/**
* crt-calibrator – Calibration utility for CRT monitors
* Copyright © 2014 Mattias Andrée (maandree@member.fsf.org)
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* 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.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef CRT_CALIBRATOR_FRAMEBUFFER_H
#define CRT_CALIBRATOR_FRAMEBUFFER_H
#include <stddef.h>
#include <stdint.h>
/**
* Framebuffer information
*/
typedef struct framebuffer
{
/**
* The file descriptor used to access the framebuffer, -1 if not opened
*/
int fd;
/**
* The width of the display in pixels
*/
uint32_t width;
/**
* The height of the display in pixels
*/
uint32_t height;
/**
* Increment for `mem` to move to next pixel on the line
*/
uint32_t bytes_per_pixel;
/**
* Increment for `mem` to move down one line but stay in the same column
*/
uint32_t line_length;
/**
* Framebuffer pointer, `MAP_FAILED` (from <sys/mman.h>) if not mapped
*/
int8_t* mem;
} framebuffer_t;
/**
* Figure out how many framebuffers there are on the system
*
* @return The number of framebuffers on the system
*/
size_t fb_count(void);
/**
* Open a framebuffer
*
* @param index The index of the framebuffer to open
* @param fb Framebuffer information to fill in
* @return Zero on success, -1 on error
*/
int fb_open(size_t index, framebuffer_t* restrict fb);
/**
* Close a framebuffer
*
* @param fb The framebuffer information
*/
void fb_close(framebuffer_t* restrict fb);
/**
* Construct an sRGB colour in 32-bit XRGB encoding to
* use when specifying colours
*
* @param red The red component from [0, 255] sRGB
* @param green The green component from [0, 255] sRGB
* @param blue The blue component from [0, 255] sRGB
* @return The colour as one 32-bit integer
*/
uint32_t fb_colour(int red, int green, int blue) __attribute__((const));
/**
* Print a filled in rectangle to a framebuffer
*
* @param fb The framebuffer
* @param colour The colour to use when drawing the rectangle
* @param x The starting pixel on the X axis for the rectangle
* @param y The starting pixel on the Y axis for the rectangle
* @param width The width of the rectangle, in pixels
* @param height The height of the rectangle, in pixels
*/
void fb_fill_rectangle(framebuffer_t* restrict fb, uint32_t colour,
uint32_t x, uint32_t y, uint32_t width, uint32_t height);
/**
* Draw a horizontal line segment on a framebuffer
*
* @param fb The framebuffer
* @param colour The colour to use when drawing the rectangle
* @param x The starting pixel on the X axis for the line segment
* @param y The starting pixel on the Y axis for the line segment
* @param length The length of the line segment, in pixels
*/
void fb_draw_horizontal_line(framebuffer_t* restrict fb, uint32_t colour,
uint32_t x, uint32_t y, uint32_t length);
/**
* Draw a vertical line segment on a framebuffer
*
* @param fb The framebuffer
* @param colour The colour to use when drawing the rectangle
* @param x The starting pixel on the X axis for the line segment
* @param y The starting pixel on the Y axis for the line segment
* @param length The length of the line segment, in pixels
*/
void fb_draw_vertical_line(framebuffer_t* restrict fb, uint32_t colour,
uint32_t x, uint32_t y, uint32_t length);
/**
* Draw a single on a framebuffer
*
* @param fb The framebuffer
* @param colour The colour to use when drawing the rectangle
* @param x The pixel's position on the X axis
* @param y The pixel's position on the Y axis
*/
static inline void fb_draw_pixel(framebuffer_t* restrict fb, uint32_t colour,
uint32_t x, uint32_t y)
{
int8_t* mem = fb->mem + y * fb->line_length + x * fb->bytes_per_pixel;
*(uint32_t*)mem = colour;
}
#endif
