/** * \file GuiFontMetrics.cpp * This file is part of LyX, the document processor. * Licence details can be found in the file COPYING. * * \author unknown * \author John Levon * * Full author contact details are available in file CREDITS. */ #include #include "GuiFontMetrics.h" #include "qt_helpers.h" #include "Dimension.h" #include "Language.h" #include "LyXRC.h" #include "insets/Inset.h" #include "support/lassert.h" #include using namespace std; using namespace lyx::support; namespace lyx { namespace frontend { namespace { /** * Convert a UCS4 character into a QChar. * This is a hack (it does only make sense for the common part of the UCS4 * and UTF16 encodings) and should not be used. * This does only exist because of performance reasons (a real conversion * using iconv is too slow on windows). * * This is no real conversion but a simple cast in reality. This is the reason * why this works well for symbol fonts used in mathed too, even though * these are not real ucs4 characters. These are codepoints in the * computer modern fonts used, nothing unicode related. * See comment in GuiPainter::text() for more explanation. **/ inline QChar const ucs4_to_qchar(char_type const ucs4) { LATTEST(is_utf16(ucs4)); return QChar(static_cast(ucs4)); } } // anon namespace GuiFontMetrics::GuiFontMetrics(QFont const & font) : font_(font), metrics_(font, 0) { } int GuiFontMetrics::maxAscent() const { return metrics_.ascent(); } int GuiFontMetrics::maxDescent() const { // We add 1 as the value returned by QT is different than X // See http://doc.trolltech.com/2.3/qfontmetrics.html#200b74 return metrics_.descent() + 1; } int GuiFontMetrics::em() const { return QFontInfo(font_).pixelSize(); } int GuiFontMetrics::lbearing(char_type c) const { if (!is_utf16(c)) // FIXME: QFontMetrics::leftBearingdoes not support the // full unicode range. Once it does, we could use: //return metrics_.leftBearing(toqstr(docstring(1, c))); return 0; return metrics_.leftBearing(ucs4_to_qchar(c)); } namespace { int const outOfLimitMetric = -10000; } int GuiFontMetrics::rbearing(char_type c) const { int value = rbearing_cache_.value(c, outOfLimitMetric); if (value != outOfLimitMetric) return value; // Qt rbearing is from the right edge of the char's width(). if (is_utf16(c)) { QChar sc = ucs4_to_qchar(c); value = width(c) - metrics_.rightBearing(sc); } else { // FIXME: QFontMetrics::leftBearing does not support the // full unicode range. Once it does, we could use: // metrics_.rightBearing(toqstr(docstring(1, c))); value = width(c); } rbearing_cache_.insert(c, value); return value; } int GuiFontMetrics::width(docstring const & s) const { int w = 0; map::const_iterator it = strwidth_cache_.find(s); if (it != strwidth_cache_.end()) { w = it->second; } else { w = metrics_.width(toqstr(s)); strwidth_cache_[s] = w; } return w; } int GuiFontMetrics::width(QString const & ucs2) const { return width(qstring_to_ucs4(ucs2)); } int GuiFontMetrics::signedWidth(docstring const & s) const { if (s.empty()) return 0; if (s[0] == '-') return -width(s.substr(1, s.size() - 1)); else return width(s); } namespace { void setTextLayout(QTextLayout & tl, docstring const & s, QFont const & font, bool const rtl) { tl.setText(toqstr(s)); tl.setFont(font); // Note that both setFlags and the enums are undocumented tl.setFlags(rtl ? Qt::TextForceRightToLeft : Qt::TextForceLeftToRight); tl.beginLayout(); tl.createLine(); tl.endLayout(); } } int GuiFontMetrics::pos2x(docstring const & s, int const pos, bool const rtl) const { QTextLayout tl; setTextLayout(tl, s, font_, rtl); return static_cast(tl.lineForTextPosition(pos).cursorToX(pos)); } int GuiFontMetrics::x2pos(docstring const & s, int & x, bool const rtl) const { QTextLayout tl; setTextLayout(tl, s, font_, rtl); int pos = tl.lineForTextPosition(0).xToCursor(x); // correct x value to the actual cursor position. x = static_cast(tl.lineForTextPosition(0).cursorToX(pos)); return pos; } bool GuiFontMetrics::breakAt(docstring & s, int & x, bool const rtl, bool const force) const { if (s.empty()) return false; QTextLayout tl; tl.setText(toqstr(s)); tl.setFont(font_); // Note that both setFlags and the enums are undocumented tl.setFlags(rtl ? Qt::TextForceRightToLeft : Qt::TextForceLeftToRight); QTextOption to; to.setWrapMode(force ? QTextOption::WrapAnywhere : QTextOption::WordWrap); tl.setTextOption(to); tl.beginLayout(); QTextLine line = tl.createLine(); line.setLineWidth(x); tl.createLine(); tl.endLayout(); if (int(line.naturalTextWidth()) > x) return false; x = int(line.naturalTextWidth()); s = s.substr(0, line.textLength()); return true; } void GuiFontMetrics::rectText(docstring const & str, int & w, int & ascent, int & descent) const { static int const d = Inset::TEXT_TO_INSET_OFFSET / 2; w = width(str) + Inset::TEXT_TO_INSET_OFFSET; ascent = metrics_.ascent() + d; descent = metrics_.descent() + d; } void GuiFontMetrics::buttonText(docstring const & str, int & w, int & ascent, int & descent) const { rectText(str, w, ascent, descent); w += Inset::TEXT_TO_INSET_OFFSET; } Dimension const GuiFontMetrics::defaultDimension() const { return Dimension(0, maxAscent(), maxDescent()); } Dimension const GuiFontMetrics::dimension(char_type c) const { return Dimension(width(c), ascent(c), descent(c)); } GuiFontMetrics::AscendDescend const GuiFontMetrics::fillMetricsCache( char_type c) const { QRect r; if (is_utf16(c)) r = metrics_.boundingRect(ucs4_to_qchar(c)); else r = metrics_.boundingRect(toqstr(docstring(1, c))); AscendDescend ad = { -r.top(), r.bottom() + 1}; // We could as well compute the width but this is not really // needed for now as it is done directly in width() below. metrics_cache_.insert(c, ad); return ad; } int GuiFontMetrics::width(char_type c) const { int value = width_cache_.value(c, outOfLimitMetric); if (value != outOfLimitMetric) return value; if (is_utf16(c)) value = metrics_.width(ucs4_to_qchar(c)); else value = metrics_.width(toqstr(docstring(1, c))); width_cache_.insert(c, value); return value; } int GuiFontMetrics::ascent(char_type c) const { static AscendDescend const outOfLimitAD = {outOfLimitMetric, outOfLimitMetric}; AscendDescend value = metrics_cache_.value(c, outOfLimitAD); if (value.ascent != outOfLimitMetric) return value.ascent; value = fillMetricsCache(c); return value.ascent; } int GuiFontMetrics::descent(char_type c) const { static AscendDescend const outOfLimitAD = {outOfLimitMetric, outOfLimitMetric}; AscendDescend value = metrics_cache_.value(c, outOfLimitAD); if (value.descent != outOfLimitMetric) return value.descent; value = fillMetricsCache(c); return value.descent; } } // namespace frontend } // namespace lyx