qcam: viewfinder: Display icon when stopping capture

When stopping capture, display an icon instead of the last frame. This
is required to be able to release the last buffer when the viewfinder
operators in zero-copy mode.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

3 files changed, 39 insertions, 1 deletions

diff --git a/src/qcam/assets/feathericons/feathericons.qrc b/src/qcam/assets/feathericons/feathericons.qrc
index 6ca3a846..c4eb7a0b 100644
--- a/src/qcam/assets/feathericons/feathericons.qrc
+++ b/src/qcam/assets/feathericons/feathericons.qrc
@@ -1,5 +1,6 @@
 <!DOCTYPE RCC><RCC version="1.0">
 <qresource>
+<file>./camera-off.svg</file>
 <file>./play-circle.svg</file>
 <file>./save.svg</file>
 <file>./stop-circle.svg</file>
diff --git a/src/qcam/viewfinder.cpp b/src/qcam/viewfinder.cpp
index 3f984efb..45e226b5 100644
--- a/src/qcam/viewfinder.cpp
+++ b/src/qcam/viewfinder.cpp
@@ -20,6 +20,7 @@
 ViewFinder::ViewFinder(QWidget *parent)
 	: QWidget(parent), buffer_(nullptr)
 {
+	icon_ = QIcon(":camera-off.svg");
 }
 
 ViewFinder::~ViewFinder()
@@ -114,7 +115,36 @@ QImage ViewFinder::getCurrentImage()
 void ViewFinder::paintEvent(QPaintEvent *)
 {
 	QPainter painter(this);
-	painter.drawImage(rect(), image_, image_.rect());
+
+	/* If we have an image, draw it. */
+	if (!image_.isNull()) {
+		painter.drawImage(rect(), image_, image_.rect());
+		return;
+	}
+
+	/*
+	 * Otherwise, draw the camera stopped icon. Render it to the pixmap if
+	 * the size has changed.
+	 */
+	constexpr int margin = 20;
+
+	if (vfSize_ != size() || pixmap_.isNull()) {
+		QSize vfSize = size() - QSize{ 2 * margin, 2 * margin };
+		QSize pixmapSize{ 1, 1 };
+		pixmapSize.scale(vfSize, Qt::KeepAspectRatio);
+		pixmap_ = icon_.pixmap(pixmapSize);
+
+		vfSize_ = size();
+	}
+
+	QPoint point{ margin, margin };
+	if (pixmap_.width() < width() - 2 * margin)
+		point.setX((width() - pixmap_.width()) / 2);
+	else
+		point.setY((height() - pixmap_.height()) / 2);
+
+	painter.setBackgroundMode(Qt::OpaqueMode);
+	painter.drawPixmap(point, pixmap_);
 }
 
 QSize ViewFinder::sizeHint() const
diff --git a/src/qcam/viewfinder.h b/src/qcam/viewfinder.h
index 4d0622a8..1a27f99e 100644
--- a/src/qcam/viewfinder.h
+++ b/src/qcam/viewfinder.h
@@ -9,6 +9,7 @@
 
 #include <stddef.h>
 
+#include <QIcon>
 #include <QImage>
 #include <QMutex>
 #include <QSize>
@@ -53,6 +54,12 @@ private:
 	libcamera::PixelFormat format_;
 	QSize size_;
 
+	/* Camera stopped icon */
+	QSize vfSize_;
+	QIcon icon_;
+	QPixmap pixmap_;
+
+	/* Buffer and render image */
 	libcamera::FrameBuffer *buffer_;
 	QImage image_;
 	QMutex mutex_; /* Prevent concurrent access to image_ */