lyx_mirror/src/lyxlength.C

/**
 * \file lyxlength.C
 * This file is part of LyX, the document processor.
 * Licence details can be found in the file COPYING.
 *
 * \author Matthias Ettrich
 * \author Lars Gullik Bjønnes
 * \author Jean-Marc Lasgouttes
 * \author Angus Leeming
 * \author John Levon
 * \author Dekel Tsur
 *
 * Full author contact details are available in file CREDITS.
 */

#include <config.h>

#include "lyxlength.h"
#include "lengthcommon.h"
#include "lyxrc.h"

#include <sstream>
#include <iomanip>


using std::ostringstream;
using std::string;


LyXLength::LyXLength()
	: val_(0), unit_(LyXLength::UNIT_NONE)
{}


LyXLength::LyXLength(double v, LyXLength::UNIT u)
	: val_(v), unit_(u)
{}


LyXLength::LyXLength(string const & data)
	: val_(0), unit_(LyXLength::PT)
{
	LyXLength tmp;

	if (!isValidLength(data, &tmp))
		return; // should raise an exception

	val_  = tmp.val_;
	unit_ = tmp.unit_;
}


string const LyXLength::asString() const
{
	ostringstream os;
	os << val_ << unit_name[unit_]; // setw?
	return os.str();
}


string const LyXLength::asLatexString() const
{
	ostringstream os;
	switch (unit_) {
	case PTW:
		os << val_ / 100.0 << "\\textwidth";
		break;
	case PCW:
		os << val_ / 100.0 << "\\columnwidth";
		break;
	case PPW:
		os << val_ / 100.0 << "\\paperwidth";
		break;
	case PLW:
		os << val_ / 100.0 << "\\linewidth";
		break;
	case PPH:
		os << val_ / 100.0 << "\\paperheight";
		break;
	case PTH:
		os << val_ / 100.0 << "\\textheight";
		break;
	default:
		os << val_ << unit_name[unit_];
	  break;
	}
	return os.str();
}


double LyXLength::value() const
{
	return val_;
}


LyXLength::UNIT LyXLength::unit() const
{
	return unit_;
}


void LyXLength::value(double v)
{
	val_ = v;
}


void LyXLength::unit(LyXLength::UNIT u)
{
	unit_ = u;
}


bool LyXLength::zero() const
{
	return val_ == 0.0;
}


bool LyXLength::empty() const
{
	return unit_ == LyXLength::UNIT_NONE;
}


int LyXLength::inPixels(int text_width, int em_width_base) const
{
	// 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]

	double const em_width = (em_width_base > 0)
		? em_width_base
		: 10*(dpi/72.27)*zoom;
	// A different estimate for em_width is
	// font_metrics::width('M', LyXFont(LyXFont::ALL_SANE))
	// but this estimate might not be more accurate as the screen font
	// is different then the latex font.

	// Pixel values are scaled so that the ratio
	// between lengths and font sizes on the screen
	// is the same as on paper.

	double result = 0.0;

	switch (unit_) {
	case LyXLength::SP:
		// Scaled point: sp = 1/65536 pt
		result = zoom * dpi * val_
			/ (72.27 * 65536); // 4736286.7
		break;
	case LyXLength::PT:
		// Point: 1 pt = 1/72.27 inch
		result = zoom * dpi * val_
			/ 72.27; // 72.27
		break;
	case LyXLength::BP:
		// Big point: 1 bp = 1/72 inch
		result = zoom * dpi * val_
			/ 72; // 72
		break;
	case LyXLength::DD:
		// Didot: 1157dd = 1238 pt?
		result = zoom * dpi * val_
			/ (72.27 / (0.376 * 2.845)); // 67.559735
		break;
	case LyXLength::MM:
		// Millimeter: 1 mm = 1/25.4 inch
		result = zoom * dpi * val_
			/ 25.4; // 25.4
		break;
	case LyXLength::PC:
		// Pica: 1 pc = 12 pt
		result = zoom * dpi * val_
			/ (72.27 / 12); // 6.0225
		break;
	case LyXLength::CC:
		// Cicero: 1 cc = 12 dd
		result = zoom * dpi * val_
			/ (72.27 / (12 * 0.376 * 2.845)); // 5.6299779
		break;
	case LyXLength::CM:
		// Centimeter: 1 cm = 1/2.54 inch
		result = zoom * dpi * val_
			/ 2.54; // 2.54
		break;
	case LyXLength::IN:
		// Inch
		result = zoom * dpi * val_;
		break;
	case LyXLength::EX:
		// Ex: The height of an "x"
		// 0.4305 is the ration between 1ex and 1em in cmr10
		result = val_ * em_width * 0.4305;
		break;
	case LyXLength::EM:
		// Em: The width of an "m"
		result = val_ * em_width;
		break;
	case LyXLength::MU:
		// math unit = 1/18em
		result = val_ * em_width / 18;
		break;
	case LyXLength::PCW: // Always % of workarea
	case LyXLength::PTW:
	case LyXLength::PLW:
		result = val_ * text_width / 100;
		break;
	case LyXLength::PPW:
		// paperwidth/textwidth is 1.7 for A4 paper with default margins
		result = val_ * text_width * 1.7 / 100;
		break;
	case LyXLength::PTH:
		result = val_ * text_width * 1.787 / 100;
		break;
	case LyXLength::PPH:
		result = val_ * text_width * 2.2 / 100;
		break;
	case LyXLength::UNIT_NONE:
		result = 0;  // this cannot happen
		break;
	}
	return static_cast<int>(result + ((result >= 0) ? 0.5 : -0.5));
}


int LyXLength::inBP() const
{
	// return any LyXLength value as a one with
	// the PostScript point, called bp (big points)
	double result = 0.0;
	switch (unit_) {
	case LyXLength::CM:
		// 1bp = 0.2835cm
		result = val_ * 28.346;
		break;
	case LyXLength::MM:
		// 1bp = 0.02835mm
		result = val_ * 2.8346;
		break;
	case LyXLength::IN:
		// 1pt = 1/72in
		result = val_ * 72.0;
		break;
	default:
		// no other than bp possible
		result = val_;
		break;
	}
	return static_cast<int>(result + 0.5);
}


bool operator==(LyXLength const & l1, LyXLength const & l2)
{
	return l1.value() == l2.value() && l1.unit() == l2.unit();
}


bool operator!=(LyXLength const & l1, LyXLength const & l2)
{
	return !(l1 == l2);
}