seer/src/SeerPlainTextEdit.cpp

// SPDX-FileCopyrightText: 2021 Ernie Pasveer <epasveer@att.net>
//
// SPDX-License-Identifier: GPL-3.0-or-later

#include <QtWidgets/QApplication>
#include "SeerPlainTextEdit.h"
#include <QtGui/QPainter>
#include <QtGui/QTextCursor>
#include <QtGui/QPaintEvent>
#include <QTextBlock>
#include <QColor>

SeerPlainTextEdit::SeerPlainTextEdit(const QString& text, QWidget* parent) : QPlainTextEdit(text, parent) {

    // Turn off the widget's cursor. We'll do our own in the paintEvent.
    setCursorWidth(0);

    _cursorVisible = true;
    _cursorTimer   = new QTimer(this);

    QObject::connect(_cursorTimer, &QTimer::timeout, this, &SeerPlainTextEdit::blinkCursor);
    QObject::connect(this, &QPlainTextEdit::cursorPositionChanged, this, &SeerPlainTextEdit::handleCursorPositionChanged);

    _cursorTimer->start(500);
}

SeerPlainTextEdit::SeerPlainTextEdit(QWidget* parent) : QPlainTextEdit(parent) {

    // Turn off the widget's cursor. We'll do our own in the paintEvent.
    setCursorWidth(0);

    _cursorVisible = true;
    _cursorTimer   = new QTimer(this);

    QObject::connect(_cursorTimer, &QTimer::timeout, this, &SeerPlainTextEdit::blinkCursor);
    QObject::connect(this, &QPlainTextEdit::cursorPositionChanged, this, &SeerPlainTextEdit::handleCursorPositionChanged);

    _cursorTimer->start(500);
}

SeerPlainTextEdit::~SeerPlainTextEdit () {
}

void SeerPlainTextEdit::forwardViewportEvent(QEvent* event) {

    viewportEvent(event);
}

void SeerPlainTextEdit::blinkCursor() {

    _cursorVisible = !_cursorVisible;

    viewport()->update(); // Trigger a repaint of the viewport
}

void SeerPlainTextEdit::paintEvent(QPaintEvent* event) {

    // First, let the standard QPlainTextEdit handle its painting.
    QPlainTextEdit::paintEvent(event);

    // Get our painter.
    QPainter painter(viewport());

    // Draw the cursor manually.
    if (_cursorVisible) {
        QRect r = cursorRect();
        r.setWidth(CURSOR_WIDTH);
        painter.fillRect(r, palette().text().color());
    }

    // Add margin highlight for current line
    QTextCursor cursor = textCursor();
    QTextBlock  block  = cursor.block();

    // Get the rectangle of the current line (block)
    QRectF rect = blockBoundingGeometry(block).translated(contentOffset());

    // Optional: add a few pixels margin around the block
    rect.adjust(-2, 0, 2, 0);

    // Draw a visible border
    QPen pen(QColor(200, 200, 200), 0.5);
    painter.setPen(pen);
    painter.drawRect(rect);
}

// Add margin highlight for current line
void SeerPlainTextEdit::handleCursorPositionChanged() {
    viewport()->update();
}

//
//
//

SeerPlainTextWheelEventForwarder::SeerPlainTextWheelEventForwarder (SeerPlainTextEdit* target ) : QObject(), _target(target) {
}

SeerPlainTextWheelEventForwarder::~SeerPlainTextWheelEventForwarder() {
    _target = NULL;
}

bool SeerPlainTextWheelEventForwarder::eventFilter (QObject* obj, QEvent* event) {

    Q_UNUSED(obj);

    if (_target == 0) {
        return false;
    }

    if (event->type() == QEvent::Wheel) {
        _target->forwardViewportEvent(event);
    }

    // do not filter the event
    return false;
}