grabdisplay.cpp

#include <getopt.h>
#include <math.h>
#include <png.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "grabdisplay.h"

GrabDisplay::GrabDisplay(int displayNumber)
{
	//bcm_host_init();
	displayHandle = vc_dispmanx_display_open(displayNumber);

	if (displayHandle == 0)
	{
		fprintf(stderr,
				" unable to open display %d\n",

				displayNumber);

		exit(EXIT_FAILURE);
	}

	int result = 0;
	DISPMANX_MODEINFO_T modeInfo;
	result = vc_dispmanx_display_get_info(displayHandle, &modeInfo);

	if (result != 0)
	{
		fprintf(stderr, " unable to get display information\n");
		exit(EXIT_FAILURE);
	}
	DisplayWidth = (modeInfo.width >> 5) << 5;
	DisplayHeight = (modeInfo.height >> 4) << 4;
	dmxPitch = DisplayWidth * 4; //4 BYTES IN RGBA //2 BYTE PAR PIXEL IN RGB565
	resourceHandle = vc_dispmanx_resource_create(imageType,
												 DisplayWidth,
												 DisplayHeight,
												 &vcImagePtr);
}
GrabDisplay::~GrabDisplay()
{
	vc_dispmanx_resource_delete(resourceHandle);
	vc_dispmanx_display_close(displayHandle);
}

void GrabDisplay::GetDisplaySize(int &Width, int &Height, int &Rotate)
{
	Width = DisplayWidth;
	Height = DisplayHeight;
	Rotate = 0;
}

void GrabDisplay::SetOmxBuffer(unsigned char *Buffer)
{
	OmxBuffer = Buffer;
}

void GrabDisplay::GetPicture()
{
	// FOR YUV420
	//https://www.raspberrypi.org/forums/viewtopic.php?t=45711&p=481480
	//https://github.com/raspberrypi/firmware/issues/235
	int result = vc_dispmanx_snapshot(displayHandle,
									  resourceHandle,
									  DISPMANX_NO_ROTATE);
	if (result != 0)
	{
		vc_dispmanx_resource_delete(resourceHandle);
		vc_dispmanx_display_close(displayHandle);

		fprintf(stderr, " vc_dispmanx_snapshot() failed\n");
		exit(EXIT_FAILURE);
	}

	VC_RECT_T rect;
	result = vc_dispmanx_rect_set(&rect, 0, 0, DisplayWidth, DisplayHeight);

	if (result != 0)
	{
		vc_dispmanx_resource_delete(resourceHandle);
		vc_dispmanx_display_close(displayHandle);

		fprintf(stderr, " vc_dispmanx_rect_set() failed\n");
		exit(EXIT_FAILURE);
	}

	result = vc_dispmanx_resource_read_data(resourceHandle,
											&rect,
											OmxBuffer,
											dmxPitch);
}