Qt: Using lightweight dataViewer.

Author: 7134956

qt/buffer_table_model.cpp

@@ -0,0 +1,210 @@
+#include "dataviewer.h"
+
+#include <QPainter>
+#include <QScrollBar>
+
+DataViewer::DataViewer(QWidget *parent):
+    QAbstractScrollArea(parent)
+{
+    ioDevice = new QBuffer(this);
+    size = 0;
+    init();
+    connect(verticalScrollBar(), &QScrollBar::valueChanged, this,
+          &DataViewer::adjustContent);
+    connect(horizontalScrollBar(), &QScrollBar::valueChanged, this,
+          &DataViewer::adjustContent);
+}
+
+DataViewer::~DataViewer()
+{
+}
+
+void DataViewer::init()
+{
+    nCharAddress = 8;
+    qint64 x = size >> (nCharAddress * 4);
+    while(x)
+    {
+        nCharAddress++;
+        x /= 16;
+    }
+    mBytesPerLine = 16;
+
+    pxWidth = fontMetrics().horizontalAdvance(QChar('0'));
+    pxHeight = fontMetrics().height() * 1.25;
+}
+
+int DataViewer::addressWidth()
+{
+    return (nCharAddress + 1) * pxWidth;
+}
+
+int DataViewer::hexWidth()
+{
+    return (mBytesPerLine * 3) * pxWidth;
+}
+
+int DataViewer::asciiWidth()
+{
+    return (mBytesPerLine + 1) * pxWidth;
+}
+
+QByteArray DataViewer::data(qint64 pos, qint64 count)
+{
+    QByteArray buffer;
+
+    if (pos >= size)
+        return buffer;
+
+    if (count < 0)
+        count = size;
+    else if ((pos + count) > size)
+        count = size - pos;
+
+    if (ioDevice->open(QIODevice::ReadOnly))
+    {
+        ioDevice->seek(pos);
+        buffer = ioDevice->read(count);
+        ioDevice->close();
+    }
+    return buffer;
+}
+
+void DataViewer::setFile(QString filePath)
+{
+    file.setFileName(filePath);
+    if (file.open(QIODevice::ReadOnly))
+    {
+        size = file.size();
+        ioDevice = &file;
+        ioDevice->close();
+    }
+    else
+    {
+        size = 0;
+    }
+    init();
+    adjustContent();
+}
+
+void DataViewer::resizeEvent(QResizeEvent *)
+{
+    adjustContent();
+}
+
+void DataViewer::paintEvent(QPaintEvent *)
+{
+    QPainter painter(viewport());
+
+    int offsetX = horizontalScrollBar()->value();
+
+    //Draw grid
+    int lx = addressWidth();
+
+    int x = lx - offsetX + 3 * pxWidth;
+    int y = pxHeight + pxHeight / 4;
+    int w = 3 * pxWidth;
+    for (int col = 0; col < mBytesPerLine / 2; col++)
+    {
+        painter.fillRect(x, y, w, height(),
+                       viewport()->palette().color(QPalette::AlternateBase));
+        x += 6 * pxWidth;
+    }
+
+    painter.setPen(viewport()->palette().color(QPalette::Mid));
+    painter.drawLine(lx - offsetX, 0, lx - offsetX, height());
+    lx = addressWidth() + hexWidth();
+    painter.drawLine(lx - offsetX, 0, lx - offsetX, height());
+
+    for (int row = 1; row < nRowsVisible; row++)
+    {
+        painter.drawLine(0, y, width(), y);
+        y += pxHeight;
+    }
+
+    //Draw column ADDRESS
+    y = pxHeight;
+    painter.setPen(viewport()->palette().color(QPalette::WindowText));
+    painter.drawText(pxWidth / 2 + (pxWidth * nCharAddress - pxWidth * 7)
+                     / 2 - offsetX,  y - pxHeight * 0.2, "ADDRESS");
+    y += pxHeight;
+    for (int row = 1; row < nRowsVisible; row++)
+    {
+        QString address = QString("%1")
+                .arg(startPos + mBytesPerLine * (row - 1),
+                nCharAddress, 16, QChar('0')).toUpper();
+        painter.drawText(pxWidth / 2 - offsetX, y, address);
+        y += pxHeight;
+    }
+
+    //Draw column HEX
+    lx = addressWidth();
+    lx += pxWidth / 2;
+    y = pxHeight;
+    painter.drawText(lx + pxWidth / 2 + (pxWidth * 3 * 16 - pxWidth * 3)
+                   / 2 - offsetX, y - pxHeight * 0.2, "HEX");
+    y += pxHeight;
+    int bPos = 0;
+    for (int row = 1; row < nRowsVisible; row++)
+    {
+        x = lx - offsetX;
+        for (int col = 0; (col < mBytesPerLine) && (bPos < dataHex.size());
+             col++)
+        {
+            QString str = dataHex.mid(bPos * 2, 2).toUpper();
+            painter.drawText(x, y, str);
+            x += 3 * pxWidth;
+            bPos += 1;
+        }
+        y += pxHeight;
+    }
+
+  //Draw column ASCII
+    lx += hexWidth();
+    bPos = 0;
+    y = pxHeight;
+
+    painter.drawText(lx + pxWidth / 2 + (pxWidth * mBytesPerLine - pxWidth * 5)
+                   / 2 - offsetX, y - pxHeight * 0.2, "ASCII");
+    y += pxHeight;
+    QChar ch;
+    for (int row = 1; row < nRowsVisible; row++)
+    {
+        x = lx - offsetX;
+        for (int col = 0; (col < mBytesPerLine) && (bPos < dataVisible.size());
+                 col++)
+        {
+            ch = QChar(dataVisible.at(bPos));
+            if (!ch.isPrint())
+              ch = QChar('.');
+            painter.drawText(x, y, ch);
+            x += pxWidth;
+            bPos += 1;
+        }
+        y += pxHeight;
+    }
+}
+
+void DataViewer::adjustContent()
+{
+    int w = addressWidth() + hexWidth() + asciiWidth();
+    horizontalScrollBar()->setRange(0, w - viewport()->width());
+    horizontalScrollBar()->setPageStep(viewport()->width());
+
+    nRowsVisible = viewport()->height() / pxHeight;
+    int val = verticalScrollBar()->value();
+    startPos = (qint64)val * mBytesPerLine;
+    endPos = startPos + nRowsVisible * mBytesPerLine - 1;
+
+    int lineCount = (size + mBytesPerLine - 1) / mBytesPerLine;
+    verticalScrollBar()->setRange(0, lineCount - nRowsVisible + 1);
+    verticalScrollBar()->setPageStep(nRowsVisible);
+
+    if (endPos >= size)
+    {
+        endPos = size - 1;
+    }
+    dataVisible = data(startPos, endPos - startPos + mBytesPerLine + 1);
+    dataHex = dataVisible.toHex();
+    viewport()->update();
+}