Initial commit

1 files changed, 134 insertions, 0 deletions

diff --git a/src/font.c b/src/font.c
new file mode 100644
index 0000000..33c81aa
--- /dev/null
+++ b/src/font.c
@@ -0,0 +1,134 @@
+#include "aplos.h"
+
+static const uint8_t font_data[] = {
+	#embed "../external/spleen/spleen-8x16.psfu"
+//	#embed "../external/spleen/spleen-12x24.psfu"
+//	#embed "../external/spleen/spleen-16x32.psfu"
+};
+
+static uint32_t header_size;
+static uint32_t glyph_count;
+static uint32_t bytes_per_glyph;
+static uint32_t char_height;
+static uint32_t char_width;
+
+static void font_init_psf1(void);
+static void font_init_psf2(void);
+
+static const uint8_t *font_bitmap(char8_t *c);
+static uint64_t lookup_psf1(char8_t *);
+static uint64_t lookup_psf2(char8_t *);
+
+static uint64_t (*lookup)(char8_t *);
+
+void
+font_init(void)
+{
+	if(read_uint16_le(font_data) == 0x0436)
+		font_init_psf1();
+	else if(read_uint32_le(font_data) == 0x864AB572)
+		font_init_psf2();
+	else
+		halt();
+}
+
+static void
+font_init_psf1(void)
+{
+	header_size = 4;
+	glyph_count = (font_data[2] & 1) ? 512 : 256; 
+	bytes_per_glyph = font_data[3];
+	char_height = bytes_per_glyph;
+	char_width = 8;
+	lookup = lookup_psf1;
+}
+
+static void
+font_init_psf2(void)
+{
+	header_size = read_uint32_le(font_data+8);
+	glyph_count = read_uint32_le(font_data+16);
+	bytes_per_glyph = read_uint32_le(font_data+20);
+	char_height = read_uint32_le(font_data+24);
+	char_width = read_uint32_le(font_data+28);
+	lookup = lookup_psf2;
+}
+
+void
+font_draw(char8_t *c, uint32_t row, uint32_t col, uint32_t bg, uint32_t fg)
+{
+	uint32_t x0 = char_width * col;
+	uint32_t y0 = char_height * row;
+
+	const uint8_t *data = font_bitmap(c);
+	data--;
+
+	for(uint32_t y = 0; y < char_height; y++){
+		int shift = 0;
+		for(uint32_t x = 0; x < char_width; x++){
+			if(shift == 0){
+				shift = 8;
+				data++;
+			}
+			shift--;
+
+			uint8_t val = *data;
+			uint8_t mask = 1<<shift;
+			screen_draw_pixel(x0+x, y0+y, (val&mask) ? fg : bg);
+		}
+	}	
+}
+
+static const uint8_t *
+font_bitmap(char8_t *c)
+{
+	uint64_t index = lookup(c);
+	if(index == UINT64_MAX){
+		if(*c == '?')
+			index = 0;
+		else
+			index = lookup(u8"?");
+	}
+	return font_data + header_size + bytes_per_glyph * index;
+}
+
+static uint64_t
+lookup_psf1(char8_t *c)
+{
+	uint64_t offset = 0;
+	uint32_t v = utf8_value(c);
+	if(v > UINT16_MAX)
+		return 0;
+
+	const uint8_t *p = font_data + header_size + glyph_count * bytes_per_glyph;
+	while(p < &font_data[nelem(font_data)]){
+		uint16_t x = read_uint16_le(p);
+		p += 2;
+		if(x == 0xFFFF)
+			offset++;
+		else if(x == v)
+			return offset;
+	}
+	return UINT64_MAX;
+}
+
+static uint64_t
+lookup_psf2(char8_t *c)
+{
+	int char_len = utf8_char_length(c);
+	uint64_t offset = 0;
+	const uint8_t *p = font_data + header_size + glyph_count * bytes_per_glyph;
+	while(p < &font_data[nelem(font_data)]){
+		if(*p == 0xFF){
+			offset++;
+			p++;
+		}else if(memcmp(p, c, char_len) == 0){
+			return offset;
+		}else if(*p == 0xFE){
+			p++;
+		}else{
+			p += utf8_char_length(p);
+		}
+	}
+	return UINT64_MAX;
+}