From: Joel Holdsworth <redacted>
Date: Wed, 17 Oct 2012 20:11:41 +0000 (+0100)
Subject: Cache signal label text size at draw time for later use
X-Git-Tag: pulseview-0.1.0~242
X-Git-Url: https://sigrok.org/gitweb/?p=pulseview.git;a=commitdiff_plain;h=ed6f0f4f84a26aadacfd4d3a745a8d7f1094efc5

Cache signal label text size at draw time for later use
---

diff --git a/pv/signal.cpp b/pv/signal.cpp
index 7d3dd663..091dd8d4 100644
--- a/pv/signal.cpp
+++ b/pv/signal.cpp
@@ -43,7 +43,9 @@ void Signal::paint_label(QPainter &p, const QRect &rect, bool hover)
 
 	const QColor colour = get_colour();
 	const float nominal_offset = get_nominal_offset(rect);
-	const QRectF label_rect = get_label_rect(p, rect);
+
+	compute_text_size(p);
+	const QRectF label_rect = get_label_rect(rect);
 
 	// Paint the label
 	const QPointF points[] = {
@@ -79,10 +81,9 @@ void Signal::paint_label(QPainter &p, const QRect &rect, bool hover)
 	p.drawText(label_rect, Qt::AlignCenter | Qt::AlignVCenter, _name);
 }
 
-bool Signal::pt_in_label_rect(QPainter &p,
-	const QRect &rect, const QPoint &point)
+bool Signal::pt_in_label_rect(const QRect &rect, const QPoint &point)
 {
-	const QRectF label = get_label_rect(p, rect);
+	const QRectF label = get_label_rect(rect);
 	return QRectF(
 		QPointF(label.left() - LabelHitPadding,
 			label.top() - LabelHitPadding),
@@ -91,15 +92,17 @@ bool Signal::pt_in_label_rect(QPainter &p,
 		).contains(point);
 }
 
-QRectF Signal::get_label_rect(QPainter &p, const QRect &rect)
+void Signal::compute_text_size(QPainter &p)
 {
-	const QSizeF text_size = p.boundingRect(
-		QRectF(0, 0, rect.width(), 0), 0, _name).size();
+	_text_size = p.boundingRect(QRectF(), 0, _name).size();
+}
 
+QRectF Signal::get_label_rect(const QRect &rect)
+{
 	const float nominal_offset = get_nominal_offset(rect);
 	const QSizeF label_size(
-		text_size.width() + LabelPadding.width() * 2,
-		text_size.height() + LabelPadding.height() * 2);
+		_text_size.width() + LabelPadding.width() * 2,
+		_text_size.height() + LabelPadding.height() * 2);
 	const float label_arrow_length = label_size.height() / 2;
 	return QRectF(
 		rect.right() - label_arrow_length - label_size.width(),
diff --git a/pv/signal.h b/pv/signal.h
index 8faff77c..b4c4244c 100644
--- a/pv/signal.h
+++ b/pv/signal.h
@@ -65,21 +65,25 @@ public:
 
 	/**
 	 * Determines if a point is in the header label rect.
-	 * @param p the QPainter to paint into.
 	 * @param rect the rectangular area to draw the label into.
 	 * @param point the point to test.
 	 */
-	bool pt_in_label_rect(QPainter &p, const QRect &rect,
-		const QPoint &point);
+	bool pt_in_label_rect(const QRect &rect, const QPoint &point);
 
 private:
+
+	/**
+	 * Computes an caches the size of the label text.
+	 */
+	void compute_text_size(QPainter &p);
+
 	/**
 	 * Computes the outline rectangle of a label.
 	 * @param p the QPainter to lay out text with.
 	 * @param rect The rectangle of the signal header.
 	 * @return Returns the rectangle of the signal label.
 	 */
-	virtual QRectF get_label_rect(QPainter &p, const QRect &rect);
+	QRectF get_label_rect(const QRect &rect);
 
 protected:
 	/**
@@ -95,6 +99,7 @@ protected:
 
 protected:
 	QString _name;
+	QSizeF _text_size;
 };
 
 } // namespace pv
diff --git a/pv/view/header.cpp b/pv/view/header.cpp
index 4eebf1f5..8fe9d485 100644
--- a/pv/view/header.cpp
+++ b/pv/view/header.cpp
@@ -63,8 +63,7 @@ void Header::paintEvent(QPaintEvent *event)
 			0, offset, w, View::SignalHeight);
 
 		s->paint_label(painter, signal_heading_rect,
-			s->pt_in_label_rect(painter,
-				signal_heading_rect, _mouse_point));
+			s->pt_in_label_rect(signal_heading_rect, _mouse_point));
 
 		offset += View::SignalHeight;
 	}