Files
jsix/src/modules/main/font.cpp
2018-04-09 13:56:14 -07:00

85 lines
1.9 KiB
C++

#include "font.h"
/* PSF2 header format
* Taken from the Linux KBD documentation
* http://www.win.tue.nl/~aeb/linux/kbd/font-formats-1.html
*/
const static uint8_t magic[] = {0x72, 0xb5, 0x4a, 0x86};
const static uint32_t max_version = 0;
const static uint8_t unicode_sep = 0xff;
const static uint8_t unicode_start = 0xfe;
/* bits used in flags */
enum psf2_flags {
psf2_has_unicode = 0x00000001
};
struct psf2_header {
uint8_t magic[4];
uint32_t version;
uint32_t header_size; // offset of bitmaps in file
uint32_t flags;
uint32_t length; // number of glyphs
uint32_t charsize; // number of bytes for each character
uint32_t height, width; // max dimensions of glyphs
};
font
font::load(void const *data)
{
psf2_header const *psf2 = static_cast<psf2_header const *>(data);
for (int i = 0; i < sizeof(magic); ++i) {
if (psf2->magic[i] != magic[i]) {
return font{};
}
}
uint8_t const *font_data = static_cast<uint8_t const *>(data) + psf2->header_size;
return font{
psf2->height,
psf2->width,
psf2->length,
font_data};
}
font::font() :
m_height(0),
m_width(0),
m_count(0),
m_data(nullptr)
{}
font::font(unsigned height, unsigned width, unsigned count, uint8_t const *data) :
m_height(height),
m_width(width),
m_count(count),
m_data(data)
{}
void
font::draw_glyph(
screen &s,
uint32_t glyph,
screen::pixel_t color,
screen::coord_t x,
screen::coord_t y) const
{
unsigned bwidth = (m_width+7)/8;
uint8_t const *data = m_data + (glyph * glyph_bytes());
for (int dy = 0; dy < m_height; ++dy) {
for (int dx = 0; dx < bwidth; ++dx) {
uint8_t byte = data[dy * bwidth + dx];
for (int i = 0; i < 8; ++i) {
if (dx*8 + i >= m_width) continue;
const uint8_t mask = 1 << (7-i);
uint32_t c = (byte & mask) ? color : 0;
s.draw_pixel(x + dx*8 + i, y + dy, c);
}
}
}
}