lyx_mirror/src/vspace.C

/* This file is part of
 * ======================================================
 *
 *           LyX, The Document Processor
 * 	
 *           Copyright 1995 Matthias Ettrich
 *           Copyright 1995-2001 The LyX Team.
 *
 * ====================================================== */

#include <config.h>

#ifdef __GNUG__
#pragma implementation
#endif

#include "vspace.h"
#include "lengthcommon.h"
#include "lyx_main.h"
#include "buffer.h"
#include "lyxrc.h"
#include "lyxtext.h"
#include "BufferView.h"

#include "support/lstrings.h"

#include <cstdio>


namespace {

double           number[4] = { 0, 0, 0, 0 };
LyXLength::UNIT unit[4]   = { LyXLength::UNIT_NONE,
			      LyXLength::UNIT_NONE,
			      LyXLength::UNIT_NONE,
			      LyXLength::UNIT_NONE };

int number_index;
int unit_index;

inline
void lyx_advance(string & data, string::size_type n)
{
	data.erase(0, n);
}


inline
bool isEndOfData(string const & data)
{
	return frontStrip(data).empty();
}


char nextToken(string & data)
{
	data = frontStrip(data);
	if (data.empty())
		return '\0';
	else if (data[0] == '+') {
		lyx_advance(data, 1);
		return '+';
	} else if (prefixIs(data, "plus")) {
		lyx_advance(data, 4);
		return '+';
	} else if (data[0] == '-') {
		lyx_advance(data, 1);
		return '-';
	} else if (prefixIs(data, "minus")) {
		lyx_advance(data, 5);
		return '-';
	} else {
		string::size_type i = data.find_first_not_of("0123456789.");

		if (i != 0) {
			if (number_index > 3) return 'E';

			string buffer;
		
			// we have found some number
			if (i == string::npos) {
				buffer = data;
				i = data.size() + 1;
			} else
				buffer = data.substr(0, i);

			lyx_advance(data, i);

			if (isStrDbl(buffer)) {
				number[number_index] = strToDbl(buffer);
				++number_index;
				return 'n';
			} else return 'E';
		}
		
		i = data.find_first_not_of("abcdefghijklmnopqrstuvwxyz%");
		if (i != 0) {
			if (unit_index > 3) return 'E';

			string buffer;
		
			// we have found some alphabetical string
			if (i == string::npos) {
				buffer = data;
				i = data.size() + 1;
			} else
				buffer = data.substr(0, i);

			// possibly we have "mmplus" string or similar
			if (buffer.size() > 5 && (buffer.substr(2,4) == string("plus") || buffer.substr(2,5) == string("minus"))) {
				lyx_advance(data, 2);
				unit[unit_index] = unitFromString(buffer.substr(0, 2));
			} else {
				lyx_advance(data, i);
				unit[unit_index] = unitFromString(buffer);
			}

			if (unit[unit_index] != LyXLength::UNIT_NONE) {
				++unit_index;
				return 'u';
			} else return 'E';  // Error
		}
		return 'E';  // Error
	}
}


struct LaTeXLength {
	char const * pattern;
	int  plus_val_index;
	int  minus_val_index;
	int  plus_uni_index;
	int  minus_uni_index;
};


LaTeXLength table[] = {
	{ "nu",       0, 0, 0, 0 },
	{ "nu+nu",    2, 0, 2, 0 },
	{ "nu+nu-nu", 2, 3, 2, 3 },
	{ "nu+-nu",   2, 2, 2, 2 },
	{ "nu-nu",    0, 2, 0, 2 },
	{ "nu-nu+nu", 3, 2, 3, 2 },
	{ "nu-+nu",   2, 2, 2, 2 },
	{ "n+nu",     2, 0, 1, 0 },
	{ "n+n-nu",   2, 3, 1, 1 },
	{ "n+-nu",    2, 2, 1, 1 },
	{ "n-nu",     0, 2, 0, 1 },
	{ "n-n+nu",   3, 2, 1, 1 },
	{ "n-+nu",    2, 2, 1, 1 },
	{ "",         0, 0, 0, 0 }   // sentinel, must be empty
};


} // namespace anon

const char * stringFromUnit(int unit)
{
	if (unit < 0 || unit >= num_units)
		return 0;
	return unit_name[unit];
}


bool isValidGlueLength(string const & data, LyXGlueLength * result)
{
	// This parser is table-driven.  First, it constructs a "pattern"
	// that describes the sequence of tokens in "data".  For example,
	// "n-nu" means: number, minus sign, number, unit.  As we go along,
	// numbers and units are stored into static arrays.  Then, "pattern"
	// is searched in the "table".  If it is found, the associated
	// table entries tell us which number and unit should go where
	// in the LyXLength structure.  Example: if "data" has the "pattern"
	// "nu+nu-nu", the associated table entries are "2, 3, 2, 3".
	// That means, "plus_val" is the second number that was seen
	// in the input, "minus_val" is the third number, and "plus_uni"
	// and "minus_uni" are the second and third units, respectively.
	// ("val" and "uni" are always the first items seen in "data".)
	// This is the most elegant solution I could find -- a straight-
	// forward approach leads to very long, tedious code that would be
	// much harder to understand and maintain. (AS)

	if (data.empty())
		return true;
	string buffer = frontStrip(data);

	// To make isValidGlueLength recognize negative values as
	// the first number this little hack is needed:
	int val_sign = 1; // positive as default
	switch (buffer[0]) {
	case '-':
		lyx_advance(buffer, 1);
		val_sign = -1;
		break;
	case '+':
		lyx_advance(buffer, 1);
		// fall through
	default:
		// no action
		break;
	}
	// end of hack
	
	int  pattern_index = 0;
	int  table_index = 0;
	char pattern[20];

	number_index = 1;
	unit_index = 1;  // entries at index 0 are sentinels

	// construct "pattern" from "data"
	while (!isEndOfData (buffer)) {
		if (pattern_index > 20) return false;
		pattern[pattern_index] = nextToken (buffer);
		if (pattern[pattern_index] == 'E') return false;
		++pattern_index;
	}
	pattern[pattern_index] = '\0';

	// search "pattern" in "table"
	table_index = 0;
	while (compare(pattern, table[table_index].pattern)) {
		++table_index;
		if (!*table[table_index].pattern)
			return false;
	}
	
	// Get the values from the appropriate places.  If an index
	// is zero, the corresponding array value is zero or UNIT_NONE,
	// so we needn't check this.
	if (result) {
		result->len_.value  (number[1] * val_sign);
		result->len_.unit   (unit[1]);
		result->plus_.value (number[table[table_index].plus_val_index]);
		result->plus_.unit  (unit  [table[table_index].plus_uni_index]);
		result->minus_.value(number[table[table_index].minus_val_index]);
		result->minus_.unit (unit  [table[table_index].minus_uni_index]);
	}
	return true;
}


bool isValidLength(string const & data, LyXLength * result)
{
	/// This is a trimmed down version of isValidGlueLength.
	/// The parser may seem overkill for lengths without
	/// glue, but since we already have it, using it is
	/// easier than writing something from scratch.
	if (data.empty())
		return true;

	string   buffer = data;
	int      pattern_index = 0;
	char     pattern[3];

	// To make isValidLength recognize negative values
	// this little hack is needed:
	int val_sign = 1; // positive as default
	switch (buffer[0]) {
	case '-':
		lyx_advance(buffer, 1);
		val_sign = -1;
		break;
	case '+':
		lyx_advance(buffer, 1);
		// fall through
	default:
		// no action
		break;
	}
	// end of hack
	
	number_index = unit_index = 1;  // entries at index 0 are sentinels

	// construct "pattern" from "data"
	while (!isEndOfData (buffer)) {
		if (pattern_index > 2)
			return false;
		pattern[pattern_index] = nextToken (buffer);
		if (pattern[pattern_index] == 'E')
			return false;
		++pattern_index;
	}
	pattern[pattern_index] = '\0';

	// only the most basic pattern is accepted here
	if (compare(pattern, "nu") != 0) return false;		
	
	// It _was_ a correct length string.
	// Store away the values we found.
	if (result) {
		result->val_  = number[1] * val_sign;
		result->unit_ = unit[1];
	}
	return true;
}


//
//  VSpace class
//

VSpace::VSpace()
	: kind_(NONE), len_(), keep_(false)
{}


VSpace::VSpace(vspace_kind k)
	: kind_(k), len_(), keep_(false)
{}


VSpace::VSpace(LyXLength const & l)
	: kind_(LENGTH), len_(l), keep_(false)
{}


VSpace::VSpace(LyXGlueLength const & l)
	: kind_(LENGTH), len_(l), keep_(false)
{}


VSpace::VSpace(string const & data)
	: kind_(NONE), len_(), keep_(false)
{
	if (data.empty())
		return;
	double value;
	string input  = strip(data);

	string::size_type const length = input.length();

	if (length > 1 && input[length-1] == '*') {
		keep_ = true;
		input.erase(length - 1);
	}

	if      (prefixIs (input, "defskip"))    kind_ = DEFSKIP;
	else if (prefixIs (input, "smallskip"))  kind_ = SMALLSKIP;
	else if (prefixIs (input, "medskip"))    kind_ = MEDSKIP;
	else if (prefixIs (input, "bigskip"))    kind_ = BIGSKIP;
	else if (prefixIs (input, "vfill"))      kind_ = VFILL;
	else if (isValidGlueLength(input, &len_)) kind_ = LENGTH;
	else if (sscanf(input.c_str(), "%lf", &value) == 1) {
		// This last one is for reading old .lyx files
		// without units in added_space_top/bottom.
		// Let unit default to centimeters here.
		kind_ = LENGTH;
		len_  = LyXGlueLength(LyXLength(value, LyXLength::CM));
	}
}


VSpace::vspace_kind VSpace::kind() const
{
	return kind_;
}


LyXGlueLength VSpace::length() const
{
	return len_;
}


bool VSpace::keep() const
{
	return keep_;
}


void VSpace::setKeep(bool val)
{
	keep_ = val;
}


bool VSpace::operator==(VSpace const & other) const
{
	if (kind_ != other.kind_)
		return false;

	if (kind_ != LENGTH)
		return this->keep_ == other.keep_;

	if (len_ != other.len_)
		return false;

	return keep_ == other.keep_;
}


string const VSpace::asLyXCommand() const
{
	string result;
	switch (kind_) {
	case NONE:      break;
	case DEFSKIP:   result = "defskip";      break;
	case SMALLSKIP: result = "smallskip";    break;
	case MEDSKIP:   result = "medskip";      break;
	case BIGSKIP:   result = "bigskip";      break;
	case VFILL:     result = "vfill";        break;
	case LENGTH:    result = len_.asString(); break;
	}
	if (keep_ && kind_ != NONE && kind_ != DEFSKIP)
		result += '*';
	return result;
}


string const VSpace::asLatexCommand(BufferParams const & params) const
{
	switch (kind_) {
	case NONE:      return string();
	case DEFSKIP:
		return params.getDefSkip().asLatexCommand(params);
	case SMALLSKIP: return keep_ ? "\\vspace*{\\smallskipamount}"
				: "\\smallskip{}";
	case MEDSKIP:   return keep_ ? "\\vspace*{\\medskipamount}"
				: "\\medskip{}";
	case BIGSKIP:   return keep_ ? "\\vspace*{\\bigskipamount}"
				: "\\bigskip{}";
	case VFILL:     return keep_ ? "\\vspace*{\\fill}"
				: "\\vfill{}";
	case LENGTH:    return keep_ ? "\\vspace*{" + len_.asLatexString() + '}'
				: "\\vspace{" + len_.asLatexString() + '}';
	}
	return string();  // should never be reached
}


int VSpace::inPixels(BufferView * bv) const
{
	// Height of a normal line in pixels (zoom factor considered)
	int default_height = bv->text->defaultHeight(); // [pixels]
	int default_skip   = 0;
	int default_width  = bv->workWidth();

	if (kind_ == DEFSKIP)
		default_skip = bv->buffer()->params.getDefSkip().inPixels(bv);

	// Height of a normal line in pixels (zoom factor considered)
	int height = default_height; // [pixels]
	
	// Zoom factor specified by user in percent
	double const zoom = lyxrc.zoom / 100.0; // [percent]

	// DPI setting for monitor: pixels/inch
	double const dpi = lyxrc.dpi; // screen resolution [pixels/inch]

	// We want the result in pixels
	double result;
	double value;

	switch (kind_) {
	case NONE:
		return 0;

	case DEFSKIP:
		return default_skip;

		// This is how the skips are normally defined by
		// LateX.  But there should be some way to change
		// this per document.
	case SMALLSKIP: return height / 4;
	case MEDSKIP:   return height / 2;
	case BIGSKIP:   return height;
	case VFILL:     return 3 * height;
		// leave space for the vfill symbol
	case LENGTH:
		// Pixel values are scaled so that the ratio
		// between lengths and font sizes on the screen
		// is the same as on paper.

		// we don't care about sign of value, we
		// display negative space with text too
		result = 0.0;
		value  = len_.len().value();
		int val_sign = value < 0.0 ? -1 : 1;
		
		switch (len_.len().unit()) {
		case LyXLength::SP:
			// Scaled point: sp = 1/65536 pt
			result = zoom * dpi * value
				/ (72.27 * 65536); // 4736286.7
			break;
		case LyXLength::PT:
			// Point: 1 pt = 1/72.27 inch
			result = zoom * dpi * value
				/ 72.27; // 72.27
			break;
		case LyXLength::BP:
			// Big point: 1 bp = 1/72 inch
			result = zoom * dpi * value
				/ 72; // 72
			break;
		case LyXLength::DD:
			// Didot: 1157dd = 1238 pt?
			result = zoom * dpi * value
				/ (72.27 / (0.376 * 2.845)); // 67.559735
			break;
		case LyXLength::MM:
			// Millimeter: 1 mm = 1/25.4 inch
			result = zoom * dpi * value
				/ 25.4; // 25.4
			break;
		case LyXLength::PC:
			// Pica: 1 pc = 12 pt
			result = zoom * dpi * value
				/ (72.27 / 12); // 6.0225
			break;
		case LyXLength::CC:
			// Cicero: 1 cc = 12 dd
			result = zoom * dpi * value
				/ (72.27 / (12 * 0.376 * 2.845)); // 5.6299779
			break;
		case LyXLength::CM:
			// Centimeter: 1 cm = 1/2.54 inch
			result = zoom * dpi * value
				/ 2.54; // 2.54
			break;
		case LyXLength::IN:
			// Inch
			result = zoom * dpi * value;
			break;
		case LyXLength::EX:
			// Ex: The height of an "x"
			result = zoom * value * height / 2; // what to / width?
			break;
		case LyXLength::EM: // what to / width?
			// Em: The width of an "m"
			result = zoom * value * height / 2; // Why 2?
			break;
		case LyXLength::MU: // This is probably only allowed in
			// math mode
			result = zoom * value * height;
			break;
		case LyXLength::PW: // Always % of workarea
		case LyXLength::PE:
		case LyXLength::PP:
		case LyXLength::PL:
			result = value * default_width / 100;
			break;
		case LyXLength::UNIT_NONE:
			result = 0;  // this cannot happen
			break;
		}
		return static_cast<int>(result * val_sign + 0.5);
	}
	return 0; // never reached
}