text.c

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#include <gfx/gfx.h>
#include <gfx/font.h>
#include <gfx/text.h>

#include <gfx/gfx_p.h> // FIXME: BM_DRAWPIXEL

#include <cfg/debug.h>


static bool ansi_mode = false;

void text_setCoord(struct Bitmap *bm, int x, int y)
{
    bm->penX = x;
    bm->penY = y;
}


void text_moveTo(struct Bitmap *bm, int row, int col)
{
    ASSERT(col >= 0);
    ASSERT(col < bm->width / bm->font->width);
    ASSERT(row >= 0);
    ASSERT(row < bm->height / bm->font->height);

    text_setCoord(bm, col * bm->font->width, row * bm->font->height);
}


static int text_putglyph(char c, struct Bitmap *bm)
{
    const uint8_t * PROGMEM glyph;  /* font is in progmem */
    uint8_t glyph_width, glyph_height, glyph_height_bytes;
    unsigned char index = (unsigned char)c;

    /* Check for out of range char and replace with '?' or first char in font. */
    if (UNLIKELY(!FONT_HAS_GLYPH(bm->font, index)))
    {
        kprintf("Illegal char '%c' (0x%02x)\n", index, index);
        if (FONT_HAS_GLYPH(bm->font, '?'))
            index = '?';
        else
            index = bm->font->first;
    }

    /* Make character relative to font start */
    index -= bm->font->first;

    glyph_height = bm->font->height;
    // FIXME: for vertical fonts only
    glyph_height_bytes = (glyph_height + 7) / 8;

    if (bm->font->offset)
    {
        /* Proportional font */
        glyph_width = bm->font->widths[index]; /* TODO: optimize away */
        glyph = bm->font->glyph + bm->font->offset[index];
    }
    else
    {
        /*
         * Fixed-width font: compute the first column of pixels
         * of the selected glyph using the character code to index
         * the glyph array.
         */
        glyph_width = bm->font->width;

        //For horizontal fonts
        //glyph = bm->font->glyph + index * (((glyph_width + 7) / 8) * glyph_height);
        glyph = bm->font->glyph + index * glyph_height_bytes * glyph_width;
    }

    /* Slow path for styled glyphs */
    if (UNLIKELY(bm->styles))
    {
        uint8_t styles = bm->styles;
        uint8_t prev_dots = 0, italic_prev_dots = 0;
        uint8_t dots;
        uint8_t row, col, row_bit;

        /*
         * To avoid repeating clipping and other expensive computations,
         * we cluster calls to gfx_blitRaster() using a small buffer.
         */
        #define CONFIG_TEXT_RENDER_OPTIMIZE 1
        #if CONFIG_TEXT_RENDER_OPTIMIZE
            #define RENDER_BUF_WIDTH 12
            #define RENDER_BUF_HEIGHT 8
            uint8_t render_buf[RAST_SIZE(RENDER_BUF_WIDTH, RENDER_BUF_HEIGHT)];
            uint8_t render_xpos = 0;
        #endif

        /* This style alone could be handled by the fast path too */
        if (bm->styles & STYLEF_CONDENSED)
            --glyph_width;

        if (bm->styles & STYLEF_EXPANDED)
            glyph_width *= 2;

        for (row = 0, row_bit = 0; row < glyph_height_bytes; ++row, row_bit += 8)
        {
            /* For each dot column in the glyph... */
            for (col = 0; col < glyph_width; ++col)
            {
                uint8_t src_col = col;

                /* Expanded style: advances only once every two columns. */
                if (styles & STYLEF_EXPANDED)
                    src_col /= 2;

                /* Fetch a column of dots from glyph. */
                dots = PGM_READ_CHAR(RAST_ADDR(glyph, src_col, row_bit, glyph_width));

                /* Italic: get lower 4 dots from previous column */
                if (styles & STYLEF_ITALIC)
                {
                    uint8_t new_dots = dots;
                    dots = (dots & 0xF0) | italic_prev_dots;
                    italic_prev_dots = new_dots & 0x0F;
                }

                /* Bold: "or" pixels with the previous column */
                if (styles & STYLEF_BOLD)
                {
                    uint8_t new_dots = dots;
                    dots |= prev_dots;
                    prev_dots = new_dots;
                }

                /* Underlined: turn on base pixel */
                if ((styles & STYLEF_UNDERLINE)
                    && (row == glyph_height_bytes - 1))
                    dots |= (1 << (glyph_height - row_bit - 1));

                /* Inverted: invert pixels */
                if (styles & STYLEF_INVERT)
                    dots = ~dots;

                /* Output dots */
                #if CONFIG_TEXT_RENDER_OPTIMIZE
                    render_buf[render_xpos++] = dots;
                    if (render_xpos == RENDER_BUF_WIDTH)
                    {
                        gfx_blitRaster(bm, bm->penX + col - render_xpos + 1, bm->penY + row_bit,
                            render_buf, render_xpos,
                            MIN((uint8_t)RENDER_BUF_HEIGHT, (uint8_t)(glyph_height - row_bit)),
                            RENDER_BUF_WIDTH);
                        render_xpos = 0;
                    }
                #else
                    gfx_blitRaster(bm, bm->penX + col, bm->penY + row_bit,
                        &dots, 1, MIN((uint8_t)8, glyph_height - row_bit), 1);
                #endif
            }

            #if CONFIG_TEXT_RENDER_OPTIMIZE
                /* Flush out rest of render buffer */
                if (render_xpos != 0)
                {
                    gfx_blitRaster(bm, bm->penX + col - render_xpos, bm->penY + row_bit,
                        render_buf, render_xpos,
                        MIN((uint8_t)RENDER_BUF_HEIGHT, (uint8_t)(glyph_height - row_bit)),
                        RENDER_BUF_WIDTH);
                    render_xpos = 0;
                }
            #endif
        }
    }
    else
    {
        /* No style: fast vanilla copy of glyph to bitmap */
        gfx_blitRaster(bm, bm->penX, bm->penY, glyph, glyph_width, glyph_height, glyph_width);
    }

    /* Update current pen position */
    bm->penX += glyph_width;

    return c;
}


int text_putchar(char c, struct Bitmap *bm)
{
    /* Handle ANSI escape sequences */
    if (UNLIKELY(ansi_mode))
    {
        switch (c)
        {
        case ANSI_ESC_CLEARSCREEN:
            gfx_bitmapClear(bm);
            bm->penX = 0;
            bm->penY = 0;
            text_style(bm, 0, STYLEF_MASK);
            break;
        DB(default:
            kprintf("Unknown ANSI esc code: %x\n", c);)
        }
        ansi_mode = false;
    }
    else if (c == '\033')  /* Enter ANSI ESC mode */
    {
        ansi_mode = true;
    }
    else if (c == '\n')  /* Go one line down on a line-feed */
    {
        if (bm->penY + bm->font->height < bm->height)
        {
            bm->penY += bm->font->height;
            bm->penX = 0;
        }
    }
    else
    {
        text_putglyph(c, bm);
    }
    return c;
}


void text_clear(struct Bitmap *bmp)
{
    text_putchar('\x1b', bmp);
    text_putchar('c', bmp);
}


void text_clearLine(struct Bitmap *bm, int line)
{
    gfx_rectClear(bm, 0, line * bm->font->height, bm->width, (line + 1) * bm->font->height);
}


uint8_t text_style(struct Bitmap *bm, uint8_t flags, uint8_t mask)
{
    uint8_t old = bm->styles;
    bm->styles = (bm->styles & ~mask) | flags;
    return old;
}