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[client] freetype: implement UTF-8 handling

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Quantum 2021-02-23 23:19:38 -05:00 committed by Geoffrey McRae
parent 5a075744bd
commit 1111045546
1 changed files with 53 additions and 8 deletions
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61
client/fonts/freetype/src/freetype.c
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@ -97,6 +97,13 @@ static bool lgf_freetype_create(LG_FontObj * opaque, const char * font_name, uns
goto fail_match;
}
if (FT_Select_Charmap(this->face, ft_encoding_unicode))
{
DEBUG_ERROR("FT_Select_Charmap failed");
FT_Done_Face(this->face);
goto fail_match;
}
FT_Set_Pixel_Sizes(this->face, 0, size);
this->height = size;
}
@ -154,6 +161,42 @@ static void lgf_freetype_destroy(LG_FontObj opaque)
}
}
// A very simple UTF-8 decoder that assumes the input is valid.
static unsigned int utf8_decode(const char * str)
{
const unsigned char * ptr = (const unsigned char *) str;
// Handle the 4 byte case: 1111 0xxx 10xx xxxx 10xx xxxx 10xx xxxx.
if ((*ptr & 0xf8) == 0xf0)
return (ptr[0] & 0x07) << 18 | (ptr[1] & 0x3f) << 12 | (ptr[2] & 0x3f) << 6 | (ptr[3] & 0x3f);
// Handle the 3 byte case: 1110 xxxx 10xx xxxx 10xx xxxx.
else if ((*ptr & 0xf0) == 0xe0)
return (ptr[0] & 0x0f) << 12 | (ptr[1] & 0x3f) << 6 | (ptr[2] & 0x3f);
// Handle the 2 byte case: 110x xxxx 10xx xxxx.
else if ((*ptr & 0xe0) == 0xc0)
return (ptr[0] & 0x1f) << 6 | (ptr[1] & 0x3f);
// Everything else is the 1 byte case.
else
return *ptr;
}
// Return the length of the current UTF-8 character. Assumes the input is valid.
static unsigned int utf8_advance(const char * str)
{
const unsigned char * ptr = (const unsigned char *) str;
// 4 byte case starts with 1111 0xxx.
if ((*ptr & 0xf8) == 0xf0)
return 4;
// 3 byte case starts with 1110 xxxx.
else if ((*ptr & 0xf0) == 0xe0)
return 3;
// 2 byte case starts with 110x xxxx.
else if ((*ptr & 0xe0) == 0xc0)
return 2;
// Everything else is the 1 byte case.
else
return 1;
}
static LG_FontBitmap * lgf_freetype_render(LG_FontObj opaque, unsigned int fg_color, const char * text)
{
struct Inst * this = (struct Inst *)opaque;
@ -164,18 +207,19 @@ static LG_FontBitmap * lgf_freetype_render(LG_FontObj opaque, unsigned int fg_co
int topAscend = 0;
int bottomDescend = 0;
for (const char * ptr = text; *ptr; ++ptr)
for (const char * ptr = text; *ptr; ptr += utf8_advance(ptr))
{
if (*ptr == '\n')
unsigned int ch = utf8_decode(ptr);
if (ch == '\n')
{
if (!*(ptr + 1))
if (!ptr[1])
break;
if (rowWidth > width)
width = rowWidth;
rowWidth = bottomDescend = 0;
++row;
}
else if (FT_Load_Char(this->face, *ptr, FT_LOAD_RENDER))
else if (FT_Load_Char(this->face, ch, FT_LOAD_RENDER))
{
DEBUG_ERROR("Failed to load character: %c", *ptr);
return NULL;
@ -213,16 +257,17 @@ static LG_FontBitmap * lgf_freetype_render(LG_FontObj opaque, unsigned int fg_co
unsigned int b = (fg_color & 0x0000ff00) >> 8;
uint32_t color = (r << 0) | (g << 8) | (b << 16);
for (const char * ptr = text; *ptr; ++ptr)
for (const char * ptr = text; *ptr; ptr += utf8_advance(ptr))
{
if (*ptr == '\n')
unsigned int ch = utf8_decode(ptr);
if (ch == '\n')
{
baseline += this->height;
x = 0;
}
else if (FT_Load_Char(this->face, *ptr, FT_LOAD_RENDER))
else if (FT_Load_Char(this->face, ch, FT_LOAD_RENDER))
{
DEBUG_ERROR("Failed to load character: %c", *ptr);
DEBUG_ERROR("Failed to load character: U+%x", ch);
return NULL;
}
else