/////////////////////////////////////////////////////////////////////////////

// Name: scrollsynchronizer.cpp

// Purpose: Synchronize scrolling of MD editor with MD viewer

// Author: Jan Buchholz

// Created: 2025-11-20

/////////////////////////////////////////////////////////////////////////////

#include "scrollsynchronizer.h"

#include <QScrollBar>

ScrollSynchronizer::ScrollSynchronizer(QTextEdit* editor, QTextBrowser* browser, QSplitter* parentSplitter)

: QObject(parentSplitter), m_editor(editor), m_viewer(browser), m_splitter(parentSplitter), m_syncing(false) {

connect(m_editor->verticalScrollBar(), &QScrollBar::valueChanged,

this, &ScrollSynchronizer::sync);

}

void ScrollSynchronizer::setEnabled(bool enabled) {

m_enabled = enabled;

}

void ScrollSynchronizer::sync() {

if (m_syncing || !m_enabled) return;

m_syncing = true;

QScrollBar* sourceBar = m_editor->verticalScrollBar();

QScrollBar* targetBar = m_viewer->verticalScrollBar();

int sourceRange = sourceBar->maximum() - sourceBar->minimum();

int targetRange = targetBar->maximum() - targetBar->minimum();

if (sourceRange > 0 && targetRange > 0) {

double ratio = double(sourceBar->value() - sourceBar->minimum()) / sourceRange;

int newValue = targetBar->minimum() + ratio * targetRange;

if (std::abs(targetBar->value() - newValue) > 1) targetBar->setValue(newValue);

}

m_syncing = false;

}