+/*
+ * This file is part of the sigrok project.
+ *
+ * Copyright (C) 2012 Joel Holdsworth <joel@airwebreathe.org.uk>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "ruler.h"
+#include "view.h"
+
+#include "../../extdef.h"
+
+#include <assert.h>
+#include <math.h>
+
+#include <QPainter>
+#include <QTextStream>
+
+namespace pv {
+namespace view {
+
+const int Ruler::MinorTickSubdivision = 4;
+const int Ruler::ScaleUnits[3] = {1, 2, 5};
+
+const QString Ruler::SIPrefixes[9] =
+ {"f", "p", "n", QChar(0x03BC), "m", "", "k", "M", "G"};
+const int Ruler::FirstSIPrefixPower = -15;
+
+Ruler::Ruler(View &parent) :
+ QWidget(&parent),
+ _view(parent)
+{
+}
+
+void Ruler::paintEvent(QPaintEvent *event)
+{
+ QPainter p(this);
+
+ const double MinSpacing = 80;
+
+ const double min_period = _view.scale() * MinSpacing;
+
+ const int order = (int)floorf(log10f(min_period));
+ const double order_decimal = pow(10, order);
+
+ int unit = 0;
+ double tick_period = 0.0f;
+
+ do
+ {
+ tick_period = order_decimal * ScaleUnits[unit++];
+ } while(tick_period < min_period && unit < countof(ScaleUnits));
+
+ const int prefix = (order - FirstSIPrefixPower) / 3;
+ assert(prefix >= 0);
+ assert(prefix < countof(SIPrefixes));
+
+ const int text_height = p.boundingRect(0, 0, INT_MAX, INT_MAX,
+ Qt::AlignLeft | Qt::AlignTop, "8").height();
+
+ // Draw the tick marks
+ p.setPen(Qt::black);
+
+ const double minor_tick_period = tick_period / MinorTickSubdivision;
+ const double first_major_division =
+ floor(_view.offset() / tick_period);
+ const double first_minor_division =
+ ceil(_view.offset() / minor_tick_period);
+ const double t0 = first_major_division * tick_period;
+
+ int division = (int)round(first_minor_division -
+ first_major_division * MinorTickSubdivision);
+ while(1)
+ {
+ const double t = t0 + division * minor_tick_period;
+ const double x = (t - _view.offset()) / _view.scale();
+
+ if(x >= width())
+ break;
+
+ if(division % MinorTickSubdivision == 0)
+ {
+ // Draw a major tick
+ QString s;
+ QTextStream ts(&s);
+ ts << (t / order_decimal) << SIPrefixes[prefix] << "s";
+ p.drawText(x, 0, 0, text_height, Qt::AlignCenter |
+ Qt::AlignTop | Qt::TextDontClip, s);
+ p.drawLine(x, text_height, x, height());
+ }
+ else
+ {
+ // Draw a minor tick
+ p.drawLine(x, (text_height + height()) / 2,
+ x, height());
+ }
+
+ division++;
+ }
+
+ p.end();
+}
+
+} // namespace view
+} // namespace pv
projects / pulseview.git / commitdiff