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

diff --git a/lrameter.cpp b/lrameter.cpp
index 6e9fed429a5862563c79144424acd2d0a70e2ff7..d0304e1a9e5a05082938ae817b4b21b9df5840b0 100644 (file)
--- 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 bcd8377036b7915f7dd858b260f4d19adc8b03de..382fcd33107c5b4e5ffe9cc03fb0ec3e023e57c0 100644 (file)
--- 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 06a971f409fb9f4e3ac3c1cbe4c66bf049ac0e04..aa577214b191287b0c0d032a335d005c63bf8fe6 100644 (file)
--- 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 ab40fceff699ec13df3f3db1c86eefdbd73ed3bf..9fca7ddc1c8712e5c214ff9b4bda313caf73018d 100644 (file)
--- 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 12afdc6398dfd2ec42128dd7272bab92b6c33533..7015091aa0f1d307f4aee97e5a58f60bfb5a6c79 100644 (file)
--- 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