Font table compression

Firmware/Fonts/FontGen.py

@@ -42,13 +42,25 @@ fontTable = [
 
 def generateLineInTable(index, chars):
     pixels = chars[index]["PIXELS"].split(',')
+    
+    # Generate the rows binary data
     rows = []
     for i in range(8):
         rows.append(0)
         for j in range(5):
             rows[i] |= (1 << (5 - j - 1)) if pixels[j * 8 + i] == "0" else 0
-    line = "{{"
-    for r in rows:
+    
+    # compress the rows data
+    colByte = 0
+    compressedRows = []
+    for i in range(4):
+        rowByte = ((rows[i * 2 + 1] >> 1) & 0xF) | (((rows[i * 2 + 0] >> 1) & 0xF) << 4)
+        colByte |= (1 << i * 2 + 0) if (rows[i * 2 + 0] & 0x1) else 0
+        colByte |= (1 << i * 2 + 1) if (rows[i * 2 + 1] & 0x1) else 0
+        compressedRows.append(rowByte)
+
+    line = f"{{0x{colByte:02X}, {{"
+    for r in compressedRows:
         line += f"0x{r:02X}, "
     line += f"}}, '{fontTable[index].alternate}'}}, // '{fontTable[index].utf}', \\x{fontTable[index].default:02X}"
     return line

Firmware/Fonts/FontTable.h

@@ -1,18 +1,18 @@
-{{0x00, 0x1F, 0x15, 0x11, 0x15, 0x1F, 0x00, 0x00, }, 'H'}, // '🄷', \x80
-{{0x0C, 0x12, 0x12, 0x0C, 0x00, 0x00, 0x00, 0x00, }, '\xdf'}, // '°', \x81
-{{0x04, 0x0A, 0x0A, 0x0A, 0x0A, 0x11, 0x11, 0x0E, }, 'h'}, // '🌡', \x82
-{{0x04, 0x0E, 0x1F, 0x04, 0x1C, 0x00, 0x00, 0x00, }, '^'}, // '⬏', \x83
-{{0x00, 0x06, 0x19, 0x18, 0x03, 0x13, 0x0C, 0x00, }, '\xf3'}, // '🔃', \x84
-{{0x00, 0x1C, 0x1F, 0x11, 0x11, 0x1F, 0x00, 0x00, }, '\xdb'}, // '🗀', \x85
-{{0x00, 0x04, 0x12, 0x09, 0x12, 0x04, 0x00, 0x00, }, '>'}, // '»', \x86
-{{0x00, 0x0E, 0x13, 0x15, 0x11, 0x0E, 0x00, 0x00, }, '\xe5'}, // '🕑', \x87
-{{0x00, 0x00, 0x11, 0x0A, 0x04, 0x11, 0x0A, 0x04, }, '\x7e'}, // '⏬', \x88
-{{0x00, 0x01, 0x03, 0x16, 0x1C, 0x08, 0x00, 0x00, }, '\x7e'}, // '✔', \x89
-{{0x11, 0x0E, 0x00, 0x0E, 0x01, 0x0F, 0x11, 0x0F, }, 'a'}, // 'ă', \x8A
-{{0x04, 0x0A, 0x00, 0x0E, 0x01, 0x0F, 0x11, 0x0F, }, 'a'}, // 'â', \x8B
-{{0x04, 0x0A, 0x00, 0x0C, 0x04, 0x04, 0x04, 0x0E, }, 'i'}, // 'î', \x8C
-{{0x00, 0x0E, 0x10, 0x0E, 0x01, 0x1E, 0x04, 0x08, }, 's'}, // 'ș', \x8D
-{{0x08, 0x1C, 0x08, 0x08, 0x09, 0x06, 0x04, 0x08, }, 't'}, // 'ț', \x8E
-{{0x04, 0x0A, 0x00, 0x0E, 0x04, 0x04, 0x04, 0x0E, }, 'I'}, // 'Î', \x8F
-{{0x0E, 0x11, 0x0C, 0x06, 0x11, 0x0E, 0x04, 0x08, }, 'S'}, // 'Ș', \x90
-{{0x1F, 0x04, 0x04, 0x04, 0x04, 0x00, 0x04, 0x08, }, 'T'}, // 'Ț', \x91
+{0x3E, {0x0F, 0xA8, 0xAF, 0x00, }, 'H'}, // '🄷', \x80
+{0x00, {0x69, 0x96, 0x00, 0x00, }, '\xdf'}, // '°', \x81
+{0x60, {0x25, 0x55, 0x58, 0x87, }, 'h'}, // '🌡', \x82
+{0x04, {0x27, 0xF2, 0xE0, 0x00, }, '^'}, // '⬏', \x83
+{0x34, {0x03, 0xCC, 0x19, 0x60, }, '\xf3'}, // '🔃', \x84
+{0x3C, {0x0E, 0xF8, 0x8F, 0x00, }, '\xdb'}, // '🗀', \x85
+{0x08, {0x02, 0x94, 0x92, 0x00, }, '>'}, // '»', \x86
+{0x1C, {0x07, 0x9A, 0x87, 0x00, }, '\xe5'}, // '🕑', \x87
+{0x24, {0x00, 0x85, 0x28, 0x52, }, '\x7e'}, // '⏬', \x88
+{0x06, {0x00, 0x1B, 0xE4, 0x00, }, '\x7e'}, // '✔', \x89
+{0xF1, {0x87, 0x07, 0x07, 0x87, }, 'a'}, // 'ă', \x8A
+{0xF0, {0x25, 0x07, 0x07, 0x87, }, 'a'}, // 'â', \x8B
+{0x00, {0x25, 0x06, 0x22, 0x27, }, 'i'}, // 'î', \x8C
+{0x10, {0x07, 0x87, 0x0F, 0x24, }, 's'}, // 'ș', \x8D
+{0x10, {0x4E, 0x44, 0x43, 0x24, }, 't'}, // 'ț', \x8E
+{0x00, {0x25, 0x07, 0x22, 0x27, }, 'I'}, // 'Î', \x8F
+{0x12, {0x78, 0x63, 0x87, 0x24, }, 'S'}, // 'Ș', \x90
+{0x01, {0xF2, 0x22, 0x20, 0x24, }, 'T'}, // 'Ț', \x91

Firmware/lcd.cpp

@@ -376,13 +376,42 @@ void lcd_set_cursor_column(uint8_t col)
 
 // Allows us to fill the first 8 CGRAM locations
 // with custom characters
-void lcd_createChar_P(uint8_t location, const uint8_t* charmap)
+void lcd_createChar_P(uint8_t location, const CustomCharacter *char_p)
 {
-  location &= 0x7; // we only have 8 locations 0-7
-  lcd_command(LCD_SETCGRAMADDR | (location << 3));
-  for (uint8_t i = 0; i < 8; i++)
-    lcd_send(pgm_read_byte(&charmap[i]), HIGH);
-  lcd_command(LCD_SETDDRAMADDR | lcd_ddram_address); // no need for masking the address
+	uint8_t charmap[8];
+
+	uint8_t temp;
+	uint8_t colByte;
+	__asm__ __volatile__ (
+		// load colByte
+		"lpm %1, Z+" "\n\t"
+		
+		// begin for loop
+		"ldi %0, 8" "\n\t"
+		"mov __zero_reg__, %0" "\n\t"		// use zero_reg as loop counter
+		"forBegin_%=: " "\n\t"
+			"sbrs __zero_reg__, 0" "\n\t"	// test LSB of counter. Fetch new data if counter is even
+			"lpm __tmp_reg__, Z+" "\n\t"	// load next data byte from progmem, increment
+			"swap __tmp_reg__" "\n\t"		// swap the nibbles
+			"mov %0, __tmp_reg__" "\n\t"	// copy row data to temp
+
+			"andi %0, 0xF" "\n\t"			// mask lower nibble
+			"ror %1" "\n\t" 				// consume LSB of colByte and push it to the carry
+			"rol %0" "\n\t"					// insert the column LSB from carry
+			"st %a3+, %0" "\n\t"			// push the generated row data to the output
+		// end for loop
+		"dec __zero_reg__" "\n\t"
+		"brne forBegin_%=" "\n\t"
+		
+		: "=&d" (temp), "=&r" (colByte)
+		: "z" (char_p), "e" (charmap)
+	);
+
+	lcd_command(LCD_SETCGRAMADDR | (location << 3));
+	for (uint8_t i = 0; i < 8; i++) {
+		lcd_send(charmap[i], HIGH);
+	}
+	lcd_command(LCD_SETDDRAMADDR | lcd_ddram_address); // no need for masking the address
 }
 
 #ifdef VT100
@@ -854,7 +883,7 @@ static void lcd_print_custom(uint8_t c) {
 	// try to find a slot where it could be placed
 	for (uint8_t i = 0; i < 8; i++) {
 		if (lcd_custom_characters[i] == 0x7F) { //found an empty slot. create a new custom character and send it
-			lcd_createChar_P(i, Font[c - 0x80].data);
+			lcd_createChar_P(i, &Font[c - 0x80]);
 			lcd_custom_characters[i] = c; // mark the custom character as used
 #ifdef DEBUG_CUSTOM_CHARACTERS
 			printf_P(PSTR("created char %02x at slot %u\n"), c, i);

Firmware/lcd.h

@@ -186,8 +186,9 @@ private:
 #define LCD_STR_SOLID_BLOCK  "\xFF"  //from the default character set
 
 struct CustomCharacter {
-    const uint8_t data[8];
-    const char alternate;
+    uint8_t colByte;
+    uint8_t rowData[4];
+    char alternate;
 };
 
 extern void lcd_frame_start();