Bug 461663 - 16 bits colour channel values should not have lower bits zeroed. r=gavin

browser/components/shell/src/nsGNOMEShellService.cpp

@@ -451,7 +451,7 @@ nsGNOMEShellService::SetDesktopBackground(nsIDOMElement* aElement,
 }
 
 #define COLOR_16_TO_8_BIT(_c) ((_c) >> 8)
-#define COLOR_8_TO_16_BIT(_c) ((_c) << 8)
+#define COLOR_8_TO_16_BIT(_c) ((_c) << 8 | (_c))
 
 NS_IMETHODIMP
 nsGNOMEShellService::GetDesktopBackgroundColor(PRUint32 *aColor)
@@ -480,37 +480,25 @@ nsGNOMEShellService::GetDesktopBackgroundColor(PRUint32 *aColor)
 static void
 ColorToCString(PRUint32 aColor, nsCString& aResult)
 {
-#if GTK_CHECK_VERSION(2,12,0)
-  GdkColor color;
-  color.red = COLOR_8_TO_16_BIT(aColor >> 16);
-  color.green = COLOR_8_TO_16_BIT((aColor >> 8) & 0xff);
-  color.blue = COLOR_8_TO_16_BIT(aColor & 0xff);
-
-  gchar *colorString = gdk_color_to_string(&color);
-  aResult.Assign(colorString);
-  g_free(colorString);
-
-#else // GTK 2.12.0
-
   // The #rrrrggggbbbb format is used to match gdk_color_to_string()
   char *buf = aResult.BeginWriting(13);
   if (!buf)
     return;
 
-  PRUint8 red = (aColor >> 16);
+  PRUint16 red = COLOR_8_TO_16_BIT((aColor >> 16) & 0xff);
-  PRUint8 green = (aColor >> 8) & 0xff;
+  PRUint16 green = COLOR_8_TO_16_BIT((aColor >> 8) & 0xff);
-  PRUint8 blue = aColor & 0xff;
+  PRUint16 blue = COLOR_8_TO_16_BIT(aColor & 0xff);
 
-  PR_snprintf(buf, 14, "#%02x00%02x00%02x00", red, green, blue);
+  PR_snprintf(buf, 14, "#%04x%04x%04x", red, green, blue);
-#endif // GTK 2.12.0
 }
 
 NS_IMETHODIMP
 nsGNOMEShellService::SetDesktopBackgroundColor(PRUint32 aColor)
 {
+  NS_ASSERTION(aColor <= 0xffffff, "aColor has extra bits");
   nsCOMPtr<nsIGConfService> gconf = do_GetService(NS_GCONFSERVICE_CONTRACTID);
 
-  nsCString colorString;
+  nsCAutoString colorString;
   ColorToCString(aColor, colorString);
 
   gconf->SetString(NS_LITERAL_CSTRING(kDesktopColorKey), colorString);

browser/components/shell/test/unit/test_421977.js

@@ -102,11 +102,11 @@ function run_test() {
     checkGConfToShellColor("#ffffffffffff", "#FFFFFF");
 
     checkShellToGConfColor("#000000", "#000000000000");
-    checkShellToGConfColor("#0000FF", "#00000000ff00");
+    checkShellToGConfColor("#0000FF", "#00000000ffff");
-    checkShellToGConfColor("#FFFFFF", "#ff00ff00ff00");
+    checkShellToGConfColor("#FFFFFF", "#ffffffffffff");
-    checkShellToGConfColor("#0A0B0C", "#0a000b000c00");
+    checkShellToGConfColor("#0A0B0C", "#0a0a0b0b0c0c");
-    checkShellToGConfColor("#A0B0C0", "#a000b000c000");
+    checkShellToGConfColor("#A0B0C0", "#a0a0b0b0c0c0");
-    checkShellToGConfColor("#AABBCC", "#aa00bb00cc00");
+    checkShellToGConfColor("#AABBCC", "#aaaabbbbcccc");
 
   } finally {
     gGConf.setString(GCONF_BG_COLOR_KEY, origGConfColor);