[libcamera-devel] [PATCH 20/21] qcam: viewfinder: Display icon when stopping capture

[Laurent Pinchart]

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 at ideasonboard.com>
---
 src/qcam/assets/feathericons/feathericons.qrc |  1 +
 src/qcam/main_window.cpp                      |  2 +
 src/qcam/viewfinder.cpp                       | 44 ++++++++++++++++++-
 src/qcam/viewfinder.h                         |  8 ++++
 4 files changed, 54 insertions(+), 1 deletion(-)

diff --git a/src/qcam/assets/feathericons/feathericons.qrc b/src/qcam/assets/feathericons/feathericons.qrc
index 6ca3a846803c..c4eb7a0be688 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/main_window.cpp b/src/qcam/main_window.cpp
index b68e171c5e01..a77d10bb7076 100644
--- a/src/qcam/main_window.cpp
+++ b/src/qcam/main_window.cpp
@@ -412,6 +412,8 @@ void MainWindow::stopCapture()
 	if (!isCapturing_)
 		return;
 
+	viewfinder_->stop();
+
 	int ret = camera_->stop();
 	if (ret)
 		qInfo() << "Failed to stop capture";
diff --git a/src/qcam/viewfinder.cpp b/src/qcam/viewfinder.cpp
index 4c35659e24aa..a40b2b400daa 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()
@@ -89,6 +90,18 @@ void ViewFinder::render(libcamera::FrameBuffer *buffer, MappedBuffer *map)
 		renderComplete(buffer);
 }
 
+void ViewFinder::stop()
+{
+	image_ = QImage();
+
+	if (buffer_) {
+		renderComplete(buffer_);
+		buffer_ = nullptr;
+	}
+
+	update();
+}
+
 QImage ViewFinder::getCurrentImage()
 {
 	QMutexLocker locker(&mutex_);
@@ -99,7 +112,36 @@ 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()) {
+		vfSize_ = size();
+
+		QSize pixmapSize{ 1, 1 };
+		pixmapSize.scale(vfSize_.shrunkBy({ margin, margin, margin, margin }),
+				 Qt::KeepAspectRatio);
+		pixmap_ = icon_.pixmap(pixmapSize);
+	}
+
+	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 b5153160f70e..1a27f99ea202 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>
@@ -36,6 +37,7 @@ public:
 
 	int setFormat(const libcamera::PixelFormat &format, const QSize &size);
 	void render(libcamera::FrameBuffer *buffer, MappedBuffer *map);
+	void stop();
 
 	QImage getCurrentImage();
 
@@ -52,6 +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_ */
-- 
Regards,

Laurent Pinchart