Expose character mapping internals and add invert

Allowing the faces to access the internal segment mapping code makes
it easier to have custom characters and have fancy effects.

movement/watch_faces/clock/minute_repeater_decimal_face.c

@@ -129,8 +129,8 @@ bool minute_repeater_decimal_face_loop(movement_event_t event, movement_settings
 
             if ((date_time.reg >> 6) == (previous_date_time >> 6) && event.event_type != EVENT_LOW_ENERGY_UPDATE) {
                 // everything before seconds is the same, don't waste cycles setting those segments.
-                watch_display_character_lp_seconds('0' + date_time.unit.second / 10, 8);
-                watch_display_character_lp_seconds('0' + date_time.unit.second % 10, 9);
+                watch_display_character_lp('0' + date_time.unit.second / 10, 8);
+                watch_display_character_lp('0' + date_time.unit.second % 10, 9);
                 break;
             } else if ((date_time.reg >> 12) == (previous_date_time >> 12) && event.event_type != EVENT_LOW_ENERGY_UPDATE) {
                 // everything before minutes is the same.

movement/watch_faces/clock/repetition_minute_face.c

@@ -114,8 +114,8 @@ bool repetition_minute_face_loop(movement_event_t event, movement_settings_t *se
 
             if ((date_time.reg >> 6) == (previous_date_time >> 6) && event.event_type != EVENT_LOW_ENERGY_UPDATE) {
                 // everything before seconds is the same, don't waste cycles setting those segments.
-                watch_display_character_lp_seconds('0' + date_time.unit.second / 10, 8);
-                watch_display_character_lp_seconds('0' + date_time.unit.second % 10, 9);
+                watch_display_character_lp('0' + date_time.unit.second / 10, 8);
+                watch_display_character_lp('0' + date_time.unit.second % 10, 9);
                 break;
             } else if ((date_time.reg >> 12) == (previous_date_time >> 12) && event.event_type != EVENT_LOW_ENERGY_UPDATE) {
                 // everything before minutes is the same.

movement/watch_faces/clock/simple_clock_bin_led_face.c

@@ -140,8 +140,8 @@ bool simple_clock_bin_led_face_loop(movement_event_t event, movement_settings_t
 
                 if ((date_time.reg >> 6) == (previous_date_time >> 6) && event.event_type != EVENT_LOW_ENERGY_UPDATE) {
                     // everything before seconds is the same, don't waste cycles setting those segments.
-                    watch_display_character_lp_seconds('0' + date_time.unit.second / 10, 8);
-                    watch_display_character_lp_seconds('0' + date_time.unit.second % 10, 9);
+                    watch_display_character_lp('0' + date_time.unit.second / 10, 8);
+                    watch_display_character_lp('0' + date_time.unit.second % 10, 9);
                     break;
                 } else if ((date_time.reg >> 12) == (previous_date_time >> 12) && event.event_type != EVENT_LOW_ENERGY_UPDATE) {
                     // everything before minutes is the same.

movement/watch_faces/clock/simple_clock_face.c

@@ -97,8 +97,8 @@ bool simple_clock_face_loop(movement_event_t event, movement_settings_t *setting
 
             if ((date_time.reg >> 6) == (previous_date_time >> 6) && event.event_type != EVENT_LOW_ENERGY_UPDATE) {
                 // everything before seconds is the same, don't waste cycles setting those segments.
-                watch_display_character_lp_seconds('0' + date_time.unit.second / 10, 8);
-                watch_display_character_lp_seconds('0' + date_time.unit.second % 10, 9);
+                watch_display_character_lp('0' + date_time.unit.second / 10, 8);
+                watch_display_character_lp('0' + date_time.unit.second % 10, 9);
                 break;
             } else if ((date_time.reg >> 12) == (previous_date_time >> 12) && event.event_type != EVENT_LOW_ENERGY_UPDATE) {
                 // everything before minutes is the same.

watch-library/shared/watch/watch_private_display.c

@@ -33,7 +33,9 @@ static const uint32_t IndicatorSegments[] = {
     SLCD_SEGID(1, 10), // WATCH_INDICATOR_LAP
 };
 
-void watch_display_character(uint8_t character, uint8_t position) {
+static bool invert = false;
+
+uint8_t watch_convert_char_to_segdata(uint8_t character, uint8_t position) {
     // special cases for positions 4 and 6
     if (position == 4 || position == 6) {
         if (character == '7') character = '&'; // "lowercase" 7
@@ -64,65 +66,72 @@ void watch_display_character(uint8_t character, uint8_t position) {
     } else {
         if (character == 'R') character = 'r'; // R needs to be lowercase almost everywhere
     }
-    if (position == 0) {
-        watch_clear_pixel(0, 15); // clear funky ninth segment
-    } else {
+    if (position != 0) {
         if (character == 'I') character = 'l'; // uppercase I only works in position 0
     }
 
-    uint64_t segmap = Segment_Map[position];
-    uint64_t segdata = Character_Set[character - 0x20];
+    return Character_Set[character - 0x20];
+}
 
-    for (int i = 0; i < 8; i++) {
-        uint8_t com = (segmap & 0xFF) >> 6;
-        if (com > 2) {
-            // COM3 means no segment exists; skip it.
-            segmap = segmap >> 8;
-            segdata = segdata >> 1;
-            continue;
-        }
-        uint8_t seg = segmap & 0x3F;
-
-        if (segdata & 1)
-          watch_set_pixel(com, seg);
-        else
-          watch_clear_pixel(com, seg);
-
-        segmap = segmap >> 8;
-        segdata = segdata >> 1;
-    }
+uint8_t watch_convert_char_to_segdata_lp(uint8_t character) {
+    // i.e. remove any special casing cf watch_convert_char_to_segdata
+    return Character_Set[character - 0x20];
+}
+
+void watch_display_character(uint8_t character, uint8_t position) {
+    watch_display_segdata(watch_convert_char_to_segdata(character, position), position);
+
+    // Handle the segments that are not in our usual map at all.
+    if (position == 0) {
+        if (character == 'B' || character == 'D' || character == '@') watch_set_pixel(0, 15); // bottom left serif
+        else watch_clear_pixel(0, 15);
+
+    } else if (position == 1) {
+        if (character == 'T') watch_set_pixel(1, 12); // add descender (left hand side vertical line)
 
-    if (character == 'T' && position == 1) watch_set_pixel(1, 12); // add descender
-    else if (position == 0 && (character == 'B' || character == 'D' || character == '@')) watch_set_pixel(0, 15); // add funky ninth segment
-    else if (position == 1 && (character == 'B' || character == 'D' || character == '@')) watch_set_pixel(0, 12); // add funky ninth segment
+        if (character == 'B' || character == 'D' || character == '@') watch_set_pixel(0, 12); // top left serif
+        else watch_clear_pixel(0, 12);
+    }
 }
 
-void watch_display_character_lp_seconds(uint8_t character, uint8_t position) {
-    // Will only work for digits and for positions  8 and 9 - but less code & checks to reduce power consumption
+// Allow us to rotate characters 180 degrees (see watch_private_display.h for bit position diagram).
+static const uint8_t vert_invert_map[8] = {
+    3, 4, 5, 0, 1, 2, 6, 7,
+};
+
+void watch_display_segment(uint8_t bit_pos, uint8_t position, bool on) {
+    uint64_t segmap = Segment_Map[position] >> (8 * bit_pos);
+    uint8_t com = (segmap & 0xFF) >> 6;
 
-    uint64_t segmap = Segment_Map[position];
-    uint64_t segdata = Character_Set[character - 0x20];
+    if (com > 2) {
+        // COM3 means no segment exists; skip it.
+        return;
+    }
 
+    uint8_t seg = segmap & 0x3F;
+
+    if (on) {
+        watch_set_pixel(com, seg);
+    } else {
+        watch_clear_pixel(com, seg);
+    }
+}
+
+void watch_display_segdata(uint8_t segdata, uint8_t position) {
     for (int i = 0; i < 8; i++) {
-        uint8_t com = (segmap & 0xFF) >> 6;
-        if (com > 2) {
-            // COM3 means no segment exists; skip it.
-            segmap = segmap >> 8;
-            segdata = segdata >> 1;
-            continue;
-        }
-        uint8_t seg = segmap & 0x3F;
-
-        if (segdata & 1)
-          watch_set_pixel(com, seg);
-        else
-          watch_clear_pixel(com, seg);
-
-        segmap = segmap >> 8;
-        segdata = segdata >> 1;
+        uint8_t bit_pos = invert ? vert_invert_map[i] : i;
+        watch_display_segment(bit_pos, position, (1 << i) & segdata);
     }
 }
 
+void watch_display_invert(bool inv) {
+    invert = inv;
+}
+
+void watch_display_character_lp(uint8_t character, uint8_t position) {
+    watch_display_segdata(watch_convert_char_to_segdata_lp(character), position);
+}
+
 void watch_display_string(char *string, uint8_t position) {
     size_t i = 0;
     while(string[i] != 0) {
@@ -133,7 +142,7 @@ void watch_display_string(char *string, uint8_t position) {
     // uncomment this line to see screen output on terminal, i.e.
     //   FR  29
     // 11 50 23
-    // note that for partial displays (positon > 0) it will only show the characters that were updated.
+    // note that for partial displays (position > 0) it will only show the characters that were updated.
     // printf("________\n  %c%c  %c%c\n%c%c %c%c %c%c\n--------\n", (position > 0) ? ' ' : string[0], (position > 1) ? ' ' : string[1 - position], (position > 2) ? ' ' : string[2 - position], (position > 3) ? ' ' : string[3 - position], (position > 4) ? ' ' : string[4 - position], (position > 5) ? ' ' : string[5 - position], (position > 6) ? ' ' : string[6 - position], (position > 7) ? ' ' : string[7 - position], (position > 8) ? ' ' : string[8 - position], (position > 9) ? ' ' : string[9 - position]);
 }
 

watch-library/shared/watch/watch_private_display.h

@@ -27,6 +27,20 @@
 #include "hpl_slcd_config.h"
 #include "driver_init.h"
 
+// Bit position -> segment mapping for Character_Set.
+//  --0--
+// |     |
+// 5     1
+// |     |
+//  --6--
+// |     |
+// 4     2
+// |     |
+//  --3--
+//
+// 7 is the middle divider (i.e. only position 0).
+
+
 static const uint8_t Character_Set[] =
 {
     0b00000000, //  
@@ -141,8 +155,4 @@ static const uint64_t Segment_Map[] = {
 
 static const uint8_t Num_Chars = 10;
 
-void watch_display_character(uint8_t character, uint8_t position);
-void watch_display_character_lp_seconds(uint8_t character, uint8_t position);
-
-
 #endif

watch-library/shared/watch/watch_slcd.h

@@ -74,7 +74,7 @@ void watch_clear_pixel(uint8_t com, uint8_t seg);
 void watch_clear_display(void);
 
 /** @brief Displays a string at the given position, starting from the top left. There are ten digits.
-           A space in any position will clear that digit.
+  *        A space in any position will clear that digit.
   * @param string A null-terminated string.
   * @param position The position where you wish to start displaying the string. The day of week digits
   *                 are positions 0 and 1; the day of month digits are positions 2 and 3, and the main
@@ -84,6 +84,79 @@ void watch_clear_display(void);
   */
 void watch_display_string(char *string, uint8_t position);
 
+/** @brief Displays a character at the given position, starting from the top left. There are ten digits.
+  *        A space in any position will clear that digit.
+  * @param character A single character to display.
+  * @param position The position where you wish to display the character. The day of week digits
+  *                 are positions 0 and 1; the day of month digits are positions 2 and 3, and the main
+  *                 clock line occupies positions 4-9.
+  */
+void watch_display_character(uint8_t character, uint8_t position);
+
+/** @brief Displays a character at the given position, starting from the top left. There are ten digits.
+  *        lp refers to 'low-power', as this does _not_ do any special casing to try to handle the pecularities of each position,
+  *        This means it's best used to display numbers in the expected form.
+  * @param character A single character to display.
+  * @param position The position where you wish to display the character. The day of week digits
+  *                 are positions 0 and 1; the day of month digits are positions 2 and 3, and the main
+  *                 clock line occupies positions 4-9.
+  */
+void watch_display_character_lp(uint8_t character, uint8_t position);
+
+/** @brief Attempt to invert the display (i.e. rotate all characters 180 degrees).
+ *         As with watch_display_character_lp, due to the limitations of the display this works best
+ *         with numbers. This affects all subsequent calls to watch_display_string/character.
+ *  @param inv whether to invert (true) or not invert (false).
+ */
+void watch_display_invert(bool inv);
+
+/** @brief Display arbitrary segment data at a particular position.
+ *         cf watch_display_character.
+ *  @param segdata Raw bits which are mapped to the position. See below.
+ *  @param position The position where you wish to display the character. The day of week digits
+ *                  are positions 0 and 1; the day of month digits are positions 2 and 3, and the main
+ *                  clock line occupies positions 4-9.
+ *  @note The bits are mapped as follows:
+ *
+ *  --0-- 
+ * |     |
+ * 5     1
+ * |     |
+ *  --6--
+ * |     |
+ * 4     2
+ * |     |
+ *  --3--
+ *
+ * 7 is the middle divider. i.e. only position 0.
+ *
+ * If you want to display/clear an individual segment, use watch_display_segment.
+ */
+void watch_display_segdata(uint8_t segdata, uint8_t position);
+
+/** @brief Generate segdata for a position that could be used as input to watch_display_segdata.
+ *  @param character A single character to convert.
+ *  @param position The position to generate the character for.
+ *  @note You might wonder why the position is necessary for this function even though
+ *        we don't actually display the character here. This is because we generate different segment
+ *        data depending on the characte to handle the limitiations of the position.
+ */
+uint8_t watch_convert_char_to_segdata(uint8_t character, uint8_t position);
+
+/** @brief Generate segdata for a position that could be used as input to watch_display_segdata (lp).
+ *         This is analagous to watch_display_character_lp.
+ *  @param character A single character to convert.
+ */
+uint8_t watch_convert_char_to_segdata_lp(uint8_t character);
+
+/** @brief Map an individual segment to a particular position. See watch_display_segdata for segment info.
+ *         This is similar to watch_set_pixel, but maps the segments for an arbitrary spot on the display.
+ *  @param bit_pos Bit position (0 to 7).
+ *  @param position Character position.
+ *  @param on Whether to set or clear at that position.
+ */
+void watch_display_segment(uint8_t bit_pos, uint8_t position, bool on);
+
 /** @brief Turns the colon segment on.
   */
 void watch_set_colon(void);
@@ -147,5 +220,6 @@ bool watch_tick_animation_is_running(void);
   * @details This will stop the animation and clear all segments in position 8.
   */
 void watch_stop_tick_animation(void);
+
 /// @}
 #endif