qcam: Use Image class to access pixel data

Replace the manual implementation of frame buffer mapping with the Image
class to improve code sharing. The ViewFinder API is updated to take an
Image pointer in the render() function to prepare for multi-planar
buffer support.

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

src/qcam/main_window.cpp

@@ -7,10 +7,9 @@
 
 #include "main_window.h"
 
+#include <assert.h>
 #include <iomanip>
 #include <string>
-#include <sys/mman.h>
-#include <unistd.h>
 
 #include <QComboBox>
 #include <QCoreApplication>
@@ -29,6 +28,7 @@
 #include <libcamera/camera_manager.h>
 #include <libcamera/version.h>
 
+#include "../cam/image.h"
 #include "dng_writer.h"
 #ifndef QT_NO_OPENGL
 #include "viewfinder_gl.h"
@@ -473,15 +473,10 @@ int MainWindow::startCapture()
 
 		for (const std::unique_ptr<FrameBuffer> &buffer : allocator_->buffers(stream)) {
 			/* Map memory buffers and cache the mappings. */
-			const FrameBuffer::Plane &plane = buffer->planes().front();
-			size_t length = lseek(plane.fd.fd(), 0, SEEK_END);
-			void *memory = mmap(NULL, length, PROT_READ, MAP_SHARED,
-					    plane.fd.fd(), 0);
-
-			mappedBuffers_[buffer.get()] = { static_cast<uint8_t *>(memory),
-							 plane.length };
-			planeData_[buffer.get()] = { static_cast<uint8_t *>(memory) + plane.offset,
-						     plane.length };
+			std::unique_ptr<Image> image =
+				Image::fromFrameBuffer(buffer.get(), Image::MapMode::ReadOnly);
+			assert(image != nullptr);
+			mappedBuffers_[buffer.get()] = std::move(image);
 
 			/* Store buffers on the free list. */
 			freeBuffers_[stream].enqueue(buffer.get());
@@ -543,12 +538,7 @@ error_disconnect:
 error:
 	requests_.clear();
 
-	for (auto &iter : mappedBuffers_) {
-		const Span<uint8_t> &buffer = iter.second;
-		munmap(buffer.data(), buffer.size());
-	}
 	mappedBuffers_.clear();
-	planeData_.clear();
 
 	freeBuffers_.clear();
 
@@ -580,12 +570,7 @@ void MainWindow::stopCapture()
 
 	camera_->requestCompleted.disconnect(this);
 
-	for (auto &iter : mappedBuffers_) {
-		const Span<uint8_t> &buffer = iter.second;
-		munmap(buffer.data(), buffer.size());
-	}
 	mappedBuffers_.clear();
-	planeData_.clear();
 
 	requests_.clear();
 	freeQueue_.clear();
@@ -682,7 +667,7 @@ void MainWindow::processRaw(FrameBuffer *buffer,
 							"DNG Files (*.dng)");
 
 	if (!filename.isEmpty()) {
-		uint8_t *memory = planeData_[buffer].data();
+		uint8_t *memory = mappedBuffers_[buffer]->data(0).data();
 		DNGWriter::write(filename.toStdString().c_str(), camera_.get(),
 				 rawStream_->configuration(), metadata, buffer,
 				 memory);
@@ -766,7 +751,7 @@ void MainWindow::processViewfinder(FrameBuffer *buffer)
 		<< "fps:" << Qt::fixed << qSetRealNumberPrecision(2) << fps;
 
 	/* Render the frame on the viewfinder. */
-	viewfinder_->render(buffer, planeData_[buffer]);
+	viewfinder_->render(buffer, mappedBuffers_[buffer].get());
 }
 
 void MainWindow::queueRequest(FrameBuffer *buffer)

src/qcam/main_window.h

@@ -34,6 +34,7 @@ using namespace libcamera;
 class QAction;
 class QComboBox;
 
+class Image;
 class HotplugEvent;
 
 enum {
@@ -106,8 +107,7 @@ private:
 	FrameBufferAllocator *allocator_;
 
 	std::unique_ptr<CameraConfiguration> config_;
-	std::map<FrameBuffer *, Span<uint8_t>> mappedBuffers_;
-	std::map<FrameBuffer *, Span<uint8_t>> planeData_;
+	std::map<FrameBuffer *, std::unique_ptr<Image>> mappedBuffers_;
 
 	/* Capture state, buffers queue and statistics */
 	bool isCapturing_;

src/qcam/meson.build

@@ -15,6 +15,7 @@ endif
 qcam_enabled = true
 
 qcam_sources = files([
+    '../cam/image.cpp',
     '../cam/options.cpp',
     '../cam/stream_options.cpp',
     'format_converter.cpp',

src/qcam/viewfinder.h

@@ -11,11 +11,11 @@
 #include <QList>
 #include <QSize>
 
-#include <libcamera/base/span.h>
-
 #include <libcamera/formats.h>
 #include <libcamera/framebuffer.h>
 
+class Image;
+
 class ViewFinder
 {
 public:
@@ -24,7 +24,7 @@ public:
 	virtual const QList<libcamera::PixelFormat> &nativeFormats() const = 0;
 
 	virtual int setFormat(const libcamera::PixelFormat &format, const QSize &size) = 0;
-	virtual void render(libcamera::FrameBuffer *buffer, libcamera::Span<uint8_t> mem) = 0;
+	virtual void render(libcamera::FrameBuffer *buffer, Image *image) = 0;
 	virtual void stop() = 0;
 
 	virtual QImage getCurrentImage() = 0;

src/qcam/viewfinder_gl.cpp

@@ -13,6 +13,8 @@
 
 #include <libcamera/formats.h>
 
+#include "../cam/image.h"
+
 static const QList<libcamera::PixelFormat> supportedFormats{
 	/* YUV - packed (single plane) */
 	libcamera::formats::UYVY,
@@ -110,8 +112,7 @@ QImage ViewFinderGL::getCurrentImage()
 	return grabFramebuffer();
 }
 
-void ViewFinderGL::render(libcamera::FrameBuffer *buffer,
-			  libcamera::Span<uint8_t> mem)
+void ViewFinderGL::render(libcamera::FrameBuffer *buffer, Image *image)
 {
 	if (buffer->planes().size() != 1) {
 		qWarning() << "Multi-planar buffers are not supported";
@@ -121,7 +122,7 @@ void ViewFinderGL::render(libcamera::FrameBuffer *buffer,
 	if (buffer_)
 		renderComplete(buffer_);
 
-	data_ = mem.data();
+	data_ = image->data(0).data();
 	/*
 	 * \todo Get the stride from the buffer instead of computing it naively
 	 */

src/qcam/viewfinder_gl.h

@@ -39,7 +39,7 @@ public:
 	const QList<libcamera::PixelFormat> &nativeFormats() const override;
 
 	int setFormat(const libcamera::PixelFormat &format, const QSize &size) override;
-	void render(libcamera::FrameBuffer *buffer, libcamera::Span<uint8_t> mem) override;
+	void render(libcamera::FrameBuffer *buffer, Image *image) override;
 	void stop() override;
 
 	QImage getCurrentImage() override;

src/qcam/viewfinder_qt.cpp

@@ -19,6 +19,7 @@
 
 #include <libcamera/formats.h>
 
+#include "../cam/image.h"
 #include "format_converter.h"
 
 static const QMap<libcamera::PixelFormat, QImage::Format> nativeFormats
@@ -78,15 +79,14 @@ int ViewFinderQt::setFormat(const libcamera::PixelFormat &format,
 	return 0;
 }
 
-void ViewFinderQt::render(libcamera::FrameBuffer *buffer,
-			  libcamera::Span<uint8_t> mem)
+void ViewFinderQt::render(libcamera::FrameBuffer *buffer, Image *image)
 {
 	if (buffer->planes().size() != 1) {
 		qWarning() << "Multi-planar buffers are not supported";
 		return;
 	}
 
-	unsigned char *memory = mem.data();
+	unsigned char *memory = image->data(0).data();
 	size_t size = buffer->metadata().planes()[0].bytesused;
 
 	{

src/qcam/viewfinder_qt.h

@@ -32,7 +32,7 @@ public:
 	const QList<libcamera::PixelFormat> &nativeFormats() const override;
 
 	int setFormat(const libcamera::PixelFormat &format, const QSize &size) override;
-	void render(libcamera::FrameBuffer *buffer, libcamera::Span<uint8_t> mem) override;
+	void render(libcamera::FrameBuffer *buffer, Image *image) override;
 	void stop() override;
 
 	QImage getCurrentImage() override;