2 * \file GuiFontMetrics.cpp
3 * This file is part of LyX, the document processor.
4 * Licence details can be found in the file COPYING.
9 * Full author contact details are available in file CREDITS.
14 #include "GuiFontMetrics.h"
16 #include "qt_helpers.h"
18 #include "Dimension.h"
22 #include "insets/Inset.h"
24 #include "support/lassert.h"
26 #include <QTextLayout>
29 using namespace lyx::support;
36 * Convert a UCS4 character into a QChar.
37 * This is a hack (it does only make sense for the common part of the UCS4
38 * and UTF16 encodings) and should not be used.
39 * This does only exist because of performance reasons (a real conversion
40 * using iconv is too slow on windows).
42 * This is no real conversion but a simple cast in reality. This is the reason
43 * why this works well for symbol fonts used in mathed too, even though
44 * these are not real ucs4 characters. These are codepoints in the
45 * computer modern fonts used, nothing unicode related.
46 * See comment in GuiPainter::text() for more explanation.
48 inline QChar const ucs4_to_qchar(char_type const ucs4)
50 LATTEST(is_utf16(ucs4));
51 return QChar(static_cast<unsigned short>(ucs4));
56 GuiFontMetrics::GuiFontMetrics(QFont const & font) : font_(font), metrics_(font, 0)
61 int GuiFontMetrics::maxAscent() const
63 return metrics_.ascent();
67 int GuiFontMetrics::maxDescent() const
69 // We add 1 as the value returned by QT is different than X
70 // See http://doc.trolltech.com/2.3/qfontmetrics.html#200b74
71 return metrics_.descent() + 1;
75 int GuiFontMetrics::em() const
77 return QFontInfo(font_).pixelSize();
81 int GuiFontMetrics::lbearing(char_type c) const
84 // FIXME: QFontMetrics::leftBearingdoes not support the
85 // full unicode range. Once it does, we could use:
86 //return metrics_.leftBearing(toqstr(docstring(1, c)));
89 return metrics_.leftBearing(ucs4_to_qchar(c));
94 int const outOfLimitMetric = -10000;
98 int GuiFontMetrics::rbearing(char_type c) const
100 int value = rbearing_cache_.value(c, outOfLimitMetric);
101 if (value != outOfLimitMetric)
104 // Qt rbearing is from the right edge of the char's width().
106 QChar sc = ucs4_to_qchar(c);
107 value = width(c) - metrics_.rightBearing(sc);
109 // FIXME: QFontMetrics::leftBearing does not support the
110 // full unicode range. Once it does, we could use:
111 // metrics_.rightBearing(toqstr(docstring(1, c)));
115 rbearing_cache_.insert(c, value);
121 int GuiFontMetrics::width(docstring const & s) const
124 map<docstring, int>::const_iterator it = strwidth_cache_.find(s);
125 if (it != strwidth_cache_.end()) {
128 w = metrics_.width(toqstr(s));
129 strwidth_cache_[s] = w;
135 int GuiFontMetrics::width(QString const & ucs2) const
137 return width(qstring_to_ucs4(ucs2));
141 int GuiFontMetrics::signedWidth(docstring const & s) const
147 return -width(s.substr(1, s.size() - 1));
153 void setTextLayout(QTextLayout & tl, docstring const & s, QFont const & font,
156 tl.setText(toqstr(s));
158 // Note that both setFlags and the enums are undocumented
159 tl.setFlags(rtl ? Qt::TextForceRightToLeft : Qt::TextForceLeftToRight);
167 int GuiFontMetrics::pos2x(docstring const & s, int const pos, bool const rtl) const
170 setTextLayout(tl, s, font_, rtl);
171 return static_cast<int>(tl.lineForTextPosition(pos).cursorToX(pos));
175 int GuiFontMetrics::x2pos(docstring const & s, int & x, bool const rtl) const
178 setTextLayout(tl, s, font_, rtl);
179 int pos = tl.lineForTextPosition(0).xToCursor(x);
180 // correct x value to the actual cursor position.
181 x = static_cast<int>(tl.lineForTextPosition(0).cursorToX(pos));
186 bool GuiFontMetrics::breakAt(docstring & s, int & x, bool const rtl, bool const force) const
191 tl.setText(toqstr(s));
193 // Note that both setFlags and the enums are undocumented
194 tl.setFlags(rtl ? Qt::TextForceRightToLeft : Qt::TextForceLeftToRight);
196 to.setWrapMode(force ? QTextOption::WrapAnywhere : QTextOption::WordWrap);
197 tl.setTextOption(to);
199 QTextLine line = tl.createLine();
200 line.setLineWidth(x);
203 if (int(line.naturalTextWidth()) > x)
205 x = int(line.naturalTextWidth());
206 s = s.substr(0, line.textLength());
211 void GuiFontMetrics::rectText(docstring const & str,
212 int & w, int & ascent, int & descent) const
214 static int const d = Inset::TEXT_TO_INSET_OFFSET / 2;
216 w = width(str) + Inset::TEXT_TO_INSET_OFFSET;
217 ascent = metrics_.ascent() + d;
218 descent = metrics_.descent() + d;
223 void GuiFontMetrics::buttonText(docstring const & str,
224 int & w, int & ascent, int & descent) const
226 rectText(str, w, ascent, descent);
227 w += Inset::TEXT_TO_INSET_OFFSET;
231 Dimension const GuiFontMetrics::defaultDimension() const
233 return Dimension(0, maxAscent(), maxDescent());
237 Dimension const GuiFontMetrics::dimension(char_type c) const
239 return Dimension(width(c), ascent(c), descent(c));
243 GuiFontMetrics::AscendDescend const GuiFontMetrics::fillMetricsCache(
248 r = metrics_.boundingRect(ucs4_to_qchar(c));
250 r = metrics_.boundingRect(toqstr(docstring(1, c)));
252 AscendDescend ad = { -r.top(), r.bottom() + 1};
253 // We could as well compute the width but this is not really
254 // needed for now as it is done directly in width() below.
255 metrics_cache_.insert(c, ad);
261 int GuiFontMetrics::width(char_type c) const
263 int value = width_cache_.value(c, outOfLimitMetric);
264 if (value != outOfLimitMetric)
268 value = metrics_.width(ucs4_to_qchar(c));
270 value = metrics_.width(toqstr(docstring(1, c)));
272 width_cache_.insert(c, value);
278 int GuiFontMetrics::ascent(char_type c) const
280 static AscendDescend const outOfLimitAD =
281 {outOfLimitMetric, outOfLimitMetric};
282 AscendDescend value = metrics_cache_.value(c, outOfLimitAD);
283 if (value.ascent != outOfLimitMetric)
286 value = fillMetricsCache(c);
291 int GuiFontMetrics::descent(char_type c) const
293 static AscendDescend const outOfLimitAD =
294 {outOfLimitMetric, outOfLimitMetric};
295 AscendDescend value = metrics_cache_.value(c, outOfLimitAD);
296 if (value.descent != outOfLimitMetric)
297 return value.descent;
299 value = fillMetricsCache(c);
300 return value.descent;
303 } // namespace frontend