Initial version

src/text.cpp

@@ -0,0 +1,110 @@
+#include <QGraphicsPixmapItem>
+#include <QFontMetrics>
+#include <QPainter>
+#include "text.h"
+#include "textpathitem.h"
+
+
+static QPainterPath subpath(const QPainterPath &path, int start, int end)
+{
+	QPainterPath p(path.elementAt(start));
+	for (int i = start + 1; i <= end; i++)
+		p.lineTo(path.elementAt(i));
+	return p;
+}
+
+static QList<QPainterPath> segments(const QPainterPath &path, qreal segmentLimit,
+  qreal pathLimit)
+{
+	QList<QPainterPath> list;
+	int start = 0;
+	qreal length = 0;
+
+	for (int i = 1; i < path.elementCount(); i++) {
+		QLineF l(path.elementAt(i-1), path.elementAt(i));
+		qreal sl = l.length();
+		if (sl < segmentLimit || length > pathLimit) {
+			if (length > pathLimit)
+				list.append(subpath(path, start, i - 1));
+			start = i;
+			length = 0;
+		} else
+			length += sl;
+	}
+
+	if (length > pathLimit)
+		list.append(subpath(path, start, path.elementCount() - 1));
+
+	return list;
+}
+
+static bool reverse(const QPainterPath &path)
+{
+	QLineF l(path.elementAt(0), path.elementAt(1));
+	qreal angle = l.angle();
+	return (angle > 90 && angle < 270) ? true : false;
+}
+
+void Text::addLabel(const QString &text, const QPointF &pos, const QFont &font,
+  const QPen &pen, qreal maxTextWidth)
+{
+	if (text.isEmpty())
+		return;
+
+	QFontMetrics fm(font);
+	int limit = fm.width('M') * maxTextWidth;
+	int flags = Qt::AlignCenter | Qt::TextWordWrap | Qt::TextDontClip;
+
+	QRect br = fm.boundingRect(QRect(0, 0, limit, 0), flags, text);
+	if (!br.isValid())
+		return;
+	br.moveTo((pos - QPointF(br.width() / 2.0, br.height() / 2.0)).toPoint());
+	if (!sceneRect().contains(br))
+		return;
+	QPixmap pm(br.size());
+	pm.fill(Qt::transparent);
+	QPainter p(&pm);
+	p.setFont(font);
+	p.setPen(pen);
+	p.drawText(pm.rect(), flags, text);
+
+	QGraphicsPixmapItem *pi = addPixmap(pm);
+	pi->setPos(br.topLeft());
+
+	QList<QGraphicsItem*> ci = collidingItems(pi);
+	for (int i = 0; i < ci.size(); i++)
+		ci[i]->setVisible(false);
+}
+
+void Text::addLabel(const QString &text, const QPainterPath &path,
+  const QFont &font, const QPen &pen)
+{
+	if (path.elementCount() < 2 || !path.elementAt(0).isMoveTo())
+		return;
+	if (text.isEmpty())
+		return;
+
+	QFontMetrics fm(font);
+	int textWidth = fm.width(text);
+
+	if (textWidth > path.length())
+		return;
+
+	QList<QPainterPath> list(segments(path, fm.width('M'), textWidth));
+	for (int i = 0; i < list.size(); i++) {
+		const QPainterPath &segment = list.at(i);
+		TextPathItem *pi = new TextPathItem(text, reverse(segment)
+		  ? segment.toReversed() : segment, font);
+		pi->setPen(pen);
+		addItem(pi);
+
+		if (!sceneRect().contains(pi->sceneBoundingRect())) {
+			delete pi;
+			continue;
+		}
+
+		QList<QGraphicsItem*> ci = collidingItems(pi);
+		for (int j = 0; j < ci.size(); j++)
+			ci[j]->setVisible(false);
+	}
+}