hyperion.ng/libsrc/grabber/framebuffer/FramebufferFrameGrabber.cpp

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <linux/fb.h>
#include <sys/mman.h>
#include <sys/ioctl.h>

// STL includes
#include <iostream>

// Local includes
#include <grabber/FramebufferFrameGrabber.h>

FramebufferFrameGrabber::FramebufferFrameGrabber(const QString & device, const unsigned width, const unsigned height)
	: Grabber("FRAMEBUFFERGRABBER", width, height)
	, _fbfd(0)
	, _fbp(0)
	, _fbDevice(device)
{
	int result;
	struct fb_var_screeninfo vinfo;

	// Check if the framebuffer device can be opened and display the current resolution
	_fbfd = open(QSTRING_CSTR(_fbDevice), O_RDONLY);
	if (_fbfd == 0)
	{
		Error(_log, "Error openning %s", QSTRING_CSTR(_fbDevice));
	}
	else 
	{
		// get variable screen information
		result = ioctl (_fbfd, FBIOGET_VSCREENINFO, &vinfo);
		if (result != 0)
		{
			Error(_log, "Could not get screen information");
		}
		else
		{
			Error(_log, "Display opened with resolution: %dx%d@%dbit", vinfo.xres, vinfo.yres, vinfo.bits_per_pixel);			
		}
		close(_fbfd);
	}
}

FramebufferFrameGrabber::~FramebufferFrameGrabber()
{
}

int FramebufferFrameGrabber::grabFrame(Image<ColorRgb> & image)
{
	struct fb_var_screeninfo vinfo;
	unsigned capSize, bytesPerPixel;
	PixelFormat pixelFormat;

	/* Open the framebuffer device */
	_fbfd = open(QSTRING_CSTR(_fbDevice), O_RDONLY);

	/* get variable screen information */
	ioctl (_fbfd, FBIOGET_VSCREENINFO, &vinfo);

	bytesPerPixel = vinfo.bits_per_pixel / 8;
	capSize = vinfo.xres * vinfo.yres * bytesPerPixel;
	
	switch (vinfo.bits_per_pixel)
	{
		case 16: pixelFormat = PIXELFORMAT_BGR16; break;
		case 24: pixelFormat = PIXELFORMAT_BGR24; break;
		case 32: pixelFormat = PIXELFORMAT_BGR32; break;
		default:
			Error(_log, "Unknown pixel format: %d bits per pixel", vinfo.bits_per_pixel);
			close(_fbfd);
			return -1;
	}

	/* map the device to memory */
	_fbp = (unsigned char*)mmap(0, capSize, PROT_READ, MAP_PRIVATE | MAP_NORESERVE, _fbfd, 0);	

	_imageResampler.setHorizontalPixelDecimation(vinfo.xres/_width);
	_imageResampler.setVerticalPixelDecimation(vinfo.yres/_height);
	_imageResampler.processImage(_fbp,
								vinfo.xres,
								vinfo.yres,
								vinfo.xres * bytesPerPixel,
								pixelFormat,
								image);
	
	munmap(_fbp, capSize);
	close(_fbfd);

	return 0;
}