view layer/PaintAssistant.cpp @ 1393:a0bfe366f9cb spectrogramparam

Correct positioning for centre line when antialiasing with non-0-width pen

/* -*- 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 "LayerGeometryProvider.h"

#include "base/AudioLevel.h"
#include "base/Strings.h"
#include "base/Debug.h"

#include <QPaintDevice>
#include <QPainter>

#include <iostream>
#include <cmath>

void
PaintAssistant::paintVerticalLevelScale(QPainter &paint, QRect rect,
                                        double minVal, double maxVal,
                                        Scale scale, int &mult,
                                        std::vector<int> *vy)
{
    static double 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();

    double step = 0;
    mult = 1;
    if (scale == LinearScale) {
        step = (maxVal - minVal) / n;
        int round = 0, limit = 10000000;
        do {
            round = int(minVal + step * mult);
            mult *= 10;
        } while (!round && mult < limit);
        if (round) {
            mult /= 10;
            step = double(round) / mult;
            n = int(lrint((maxVal - minVal) / step));
            if (mult > 1) {
                mult /= 10;
            }
        }
    }

    for (int i = 0; i <= n; ++i) {
        
        double val = 0.0, nval = 0.0;
        QString text = "";

        switch (scale) {
                
        case LinearScale:
            val = (minVal + (i * step));
            text = QString("%1").arg(mult * val);
            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 = Strings::minus_infinity;
                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 = Strings::minus_infinity;
                val = 0.0;
            }
            break;
        }

        if (val < minVal || val > maxVal) continue;

        int y = getYForValue(scale, val, minVal, maxVal, rect.y(), h);
            
        int ny = y;
        if (nval != 0.0) {
            ny = getYForValue(scale, nval, minVal, maxVal, rect.y(), h);
        }

//        SVDEBUG << "PaintAssistant::paintVerticalLevelScale: val = "
//                  << val << ", y = " << y << ", h = " << h << endl;

        bool spaceForLabel = (i == 0 ||
                              abs(y - lastLabelledY) >= textHeight - 1);
        
        if (spaceForLabel) {
            
            int tx = 3;
            if (paint.fontMetrics().width(text) < w - 10) {
                tx = w - 10 - paint.fontMetrics().width(text);
            }
            
            int ty = y;

            if (ty < paint.fontMetrics().ascent()) {
                ty = paint.fontMetrics().ascent();
            } else {
                ty += toff;
            }

            paint.drawText(tx, ty, text);
            
            lastLabelledY = ty - toff;

            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(double sample, int m, double maxVal, double minVal) 
{
    if (sample < 0.0) return dBscale(-sample, m, maxVal, minVal);
    double dB = AudioLevel::multiplier_to_dB(sample);
    double mindB = AudioLevel::multiplier_to_dB(minVal);
    double 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, double value, 
                             double minVal, double maxVal,
                             int minY, int height)
{
    int vy = 0;

    switch (scale) {

    case LinearScale:
        vy = minY + height - int(((value - minVal) / (maxVal - minVal)) * height);
        break;

    case MeterScale:
        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;
}

void
PaintAssistant::drawVisibleText(const LayerGeometryProvider *v,
                                QPainter &paint, int x, int y,
                                QString text, TextStyle style)
{
    if (style == OutlinedText || style == OutlinedItalicText) {

        paint.save();

        if (style == OutlinedItalicText) {
            QFont f(paint.font());
            f.setItalic(true);
            paint.setFont(f);
        }

        QColor penColour, surroundColour, boxColour;

        penColour = v->getForeground();
        surroundColour = v->getBackground();
        boxColour = surroundColour;
        boxColour.setAlpha(127);

        paint.setPen(Qt::NoPen);
        paint.setBrush(boxColour);
        
        QRect r = paint.fontMetrics().boundingRect(text);
        r.translate(QPoint(x, y));
        paint.drawRect(r);
        paint.setBrush(Qt::NoBrush);

        paint.setPen(surroundColour);

        for (int dx = -1; dx <= 1; ++dx) {
            for (int dy = -1; dy <= 1; ++dy) {
                if (!(dx || dy)) continue;
                paint.drawText(x + dx, y + dy, text);
            }
        }

        paint.setPen(penColour);

        paint.drawText(x, y, text);

        paint.restore();

    } else {

        std::cerr << "ERROR: PaintAssistant::drawVisibleText: Boxed style not yet implemented!" << std::endl;
    }
}

double
PaintAssistant::scaleSize(double size)
{
    static double ratio = 0.0;
    if (ratio == 0.0) {
        double baseEm;
#ifdef Q_OS_MAC
        baseEm = 17.0;
#else
        baseEm = 15.0;
#endif
        double em = QFontMetrics(QFont()).height();
        ratio = em / baseEm;

        SVDEBUG << "PaintAssistant::scaleSize: ratio is " << ratio
                << " (em = " << em << ")" << endl;

        if (ratio < 1.0) {
            SVDEBUG << "PaintAssistant::scaleSize: rounding ratio up to 1.0"
                    << endl;
            ratio = 1.0;
        }
    }

    return size * ratio;
}

double
PaintAssistant::scalePenWidth(double width)
{
    if (width <= 0) {
        // zero-width pen, produce a scaled one-pixel pen
        width = 1;
    }

    return scaleSize(width);
}

QPen
PaintAssistant::scalePen(QPen pen)
{
    return QPen(pen.color(), scalePenWidth(pen.width()));
}