ScreenWindow.cpp

/*
    SPDX-FileCopyrightText: 2007 Robert Knight <robertknight@gmail.com>
 
    SPDX-License-Identifier: GPL-2.0-or-later
 
    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, write to the Free Software
    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
    02110-1301  USA.
*/
 
// Own
#include "ScreenWindow.h"
 
// Qt
#include <QtDebug>
 
// Konsole
#include "Screen.h"
 
using namespace Konsole;
 
ScreenWindow::ScreenWindow(QObject *parent)
    : QObject(parent)
    , _screen(nullptr)
    , _windowBufferSize(0)
    , _bufferNeedsUpdate(true)
    , _windowLines(1)
    , _currentLine(0)
    , _trackOutput(true)
    , _scrollCount(0)
{
}
ScreenWindow::~ScreenWindow() = default;
 
void ScreenWindow::setScreen(Screen *screen)
{
    Q_ASSERT(screen);
 
    _screen = screen;
}
 
Screen *ScreenWindow::screen() const
{
    return _screen;
}
 
std::span<Character> ScreenWindow::getImage()
{
    // reallocate internal buffer if the window size has changed
    int size = windowLines() * windowColumns();
    if (_windowBuffer.empty() || _windowBufferSize != size) {
        _windowBufferSize = size;
        _windowBuffer = std::vector<Character>(size);
        _bufferNeedsUpdate = true;
    }
 
    if (!_bufferNeedsUpdate)
        return _windowBuffer;
 
    _screen->getImage(_windowBuffer, size, currentLine(), endWindowLine());
 
    // this window may look beyond the end of the screen, in which
    // case there will be an unused area which needs to be filled
    // with blank characters
    fillUnusedArea();
 
    _bufferNeedsUpdate = false;
    return _windowBuffer;
}
 
void ScreenWindow::fillUnusedArea()
{
    int screenEndLine = _screen->getHistLines() + _screen->getLines() - 1;
    int windowEndLine = currentLine() + windowLines() - 1;
 
    int unusedLines = windowEndLine - screenEndLine;
 
    // stop when unusedLines is negative; there is an issue w/ charsToFill
    //  being greater than an int can hold
    if (unusedLines <= 0) {
        return;
    }
 
    int charsToFill = unusedLines * windowColumns();
 
    Screen::fillWithDefaultChar(std::span(_windowBuffer).subspan(_windowBufferSize - charsToFill), charsToFill);
}
 
// return the index of the line at the end of this window, or if this window
// goes beyond the end of the screen, the index of the line at the end
// of the screen.
//
// when passing a line number to a Screen method, the line number should
// never be more than endWindowLine()
//
int ScreenWindow::endWindowLine() const
{
    return qMin(currentLine() + windowLines() - 1, lineCount() - 1);
}
QVector<LineProperty> ScreenWindow::getLineProperties()
{
    QVector<LineProperty> result = _screen->getLineProperties(currentLine(), endWindowLine());
 
    if (result.size() != windowLines())
        result.resize(windowLines());
 
    return result;
}
 
QString ScreenWindow::selectedText(bool preserveLineBreaks) const
{
    return _screen->selectedText(preserveLineBreaks);
}
 
void ScreenWindow::getSelectionStart(int &column, int &line)
{
    _screen->getSelectionStart(column, line);
    line -= currentLine();
}
void ScreenWindow::getSelectionEnd(int &column, int &line)
{
    _screen->getSelectionEnd(column, line);
    line -= currentLine();
}
void ScreenWindow::setSelectionStart(int column, int line, bool columnMode)
{
    _screen->setSelectionStart(column, qMin(line + currentLine(), endWindowLine()), columnMode);
 
    _bufferNeedsUpdate = true;
    Q_EMIT selectionChanged();
}
 
void ScreenWindow::setSelectionEnd(int column, int line)
{
    _screen->setSelectionEnd(column, qMin(line + currentLine(), endWindowLine()));
 
    _bufferNeedsUpdate = true;
    Q_EMIT selectionChanged();
}
 
bool ScreenWindow::isSelected(int column, int line)
{
    return _screen->isSelected(column, qMin(line + currentLine(), endWindowLine()));
}
 
void ScreenWindow::clearSelection()
{
    _screen->clearSelection();
 
    Q_EMIT selectionChanged();
}
 
void ScreenWindow::setWindowLines(int lines)
{
    Q_ASSERT(lines > 0);
    _windowLines = lines;
}
int ScreenWindow::windowLines() const
{
    return _windowLines;
}
 
int ScreenWindow::windowColumns() const
{
    return _screen->getColumns();
}
 
int ScreenWindow::lineCount() const
{
    return _screen->getHistLines() + _screen->getLines();
}
 
int ScreenWindow::columnCount() const
{
    return _screen->getColumns();
}
 
QPoint ScreenWindow::cursorPosition() const
{
    QPoint position;
 
    position.setX(_screen->getCursorX());
    position.setY(_screen->getCursorY());
 
    return position;
}
 
int ScreenWindow::currentLine() const
{
    return qBound(0, _currentLine, lineCount() - windowLines());
}
 
void ScreenWindow::scrollBy(RelativeScrollMode mode, int amount)
{
    if (mode == ScrollLines) {
        scrollTo(currentLine() + amount);
    } else if (mode == ScrollPages) {
        scrollTo(currentLine() + amount * (windowLines() / 2));
    }
}
 
bool ScreenWindow::atEndOfOutput() const
{
    return currentLine() == (lineCount() - windowLines());
}
 
void ScreenWindow::scrollTo(int line)
{
    int maxCurrentLineNumber = lineCount() - windowLines();
    line = qBound(0, line, maxCurrentLineNumber);
 
    const int delta = line - _currentLine;
    _currentLine = line;
 
    // keep track of number of lines scrolled by,
    // this can be reset by calling resetScrollCount()
    _scrollCount += delta;
 
    _bufferNeedsUpdate = true;
 
    Q_EMIT scrolled(_currentLine);
}
 
void ScreenWindow::setTrackOutput(bool trackOutput)
{
    _trackOutput = trackOutput;
}
 
bool ScreenWindow::trackOutput() const
{
    return _trackOutput;
}
 
int ScreenWindow::scrollCount() const
{
    return _scrollCount;
}
 
void ScreenWindow::resetScrollCount()
{
    _scrollCount = 0;
}
 
QRect ScreenWindow::scrollRegion() const
{
    bool equalToScreenSize = windowLines() == _screen->getLines();
 
    if (atEndOfOutput() && equalToScreenSize)
        return _screen->lastScrolledRegion();
    else
        return {0, 0, windowColumns(), windowLines()};
}
 
void ScreenWindow::notifyOutputChanged()
{
    // move window to the bottom of the screen and update scroll count
    // if this window is currently tracking the bottom of the screen
    if (_trackOutput) {
        _scrollCount -= _screen->scrolledLines();
        _currentLine = qMax(0, _screen->getHistLines() - (windowLines() - _screen->getLines()));
    } else {
        // if the history is not unlimited then it may
        // have run out of space and dropped the oldest
        // lines of output - in this case the screen
        // window's current line number will need to
        // be adjusted - otherwise the output will scroll
        _currentLine = qMax(0, _currentLine - _screen->droppedLines());
 
        // ensure that the screen window's current position does
        // not go beyond the bottom of the screen
        _currentLine = qMin(_currentLine, _screen->getHistLines());
    }
 
    _bufferNeedsUpdate = true;
 
    Q_EMIT outputChanged();
}
 
void ScreenWindow::handleCommandFromKeyboard(KeyboardTranslator::Command command)
{
    // Keyboard-based navigation
    bool update = false;
 
    // EraseCommand is handled in Vt102Emulation
    if (command & KeyboardTranslator::ScrollPageUpCommand) {
        scrollBy(ScreenWindow::ScrollPages, -1);
        update = true;
    }
    if (command & KeyboardTranslator::ScrollPageDownCommand) {
        scrollBy(ScreenWindow::ScrollPages, 1);
        update = true;
    }
    if (command & KeyboardTranslator::ScrollLineUpCommand) {
        scrollBy(ScreenWindow::ScrollLines, -1);
        update = true;
    }
    if (command & KeyboardTranslator::ScrollLineDownCommand) {
        scrollBy(ScreenWindow::ScrollLines, 1);
        update = true;
    }
    if (command & KeyboardTranslator::ScrollDownToBottomCommand) {
        Q_EMIT scrollToEnd();
        update = true;
    }
    if (command & KeyboardTranslator::ScrollUpToTopCommand) {
        scrollTo(0);
        update = true;
    }
    // TODO: KeyboardTranslator::ScrollLockCommand
    // TODO: KeyboardTranslator::SendCommand
 
    if (update) {
        setTrackOutput(atEndOfOutput());
 
        Q_EMIT outputChanged();
    }
}
 
// #include "ScreenWindow.moc"