posix-uefi/examples/0A_bmpfont/bmpfont.c

#include <uefi.h>

/* Scalable Screen Font (https://gitlab.com/bztsrc/scalable-font2) */
typedef struct {
    unsigned char  magic[4];
    unsigned int   size;
    unsigned char  type;
    unsigned char  features;
    unsigned char  width;
    unsigned char  height;
    unsigned char  baseline;
    unsigned char  underline;
    unsigned short fragments_offs;
    unsigned int   characters_offs;
    unsigned int   ligature_offs;
    unsigned int   kerning_offs;
    unsigned int   cmap_offs;
} __attribute__((packed)) ssfn_font_t;

/* framebuffer properties */
unsigned int width, height, pitch;
unsigned char *lfb;
/* font to be used */
ssfn_font_t *font;

/**
 * Display string using a bitmap font without the SSFN library
 */
void printString(int x, int y, char *s)
{
    unsigned char *ptr, *chr, *frg;
    unsigned int c;
    uintptr_t o, p;
    int i, j, k, l, m, n;
    while(*s) {
        c = 0; s += mbtowc((wchar_t*)&c, (const char*)s, 4);
        if(c == '\r') { x = 0; continue; } else
        if(c == '\n') { x = 0; y += font->height; continue; }
        for(ptr = (unsigned char*)font + font->characters_offs, chr = 0, i = 0; i < 0x110000; i++) {
            if(ptr[0] == 0xFF) { i += 65535; ptr++; }
            else if((ptr[0] & 0xC0) == 0xC0) { j = (((ptr[0] & 0x3F) << 8) | ptr[1]); i += j; ptr += 2; }
            else if((ptr[0] & 0xC0) == 0x80) { j = (ptr[0] & 0x3F); i += j; ptr++; }
            else { if((unsigned int)i == c) { chr = ptr; break; } ptr += 6 + ptr[1] * (ptr[0] & 0x40 ? 6 : 5); }
        }
        if(!chr) continue;
        ptr = chr + 6; o = (uintptr_t)lfb + y * pitch + x * 4;
        for(i = n = 0; i < chr[1]; i++, ptr += chr[0] & 0x40 ? 6 : 5) {
            if(ptr[0] == 255 && ptr[1] == 255) continue;
            frg = (unsigned char*)font + (chr[0] & 0x40 ? ((ptr[5] << 24) | (ptr[4] << 16) | (ptr[3] << 8) | ptr[2]) :
                ((ptr[4] << 16) | (ptr[3] << 8) | ptr[2]));
            if((frg[0] & 0xE0) != 0x80) continue;
            o += (int)(ptr[1] - n) * pitch; n = ptr[1];
            k = ((frg[0] & 0x1F) + 1) << 3; j = frg[1] + 1; frg += 2;
            for(m = 1; j; j--, n++, o += pitch)
                for(p = o, l = 0; l < k; l++, p += 4, m <<= 1) {
                    if(m > 0x80) { frg++; m = 1; }
                    if(*frg & m) *((unsigned int*)p) = 0xFFFFFF;
                }
        }
        x += chr[4]+1; y += chr[5];
    }
}

/**
 * Display bitmap fonts
 */
int main(int argc, char **argv)
{
    efi_status_t status;
    efi_guid_t gopGuid = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID;
    efi_gop_t *gop = NULL;
    FILE *f;
    long int size;

    /* load font */
    if((f = fopen("\\0A_bmpfont\\font.sfn", "r"))) {
        fseek(f, 0, SEEK_END);
        size = ftell(f);
        fseek(f, 0, SEEK_SET);
        font = (ssfn_font_t*)malloc(size + 1);
        if(!font) {
            fprintf(stderr, "unable to allocate memory\n");
            return 1;
        }
        fread(font, size, 1, f);
        fclose(f);
    } else {
        fprintf(stderr, "Unable to load font\n");
        return 0;
    }

    /* set video mode */
    status = BS->LocateProtocol(&gopGuid, NULL, (void**)&gop);
    if(!EFI_ERROR(status) && gop) {
        status = gop->SetMode(gop, 0);
        ST->ConOut->Reset(ST->ConOut, 0);
        ST->StdErr->Reset(ST->StdErr, 0);
        if(EFI_ERROR(status)) {
            fprintf(stderr, "unable to set video mode\n");
            return 0;
        }
        /* set up destination buffer */
        lfb = (unsigned char*)gop->Mode->FrameBufferBase;
        width = gop->Mode->Information->HorizontalResolution;
        height = gop->Mode->Information->VerticalResolution;
        pitch = sizeof(unsigned int) * gop->Mode->Information->PixelsPerScanLine;
    } else {
        fprintf(stderr, "unable to get graphics output protocol\n");
        return 0;
    }

    /* display multilingual text */
    printString(10, 10, "Hello 多种语言 Многоязычный többnyelvű World!");

    /* free resources exit */
    free(font);
    return 0;
}