view base/TextAbbrev.cpp @ 335:02d2ad95ea52 spectrogram-cache-rejig

* Get storage advice for each cache in an FFT data server.  Allows us to be
  more confident about the actual memory situation and cut over from memory
  to disc part way through an FFT calculation if necessary.  StorageAdviser
  is now a bit too optimistic though (it's too keen to allocate large numbers
  of small blocks in memory).

/* -*- 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 "TextAbbrev.h"

#include <QFontMetrics>
#include <QApplication>

#include <iostream>

QString
TextAbbrev::getDefaultEllipsis()
{
    return "...";
}

int
TextAbbrev::getFuzzLength(QString ellipsis)
{
    int len = ellipsis.length();
    if (len < 3) return len + 3;
    else if (len > 5) return len + 5;
    else return len * 2;
}

int
TextAbbrev::getFuzzWidth(const QFontMetrics &metrics, QString ellipsis)
{
    int width = metrics.width(ellipsis);
    return width * 2;
}

QString
TextAbbrev::abbreviateTo(QString text, int characters, Policy policy,
                         QString ellipsis)
{
    switch (policy) {

    case ElideEnd:
    case ElideEndAndCommonPrefixes:
        text = text.left(characters) + ellipsis;
        break;
        
    case ElideStart:
        text = ellipsis + text.right(characters);
        break;

    case ElideMiddle:
        if (characters > 2) {
            text = text.left(characters/2 + 1) + ellipsis
                + text.right(characters - (characters/2 + 1));
        } else {
            text = text.left(characters) + ellipsis;
        }
        break;
    }

    return text;
}

QString
TextAbbrev::abbreviate(QString text, int maxLength, Policy policy, bool fuzzy,
                       QString ellipsis)
{
    if (ellipsis == "") ellipsis = getDefaultEllipsis();
    int fl = (fuzzy ? getFuzzLength(ellipsis) : 0);
    if (maxLength <= ellipsis.length()) maxLength = ellipsis.length() + 1;
    if (text.length() <= maxLength + fl) return text;

    int truncated = maxLength - ellipsis.length();
    return abbreviateTo(text, truncated, policy, ellipsis);
}

QString
TextAbbrev::abbreviate(QString text,
                       const QFontMetrics &metrics, int &maxWidth,
                       Policy policy, QString ellipsis)
{
    if (ellipsis == "") ellipsis = getDefaultEllipsis();

    int tw = metrics.width(text);

    if (tw <= maxWidth) {
        maxWidth = tw;
        return text;
    }

    int truncated = text.length();
    QString original = text;

    while (tw > maxWidth && truncated > 1) {

        truncated--;

        if (truncated > ellipsis.length()) {
            text = abbreviateTo(original, truncated, policy, ellipsis);
        } else {
            break;
        }

        tw = metrics.width(text);
    }

    maxWidth = tw;
    return text;
}

QStringList
TextAbbrev::abbreviate(const QStringList &texts, int maxLength,
                       Policy policy, bool fuzzy, QString ellipsis)
{
    if (policy == ElideEndAndCommonPrefixes &&
        texts.size() > 1) {

        if (ellipsis == "") ellipsis = getDefaultEllipsis();
        int fl = (fuzzy ? getFuzzLength(ellipsis) : 0);
        if (maxLength <= ellipsis.length()) maxLength = ellipsis.length() + 1;

        int maxOrigLength = 0;
        for (int i = 0; i < texts.size(); ++i) {
            int len = texts[i].length();
            if (len > maxOrigLength) maxOrigLength = len;
        }
        if (maxOrigLength <= maxLength + fl) return texts;

        return abbreviate(elidePrefixes
                          (texts, maxOrigLength - maxLength, ellipsis),
                          maxLength, ElideEnd, fuzzy, ellipsis);
    }

    QStringList results;
    for (int i = 0; i < texts.size(); ++i) {
        results.push_back
            (abbreviate(texts[i], maxLength, policy, fuzzy, ellipsis));
    }
    return results;
}

QStringList
TextAbbrev::abbreviate(const QStringList &texts, const QFontMetrics &metrics,
                       int &maxWidth, Policy policy, QString ellipsis)
{
    if (policy == ElideEndAndCommonPrefixes &&
        texts.size() > 1) {

        if (ellipsis == "") ellipsis = getDefaultEllipsis();

        int maxOrigWidth = 0;
        for (int i = 0; i < texts.size(); ++i) {
            int w = metrics.width(texts[i]);
            if (w > maxOrigWidth) maxOrigWidth = w;
        }

        return abbreviate(elidePrefixes(texts, metrics,
                                        maxOrigWidth - maxWidth, ellipsis),
                          metrics, maxWidth, ElideEnd, ellipsis);
    }

    QStringList results;
    int maxAbbrWidth = 0;
    for (int i = 0; i < texts.size(); ++i) {
        int width = maxWidth;
        QString abbr = abbreviate(texts[i], metrics, width, policy, ellipsis);
        if (width > maxAbbrWidth) maxAbbrWidth = width;
        results.push_back(abbr);
    }
    maxWidth = maxAbbrWidth;
    return results;
}

QStringList
TextAbbrev::elidePrefixes(const QStringList &texts,
                          int targetReduction,
                          QString ellipsis)
{
    if (texts.empty()) return texts;
    int plen = getPrefixLength(texts);
    int fl = getFuzzLength(ellipsis);
    if (plen < fl) return texts;

    QString prefix = texts[0].left(plen);
    int truncated = plen;
    if (plen >= targetReduction + fl) {
        truncated = plen - targetReduction;
    } else {
        truncated = fl;
    }
    prefix = abbreviate(prefix, truncated, ElideEnd, false, ellipsis);

    QStringList results;
    for (int i = 0; i < texts.size(); ++i) {
        results.push_back
            (prefix + texts[i].right(texts[i].length() - plen));
    }
    return results;
}

QStringList
TextAbbrev::elidePrefixes(const QStringList &texts,
                          const QFontMetrics &metrics,
                          int targetWidthReduction,
                          QString ellipsis)
{
    if (texts.empty()) return texts;
    int plen = getPrefixLength(texts);
    int fl = getFuzzLength(ellipsis);
    if (plen < fl) return texts;

    QString prefix = texts[0].left(plen);
    int pwid = metrics.width(prefix);
    int twid = pwid - targetWidthReduction;
    if (twid < metrics.width(ellipsis) * 2) twid = metrics.width(ellipsis) * 2;
    prefix = abbreviate(prefix, metrics, twid, ElideEnd, ellipsis);

    QStringList results;
    for (int i = 0; i < texts.size(); ++i) {
        results.push_back
            (prefix + texts[i].right(texts[i].length() - plen));
    }
    return results;
}

static bool
havePrefix(QString prefix, const QStringList &texts)
{
    for (int i = 1; i < texts.size(); ++i) {
        if (!texts[i].startsWith(prefix)) return false;
    }
    return true;
}

int
TextAbbrev::getPrefixLength(const QStringList &texts)
{
    QString reference = texts[0];

    if (reference == "" || havePrefix(reference, texts)) {
        return reference.length();
    }

    int candidate = reference.length();
    QString splitChars(";:,./#-!()$_+=[]{}\\");

    while (--candidate > 1) {
        if (splitChars.contains(reference[candidate])) {
            if (havePrefix(reference.left(candidate), texts)) {
                break;
            }
        }
    }

//    std::cerr << "TextAbbrev::getPrefixLength: prefix length is " << candidate << std::endl;
//    for (int i = 0; i < texts.size(); ++i) {
//        std::cerr << texts[i].left(candidate).toStdString() << "|" << texts[i].right(texts[i].length() - candidate).toStdString() << std::endl;
//    }

    return candidate;
}