improvements from testing with real display

src/cgram.c

@@ -372,6 +372,208 @@ const struct LcdBuf_CGRAM_Symbol CGRAM_CZ[] = {
                 },
         },
 
+        // GUI symbols
+
+        {
+                .symbol = "🌢", // Humidity
+                .fallback = 'H',
+                .data = {
+                        0b00100,
+                        0b01110,
+                        0b01110,
+                        0b11111,
+                        0b10111,
+                        0b11111,
+                        0b01110,
+                },
+        },
+
+        // Some useful glyphs for GUI with a keypad
+
+        {
+                .symbol = "🅰",
+                .fallback = 'A',
+                .data = {
+                        0b11111,
+                        0b11011,
+                        0b10101,
+                        0b10001,
+                        0b10101,
+                        0b10101,
+                        0b11111,
+                },
+        },
+        {
+                .symbol = "🅱",
+                .fallback = 'B',
+                .data = {
+                        0b11111,
+                        0b10011,
+                        0b10101,
+                        0b10011,
+                        0b10101,
+                        0b10011,
+                        0b11111,
+                },
+        },
+        {
+                .symbol = "🅲",
+                .fallback = 'C',
+                .data = {
+                        0b11111,
+                        0b11011,
+                        0b10101,
+                        0b10111,
+                        0b10101,
+                        0b11011,
+                        0b11111,
+                },
+        },
+        {
+                .symbol = "🅳",
+                .fallback = 'D',
+                .data = {
+                        0b11111,
+                        0b10011,
+                        0b10101,
+                        0b10101,
+                        0b10101,
+                        0b10011,
+                        0b11111,
+                },
+        },
+        {
+                .symbol = "❶",
+                .fallback = '1',
+                .data = {
+                        0b11111,
+                        0b11011,
+                        0b10011,
+                        0b11011,
+                        0b11011,
+                        0b10001,
+                        0b11111,
+                },
+        },
+        {
+                .symbol = "❷",
+                .fallback = '2',
+                .data = {
+                        0b11111,
+                        0b11001,
+                        0b10101,
+                        0b11101,
+                        0b11011,
+                        0b10001,
+                        0b11111,
+                },
+        },
+        {
+                .symbol = "❸",
+                .fallback = '3',
+                .data = {
+                        0b11111,
+                        0b10011,
+                        0b11101,
+                        0b10011,
+                        0b11101,
+                        0b10011,
+                        0b11111,
+                },
+        },
+        {
+                .symbol = "❹",
+                .fallback = '4',
+                .data = {
+                        0b11111,
+                        0b10101,
+                        0b10101,
+                        0b10001,
+                        0b11101,
+                        0b11101,
+                        0b11111,
+                },
+        },
+        {
+                .symbol = "⊛",
+                .fallback = '*',
+                .data = {
+                        0b11111,
+                        0b11011,
+                        0b01010,
+                        0b10001,
+                        0b01010,
+                        0b11011,
+                        0b11111,
+                },
+        },
+        {
+                .symbol = "¤",
+                .fallback = '#',
+                .data = {
+                        0b11111,
+                        0b10101,
+                        0b00000,
+                        0b10101,
+                        0b00000,
+                        0b10101,
+                        0b11111,
+                },
+        },
+        {
+                .symbol = "▌",
+                .fallback = ' ',
+                .data = {
+                        0b11100,
+                        0b11100,
+                        0b11100,
+                        0b11100,
+                        0b11100,
+                        0b11100,
+                        0b11100,
+                        0b11100,
+                },
+        },
+        {
+                .symbol = "↑",
+                .fallback = '^',
+                .data = {
+                        0b00100,
+                        0b01110,
+                        0b10101,
+                        0b00100,
+                        0b00100,
+                        0b00100,
+                        0b00100,
+                },
+        },
+        {
+                .symbol = "↓",
+                .fallback = 'v',
+                .data = {
+                        0b00100,
+                        0b00100,
+                        0b00100,
+                        0b00100,
+                        0b10101,
+                        0b01110,
+                        0b00100,
+                },
+        },
+        {
+                .symbol = "✔",
+                .fallback = 0xE8,
+                .data = {
+                        0b00000,
+                        0b00000,
+                        0b00001,
+                        0b10011,
+                        0b11110,
+                        0b01100,
+                        0b00000,
+                },
+        },
+
         {}, /* end mark */
 };
 

src/cgrom.c

@@ -97,8 +97,8 @@ const struct LcdBuf_CGROM_Entry CGROM_A00[] = {
         {.address = 123, .symbol = "{"},
         {.address = 124, .symbol = "|"},
         {.address = 125, .symbol = "}"},
-        {.address = 126, .symbol = "←"},
-        {.address = 127, .symbol = "→"},
+        {.address = 126, .symbol = "→"},
+        {.address = 127, .symbol = "←"},
 
         // lots of japanese symbols - add them yourself if you need them
         {.address = 0xA2, .symbol = "「"},

src/lcdbuf.c

@@ -15,6 +15,7 @@ void LcdBuffer_Init(struct LcdBuffer *self, const struct LcdBuf_CGROM_Entry *cgr
     assert(cgrom);
     assert(custom_symbols);
 
+    memset(self, 0, sizeof(struct LcdBuffer));
     LcdBuffer_Clear(self);
     self->cgrom = cgrom;
     self->custom_symbols = custom_symbols;
@@ -36,8 +37,37 @@ void LcdBuffer_Clear(struct LcdBuffer *self)
 /** Write what needs to be written to the HW, clear all dirty marks */
 void LcdBuffer_Flush(struct LcdBuffer *self)
 {
+    bool any_flush = self->full_repaint_required || self->cursor_dirty;
+    uint8_t flush_cgram_mask = 0;
+
+    // Check if any flushing is required
     for (int i = 0; i < LCDBUF_CGRAM_CAPACITY; i++) {
         if (self->cgram[i].refcount > 0 && self->cgram[i].dirty) {
+            any_flush = true;
+            flush_cgram_mask |= 1 << i;
+        }
+    }
+
+    if (!any_flush) {
+        // check if we have dirty areas
+        for (int e = 0; e < LCDBUF_DIRTY_LIST_LEN; e++) {
+            struct LcdBuf_DirtyExtent *ext = &self->dirty_extents[e];
+            if (ext->count) {
+                any_flush = true;
+                break;
+            }
+        }
+    }
+
+    if (!any_flush) {
+        // really nothing to do
+        return;
+    }
+
+    LcdBuffer_IO_SetCursorStyle(0); // hide cursor for the time of this function
+
+    for (int i = 0; i < LCDBUF_CGRAM_CAPACITY; i++) {
+        if (flush_cgram_mask & (1 << i)) {
             LcdBuffer_IO_WriteCGRAM(i, self->custom_symbols[self->cgram[i].symbol_index].data);
             self->cgram[i].dirty = false;
         }
@@ -57,7 +87,7 @@ void LcdBuffer_Flush(struct LcdBuffer *self)
 
         if (!any_nonspace) {
             LcdBuffer_IO_Clear();
-            return;
+            goto done;
         }
 
         for (int r = 0; r < LINE_NUM; r++) {
@@ -74,11 +104,21 @@ void LcdBuffer_Flush(struct LcdBuffer *self)
             ext->count = 0; // mark the slot as free
         }
     }
+
+    done:
+    // Restore the visible cursor
+    if (self->cursor_style != 0) {
+        LcdBuffer_IO_SetCursorPos(self->cursor_row, self->cursor_col);
+        LcdBuffer_IO_SetCursorStyle(self->cursor_style); // hide cursor for the time of this function
+    }
+    self->cursor_dirty = false;
 }
 
 /** Fully write everything to the display */
 void LcdBuffer_FlushAll(struct LcdBuffer *self)
 {
+    LcdBuffer_IO_SetCursorStyle(0); // hide cursor for the time of this function
+
     for (int i = 0; i < LCDBUF_CGRAM_CAPACITY; i++) {
         if (self->cgram[i].refcount > 0) {
             LcdBuffer_IO_WriteCGRAM(i, self->custom_symbols[self->cgram[i].symbol_index].data);
@@ -92,6 +132,14 @@ void LcdBuffer_FlushAll(struct LcdBuffer *self)
 
     memset(self->dirty_extents, 0, sizeof(self->dirty_extents));
     self->full_repaint_required = false;
+
+    // Restore the visible cursor
+    if (self->cursor_style != 0) {
+        LcdBuffer_IO_SetCursorPos(self->cursor_row, self->cursor_col);
+        LcdBuffer_IO_SetCursorStyle(self->cursor_style); // hide cursor for the time of this function
+    }
+
+    self->cursor_dirty = false;
 }
 
 //static void show_dirty_slots(const struct LcdBuffer *self) {
@@ -289,3 +337,14 @@ void LcdBuffer_Write(struct LcdBuffer *self, lcdbuf_pos_t row, lcdbuf_pos_t col,
         col++;
     }
 }
+
+
+void LcdBuffer_SetCursor(struct LcdBuffer *self, lcdbuf_pos_t row, lcdbuf_pos_t col, uint8_t cursor_style)
+{
+    if ((self->cursor_style != cursor_style) || (self->cursor_row != row) || (self->cursor_col != col)) {
+        self->cursor_style = cursor_style;
+        self->cursor_row = row;
+        self->cursor_col = col;
+        self->cursor_dirty = true;
+    }
+}

src/lcdbuf.h

@@ -71,6 +71,12 @@ struct LcdBuffer {
   /** If the dirty extents array was not sufficient to hold all changes, this flag is set,
    * indicating the dirty_extents array should be disregarded. */
   bool full_repaint_required;
+
+  /* Visible cursor - is restored after flushing */
+  uint8_t cursor_style; // two bits - blink 0b01, bar 0b10
+  lcdbuf_pos_t cursor_row;
+  lcdbuf_pos_t cursor_col;
+  bool cursor_dirty;
 };
 
 /** Initialize the struct */
@@ -91,6 +97,9 @@ void LcdBuffer_Set(struct LcdBuffer *self, lcdbuf_pos_t row, lcdbuf_pos_t col, s
 /** Write a UTF8 string at a position */
 void LcdBuffer_Write(struct LcdBuffer *self, lcdbuf_pos_t row, lcdbuf_pos_t col, char *utf_string);
 
+/** Set visible cursor position and style. style is 2 bits: blink 0b01, bar 0b10 */
+void LcdBuffer_SetCursor(struct LcdBuffer *self, lcdbuf_pos_t row, lcdbuf_pos_t col, uint8_t cursor_style);
+
 /* Callbacks - need to be implemented by the application! */
 
 /** Clear the entire screen (CGRAM can be left unchanged, but they will be written anew if needed) */
@@ -102,4 +111,8 @@ extern void LcdBuffer_IO_WriteAt(lcdbuf_pos_t row, lcdbuf_pos_t col, const uint8
 /** Write CGRAM data. Data is always 8 bytes long. */
 extern void LcdBuffer_IO_WriteCGRAM(uint8_t position, const uint8_t *data);
 
+/** Set cursor pos & style */
+extern void LcdBuffer_IO_SetCursorPos(lcdbuf_pos_t cursor_row, lcdbuf_pos_t cursor_col);
+extern void LcdBuffer_IO_SetCursorStyle(uint8_t cursor_style);
+
 #endif //HD44780UTF_LCDBUF_H

src/main.c

@@ -46,6 +46,16 @@ void LcdBuffer_IO_WriteAt(lcdbuf_pos_t row, lcdbuf_pos_t col, const uint8_t *buf
     printf("\"\n");
 }
 
+void LcdBuffer_IO_SetCursorPos(lcdbuf_pos_t cursor_row, lcdbuf_pos_t cursor_col)
+{
+    printf("CURS : %d,%d\n", cursor_row, cursor_col);
+}
+
+void LcdBuffer_IO_SetCursorStyle(uint8_t cursor_style)
+{
+    printf("CURS: style 0x%02x\n", cursor_style);
+}
+
 #define BYTE_TO_BINARY_PATTERN "%c%c%c%c%c%c%c%c"
 #define BYTE_TO_BINARY(byte)  \
   ((byte) & 0x80 ? '#' : '.'), \