pixelflut-rgb-matrix-server/include/led-matrix-c.h
2020-12-26 13:23:47 +01:00

394 lines
14 KiB
C

/* -*- mode: c; c-basic-offset: 2; indent-tabs-mode: nil; -*-
* Copyright (C) 2013 Henner Zeller <h.zeller@acm.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 version 2.
*
* 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://gnu.org/licenses/gpl-2.0.txt>
*
* Controlling 16x32 or 32x32 RGB matrixes via GPIO. It allows daisy chaining
* of a string of these, and also connecting a parallel string on newer
* Raspberry Pis with more GPIO pins available.
*
* This is a C-binding (for the C++ library) to allow easy binding and
* integration with other languages. The symbols are exported in librgbmatrix.a
* and librgbmatrix.so. You still need to call the final link with
*
* See examples-api-use/c-example.c for a usage example.
*
*/
#ifndef RPI_RGBMATRIX_C_H
#define RPI_RGBMATRIX_C_H
#include <stdint.h>
#include <stdio.h>
#include <stdbool.h>
#ifdef __cplusplus
extern "C" {
#endif
struct RGBLedMatrix;
struct LedCanvas;
struct LedFont;
/**
* Parameters to create a new matrix.
*
* To get the defaults, non-set values have to be initialized to zero, so you
* should zero out this struct before setting anything.
*/
struct RGBLedMatrixOptions {
/*
* Name of the hardware mapping used. If passed NULL here, the default
* is used.
*/
const char *hardware_mapping;
/* The "rows" are the number of rows supported by the display, so 32 or 16.
* Default: 32.
* Corresponding flag: --led-rows
*/
int rows;
/* The "cols" are the number of columns per panel. Typically something
* like 32, but also 64 is possible. Sometimes even 40.
* cols * chain_length is the total length of the display, so you can
* represent a 64 wide display as cols=32, chain=2 or cols=64, chain=1;
* same thing.
* Flag: --led-cols
*/
int cols;
/* The chain_length is the number of displays daisy-chained together
* (output of one connected to input of next). Default: 1
* Corresponding flag: --led-chain
*/
int chain_length;
/* The number of parallel chains connected to the Pi; in old Pis with 26
* GPIO pins, that is 1, in newer Pis with 40 interfaces pins, that can
* also be 2 or 3. The effective number of pixels in vertical direction is
* then thus rows * parallel. Default: 1
* Corresponding flag: --led-parallel
*/
int parallel;
/* Set PWM bits used for output. Default is 11, but if you only deal with
* limited comic-colors, 1 might be sufficient. Lower require less CPU and
* increases refresh-rate.
* Corresponding flag: --led-pwm-bits
*/
int pwm_bits;
/* Change the base time-unit for the on-time in the lowest
* significant bit in nanoseconds.
* Higher numbers provide better quality (more accurate color, less
* ghosting), but have a negative impact on the frame rate.
* Corresponding flag: --led-pwm-lsb-nanoseconds
*/
int pwm_lsb_nanoseconds;
/* The lower bits can be time-dithered for higher refresh rate.
* Corresponding flag: --led-pwm-dither-bits
*/
int pwm_dither_bits;
/* The initial brightness of the panel in percent. Valid range is 1..100
* Corresponding flag: --led-brightness
*/
int brightness;
/* Scan mode: 0=progressive, 1=interlaced
* Corresponding flag: --led-scan-mode
*/
int scan_mode;
/* Default row address type is 0, corresponding to direct setting of the
* row, while row address type 1 is used for panels that only have A/B,
* typically some 64x64 panels
*/
int row_address_type; /* Corresponding flag: --led-row-addr-type */
/* Type of multiplexing. 0 = direct, 1 = stripe, 2 = checker (typical 1:8)
*/
int multiplexing;
/* In case the internal sequence of mapping is not "RGB", this contains the
* real mapping. Some panels mix up these colors.
*/
const char *led_rgb_sequence; /* Corresponding flag: --led-rgb-sequence */
/* A string describing a sequence of pixel mappers that should be applied
* to this matrix. A semicolon-separated list of pixel-mappers with optional
* parameter.
*/
const char *pixel_mapper_config; /* Corresponding flag: --led-pixel-mapper */
/*
* Panel type. Typically just NULL, but certain panels (FM6126) require
* an initialization sequence
*/
const char *panel_type; /* Corresponding flag: --led-panel-type */
/** The following are boolean flags, all off by default **/
/* Allow to use the hardware subsystem to create pulses. This won't do
* anything if output enable is not connected to GPIO 18.
* Corresponding flag: --led-hardware-pulse
*/
char disable_hardware_pulsing;
char show_refresh_rate; /* Corresponding flag: --led-show-refresh */
char inverse_colors; /* Corresponding flag: --led-inverse */
/* Limit refresh rate of LED panel. This will help on a loaded system
* to keep a constant refresh rate. <= 0 for no limit.
*/
int limit_refresh_rate_hz; /* Corresponding flag: --led-limit-refresh */
};
/**
* Runtime options to simplify doing common things for many programs such as
* dropping privileges and becoming a daemon.
*/
struct RGBLedRuntimeOptions {
int gpio_slowdown; // 0 = no slowdown. Flag: --led-slowdown-gpio
// ----------
// If the following options are set to disabled with -1, they are not
// even offered via the command line flags.
// ----------
// Thre are three possible values here
// -1 : don't leave choise of becoming daemon to the command line parsing.
// If set to -1, the --led-daemon option is not offered.
// 0 : do not becoma a daemon, run in forgreound (default value)
// 1 : become a daemon, run in background.
//
// If daemon is disabled (= -1), the user has to call
// RGBMatrix::StartRefresh() manually once the matrix is created, to leave
// the decision to become a daemon
// after the call (which requires that no threads have been started yet).
// In the other cases (off or on), the choice is already made, so the thread
// is conveniently already started for you.
int daemon; // -1 disabled. 0=off, 1=on. Flag: --led-daemon
// Drop privileges from 'root' to 'daemon' once the hardware is initialized.
// This is usually a good idea unless you need to stay on elevated privs.
int drop_privileges; // -1 disabled. 0=off, 1=on. flag: --led-drop-privs
// By default, the gpio is initialized for you, but if you run on a platform
// not the Raspberry Pi, this will fail. If you don't need to access GPIO
// e.g. you want to just create a stream output (see content-streamer.h),
// set this to false.
bool do_gpio_init;
};
/**
* Universal way to create and initialize a matrix.
* The "options" struct (if not NULL) contains all default configuration values
* chosen by the programmer to create the matrix.
*
* If "argc" and "argv" are provided, this function also reads command line
* flags provided, that then can override any of the defaults given.
* The arguments that have been used from the command line are removed from
* the argv list (and argc is adjusted) - that way these don't mess with your
* own command line handling.
*
* The actual options used are filled back into the "options" struct if not
* NULL.
*
* Usage:
* ----------------
* int main(int argc, char **argv) {
* struct RGBLedMatrixOptions options;
* memset(&options, 0, sizeof(options));
* options.rows = 32; // You can set defaults if you want.
* options.chain_length = 1;
* struct RGBLedMatrix *matrix = led_matrix_create_from_options(&options,
* &argc, &argv);
* if (matrix == NULL) {
* led_matrix_print_flags(stderr);
* return 1;
* }
* // do additional commandline handling; then use matrix...
* }
* ----------------
*/
struct RGBLedMatrix *led_matrix_create_from_options(
struct RGBLedMatrixOptions *options, int *argc, char ***argv);
/* Same, but does not modify the argv array. */
struct RGBLedMatrix *led_matrix_create_from_options_const_argv(
struct RGBLedMatrixOptions *options, int argc, char **argv);
/**
* The way to completely initialize your matrix without using command line
* flags to initialize some things.
*
* The actual options used are filled back into the "options" and "rt_options"
* struct if not NULL. If they are null, the default value is used.
*
* Usage:
* ----------------
* int main(int argc, char **argv) {
* struct RGBLedMatrixOptions options;
* struct RGBLedRuntimeOptions rt_options;
* memset(&options, 0, sizeof(options));
* memset(&rt_options, 0, sizeof(rt_options));
* options.rows = 32; // You can set defaults if you want.
* options.chain_length = 1;
* rt_options.gpio_slowdown = 4;
* struct RGBLedMatrix *matrix = led_matrix_create_from_options_and_rt_options(&options, &rt_options);
* if (matrix == NULL) {
* return 1;
* }
* // do additional commandline handling; then use matrix...
* }
* ----------------
*/
struct RGBLedMatrix *led_matrix_create_from_options_and_rt_options(
struct RGBLedMatrixOptions *opts, struct RGBLedRuntimeOptions * rt_opts);
/**
* Print available LED matrix options.
*/
void led_matrix_print_flags(FILE *out);
/**
* Simple form of led_matrix_create_from_options() with just the few
* main options. Returns NULL if that was not possible.
* The "rows" are the number of rows supported by the display, so 32, 16 or 8.
*
* Number of "chained_display"s tells many of these are daisy-chained together
* (output of one connected to input of next).
*
* The "parallel_display" number determines if there is one or two displays
* connected in parallel to the GPIO port - this only works with newer
* Raspberry Pi that have 40 interface pins.
*
* This creates a realtime thread and requires root access to access the GPIO
* pins.
* So if you run this in a daemon, this should be called after becoming a
* daemon (as fork/exec stops threads) and before dropping privileges.
*/
struct RGBLedMatrix *led_matrix_create(int rows, int chained, int parallel);
/**
* Stop matrix and free memory.
* Always call before the end of the program to properly reset the hardware
*/
void led_matrix_delete(struct RGBLedMatrix *matrix);
/**
* Get active canvas from LED matrix for you to draw on.
* Ownership of returned pointer stays with the matrix, don't free().
*/
struct LedCanvas *led_matrix_get_canvas(struct RGBLedMatrix *matrix);
/** Return size of canvas. */
void led_canvas_get_size(const struct LedCanvas *canvas,
int *width, int *height);
/** Set pixel at (x, y) with color (r,g,b). */
void led_canvas_set_pixel(struct LedCanvas *canvas, int x, int y,
uint8_t r, uint8_t g, uint8_t b);
/** Clear screen (black). */
void led_canvas_clear(struct LedCanvas *canvas);
/** Fill matrix with given color. */
void led_canvas_fill(struct LedCanvas *canvas, uint8_t r, uint8_t g, uint8_t b);
/*** API to provide double-buffering. ***/
/**
* Create a new canvas to be used with led_matrix_swap_on_vsync()
* Ownership of returned pointer stays with the matrix, don't free().
*/
struct LedCanvas *led_matrix_create_offscreen_canvas(struct RGBLedMatrix *matrix);
/**
* Swap the given canvas (created with create_offscreen_canvas) with the
* currently active canvas on vsync (blocks until vsync is reached).
* Returns the previously active canvas. So with that, you can create double
* buffering:
*
* struct LedCanvas *offscreen = led_matrix_create_offscreen_canvas(...);
* led_canvas_set_pixel(offscreen, ...); // not shown until swap-on-vsync
* offscreen = led_matrix_swap_on_vsync(matrix, offscreen);
* // The returned buffer, assigned to offscreen, is now the inactive buffer
* // fill, then swap again.
*/
struct LedCanvas *led_matrix_swap_on_vsync(struct RGBLedMatrix *matrix,
struct LedCanvas *canvas);
uint8_t led_matrix_get_brightness(struct RGBLedMatrix *matrix);
void led_matrix_set_brightness(struct RGBLedMatrix *matrix, uint8_t brightness);
// Utility function: set an image from the given buffer containting pixels.
//
// Draw image of size "image_width" and "image_height" from pixel at
// canvas-offset "canvas_offset_x", "canvas_offset_y". Image will be shown
// cropped on the edges if needed.
//
// The canvas offset can be negative, i.e. the image start can be shifted
// outside the image frame on the left/top edge.
//
// The buffer needs to be organized as rows with columns of three bytes
// organized as rgb or bgr. Thus the size of the buffer needs to be exactly
// (3 * image_width * image_height) bytes.
//
// The "image_buffer" parameters contains the data, "buffer_size_bytes" the
// size in bytes.
//
// If "is_bgr" is 1, the buffer is treated as BGR pixel arrangement instead
// of RGB with is_bgr = 0.
void set_image(struct LedCanvas *c, int canvas_offset_x, int canvas_offset_y,
const uint8_t *image_buffer, size_t buffer_size_bytes,
int image_width, int image_height,
char is_bgr);
// Load a font given a path to a font file containing a bdf font.
struct LedFont *load_font(const char *bdf_font_file);
// Read the baseline of a font
int baseline_font(struct LedFont *font);
// Read the height of a font
int height_font(struct LedFont *font);
// Creates an outline font based on an existing font instance
struct LedFont *create_outline_font(struct LedFont *font);
// Delete a font originally created from load_font.
void delete_font(struct LedFont *font);
int draw_text(struct LedCanvas *c, struct LedFont *font, int x, int y,
uint8_t r, uint8_t g, uint8_t b,
const char *utf8_text, int kerning_offset);
int vertical_draw_text(struct LedCanvas *c, struct LedFont *font, int x, int y,
uint8_t r, uint8_t g, uint8_t b,
const char *utf8_text, int kerning_offset);
void draw_circle(struct LedCanvas *c, int x, int y, int radius,
uint8_t r, uint8_t g, uint8_t b);
void draw_line(struct LedCanvas *c, int x0, int y0, int x1, int y1,
uint8_t r, uint8_t g, uint8_t b);
#ifdef __cplusplus
} // extern C
#endif
#endif