lcd-image-converter/classes/parser/convert/fonthelper.cpp

/*
 * LCD Image Converter. Converts images and fonts for embedded applications.
 * Copyright (C) 2012 riuson
 * mailto: riuson@gmail.com
 *
 * 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 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/
 */

#include "fonthelper.h"

#include <QPixmap>
#include <QPainter>
#include <QRegExp>
#include "datacontainer.h"

FontHelper::FontHelper(QObject *parent) :
  QObject(parent)
{
}

QImage FontHelper::drawString(const DataContainer *data, const QString &value)
{
  int width = 0, height = 0;
  QImage::Format format = QImage::Format_ARGB32;

  // find summary preview image size
  for (int i = 0; i < value.length(); i++) {
    QChar ch = value.at(i);

    if (data->keys().contains(ch)) {
      const QImage *image = data->image(ch);

      format = image->format();
      width += image->width();
      height = qMax(height, image->height());
    }
  }

  // create preview image
  QImage preview = QImage(width, height, format);
  QPixmap previewPixmap = QPixmap::fromImage(preview);
  QPainter painter(&previewPixmap);

  // place characters on image
  int x = 0;

  for (int i = 0; i < value.length(); i++) {
    QChar ch = value.at(i);

    if (data->keys().contains(ch)) {
      const QImage *image = data->image(ch);
      painter.drawImage(x, 0, *image);

      x += image->width();
    }
  }

  return previewPixmap.toImage();
}

QString FontHelper::escapeControlChars(const QString &value)
{
  QString result;

  for (int i = 0; i < value.length(); i++) {
    QChar c = value.at(i);

    if (c.isNull() || !c.isPrint()) {
      quint16 code = c.unicode();
      result.append(QString("\\x%1").arg(code, 4, 16, QChar('0')));
    } else if (c == QChar('@')) {
      result.append(QString("\\x0040"));
    } else if (c == QChar(QChar::Nbsp)) {
      result.append(QString("\\x00a0"));
    } else {
      result.append(c);
    }
  }

  return result;
}

QString FontHelper::unescapeControlChars(const QString &value)
{
  QRegExp reg("\\\\x([abcdef\\d]{4})", Qt::CaseInsensitive);
  QString result = value;
  int index = -1;

  do {
    if ((index = result.indexOf(reg)) >= 0) {
      QString cap0 = reg.cap(0);
      QString cap1 = reg.cap(1);
      bool ok;
      int code = cap1.toInt(&ok, 16);

      if (ok) {
        result = result.replace(cap0, QString(QChar(code)));
      }
    }

  } while (index >= 0);

  return result;
}

QSize FontHelper::getCharacterSize(const QFontMetrics &metrics, QChar value)
{
  int charWidth = metrics.width(value);
  int charHeight = metrics.height();

  // fix width of italic style
  QRect r = metrics.boundingRect(QString(value));
  charWidth = qMax(qMax(r.left(), r.right()) + 1, charWidth);

  // check for abnormal size
  if ((charWidth > charHeight * 100) || (charWidth == 0)) {
    if (value.isNull() || !value.isPrint()) {
      charWidth = 1;
    }
  }

  return QSize(charWidth, charHeight);
}

QImage FontHelper::drawCharacter(
  const QChar value,
  const QFont &font,
  const QColor &foreground,
  const QColor &background,
  const int width,
  const int height,
  const bool antialiasing)
{
  QFontMetrics fontMetrics(font);

  QSize characterSize = FontHelper::getCharacterSize(fontMetrics, value);

  int imageWidth = width;
  int imageHeight = height;

  if (width == 0 || height == 0) {
    imageWidth = characterSize.width();
    imageHeight = characterSize.height();
  }

  QImage result;

  {
    // make image with transparent background
    QPixmap transparentPixmap(imageWidth, imageHeight);
    transparentPixmap.fill(Qt::transparent);
    result = transparentPixmap.toImage().convertToFormat(QImage::Format_ARGB32);
  }

  QPainter painter(&result);
  painter.setFont(font);

  painter.setRenderHint(QPainter::Antialiasing, antialiasing);
  painter.setRenderHint(QPainter::TextAntialiasing, antialiasing);

  // fill image with specified background color
  painter.fillRect(result.rect(), background);

  painter.setPen(foreground);

  painter.drawText((imageWidth / 2) - (characterSize.width() / 2),
                   fontMetrics.ascent(),//+4
                   QString(value));

  return result;
}