comparison layer/PaintAssistant.cpp @ 195:4a3bdde1ef13

* beginnings of spectrum scales

+/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
+
+/*
+    Sonic Visualiser
+    An audio file viewer and annotation editor.
+    Centre for Digital Music, Queen Mary, University of London.
+    This file copyright 2006-2007 Chris Cannam and QMUL.
+   
+    This program is free software; you can redistribute it and/or
+    modify it under the terms of the GNU General Public License as
+    published by the Free Software Foundation; either version 2 of the
+    License, or (at your option) any later version.  See the file
+    COPYING included with this distribution for more information.
+*/
+
+#include "PaintAssistant.h"
+
+#include "base/AudioLevel.h"
+
+#include <QPaintDevice>
+#include <QPainter>
+
+void
+PaintAssistant::paintVerticalLevelScale(QPainter &paint, QRect rect,
+					float minVal, float maxVal,
+                                        Scale scale, std::vector<int> *vy)
+{
+    static float meterdbs[] = { -40, -30, -20, -15, -10,
+                                -5, -3, -2, -1, -0.5, 0 };
+
+    int h = rect.height(), w = rect.width();
+    int textHeight = paint.fontMetrics().height();
+    int toff = -textHeight/2 + paint.fontMetrics().ascent() + 1;
+
+    int lastLabelledY = -1;
+
+    int n = 10;
+    if (vy) vy->clear();
+
+    for (int i = 0; i <= n; ++i) {
+        
+        float val = 0.0, nval = 0.0;
+        QString text = "";
+
+        switch (scale) {
+                
+        case LinearScale:
+            val = minVal + ((maxVal - minVal) * i) / n;
+            text = QString("%1").arg(val);//float(i) / n); // ... val
+/*
+            if (i == 0) text = "0.0";
+            else {
+                nval = -val;
+                if (i == n) text = "1.0";
+            }
+*/
+            break;
+            
+        case MeterScale: // ... min, max
+            val = AudioLevel::dB_to_multiplier(meterdbs[i]);
+            text = QString("%1").arg(meterdbs[i]);
+            if (i == n) text = "0dB";
+            if (i == 0) {
+                text = "-Inf";
+                val = 0.0;
+            }
+            break;
+
+        case dBScale: // ... min, max
+            val = AudioLevel::dB_to_multiplier(-(10*n) + i * 10);
+            text = QString("%1").arg(-(10*n) + i * 10);
+            if (i == n) text = "0dB";
+            if (i == 0) {
+                text = "-Inf";
+                val = 0.0;
+            }
+            break;
+        }
+
+        if (val < minVal || val > maxVal) continue;
+
+        int y = getYForValue(scale, val, minVal, maxVal, rect.y(), rect.height());
+            
+        int ny = y;
+        if (nval != 0.0) {
+            ny = getYForValue(scale, nval, minVal, maxVal, rect.y(), rect.height());
+        }
+
+        bool spaceForLabel = (i == 0 ||
+                              abs(y - lastLabelledY) >= textHeight - 1);
+        
+        if (spaceForLabel) {
+            
+            int tx = 3;
+            if (scale != LinearScale) {
+                tx = w - 10 - paint.fontMetrics().width(text);
+            }
+            
+            int ty = y;
+            if (ty < paint.fontMetrics().ascent()) {
+                ty = paint.fontMetrics().ascent();
+            } else if (ty > h - paint.fontMetrics().descent()) {
+                ty = h - paint.fontMetrics().descent();
+            } else {
+                ty += toff;
+            }
+            paint.drawText(tx, ty, text);
+            
+            lastLabelledY = ty - toff;
+            /*
+            if (ny != y) {
+                ty = ny;
+                if (ty < paint.fontMetrics().ascent()) {
+                    ty = paint.fontMetrics().ascent();
+                } else if (ty > h - paint.fontMetrics().descent()) {
+                    ty = h - paint.fontMetrics().descent();
+                } else {
+                    ty += toff;
+                }
+                paint.drawText(tx, ty, text);
+            }
+            */
+            paint.drawLine(w - 7, y, w, y);
+            if (vy) vy->push_back(y);
+
+            if (ny != y) {
+                paint.drawLine(w - 7, ny, w, ny);
+                if (vy) vy->push_back(ny);
+            }
+            
+        } else {
+            
+            paint.drawLine(w - 4, y, w, y);
+            if (vy) vy->push_back(y);
+
+            if (ny != y) {
+                paint.drawLine(w - 4, ny, w, ny);
+                if (vy) vy->push_back(ny);
+            }
+        }
+    }
+}
+
+static int
+dBscale(float sample, int m, float maxVal, float minVal) 
+{
+    if (sample < 0.0) return dBscale(-sample, m, maxVal, minVal);
+    float dB = AudioLevel::multiplier_to_dB(sample);
+    float mindB = AudioLevel::multiplier_to_dB(minVal);
+    float maxdB = AudioLevel::multiplier_to_dB(maxVal);
+    if (dB < mindB) return 0;
+    if (dB > 0.0) return m;
+    return int(((dB - mindB) * m) / (maxdB - mindB) + 0.1);
+}
+
+int
+PaintAssistant::getYForValue(Scale scale, float value, 
+                             float minVal, float maxVal,
+                             int minY, int height)
+{
+    int vy = 0;
+
+//    int m = height/2;
+//    int my = minY + m;
+
+    switch (scale) {
+
+    case LinearScale:
+//        vy = my - int(m * value);
+        vy = minY + height - int(((value - minVal) / (maxVal - minVal)) * height);
+        break;
+
+    case MeterScale:
+//        vy = my - AudioLevel::multiplier_to_preview(value, m);
+        vy = minY + height - AudioLevel::multiplier_to_preview
+            ((value - minVal) / (maxVal - minVal), height);
+        break;
+
+    case dBScale:
+        vy = minY + height - dBscale(value, height, maxVal, minVal);
+        break;
+    }
+
+    return vy;
+}