demo.text

/*
 * Image demo for the TAP (Technology Access Platform)
 *
 * Copyright (C) 2016 TheLab.ms
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 */

#include <font_ascii.h>
#include "main.h"

#define USER_DATA_SIZE 56
unsigned char user_data[USER_DATA_SIZE];
unsigned char text_data[] = " Hello, World! ";
void setup(void)
{
        // This code is invoked once to initialize the demo...
}

void move_text_frame()
{
	int time_offset = state.frame_sync % ((USER_DATA_SIZE - 1) * 8);
	time_offset /= 2;

	unsigned int row, col;
	unsigned int col_offset = state.x_address * 8;

	for (row = 0; row < 8; row++)
	{
		for (col = 0; col < 8; col++)
		{
			unsigned char brightness;
			if (!(time_offset % 2)) /* even */
			{
				int string_index = (((time_offset / 2) + col_offset) + col) / 8;
				int font_index = (((time_offset / 2) + col_offset) + col) % 8;
				unsigned char row_byte = font_ascii[text_data[string_index]][row];
				brightness = 20 * ((row_byte >> font_index) & 0x1);
			}
			else /* odd */
			{
				int string_index = (((time_offset / 2) + col_offset) + col) / 8;
				int font_index = (((time_offset / 2) + col_offset) + col) % 8;
				unsigned char row_byte = font_ascii[text_data[string_index]][row];
				bool first_on = ((row_byte >> font_index) & 0x1);
				string_index = (((time_offset / 2) + 1 + col_offset) + col) / 8;
				font_index = (((time_offset / 2) + 1 + col_offset) + col) % 8;
				row_byte = font_ascii[text_data[string_index]][row];
				bool next_on = ((row_byte >> font_index) & 0x1);

				if (first_on && next_on)
					brightness = 20;
				else if (first_on)
					brightness = 3;
				else if (next_on)
					brightness = 3;
				else
					brightness = 0;
			}
			display_buffer[row][(col * COL_SIZE) + 0] = brightness;
			display_buffer[row][(col * COL_SIZE) + 1] = brightness;
			display_buffer[row][(col * COL_SIZE) + 2] = brightness;
		}
	}
}

void loop(void)
{
	static int counter = 0;

	if (counter++ <= 3)
	{
		__delay_cycles(1000); // so transition frame is not longer
		return;
	}
	counter = 0;

	move_text_frame();
}