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139 lines
3.5 KiB
C++
139 lines
3.5 KiB
C++
/*
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* Unicode manipulation functions
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*
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* by WangLu
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* 2012.11.29
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*/
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#include <iostream>
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#include <GlobalParams.h>
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#include "unicode.h"
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namespace pdf2htmlEX {
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using std::cerr;
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using std::endl;
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using std::ostream;
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/*
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* Test legal for HTML
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*
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* A legal unicode character should be accepted by browsers, and displayed correctly.
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* Many unicode codes have special meaning which will be 'interpreted' by the browser, those should be filtered since they are not interpreted in PDF
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* This function is not complete, just to be improved.
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*/
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bool isLegalUnicode(Unicode u)
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{
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const Unicode max_small_unicode = 1024;
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static bool valid_small_unicode[max_small_unicode];
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static bool valid_small_unicode_init = false;
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if(!valid_small_unicode_init)
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{
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valid_small_unicode_init = true;
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Unicode uu = 0;
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/*
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* 9, 10 and 13 are interpreted as white-spaces in HTML
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* `word-spacing` may be applied on them
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* and the browser may not use the actualy glyphs in the font
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* So mark them as illegal
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*
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* The problem is that the correct value can not be copied out in this way
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*/
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while(uu <= 31)
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valid_small_unicode[uu++] = false;
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/*
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* 127-159 are not invalid
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* 160, or 0xa0 is NBSP, which is legal in HTML
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* But some browser will use the glyph for ' ' in the font, it there is one, instead of the glyphs for NBSP
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* Again, `word-spacing` is applied.
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* So mark it as illegal
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*
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* And the same problem as above, this character can no longer be copied out
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*/
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while(uu < 127)
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valid_small_unicode[uu++] = true;
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while(uu <= 160)
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valid_small_unicode[uu++] = false;
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/*
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* 173, or 0xad, the soft hyphen
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* which can be ignored by the browser in the middle of a line
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*/
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while(uu < 173)
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valid_small_unicode[uu++] = true;
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while(uu <= 173)
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valid_small_unicode[uu++] = false;
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while(uu < max_small_unicode)
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valid_small_unicode[uu++] = true;
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}
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if(u < max_small_unicode)
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return valid_small_unicode[u];
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/*
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* Reserved code for utf-16
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*/
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if((u >= 0xd800) && (u <= 0xdfff))
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return false;
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return true;
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}
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Unicode map_to_private(CharCode code)
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{
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Unicode private_mapping = (Unicode)(code + 0xE000);
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if(private_mapping > 0xF8FF)
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{
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private_mapping = (Unicode)((private_mapping - 0xF8FF) + 0xF0000);
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if(private_mapping > 0xFFFFD)
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{
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private_mapping = (Unicode)((private_mapping - 0xFFFFD) + 0x100000);
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if(private_mapping > 0x10FFFD)
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{
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cerr << "Warning: all private use unicode are used" << endl;
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}
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}
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}
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return private_mapping;
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}
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Unicode unicode_from_font (CharCode code, GfxFont * font)
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{
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if(!font->isCIDFont())
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{
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char * cname = dynamic_cast<Gfx8BitFont*>(font)->getCharName(code);
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// may be untranslated ligature
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if(cname)
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{
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Unicode ou = globalParams->mapNameToUnicode(cname);
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if(isLegalUnicode(ou))
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return ou;
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}
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}
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return map_to_private(code);
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}
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Unicode check_unicode(Unicode * u, int len, CharCode code, GfxFont * font)
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{
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if(len == 0)
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return map_to_private(code);
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if(len == 1)
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{
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if(isLegalUnicode(*u))
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return *u;
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}
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return unicode_from_font(code, font);
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}
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} //namespace pdf2htmlEX
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