From: Steinar H. Gunderson <sgunderson@bigfoot.com>
Date: Wed, 11 Nov 2015 19:25:56 +0000 (+0100)
Subject: Precalculate the VU/LRA meter images as pixmaps, since the painting is so slow.
X-Git-Tag: 1.0.0~132
X-Git-Url: https://git.sesse.net/?a=commitdiff_plain;h=3376a2309e8b682f8e8d0a96bbda9ccaa19c53c0;p=nageru

Precalculate the VU/LRA meter images as pixmaps, since the painting is so slow.
---

diff --git a/lrameter.cpp b/lrameter.cpp
index 6e9fed4..d0304e1 100644
--- a/lrameter.cpp
+++ b/lrameter.cpp
@@ -14,12 +14,25 @@ LRAMeter::LRAMeter(QWidget *parent)
 {
 }
 
+void LRAMeter::resizeEvent(QResizeEvent *event)
+{
+	const int margin = 5;
+
+	on_pixmap = QPixmap(width(), height());
+	QPainter on_painter(&on_pixmap);
+	on_painter.fillRect(0, 0, width(), height(), parentWidget()->palette().window());
+	draw_vu_meter(on_painter, -HUGE_VAL, HUGE_VAL, width(), height(), margin);
+
+	off_pixmap = QPixmap(width(), height());
+	QPainter off_painter(&off_pixmap);
+	off_painter.fillRect(0, 0, width(), height(), parentWidget()->palette().window());
+	draw_vu_meter(off_painter, -HUGE_VAL, -HUGE_VAL, width(), height(), margin);
+}
+
 void LRAMeter::paintEvent(QPaintEvent *event)
 {
 	QPainter painter(this);
 
-	painter.fillRect(0, 0, width(), height(), parentWidget()->palette().window());
-
 	float level_lufs;
 	float range_low_lufs;
 	float range_high_lufs;
@@ -33,8 +46,16 @@ void LRAMeter::paintEvent(QPaintEvent *event)
 	float level_lu = level_lufs + 23.0f;
 	float range_low_lu = range_low_lufs + 23.0f;
 	float range_high_lu = range_high_lufs + 23.0f;
-	const int margin = 5;
-	draw_vu_meter(painter, range_low_lu, range_high_lu, width(), height(), margin);
+	int range_low_pos = lufs_to_pos(range_low_lu, height());
+	int range_high_pos = lufs_to_pos(range_high_lu, height());
+
+	QRect top_off_rect(0, 0, width(), range_high_pos);
+	QRect on_rect(0, range_high_pos, width(), range_low_pos - range_high_pos);
+	QRect bottom_off_rect(0, range_low_pos, width(), height() - range_low_pos);
+
+	painter.drawPixmap(top_off_rect, off_pixmap, top_off_rect);
+	painter.drawPixmap(on_rect, on_pixmap, on_rect);
+	painter.drawPixmap(bottom_off_rect, off_pixmap, bottom_off_rect);
 
 	// Draw the target area (+/-1 LU is allowed EBU range).
 	// It turns green when we're within.
diff --git a/lrameter.h b/lrameter.h
index bcd8377..382fcd3 100644
--- a/lrameter.h
+++ b/lrameter.h
@@ -25,12 +25,15 @@ public:
 	}
 
 private:
+	void resizeEvent(QResizeEvent *event) override;
 	void paintEvent(QPaintEvent *event) override;
 
 	std::mutex level_mutex;
 	float level_lufs = -HUGE_VAL;
 	float range_low_lufs = -HUGE_VAL;
 	float range_high_lufs = -HUGE_VAL;
+
+	QPixmap on_pixmap, off_pixmap;
 };
 
 #endif
diff --git a/vu_common.h b/vu_common.h
index 06a971f..aa57721 100644
--- a/vu_common.h
+++ b/vu_common.h
@@ -4,6 +4,9 @@
 #include <QPainter>
 
 int lufs_to_pos(float level_lu, int height);
+
+// TODO: Now that we precalculate these as pixmaps, perhaps we don't need the
+// high/low range anymore, just a yes/no.
 void draw_vu_meter(QPainter &painter, float range_low_lu, float range_high_lu, int width, int height, int margin);
 
 #endif // !defined(_VU_COMMON_H)
diff --git a/vumeter.cpp b/vumeter.cpp
index ab40fce..9fca7dd 100644
--- a/vumeter.cpp
+++ b/vumeter.cpp
@@ -10,6 +10,17 @@ VUMeter::VUMeter(QWidget *parent)
 {
 }
 
+void VUMeter::resizeEvent(QResizeEvent *event)
+{
+	on_pixmap = QPixmap(width(), height());
+	QPainter on_painter(&on_pixmap);
+	draw_vu_meter(on_painter, -HUGE_VAL, HUGE_VAL, width(), height(), 0);
+
+	off_pixmap = QPixmap(width(), height());
+	QPainter off_painter(&off_pixmap);
+	draw_vu_meter(off_painter, -HUGE_VAL, -HUGE_VAL, width(), height(), 0);
+}
+
 void VUMeter::paintEvent(QPaintEvent *event)
 {
 	QPainter painter(this);
@@ -21,5 +32,10 @@ void VUMeter::paintEvent(QPaintEvent *event)
 	}
 
 	float level_lu = level_lufs + 23.0f;
-	draw_vu_meter(painter, -HUGE_VAL, level_lu, width(), height(), 0);
+	int on_pos = lufs_to_pos(level_lu, height());
+	QRect off_rect(0, 0, width(), on_pos);
+	QRect on_rect(0, on_pos, width(), height() - on_pos);
+
+	painter.drawPixmap(off_rect, off_pixmap, off_rect);
+	painter.drawPixmap(on_rect, on_pixmap, on_rect);
 }
diff --git a/vumeter.h b/vumeter.h
index 12afdc6..7015091 100644
--- a/vumeter.h
+++ b/vumeter.h
@@ -21,10 +21,13 @@ public:
 	}
 
 private:
+	void resizeEvent(QResizeEvent *event) override;
 	void paintEvent(QPaintEvent *event) override;
 
 	std::mutex level_mutex;
 	float level_lufs = -HUGE_VAL;
+
+	QPixmap on_pixmap, off_pixmap;
 };
 
 #endif