cinera.c: Fix colouring of topic dots

The colour computed for topic dots and put into cinera_topics.css in HSL
format has its lightness value modified depending on whether it's on a
dark or light background. Web browsers do not tell us an element's
computed colour in HSL format, but in RGB, so we would need to convert
it from RGB to HSL when setting the lightness. Previously, this
conversion was busted, calculating too small a value for the saturation.

This commit obviates the need for any RGB→HSL conversion by writing the
hue and saturation values as attributes to the elements, which the
function responsible for setting the lightness may use directly.

cinera/cinera.c

@@ -23,7 +23,7 @@ typedef struct
 version CINERA_APP_VERSION = {
     .Major = 0,
     .Minor = 10,
-    .Patch = 28
+    .Patch = 29
 };
 
 #define __USE_XOPEN2K8 // NOTE(matt): O_NOFOLLOW
@@ -4172,6 +4172,68 @@ LogEdit(edit_type_id EditType, string Lineage, string EntryID, string *EntryTitl
     }
 }
 
+#define CINERA_HSL_TRANSPARENT_HUE 65535
+
+typedef struct
+{
+    unsigned int Hue:16;
+    unsigned int Saturation:8;
+    unsigned int Lightness:8;
+} hsl_colour;
+
+hsl_colour
+CharToColour(char Char)
+{
+    hsl_colour Colour;
+    if(Char >= 'a' && Char <= 'z')
+    {
+        Colour.Hue = (((float)Char - 'a') / ('z' - 'a') * 360);
+        Colour.Saturation = (((float)Char - 'a') / ('z' - 'a') * 26 + 74);
+    }
+    else if(Char >= 'A' && Char <= 'Z')
+    {
+        Colour.Hue = (((float)Char - 'A') / ('Z' - 'A') * 360);
+        Colour.Saturation = (((float)Char - 'A') / ('Z' - 'A') * 26 + 74);
+    }
+    else if(Char >= '0' && Char <= '9')
+    {
+        Colour.Hue = (((float)Char - '0') / ('9' - '0') * 360);
+        Colour.Saturation = (((float)Char - '0') / ('9' - '0') * 26 + 74);
+    }
+    else
+    {
+        Colour.Hue = 180;
+        Colour.Saturation = 50;
+    }
+
+    return Colour;
+}
+
+void
+StringToColourHash(hsl_colour *Colour, string String)
+{
+    Colour->Hue = 0;
+    Colour->Saturation = 0;
+    Colour->Lightness = 74;
+
+    for(int i = 0; i < String.Length; ++i)
+    {
+        Colour->Hue += CharToColour(String.Base[i]).Hue;
+        Colour->Saturation += CharToColour(String.Base[i]).Saturation;
+    }
+
+    Colour->Hue = Colour->Hue % 360;
+    Colour->Saturation = Colour->Saturation % 26 + 74;
+}
+
+bool
+IsValidHSLColour(hsl_colour Colour)
+{
+    return (Colour.Hue >= 0 && Colour.Hue < 360)
+        && (Colour.Saturation >= 0 && Colour.Saturation <= 100)
+        && (Colour.Lightness >= 0 && Colour.Lightness <= 100);
+}
+
 #define SLASH 1
 #define NULLTERM 1
 typedef struct
@@ -4326,6 +4388,7 @@ typedef struct
 {
     string Marker;
     string WrittenText;
+    hsl_colour Colour;
 } category_info;
 
 #define CopyString(Dest, DestSize, Format, ...) CopyString_(__LINE__, (Dest), (DestSize), (Format), ##__VA_ARGS__)
@@ -5481,58 +5544,6 @@ TimecodeToDottedSeconds(v4 Timecode)
     return (float)Timecode.Hours * SECONDS_PER_HOUR + (float)Timecode.Minutes * SECONDS_PER_MINUTE + (float)Timecode.Seconds + (float)Timecode.Milliseconds / 1000;
 }
 
-typedef struct
-{
-    unsigned int Hue:16;
-    unsigned int Saturation:8;
-    unsigned int Lightness:8;
-} hsl_colour;
-
-hsl_colour
-CharToColour(char Char)
-{
-    hsl_colour Colour;
-    if(Char >= 'a' && Char <= 'z')
-    {
-        Colour.Hue = (((float)Char - 'a') / ('z' - 'a') * 360);
-        Colour.Saturation = (((float)Char - 'a') / ('z' - 'a') * 26 + 74);
-    }
-    else if(Char >= 'A' && Char <= 'Z')
-    {
-        Colour.Hue = (((float)Char - 'A') / ('Z' - 'A') * 360);
-        Colour.Saturation = (((float)Char - 'A') / ('Z' - 'A') * 26 + 74);
-    }
-    else if(Char >= '0' && Char <= '9')
-    {
-        Colour.Hue = (((float)Char - '0') / ('9' - '0') * 360);
-        Colour.Saturation = (((float)Char - '0') / ('9' - '0') * 26 + 74);
-    }
-    else
-    {
-        Colour.Hue = 180;
-        Colour.Saturation = 50;
-    }
-
-    return Colour;
-}
-
-void
-StringToColourHash(hsl_colour *Colour, string String)
-{
-    Colour->Hue = 0;
-    Colour->Saturation = 0;
-    Colour->Lightness = 74;
-
-    for(int i = 0; i < String.Length; ++i)
-    {
-        Colour->Hue += CharToColour(String.Base[i]).Hue;
-        Colour->Saturation += CharToColour(String.Base[i]).Saturation;
-    }
-
-    Colour->Hue = Colour->Hue % 360;
-    Colour->Saturation = Colour->Saturation % 26 + 74;
-}
-
 char *
 SanitisePunctuation(char *String)
 {
@@ -8102,7 +8113,7 @@ BuildCredits(string HMMLFilepath, buffer *CreditsMenu, HMML_VideoMetaData *Metad
 }
 
 void
-InsertCategory(_memory_book(category_info) *GlobalTopics, _memory_book(category_info) *LocalTopics, _memory_book(category_info) *GlobalMedia, _memory_book(category_info) *LocalMedia, string Marker)
+InsertCategory(_memory_book(category_info) *GlobalTopics, _memory_book(category_info) *LocalTopics, _memory_book(category_info) *GlobalMedia, _memory_book(category_info) *LocalMedia, string Marker, hsl_colour *Colour)
 {
     medium *Medium = GetMediumFromProject(CurrentProject, Marker);
 
@@ -8203,11 +8214,15 @@ InsertCategory(_memory_book(category_info) *GlobalTopics, _memory_book(category_
                 {
                     category_info *Src = GetPlaceInBook(LocalTopics, CategoryCount - 1);
                     category_info *Dest = GetPlaceInBook(LocalTopics, CategoryCount);
-                    Dest->Marker = Src->Marker;
+                    *Dest = *Src;
                 }
 
                 category_info *New = GetPlaceInBook(LocalTopics, CategoryCount);
                 New->Marker = Marker;
+                if(Colour)
+                {
+                    New->Colour = *Colour;
+                }
                 break;
             }
         }
@@ -8218,6 +8233,10 @@ InsertCategory(_memory_book(category_info) *GlobalTopics, _memory_book(category_
         {
             category_info *New = GetPlaceInBook(LocalTopics, TopicIndex);
             New->Marker = Marker;
+            if(Colour)
+            {
+                New->Colour = *Colour;
+            }
         }
 
         bool MadeGlobalSpace = FALSE;
@@ -8241,11 +8260,15 @@ InsertCategory(_memory_book(category_info) *GlobalTopics, _memory_book(category_
                     {
                         category_info *Src = GetPlaceInBook(GlobalTopics, CategoryCount - 1);
                         category_info *Dest = GetPlaceInBook(GlobalTopics, CategoryCount);
-                        Dest->Marker = Src->Marker;
+                        *Dest = *Src;
                     }
 
                     category_info *New = GetPlaceInBook(GlobalTopics, CategoryCount);
                     New->Marker = Marker;
+                    if(Colour)
+                    {
+                        New->Colour = *Colour;
+                    }
                     break;
                 }
             }
@@ -8257,6 +8280,10 @@ InsertCategory(_memory_book(category_info) *GlobalTopics, _memory_book(category_
         {
             category_info *New = GetPlaceInBook(GlobalTopics, TopicIndex);
             New->Marker = Marker;
+            if(Colour)
+            {
+                New->Colour = *Colour;
+            }
         }
     }
 }
@@ -8348,9 +8375,18 @@ BuildCategoryIcons(buffer *CategoryIcons, _memory_book(category_info) *LocalTopi
             CopyString(SanitisedMarker, sizeof(SanitisedMarker), "%.*s", (int)This->Marker.Length, This->Marker.Base);
             SanitisePunctuation(SanitisedMarker);
 
-            CopyStringToBuffer(CategoryIcons, "<div title=\"%.*s\" class=\"category %s\"></div>",
+            CopyStringToBuffer(CategoryIcons,
+                    "<div title=\"%.*s\" class=\"category %s\"",
                     (int)This->Marker.Length, This->Marker.Base,
                     SanitisedMarker);
+            if(IsValidHSLColour(This->Colour))
+            {
+                CopyStringToBuffer(CategoryIcons,
+                        " data-hue=\"%u\" data-saturation=\"%u%%\"",
+                        This->Colour.Hue, This->Colour.Saturation);
+            }
+            CopyStringToBuffer(CategoryIcons,
+                    "></div>");
         }
     }
 
@@ -8630,7 +8666,7 @@ BuildQuote(memory_book *Strings, quote_info *Info, string Speaker, int ID, bool
 }
 
 rc
-GenerateTopicColours(neighbourhood *N, string Topic)
+GenerateTopicColours(neighbourhood *N, string Topic, hsl_colour *Dest)
 {
     rc Result = RC_SUCCESS;
     // NOTE(matt): Stack-string
@@ -8641,6 +8677,15 @@ GenerateTopicColours(neighbourhood *N, string Topic)
     medium *Medium = GetMediumFromProject(CurrentProject, Topic);
     if(!Medium)
     {
+        if(StringsMatch(Topic, Wrap0("nullTopic")))
+        {
+            Dest->Hue = CINERA_HSL_TRANSPARENT_HUE;
+        }
+        else
+        {
+            StringToColourHash(Dest, Topic);
+        }
+
         file Topics = {};
         Topics.Path = 0;
         Topics.Buffer.ID = BID_TOPICS;
@@ -8706,10 +8751,8 @@ GenerateTopicColours(neighbourhood *N, string Topic)
                     }
                     else
                     {
-                        hsl_colour Colour;
-                        StringToColourHash(&Colour, Topic);
                         WriteToFile(Topics.Handle, ".category.%s { border: 1px solid hsl(%d, %d%%, %d%%); background: hsl(%d, %d%%, %d%%); }\n",
-                                SanitisedTopic, Colour.Hue, Colour.Saturation, Colour.Lightness, Colour.Hue, Colour.Saturation, Colour.Lightness);
+                                SanitisedTopic, Dest->Hue, Dest->Saturation, Dest->Lightness, Dest->Hue, Dest->Saturation, Dest->Lightness);
                     }
 
 #if DEBUG_MEM
@@ -10899,7 +10942,7 @@ ProcessTimestamp(buffers *CollationBuffers, neighbourhood *N, string Filepath, m
                 {
                     *HasFilterMenu = TRUE;
                 }
-                InsertCategory(Topics, &LocalTopics, Media, &LocalMedia, Wrap0("authored"));
+                InsertCategory(Topics, &LocalTopics, Media, &LocalMedia, Wrap0("authored"), NULL);
                 hsl_colour AuthorColour;
                 StringToColourHash(&AuthorColour, Author);
                 // TODO(matt): That EDITION_NETWORK site database API-polling stuff
@@ -10924,14 +10967,15 @@ ProcessTimestamp(buffers *CollationBuffers, neighbourhood *N, string Filepath, m
                 HMML_MarkerType Type = Timestamp->markers[MarkerIndex].type;
                 if(Type == HMML_CATEGORY)
                 {
-                    Result = GenerateTopicColours(N, Wrap0(Timestamp->markers[MarkerIndex].marker));
+                    hsl_colour TopicColour = {};
+                    Result = GenerateTopicColours(N, Wrap0(Timestamp->markers[MarkerIndex].marker), &TopicColour);
                     if(Result == RC_SUCCESS)
                     {
                         if(!*HasFilterMenu)
                         {
                             *HasFilterMenu = TRUE;
                         }
-                        InsertCategory(Topics, &LocalTopics, Media, &LocalMedia, Wrap0(Timestamp->markers[MarkerIndex].marker));
+                        InsertCategory(Topics, &LocalTopics, Media, &LocalMedia, Wrap0(Timestamp->markers[MarkerIndex].marker), &TopicColour);
                         CopyStringToBuffer(&IndexBuffers->Text, "%.*s", (int)StringLength(Readable), InPtr);
                     }
                     else
@@ -11162,14 +11206,15 @@ ProcessTimestamp(buffers *CollationBuffers, neighbourhood *N, string Filepath, m
 
                 while(MarkerIndex < Timestamp->marker_count)
                 {
-                    Result = GenerateTopicColours(N, Wrap0(Timestamp->markers[MarkerIndex].marker));
+                    hsl_colour TopicColour = {};
+                    Result = GenerateTopicColours(N, Wrap0(Timestamp->markers[MarkerIndex].marker), &TopicColour);
                     if(Result == RC_SUCCESS)
                     {
                         if(!*HasFilterMenu)
                         {
                             *HasFilterMenu = TRUE;
                         }
-                        InsertCategory(Topics, &LocalTopics, Media, &LocalMedia, Wrap0(Timestamp->markers[MarkerIndex].marker));
+                        InsertCategory(Topics, &LocalTopics, Media, &LocalMedia, Wrap0(Timestamp->markers[MarkerIndex].marker), &TopicColour);
                         ++MarkerIndex;
                     }
                     else
@@ -11182,10 +11227,11 @@ ProcessTimestamp(buffers *CollationBuffers, neighbourhood *N, string Filepath, m
                 {
                     if(LocalTopics.ItemCount == 0)
                     {
-                        Result = GenerateTopicColours(N, Wrap0("nullTopic"));
+                        hsl_colour TopicColour = {};
+                        Result = GenerateTopicColours(N, Wrap0("nullTopic"), &TopicColour);
                         if(Result == RC_SUCCESS)
                         {
-                            InsertCategory(Topics, &LocalTopics, Media, &LocalMedia, Wrap0("nullTopic"));
+                            InsertCategory(Topics, &LocalTopics, Media, &LocalMedia, Wrap0("nullTopic"), &TopicColour);
                         }
                     }
 
@@ -11193,7 +11239,7 @@ ProcessTimestamp(buffers *CollationBuffers, neighbourhood *N, string Filepath, m
                     {
                         if(LocalMedia.ItemCount == 0)
                         {
-                            InsertCategory(Topics, &LocalTopics, Media, &LocalMedia, DefaultMedium->ID);
+                            InsertCategory(Topics, &LocalTopics, Media, &LocalMedia, DefaultMedium->ID, NULL);
                         }
 
                         BuildTimestampClass(&IndexBuffers->Class, &LocalTopics, &LocalMedia, DefaultMedium->ID);
@@ -11992,12 +12038,20 @@ HMMLToBuffers(buffers *CollationBuffers, template *BespokeTemplate, string BaseF
                                             bool NullTopic = StringsMatch(This->Marker, Wrap0("nullTopic"));
                                             CopyStringToBuffer(&MenuBuffers.FilterTopics,
                                                     "                            <div%s class=\"filter_content %s\">\n"
-                                                    "                                <span class=\"icon category %s\"></span><span class=\"cineraText\">%.*s</span>\n"
+                                                    "                                <span class=\"icon category %s\"",
-                                                    "                            </div>\n",
 
                                                     NullTopic ? " title=\"Timestamps that don't fit into the above topic(s) may be filtered using this pseudo-topic\"" : "",
                                                     SanitisedMarker,
-                                                    SanitisedMarker,
+                                                    SanitisedMarker);
+                                            if(IsValidHSLColour(This->Colour))
+                                            {
+                                                CopyStringToBuffer(&MenuBuffers.FilterTopics,
+                                                        " data-hue=\"%u\" data-saturation=\"%u%%\"",
+                                                        This->Colour.Hue, This->Colour.Saturation);
+                                            }
+                                            CopyStringToBuffer(&MenuBuffers.FilterTopics,
+                                                    "></span><span class=\"cineraText\">%.*s</span>\n"
+                                                    "                            </div>\n",
                                                     NullTopic ? (int)sizeof("(null topic)")-1 : (int)This->Marker.Length,
                                                     NullTopic ? "(null topic)" : This->Marker.Base);
                                         }

cinera/cinera_pre.js

@@ -551,35 +551,6 @@ BindHelp(Button, DocumentationContainer)
     })
 }
 
-function RGBtoHSL(colour)
-{
-	var rgb = colour.slice(4, -1).split(", ");
-    var red = rgb[0];
-    var green = rgb[1];
-    var blue = rgb[2];
-    var min = Math.min(red, green, blue);
-    var max = Math.max(red, green, blue);
-    var chroma = max - min;
-    var hue = 0;
-    if(max == red)
-    {
-        hue = ((green - blue) / chroma) % 6;
-    }
-    else if(max == green)
-    {
-        hue = ((blue - red) / chroma) + 2;
-    }
-    else if(max == blue)
-    {
-        hue = ((red - green) / chroma) + 4;
-    }
-
-    var saturation = chroma / 255 * 100;
-    hue = (hue * 60) < 0 ? 360 + (hue * 60) : (hue * 60);
-
-    return [hue, saturation]
-}
-
 function getBackgroundColourRGB(element) {
     var Colour = getComputedStyle(element).getPropertyValue("background-color");
     var depth = 0;
@@ -610,6 +581,8 @@ function setTextLightness(textElement)
 {
     var textHue = textElement.getAttribute("data-hue");
     var textSaturation = textElement.getAttribute("data-saturation");
+    if(textHue && textSaturation)
+    {
         if(getBackgroundBrightness(textElement.parentNode) < 127)
         {
             textElement.style.color = ("hsl(" + textHue + ", " + textSaturation + ", 76%)");
@@ -619,19 +592,23 @@ function setTextLightness(textElement)
             textElement.style.color = ("hsl(" + textHue + ", " + textSaturation + ", 24%)");
         }
     }
+}
 
 function setDotLightness(topicDot)
 {
-    var Hue = RGBtoHSL(getComputedStyle(topicDot).getPropertyValue("background-color"))[0];
+    var dotHue = topicDot.getAttribute("data-hue");
-    var Saturation = RGBtoHSL(getComputedStyle(topicDot).getPropertyValue("background-color"))[1];
+    var dotSaturation = topicDot.getAttribute("data-saturation");
+    if(dotHue && dotSaturation)
+    {
         if(getBackgroundBrightness(topicDot.parentNode) < 127)
         {
-        topicDot.style.backgroundColor = ("hsl(" + Hue + ", " + Saturation + "%, 76%)");
+            topicDot.style.backgroundColor = ("hsl(" + dotHue + ", " + dotSaturation + ", 76%)");
-        topicDot.style.borderColor = ("hsl(" + Hue + ", " + Saturation + "%, 76%)");
+            topicDot.style.borderColor = ("hsl(" + dotHue + ", " + dotSaturation + ", 76%)");
         }
         else
         {
-        topicDot.style.backgroundColor = ("hsl(" + Hue + ", " + Saturation + "%, 47%)");
+            topicDot.style.backgroundColor = ("hsl(" + dotHue + ", " + dotSaturation + ", 47%)");
-        topicDot.style.borderColor = ("hsl(" + Hue + ", " + Saturation + "%, 47%)");
+            topicDot.style.borderColor = ("hsl(" + dotHue + ", " + dotSaturation + ", 47%)");
+        }
     }
 }