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/* Example program that shows how to use a Chafa canvas with ncurses.
*
* To build:
*
* gcc ncurses.c $(pkg-config --libs --cflags chafa) $(ncursesw6-config --libs --cflags) -o ncurses
*/
#include <locale.h>
#include <ncurses.h>
#include <chafa.h>
/* Parameters for gradient pixmap. It will be scaled automatically to fit the canvas,
* so this just needs to be big enough to avoid it getting too blurry. The number
* of channels is always four, corresponding to CHAFA_PIXEL_RGBA8_UNASSOCIATED. */
#define PIXMAP_WIDTH 1024
#define PIXMAP_HEIGHT 1024
#define PIXMAP_N_CHANNELS 4
/* Terminal size detected in main loop */
static int screen_width, screen_height;
static ChafaCanvasMode
detect_canvas_mode (void)
{
/* COLORS is a global variable defined by ncurses. It depends on termcap
* for the terminal specified in TERM. In order to test the various modes, you
* could try running this program with either of these:
*
* TERM=xterm
* TERM=xterm-16color
* TERM=xterm-256color
* TERM=xterm-direct
*/
return COLORS >= (1 << 24) ? CHAFA_CANVAS_MODE_TRUECOLOR
: COLORS >= (1 << 8) ? CHAFA_CANVAS_MODE_INDEXED_240
: COLORS >= (1 << 4) ? CHAFA_CANVAS_MODE_INDEXED_16
: COLORS >= (1 << 3) ? CHAFA_CANVAS_MODE_INDEXED_8
: CHAFA_CANVAS_MODE_FGBG;
}
static ChafaCanvas *
create_canvas (void)
{
ChafaSymbolMap *symbol_map;
ChafaCanvasConfig *config;
ChafaCanvas *canvas;
ChafaCanvasMode mode = detect_canvas_mode ();
/* Specify the symbols we want: Box drawing and block elements are both
* useful and widely supported. */
symbol_map = chafa_symbol_map_new ();
chafa_symbol_map_add_by_tags (symbol_map, CHAFA_SYMBOL_TAG_SPACE);
chafa_symbol_map_add_by_tags (symbol_map, CHAFA_SYMBOL_TAG_BLOCK);
chafa_symbol_map_add_by_tags (symbol_map, CHAFA_SYMBOL_TAG_BORDER);
/* Set up a configuration with the symbols and the canvas size in characters */
config = chafa_canvas_config_new ();
chafa_canvas_config_set_canvas_mode (config, mode);
chafa_canvas_config_set_symbol_map (config, symbol_map);
/* Reserve one row below canvas for status text */
chafa_canvas_config_set_geometry (config, screen_width, screen_height - 1);
/* Apply tweaks for low-color modes */
if (mode == CHAFA_CANVAS_MODE_INDEXED_240)
{
/* We get better color fidelity using DIN99d in 240-color mode.
* This is not needed in 16-color mode because it uses an extra
* preprocessing step instead, which usually performs better. */
chafa_canvas_config_set_color_space (config, CHAFA_COLOR_SPACE_DIN99D);
}
if (mode == CHAFA_CANVAS_MODE_FGBG)
{
/* Enable dithering in monochromatic mode so gradients become
* somewhat legible. */
chafa_canvas_config_set_dither_mode (config, CHAFA_DITHER_MODE_ORDERED);
}
/* Create canvas */
canvas = chafa_canvas_new (config);
chafa_symbol_map_unref (symbol_map);
chafa_canvas_config_unref (config);
return canvas;
}
static void
paint_canvas (ChafaCanvas *canvas)
{
guint8 *pixmap;
int x, y;
/* Generate a gradient pixmap */
pixmap = g_malloc (PIXMAP_WIDTH * PIXMAP_HEIGHT * PIXMAP_N_CHANNELS);
for (y = 0; y < PIXMAP_HEIGHT; y++)
{
for (x = 0; x < PIXMAP_WIDTH; x++)
{
guint8 *pixel = pixmap + (y * PIXMAP_WIDTH + x) * PIXMAP_N_CHANNELS;
pixel [0] = (x * 255) / PIXMAP_WIDTH;
pixel [1] = (y * 255) / PIXMAP_HEIGHT;
pixel [2] = 0;
pixel [3] = 255;
}
}
/* Paint it to the canvas */
chafa_canvas_draw_all_pixels (canvas,
CHAFA_PIXEL_RGBA8_UNASSOCIATED,
pixmap,
PIXMAP_WIDTH,
PIXMAP_HEIGHT,
PIXMAP_WIDTH * PIXMAP_N_CHANNELS);
g_free (pixmap);
}
static void
canvas_to_ncurses (ChafaCanvas *canvas)
{
ChafaCanvasMode mode = detect_canvas_mode ();
int pair = 256; /* Reserve lower pairs for application in direct-color mode */
int x, y;
for (y = 0; y < screen_height - 1; y++)
{
for (x = 0; x < screen_width; x++)
{
wchar_t wc [2];
cchar_t cch;
int fg, bg;
/* wchar_t is 32-bit in glibc, but this may not work on e.g. Windows */
wc [0] = chafa_canvas_get_char_at (canvas, x, y);
wc [1] = 0;
if (mode == CHAFA_CANVAS_MODE_TRUECOLOR)
{
chafa_canvas_get_colors_at (canvas, x, y, &fg, &bg);
init_extended_pair (pair, fg, bg);
}
else if (mode == CHAFA_CANVAS_MODE_FGBG)
{
pair = 0;
}
else
{
/* In indexed color mode, we've probably got enough pairs
* to just let ncurses allocate and reuse as needed. */
chafa_canvas_get_raw_colors_at (canvas, x, y, &fg, &bg);
pair = alloc_pair (fg, bg);
}
setcchar (&cch, wc, A_NORMAL, -1, &pair);
mvadd_wch (y, x, &cch);
pair++;
}
}
}
static void
show_image (void)
{
ChafaCanvas *canvas;
canvas = create_canvas ();
paint_canvas (canvas);
canvas_to_ncurses (canvas);
mvprintw (screen_height - 1, 0, "%d colors detected. Try resizing, or press any key to exit.", COLORS);
chafa_canvas_unref (canvas);
}
int
main (int argc, char *argv [])
{
int running = TRUE;
/* Set up locale to get proper Unicode */
setlocale (LC_ALL, "");
/* Start interactive ncurses session */
initscr ();
start_color ();
use_default_colors ();
raw ();
keypad (stdscr, TRUE);
noecho ();
curs_set (0);
/* Keep running until a key is pressed. Handle terminal resize. */
while (running)
{
clear ();
getmaxyx (stdscr, screen_height, screen_width);
show_image ();
refresh ();
if (getch () != KEY_RESIZE)
running = FALSE;
}
endwin ();
return 0;
}
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