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Upgraded font resource format. Now supports sparse glyph maps. Not co…
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…mpatible with old files.

Added UTF-8 decoding to the fctx_draw_string function.
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@jrmobley
jrmobley committed Jan 31, 2016
1 parent 41cd33c commit 9cd558f
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Showing 3 changed files with 155 additions and 34 deletions.
25 changes: 16 additions & 9 deletions fctx.c
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Original file line number Diff line number Diff line change
Expand Up @@ -911,14 +911,19 @@ void fctx_set_text_size(FContext* fctx, FFont* font, int16_t pixels) {
void fctx_draw_string(FContext* fctx, const char* text, FFont* font, GTextAlignment alignment, FTextAnchor anchor) {

FPoint advance = {0, 0};
uint16_t code_point;
uint16_t decode_state;
const char* p;

if (alignment != GTextAlignmentLeft) {
fixed_t width = 0;
decode_state = 0;
for (p = text; *p; ++p) {
FGlyph* glyph = ffont_glyph_info(font, *p);
if (glyph) {
width += glyph->horiz_adv_x;
if (0 == decode_utf8_byte(*p, &decode_state, &code_point)) {
FGlyph* glyph = ffont_glyph_info(font, *p);
if (glyph) {
width += glyph->horiz_adv_x;
}
}
}
if (alignment == GTextAlignmentRight) {
Expand All @@ -938,13 +943,15 @@ void fctx_draw_string(FContext* fctx, const char* text, FFont* font, GTextAlignm
advance.y = -font->descent;
}

decode_state = 0;
for (p = text; *p; ++p) {
char ch = *p;
FGlyph* glyph = ffont_glyph_info(font, ch);
if (glyph) {
void* path_data = ffont_glyph_outline(font, glyph);
fctx_draw_commands(fctx, advance, path_data, glyph->path_data_length);
advance.x += glyph->horiz_adv_x;
if (0 == decode_utf8_byte(*p, &decode_state, &code_point)) {
FGlyph* glyph = ffont_glyph_info(font, code_point);
if (glyph) {
void* path_data = ffont_glyph_outline(font, glyph);
fctx_draw_commands(fctx, advance, path_data, glyph->path_data_length);
advance.x += glyph->horiz_adv_x;
}
}
}
}
145 changes: 126 additions & 19 deletions ffont.c
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Original file line number Diff line number Diff line change
Expand Up @@ -12,36 +12,86 @@ FFont* ffont_create_from_resource(uint32_t resource_id) {
return NULL;
}

FGlyphRange* ffont_glyph_index(FFont* font) {
void* buffer = (void*)font;
void* index = buffer + sizeof(FFont);
return (FGlyphRange*)index;
}

FGlyph* ffont_glyph_table(FFont* font) {
return (FGlyph*)(((void*)font) + sizeof(FFont));
void* buffer = (void*)font;
void* table = buffer + sizeof(FFont)
+ font->glyph_index_length * sizeof(FGlyphRange);
return (FGlyph*)table;
}

void* ffont_path_data(FFont* font) {
void* buffer = (void*)font;
void* path_data = buffer + sizeof(FFont)
+ font->glyph_index_length * sizeof(FGlyphRange)
+ font->glyph_table_length * sizeof(FGlyph);
return path_data;
}

FGlyph* ffont_glyph_info(FFont* font, uint16_t unicode) {
if (unicode < font->unicode_offset) {
return NULL;
}
uint16_t glyph_index = unicode - font->unicode_offset;
if (glyph_index >= font->glyph_count) {
return NULL;
FGlyphRange* range = ffont_glyph_index(font);
FGlyphRange* end = range + font->glyph_index_length;
uint16_t offset = 0;
while (range < end) {
if (unicode < range->begin) {
break;
}
if (unicode < range->end) {
FGlyph* table = ffont_glyph_table(font);
FGlyph* g = table + offset + (unicode - range->begin);
/*APP_LOG(APP_LOG_LEVEL_DEBUG, "U+%04X @ U+%04X + %02X",
unicode, range->begin, unicode - range->begin);*/
return g;
}
offset += (range->end - range->begin);
++range;
}
FGlyph* glyph_table = ffont_glyph_table(font);
return glyph_table + glyph_index;
#if 0
APP_LOG(APP_LOG_LEVEL_WARNING, "U+%04x no glyph", unicode);
#endif
return NULL;
}

void* ffont_glyph_outline(FFont* font, FGlyph* glyph) {
void* buffer = (void*)font;
void* path_data = buffer + sizeof(FFont) + font->glyph_count * sizeof(FGlyph) + glyph->path_data_offset;
return path_data;
void* path_data = ffont_path_data(font);
return path_data + glyph->path_data_offset;
}

void ffont_debug_log(FFont* font) {
void ffont_debug_log(FFont* font, uint8_t log_level) {
#if 0
APP_LOG(APP_LOG_LEVEL_DEBUG, "font gc:%d uo:%d", font->glyph_count, font->unicode_offset);
FGlyph* glyphs = ffont_glyph_table(font);
for (uint16_t k = 0; k < font->glyph_count; ++k) {
FGlyph* g = glyphs + k;
APP_LOG(APP_LOG_LEVEL_DEBUG, "glyph[%d] \"%c\" |%d| : %d + %d",
k, (char)(k + font->unicode_offset), g->horiz_adv_x, g->path_data_offset, g->path_data_length);
if (log_level >= APP_LOG_LEVEL_WARNING && font == NULL) {
APP_LOG(APP_LOG_LEVEL_WARNING, "font not loaded");
return;
}

if (log_level >= APP_LOG_LEVEL_DEBUG_VERBOSE) {
APP_LOG(APP_LOG_LEVEL_DEBUG_VERBOSE, "so(FF):%d so(FGR):%d so(FG):%d", sizeof(FFont), sizeof(FGlyphRange), sizeof(FGlyph));
APP_LOG(APP_LOG_LEVEL_DEBUG_VERBOSE, "upm:%d a:%d d:%d gil:%d gtl:%d", font->units_per_em, font->ascent, font->descent, font->glyph_index_length, font->glyph_table_length);
}

if (log_level >= APP_LOG_LEVEL_DEBUG) {
uint16_t glyph_count = 0;
FGlyphRange* index = ffont_glyph_index(font);
for (uint16_t k = 0; k < font->glyph_index_length; ++k) {
FGlyphRange* r = index + k;
glyph_count += (r->end - r->begin);
APP_LOG(APP_LOG_LEVEL_DEBUG, "U+%04X-%04X", r->begin, r->end - 1);
}
APP_LOG(APP_LOG_LEVEL_DEBUG, "gc:%d", glyph_count);
}

if (log_level >= APP_LOG_LEVEL_DEBUG_VERBOSE) {
FGlyph* glyphs = ffont_glyph_table(font);
for (uint16_t k = 0; k < font->glyph_table_length; ++k) {
FGlyph* g = glyphs + k;
APP_LOG(APP_LOG_LEVEL_DEBUG, "glyph[%d] |%d| : %d + %d",
k, g->horiz_adv_x, g->path_data_offset, g->path_data_length);
}
}
#endif
}
Expand All @@ -50,3 +100,60 @@ void ffont_destroy(FFont* font) {
free(font);
}


/**
* Decode the next byte of a UTF-8 byte stream.
* Initialize state to 0 the before calling this function for the first
* time for a given stream. If the returned value is 0, then cp has been
* set to a valid code point. Other return values indicate that a multi-
* byte sequence is in progress, or there was a decoding error.
*
* @param byte the byte to decode.
* @state the current state of the decoder.
* @cp the decoded unitcode code point.
* @return the state of the decode process after decoding the byte.
*/
uint16_t decode_utf8_byte(uint8_t byte, uint16_t* state, uint16_t* cp) {

/* unicode code points are encoded as follows.
* U+00000000 – U+0000007F: 0xxxxxxx
* U+00000080 – U+000007FF: 110xxxxx 10xxxxxx
* U+00000800 – U+0000FFFF: 1110xxxx 10xxxxxx 10xxxxxx
* U+00010000 – U+001FFFFF: 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
* U+00200000 – U+03FFFFFF: 111110xx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
* U+04000000 – U+7FFFFFFF: 1111110x 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
*/

if (*state == 0 || *state == 6) {
if (byte < 0b10000000) { // (<128) ascii character
*cp = byte;
} else if (byte < 0b11000000) { // (<192) unexpected continuation byte
*cp = 0;
*state = 6;
} else if (byte < 0b11100000) { // (<224) 2 byte sequence
*cp = byte & 0b00011111;
*state = 1;
} else if (byte < 0b11110000) { // (<240) 3 byte sequence
*cp = byte & 0b00001111;
*state = 2;
} else if (byte < 0b11111000) { // (<248) 4 byte sequence
*cp = byte & 0b00000111;
*state = 3;
} else if (byte < 0b11111100) { // (<252) 5 byte sequence
*cp = byte & 0b00000011;
*state = 4;
} else if (byte < 0b11111110) { // (<254) 6 byte sequence
*cp = byte & 0b00000001;
*state = 5;
}
} else if (*state < 6) {
if (byte < 0b11000000) {
*cp = (*cp << 6) | (byte & 0b00111111);
*state = *state - 1;
} else {
*cp = 0;
*state = 6;
}
}
return *state;
}
19 changes: 13 additions & 6 deletions ffont.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -3,13 +3,18 @@
#include "fctx.h"

typedef struct __attribute__((__packed__)) FFont {
uint16_t glyph_count;
uint16_t unicode_offset;
fixed16_t units_per_em;
fixed16_t ascent;
fixed16_t descent;
fixed16_t units_per_em;
fixed16_t ascent;
fixed16_t descent;
uint16_t glyph_index_length;
uint16_t glyph_table_length;
} FFont;

typedef struct __attribute__((__packed__)) FGlyphRange {
uint16_t begin;
uint16_t end;
} FGlyphRange;

typedef struct __attribute__((__packed__)) FGlyph {
uint16_t path_data_offset;
uint16_t path_data_length;
Expand All @@ -18,6 +23,8 @@ typedef struct __attribute__((__packed__)) FGlyph {

FFont* ffont_create_from_resource(uint32_t resource_id);
void ffont_destroy(FFont* font);
void ffont_debug_log(FFont* font);
void ffont_debug_log(FFont* font, uint8_t log_level);
FGlyph* ffont_glyph_info(FFont* font, uint16_t unicode);
void* ffont_glyph_outline(FFont* font, FGlyph* glyph);

uint16_t decode_utf8_byte(uint8_t byte, uint16_t* state, uint16_t* cp);

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