Check if QPainters were initialised

Related: #745

src/scopes/abstractscopewidget.cpp

@@ -273,7 +273,15 @@ void AbstractScopeWidget::showEvent(QShowEvent *event)
 
 void AbstractScopeWidget::paintEvent(QPaintEvent *)
 {
-    QPainter davinci(this);
+    QPainter davinci;
+    bool ok = davinci.begin(this);
+    if (!ok) {
+        if (!m_scopeWarningPrinted) {
+            qDebug() << "Warning: Could not initialise painter for drawing scope.";
+            m_scopeWarningPrinted = true;
+        }
+        return;
+    }
     davinci.drawImage(m_scopeRect.topLeft(), m_imgBackground);
     davinci.drawImage(m_scopeRect.topLeft(), m_imgScope);
     davinci.drawImage(m_scopeRect.topLeft(), m_imgHUD);

src/scopes/abstractscopewidget.h

@@ -282,6 +282,8 @@ private:
     RescaleDirection m_rescaleDirection{North};
     QPoint m_rescaleStartPoint;
 
+    bool m_scopeWarningPrinted{false};
+
 protected slots:
     void slotContextMenuRequested(const QPoint &pos);
     /** To be called when a new frame has been received.

src/scopes/audioscopes/audiospectrum.cpp

@@ -252,7 +252,12 @@ QImage AudioSpectrum::renderAudioScope(uint, const audioShortVector &audioFrame,
 #endif
 
 #ifdef AUDIOSPEC_LINES
-        QPainter davinci(&spectrum);
+        QPainter davinci;
+        bool ok = davinci.begin(&spectrum);
+        if (!ok) {
+            qDebug() << "Could not initialise QPainter for Audio spectrum.";
+            return spectrum;
+        }
         davinci.setPen(QPen(QBrush(spectrumColor.rgba()), 1, Qt::SolidLine));
 #endif
 
@@ -337,7 +342,12 @@ QImage AudioSpectrum::renderHUD(uint)
         QImage hud(m_scopeRect.size(), QImage::Format_ARGB32);
         hud.fill(qRgba(0, 0, 0, 0));
 
-        QPainter davinci(&hud);
+        QPainter davinci;
+        bool ok = davinci.begin(&hud);
+        if (!ok) {
+            qDebug() << "Could not initialise QPainter for Audio spectrum HUD.";
+            return hud;
+        }
         davinci.setPen(AbstractScopeWidget::penLight);
 
         int y;

src/scopes/audioscopes/spectrogram.cpp

@@ -10,6 +10,7 @@
 
 #include "spectrogram.h"
 
+#include <QDebug>
 #include <QPainter>
 #include <QElapsedTimer>
 
@@ -182,7 +183,13 @@ QImage Spectrogram::renderHUD(uint)
         QImage hud(m_scopeRect.size(), QImage::Format_ARGB32);
         hud.fill(qRgba(0, 0, 0, 0));
 
-        QPainter davinci(&hud);
+        QPainter davinci;
+        bool ok = davinci.begin(&hud);
+        if (!ok) {
+            qDebug() << "Warning: Could not initialise QPainter for Spectrogram HUD.";
+            return hud;
+        }
+
         davinci.setPen(AbstractScopeWidget::penLight);
 
         // Frame display
@@ -292,6 +299,7 @@ QImage Spectrogram::renderHUD(uint)
     emit signalHUDRenderingFinished(0, 1);
     return QImage();
 }
+
 QImage Spectrogram::renderAudioScope(uint, const audioShortVector &audioFrame, const int freq, const int num_channels, const int num_samples, const int newData)
 {
     if (audioFrame.size() > 63 && m_innerScopeRect.width() > 0 && m_innerScopeRect.height() > 0) {
@@ -348,7 +356,14 @@ QImage Spectrogram::renderAudioScope(uint, const audioShortVector &audioFrame, c
         // Draw the spectrum
         QImage spectrum(m_scopeRect.size(), QImage::Format_ARGB32);
         spectrum.fill(qRgba(0, 0, 0, 0));
-        QPainter davinci(&spectrum);
+
+        QPainter davinci;
+        bool ok = davinci.begin(&spectrum);
+        if (!ok) {
+            qDebug() << "Warning: Could not initialise QPainter for rendering spectrogram.";
+            return spectrum;
+        }
+
         const int h = m_innerScopeRect.height();
         const int leftDist = m_innerScopeRect.left() - m_scopeRect.left();
         const int topDist = m_innerScopeRect.top() - m_scopeRect.top();

src/scopes/colorscopes/histogramgenerator.cpp

@@ -14,6 +14,7 @@
 #include "klocalizedstring.h"
 #include <QImage>
 #include <QPainter>
+#include <QDebug>
 #include <algorithm>
 #include <cmath>
 
@@ -100,7 +101,12 @@ QImage HistogramGenerator::calculateHistogram(const QSize &paradeSize, const QIm
     const int dist = 40;
 
     QImage histogram(paradeSize, QImage::Format_ARGB32);
-    QPainter davinci(&histogram);
+    QPainter davinci;
+    bool ok = davinci.begin(&histogram);
+    if (!ok) {
+        qDebug() << "Could not initialise QPainter for Histogram.";
+        return histogram;
+    }
     davinci.setPen(QColor(220, 220, 220, 255));
     histogram.fill(qRgba(0, 0, 0, 0));
 

src/scopes/colorscopes/rgbparade.cpp

@@ -10,6 +10,7 @@
 
 #include "rgbparade.h"
 #include "rgbparadegenerator.h"
+#include <QDebug>
 #include <QPainter>
 #include <QRect>
 #include <QElapsedTimer>
@@ -92,7 +93,12 @@ QImage RGBParade::renderHUD(uint)
     QImage hud(m_scopeRect.size(), QImage::Format_ARGB32);
     hud.fill(qRgba(0, 0, 0, 0));
 
-    QPainter davinci(&hud);
+    QPainter davinci;
+    bool ok = davinci.begin(&hud);
+    if (!ok) {
+        qDebug() << "Could not initialise QPainter for RGB Parade HUD.";
+        return hud;
+    }
     davinci.setPen(penLight);
 
     int x = scopeRect().width() - 30;

src/scopes/colorscopes/rgbparadegenerator.cpp

@@ -12,6 +12,7 @@
 #include "klocalizedstring.h"
 #include <QColor>
 #include <QPainter>
+#include <QDebug>
 
 #define CHOP255(a) ((255) < (a) ? (255) : int(a))
 #define CHOP1255(a) ((a) < (1) ? (1) : ((a) > (255) ? (255) : (a)))
@@ -43,7 +44,12 @@ QImage RGBParadeGenerator::calculateRGBParade(const QSize &paradeSize, const QIm
     QImage parade(paradeSize, QImage::Format_ARGB32);
     parade.fill(Qt::transparent);
 
-    QPainter davinci(&parade);
+    QPainter davinci;
+    bool ok = davinci.begin(&parade);
+    if (!ok) {
+        qDebug() << "Could not initialise QPainter for RGB parade.";
+        return parade;
+    }
 
     const uint ww = (uint)paradeSize.width();
     const uint wh = (uint)paradeSize.height();

src/scopes/colorscopes/vectorscope.cpp

@@ -223,7 +223,12 @@ QImage Vectorscope::renderHUD(uint)
         hud = QImage(m_visibleRect.size(), QImage::Format_ARGB32);
         hud.fill(qRgba(0, 0, 0, 0));
 
-        QPainter davinci(&hud);
+        QPainter davinci;
+        bool ok = davinci.begin(&hud);
+        if (!ok) {
+            qDebug() << "Could not initialise QPainter for Vectorscope HUD.";
+            return hud;
+        }
         QPoint widgetCenterPoint = m_scopeRect.topLeft() + m_centerPoint;
 
         int dx = -widgetCenterPoint.x() + m_mousePos.x();
@@ -290,7 +295,12 @@ QImage Vectorscope::renderBackground(uint)
     bg.fill(qRgba(0, 0, 0, 0));
 
     // Set up tools
-    QPainter davinci(&bg);
+    QPainter davinci;
+    bool ok = davinci.begin(&bg);
+    if (!ok) {
+        qDebug() << "Could not initialise QPainter for Vectorscope background.";
+        return bg;
+    }
     davinci.setRenderHint(QPainter::Antialiasing, true);
 
     QPoint vinciPoint;

src/scopes/colorscopes/waveform.cpp

@@ -119,7 +119,12 @@ QImage Waveform::renderHUD(uint)
     QImage hud(m_scopeRect.size(), QImage::Format_ARGB32);
     hud.fill(qRgba(0, 0, 0, 0));
 
-    QPainter davinci(&hud);
+    QPainter davinci;
+    bool ok = davinci.begin(&hud);
+    if (!ok) {
+        qDebug() << "Could not initialise QPainter for Waveform HUD.";
+        return hud;
+    }
     davinci.setPen(penLight);
 
     //    qCDebug(KDENLIVE_LOG) << values.value("width");

src/scopes/colorscopes/waveformgenerator.cpp

@@ -16,6 +16,7 @@
 #include <QImage>
 #include <QPainter>
 #include <QSize>
+#include <QDebug>
 #include <QElapsedTimer>
 #include <vector>
 
@@ -125,7 +126,13 @@ QImage WaveformGenerator::calculateWaveform(const QSize &waveformSize, const QIm
     }
 
     if (drawAxis) {
-        QPainter davinci(&wave);
+        QPainter davinci;
+        bool ok = davinci.begin(&wave);
+        if (!ok) {
+            qDebug() << "Could not initialise QPainter for Waveform.";
+            return wave;
+        }
+
         QRgb opx;
         davinci.setPen(qRgba(150, 255, 200, 32));
         davinci.setCompositionMode(QPainter::CompositionMode_Overlay);