changeset 709:def489f5ce92 tonioni

Adjustable middle-line height for waveform. Not 100% supported (only really for basic waveform rendering)

--- a/layer/WaveformLayer.cpp	Tue Jan 07 13:04:16 2014 +0000
+++ b/layer/WaveformLayer.cpp	Wed Jan 08 17:47:34 2014 +0000
@@ -43,6 +43,7 @@
     m_channelMode(SeparateChannels),
     m_channel(-1),
     m_scale(LinearScale),
+    m_middleLineHeight(0.5),
     m_aggressive(false),
     m_cache(0),
     m_cacheValid(false)
@@ -306,6 +307,15 @@
 }
 
 void
+WaveformLayer::setMiddleLineHeight(float height)
+{
+    if (m_middleLineHeight == height) return;
+    m_middleLineHeight = height;
+    m_cacheValid = false;
+    emit layerParametersChanged();
+}
+
+void
 WaveformLayer::setAggressiveCacheing(bool aggressive)
 {
     if (m_aggressive == aggressive) return;
@@ -532,6 +542,15 @@
 
     paint->setRenderHint(QPainter::Antialiasing, false);
 
+    if (m_middleLineHeight != 0.5) {
+        paint->save();
+        float space = m_middleLineHeight * 2;
+        if (space > 1.0) space = 2.0 - space;
+        float yt = h * (m_middleLineHeight - space/2);
+        paint->translate(QPointF(0, yt));
+        paint->scale(1.0, space);
+    }
+
     int x0 = 0, x1 = w - 1;
     int y0 = 0, y1 = h - 1;
 
@@ -915,6 +934,10 @@
 	}
     }
 
+    if (m_middleLineHeight != 0.5) {
+        paint->restore();
+    }
+
     if (m_aggressive) {
 
 	if (ready && rect == v->rect()) {
@@ -1314,14 +1337,16 @@
 		 "channelMode=\"%4\" "
 		 "channel=\"%5\" "
                  "scale=\"%6\" "
-		 "aggressive=\"%7\" "
-                 "autoNormalize=\"%8\"")
+                 "middleLineHeight=\"%7\" "
+		 "aggressive=\"%8\" "
+                 "autoNormalize=\"%9\"")
 	.arg(m_gain)
 	.arg(m_showMeans)
 	.arg(m_greyscale)
 	.arg(m_channelMode)
 	.arg(m_channel)
 	.arg(m_scale)
+        .arg(m_middleLineHeight)
 	.arg(m_aggressive)
         .arg(m_autoNormalize);
 
@@ -1353,10 +1378,12 @@
     int channel = attributes.value("channel").toInt(&ok);
     if (ok) setChannel(channel);
 
-    Scale scale = (Scale)
-	attributes.value("scale").toInt(&ok);
+    Scale scale = (Scale)attributes.value("scale").toInt(&ok);
     if (ok) setScale(scale);
 
+    float middleLineHeight = attributes.value("middleLineHeight").toFloat(&ok);
+    if (ok) setMiddleLineHeight(middleLineHeight);
+
     bool aggressive = (attributes.value("aggressive") == "1" ||
 		       attributes.value("aggressive") == "true");
     setUseGreyscale(aggressive);

--- a/layer/WaveformLayer.h	Tue Jan 07 13:04:16 2014 +0000
+++ b/layer/WaveformLayer.h	Wed Jan 08 17:47:34 2014 +0000
@@ -147,6 +147,19 @@
     Scale getScale() const { return m_scale; }
 
     /**
+     * Specify the height of the middle of the waveform track or
+     * tracks within the layer, from 0.0 to 1.0.
+     *
+     * A value of 0.0 would indicate that the waveform occupies
+     * effectively no space at the very top of the layer; 1.0 would
+     * indicate that the waveform occupies no space at the very
+     * bottom; the default value of 0.5 indicates that it occupies the
+     * whole layer, centred at the middle.
+     */
+    void setMiddleLineHeight(float height);
+    float getMiddleLineHeight() const { return m_middleLineHeight; }
+
+    /**
      * Enable or disable aggressive pixmap cacheing.  If enabled,
      * waveforms will be rendered to an off-screen pixmap and
      * refreshed from there instead of being redrawn from the peak
@@ -216,6 +229,7 @@
     ChannelMode  m_channelMode;
     int          m_channel;
     Scale        m_scale;
+    float        m_middleLineHeight;
     bool         m_aggressive;
 
     mutable std::vector<float> m_effectiveGains;