From 03e2e586423ada331ae433db7dea705a8b6ad3fe Mon Sep 17 00:00:00 2001
From: Behdad Esfahbod <behdad@behdad.org>
Date: Fri, 20 Jan 2023 11:24:35 -0700
Subject: [PATCH] [hb-view] Improve color parsing

Now supports 3, 4, 6, 8 digit colors.
---
 util/helper-cairo.hh | 13 +++++++------
 util/options.hh      | 40 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 47 insertions(+), 6 deletions(-)

diff --git a/util/helper-cairo.hh b/util/helper-cairo.hh
index fe4367aac..a066d6807 100644
--- a/util/helper-cairo.hh
+++ b/util/helper-cairo.hh
@@ -130,11 +130,12 @@ helper_cairo_create_scaled_font (const font_options_t *font_opts,
   {
     palette_index = HB_PAINT_PALETTE_INDEX_CUSTOM;
     char **entries = g_strsplit (view_opts->custom_palette, ",", -1);
-    for (unsigned int i = 0; entries[i]; i++)
+    for (unsigned i = 0; entries[i]; i++)
     {
-      unsigned int fr, fg, fb, fa;
-      if (sscanf (entries[i], "%2x%2x%2x%2x", &fr, &fg, &fb, &fa) == 4)
-        cairo_font_options_set_custom_palette_color (font_options, i, fr / 255., fg / 255., fb / 255., fa / 255.);
+      unsigned fr, fg, fb, fa;
+      fr = fg = fb = fa = 0;
+      parse_color (entries[i], fr, fg,fb, fa);
+      cairo_font_options_set_custom_palette_color (font_options, i, fr / 255., fg / 255., fb / 255., fa / 255.);
     }
     g_strfreev (entries);
   }
@@ -510,10 +511,10 @@ helper_cairo_create_context (double w, double h,
   const char *color;
   br = bg = bb = ba = 255;
   color = view_opts->back ? view_opts->back : DEFAULT_BACK;
-  sscanf (color + (*color=='#'), "%2x%2x%2x%2x", &br, &bg, &bb, &ba);
+  parse_color (color, br, bg, bb, ba);
   fr = fg = fb = 0; fa = 255;
   color = view_opts->fore ? view_opts->fore : DEFAULT_FORE;
-  sscanf (color + (*color=='#'), "%2x%2x%2x%2x", &fr, &fg, &fb, &fa);
+  parse_color (color, fr, fg, fb, fa);
 
   if (content == CAIRO_CONTENT_ALPHA)
   {
diff --git a/util/options.hh b/util/options.hh
index 4336a1dcd..efce20c3a 100644
--- a/util/options.hh
+++ b/util/options.hh
@@ -242,4 +242,44 @@ __inline float scalbnf (float x, int exp)
 }
 #endif
 
+static inline bool
+parse_color (const char *s,
+	     unsigned &r,
+	     unsigned &g,
+	     unsigned &b,
+	     unsigned &a)
+{
+  bool ret = false;
+
+  while (*s == ' ') s++;
+  if (*s == '#') s++;
+
+  unsigned sr, sg, sb, sa;
+  sa = 255;
+  if (sscanf (s, "%2x%2x%2x%2x", &sr, &sg, &sb, &sa) <= 2)
+  {
+    if (sscanf (s, "%1x%1x%1x%1x", &sr, &sg, &sb, &sa) >= 3)
+    {
+      sr *= 17;
+      sg *= 17;
+      sb *= 17;
+      sa *= 17;
+      ret = true;
+    }
+  }
+  else
+    ret = true;
+
+  if (ret)
+  {
+    r = sr;
+    g = sg;
+    b = sb;
+    a = sa;
+  }
+
+  return ret;
+}
+
+
 #endif