pdf2htmlEX/src/HTMLRenderer/text.cc

/*
 * text.cc
 *
 * Handling text & font, and relative stuffs
 *
 * Copyright (C) 2012 Lu Wang <coolwanglu@gmail.com>
 */


#include <algorithm>

#include "HTMLRenderer.h"

#include "util/namespace.h"
#include "util/unicode.h"

namespace pdf2htmlEX {

using std::all_of;
using std::cerr;
using std::endl;

void HTMLRenderer::drawString(GfxState * state, GooString * s)
{
    if(s->getLength() == 0)
        return;

    auto font = state->getFont();
    // unscaled
    double cur_letter_space = state->getCharSpace();
    double cur_word_space   = state->getWordSpace();

    // Writing mode fonts and Type 3 fonts are rendered as images
    // I don't find a way to display writing mode fonts in HTML except for one div for each character, which is too costly
    // For type 3 fonts, due to the font matrix, still it's hard to show it on HTML
    if( (font == nullptr) 
        || (font->getWMode())
        || (font->getType() == fontType3)
      )
    {
        return;
    }

    // see if the line has to be closed due to state change
    check_state_change(state);
    prepare_text_line(state);

    // Now ready to output
    // get the unicodes
    char *p = s->getCString();
    int len = s->getLength();

    double dx = 0;
    double dy = 0;
    double dx1,dy1;
    double ox, oy;

    int nChars = 0;
    int nSpaces = 0;
    int uLen;

    CharCode code;
    Unicode *u = nullptr;

    while (len > 0) 
    {
        auto n = font->getNextChar(p, len, &code, &u, &uLen, &dx1, &dy1, &ox, &oy);

        if(!(equal(ox, 0) && equal(oy, 0)))
        {
            cerr << "TODO: non-zero origins" << endl;
        }

        bool is_space = false;
        if (n == 1 && *p == ' ') 
        {
            /*
             * This is by standard
             * however some PDF will use ' ' as a normal encoding slot
             * such that it will be mapped to other unicodes
             * In that case, when sapce_as_offset is on, we will simply ignore that character...
             *
             * Checking mapped unicode may or may not work
             * There are always ugly PDF files with no usefull info at all.
             */
            is_space = true;
            ++nSpaces;
        }
        
        if(is_space && (param->space_as_offset))
        {
            // ignore horiz_scaling, as it's merged in CTM
            text_line_buffers.back()->append_offset((dx1 * cur_font_size + cur_letter_space + cur_word_space) * draw_text_scale); 
        }
        else
        {
            if((param->decompose_ligature) && (uLen > 1) && all_of(u, u+uLen, isLegalUnicode))
            {
                text_line_buffers.back()->append_unicodes(u, uLen);
                // TODO: decomposed characters may be not with the same width as the original ligature, need to fix it.
            }
            else
            {
                Unicode uu;
                if(cur_html_state.font_info->use_tounicode)
                {
                    uu = check_unicode(u, uLen, code, font);
                }
                else
                {
                    uu = unicode_from_font(code, font);
                }
                text_line_buffers.back()->append_unicodes(&uu, 1);
                /*
                 * In PDF, word_space is appended if (n == 1 and *p = ' ')
                 * but in HTML, word_space is appended if (uu == ' ')
                 */
                int space_count = (is_space ? 1 : 0) - (uu == ' ' ? 1 : 0);
                if(space_count != 0)
                    text_line_buffers.back()->append_offset(cur_word_space * draw_text_scale * space_count);
            }
        }

        dx += dx1;
        dy += dy1;

        ++nChars;
        p += n;
        len -= n;
    }

    double hs = state->getHorizScaling();

    // horiz_scaling is merged into ctm now, 
    // so the coordinate system is ugly
    dx = (dx * cur_font_size + nChars * cur_letter_space + nSpaces * cur_word_space) * hs;
    
    dy *= cur_font_size;

    cur_tx += dx;
    cur_ty += dy;
        
    draw_tx += dx;
    draw_ty += dy;
}

} // namespace pdf2htmlEX