diff_print_file_intro(pCfg, pOut);
           diff_print_filenames(zName, zName2, pCfg, pOut);
           blob_appendf(pOut, "%s\n", blob_str(&out));
+          diff_print_file_outro(pCfg, pOut);
         }
       }
       blob_reset(&out);
     }

@@ -708,12 +739,14 @@
     if( pCfg->diffFlags & DIFF_NUMSTAT ){
       if( !(pCfg->diffFlags & DIFF_BRIEF) ){
         fossil_print("%s %s\n", blob_str(&out), zName);
       }
     }else{
+      diff_print_file_intro(pCfg, 0);
       diff_print_filenames(zName, zName, pCfg, 0);
       fossil_print("%s\n", blob_str(&out));
+      diff_print_file_outro(pCfg, 0);
     }

     /* Release memory resources */
     blob_reset(&out);
   }else{
@@ -912,11 +945,13 @@
     }
     if( showDiff ){
       Blob content;
       if( !isLink != !file_islink(zFullName) ){
         diff_print_index(zPathname, pCfg, 0);
+        diff_print_file_intro(pCfg, 0);
         diff_print_filenames(zPathname, zPathname, pCfg, 0);
+        diff_print_file_outro(pCfg, 0);
         fossil_print("%s",DIFF_CANNOT_COMPUTE_SYMLINK);
         continue;
       }
       if( srcid>0 ){
         content_get(srcid, &content);

Against current checkout 63826bf8a4ce7300cf45ff16fe82bcd0b132fdb2. Tested by running --webpage with/without -y.

(Note: Was looking how to run all tests, accidentally ran tclsh ./test/many-www.tcl which turns out was bombing this site with requests?)