Debugger: Use primitive internal widget instead of matplotview

This practically removes any functionality beyond plain plot display,
but does that at least reliably, cross-platform, without dependency
on 3rd party python packages.

Change-Id: Iaff2f78595394522f32264c642df20dd48b83f8b
Reviewed-by: Christian Stenger <christian.stenger@theqtcompany.com>

src/plugins/debugger/imageviewer.cpp

@@ -114,11 +114,15 @@ ImageViewer::ImageViewer(QWidget *parent)
     connect(m_imageWidget, &ImageWidget::clicked, this, &ImageViewer::clicked);
 }
 
-void ImageViewer::setImage(const QImage &i)
+void ImageViewer::setImage(const QImage &image)
 {
-    m_imageWidget->setImage(i);
-    m_info = tr("Size: %1x%2, %3 byte, format: %4, depth: %5")
-            .arg(i.width()).arg(i.height()).arg(i.byteCount()).arg(i.format()).arg(i.depth());
+    m_imageWidget->setImage(image);
+    clicked(QString());
+}
+
+void ImageViewer::setInfo(const QString &info)
+{
+    m_info = info;
     clicked(QString());
 }
 
@@ -165,4 +169,77 @@ void ImageViewer::contextMenuEvent(QContextMenuEvent *ev)
         openImageViewer(image);
 }
 
+
+//
+//
+//
+
+PlotViewer::PlotViewer(QWidget *parent)
+    : QWidget(parent)
+{
+}
+
+void PlotViewer::setData(const PlotViewer::Data &data)
+{
+    m_data = data;
+    update();
+}
+
+void PlotViewer::setInfo(const QString &description)
+{
+    m_info = description;
+    update();
+}
+
+void PlotViewer::paintEvent(QPaintEvent *)
+{
+    QPainter pain(this);
+
+    const int n = int(m_data.size());
+    const int w = width();
+    const int h = height();
+    const int b = 10; // Border width.
+
+    pain.fillRect(rect(), Qt::white);
+
+    double ymin = 0;
+    double ymax = 0;
+    for (int i = 0; i < n; ++i) {
+        const double v = m_data.at(i);
+        if (v < ymin)
+            ymin = v;
+        else if (v > ymax)
+            ymax = v;
+    }
+
+    const double d = ymin == ymax ? (h / 2 - b) : (ymax - ymin);
+    const int k = 1; // Length of cross marker arms.
+
+    for (int i = 0; i + 1 < n; ++i) {
+        // Lines between points.
+        const int x1 = b + i * (w - 2 * b) / (n - 1);
+        const int x2 = b + (i + 1) * (w - 2 * b) / (n - 1);
+        const int y1 = h - (b + int((m_data[i] - ymin) * (h - 2 * b) / d));
+        const int y2 = h - (b + int((m_data[i + 1] - ymin) * (h - 2 * b) / d));
+        pain.drawLine(x1, y1, x2, y2);
+
+        if (i == 0) {
+            // Little cross marker on first point
+            pain.drawLine(x1 - k, y1 - k, x1 + k, y1 + k);
+            pain.drawLine(x1 + k, y1 - k, x1 - k, y1 + k);
+        }
+        // ... and all subsequent points.
+        pain.drawLine(x2 - k, y2 - k, x2 + k, y2 + k);
+        pain.drawLine(x2 + k, y2 - k, x2 - k, y2 + k);
+    }
+
+    if (n) {
+        pain.drawText(10, 10,
+        QString::fromLatin1("%5 items. X: %1..%2, Y: %3...%4").arg(0).arg(n).arg(ymin).arg(ymax).arg(n));
+    } else {
+        pain.drawText(10, 10,
+        QString::fromLatin1("Container is empty"));
+    }
+}
+
 #include "imageviewer.moc"