tests: Add an example that adapts to the terminal

tests/adaptive.c

@@ -0,0 +1,314 @@
+/* This file is in the public domain, and you are free to use it as you see fit.
+ *
+ * Compile with:
+ *
+ * cc adaptive.c -o adaptive $(pkg-config --libs --cflags chafa)
+ */
+
+#include <chafa.h>
+#include <stdio.h>
+#include <unistd.h>
+
+/* Include after chafa.h for G_OS_WIN32 */
+#ifdef G_OS_WIN32
+# ifdef HAVE_WINDOWS_H
+#  include <windows.h>
+# endif
+# include <io.h>
+#else
+# include <sys/ioctl.h>  /* ioctl */
+#endif
+
+typedef struct
+{
+    gint width_cells, height_cells;
+    gint width_pixels, height_pixels;
+}
+TermSize;
+
+static void
+detect_terminal (ChafaTermInfo **term_info_out, ChafaCanvasMode *mode_out, ChafaPixelMode *pixel_mode_out)
+{
+    ChafaCanvasMode mode;
+    ChafaPixelMode pixel_mode;
+    ChafaTermInfo *term_info;
+    ChafaTermInfo *fallback_info;
+    gchar **envp;
+
+    /* Examine the environment variables and guess what the terminal can do */
+
+    envp = g_get_environ ();
+    term_info = chafa_term_db_detect (chafa_term_db_get_default (), envp);
+
+    /* See which control sequences were defined, and use that to pick the most
+     * high-quality rendering possible */
+
+    if (chafa_term_info_have_seq (term_info, CHAFA_TERM_SEQ_BEGIN_KITTY_IMMEDIATE_IMAGE_V1))
+    {
+        pixel_mode = CHAFA_PIXEL_MODE_KITTY;
+        mode = CHAFA_CANVAS_MODE_TRUECOLOR;
+    }
+    else if (chafa_term_info_have_seq (term_info, CHAFA_TERM_SEQ_BEGIN_SIXELS))
+    {
+        pixel_mode = CHAFA_PIXEL_MODE_SIXELS;
+        mode = CHAFA_CANVAS_MODE_TRUECOLOR;
+    }
+    else
+    {
+        pixel_mode = CHAFA_PIXEL_MODE_SYMBOLS;
+
+        if (chafa_term_info_have_seq (term_info, CHAFA_TERM_SEQ_SET_COLOR_FGBG_DIRECT)
+            && chafa_term_info_have_seq (term_info, CHAFA_TERM_SEQ_SET_COLOR_FG_DIRECT)
+            && chafa_term_info_have_seq (term_info, CHAFA_TERM_SEQ_SET_COLOR_BG_DIRECT))
+            mode = CHAFA_CANVAS_MODE_TRUECOLOR;
+        else if (chafa_term_info_have_seq (term_info, CHAFA_TERM_SEQ_SET_COLOR_FGBG_256)
+                 && chafa_term_info_have_seq (term_info, CHAFA_TERM_SEQ_SET_COLOR_FG_256)
+                 && chafa_term_info_have_seq (term_info, CHAFA_TERM_SEQ_SET_COLOR_BG_256))
+            mode = CHAFA_CANVAS_MODE_INDEXED_240;
+        else if (chafa_term_info_have_seq (term_info, CHAFA_TERM_SEQ_SET_COLOR_FGBG_16)
+                 && chafa_term_info_have_seq (term_info, CHAFA_TERM_SEQ_SET_COLOR_FG_16)
+                 && chafa_term_info_have_seq (term_info, CHAFA_TERM_SEQ_SET_COLOR_BG_16))
+            mode = CHAFA_CANVAS_MODE_INDEXED_16;
+        else if (chafa_term_info_have_seq (term_info, CHAFA_TERM_SEQ_INVERT_COLORS)
+                 && chafa_term_info_have_seq (term_info, CHAFA_TERM_SEQ_RESET_ATTRIBUTES))
+            mode = CHAFA_CANVAS_MODE_FGBG_BGFG;
+        else
+            mode = CHAFA_CANVAS_MODE_FGBG;
+    }
+
+    /* Hand over the information to caller */
+
+    *term_info_out = term_info;
+    *mode_out = mode;
+    *pixel_mode_out = pixel_mode;
+
+    /* Cleanup */
+
+    g_strfreev (envp);
+}
+
+static void
+get_tty_size (TermSize *term_size_out)
+{
+    TermSize term_size;
+
+    term_size.width_cells
+        = term_size.height_cells
+        = term_size.width_pixels
+        = term_size.height_pixels
+        = -1;
+
+#ifdef G_OS_WIN32
+    {
+        HANDLE chd = GetStdHandle (STD_OUTPUT_HANDLE);
+        CONSOLE_SCREEN_BUFFER_INFO csb_info;
+
+        if (chd != INVALID_HANDLE_VALUE && GetConsoleScreenBufferInfo (chd, &csb_info))
+        {
+            term_size.width_cells = csb_info.srWindow.Right - csb_info.srWindow.Left + 1;
+            term_size.height_cells = csb_info.srWindow.Bottom - csb_info.srWindow.Top + 1;
+        }
+    }
+#else
+    {
+        struct winsize w;
+        gboolean have_winsz = FALSE;
+
+        if (ioctl (STDOUT_FILENO, TIOCGWINSZ, &w) >= 0
+            || ioctl (STDERR_FILENO, TIOCGWINSZ, &w) >= 0
+            || ioctl (STDIN_FILENO, TIOCGWINSZ, &w) >= 0)
+            have_winsz = TRUE;
+
+        if (have_winsz)
+        {
+            term_size.width_cells = w.ws_col;
+            term_size.height_cells = w.ws_row;
+            term_size.width_pixels = w.ws_xpixel;
+            term_size.height_pixels = w.ws_ypixel;
+        }
+    }
+#endif
+
+    if (term_size.width_cells <= 0)
+        term_size.width_cells = -1;
+    if (term_size.height_cells <= 2)
+        term_size.height_cells = -1;
+
+    /* If .ws_xpixel and .ws_ypixel are filled out, we can calculate
+     * aspect information for the font used. Sixel-capable terminals
+     * like mlterm set these fields, but most others do not. */
+
+    if (term_size.width_pixels <= 0 || term_size.height_pixels <= 0)
+    {
+        term_size.width_pixels = -1;
+        term_size.height_pixels = -1;
+    }
+
+    *term_size_out = term_size;
+}
+
+static void
+tty_init (void)
+{
+#ifdef G_OS_WIN32
+    {
+        HANDLE chd = GetStdHandle (STD_OUTPUT_HANDLE);
+
+        saved_console_output_cp = GetConsoleOutputCP ();
+        saved_console_input_cp = GetConsoleCP ();
+
+        /* Enable ANSI escape sequence parsing etc. on MS Windows command prompt */
+
+        if (chd != INVALID_HANDLE_VALUE)
+        {
+            if (!SetConsoleMode (chd,
+                                 ENABLE_PROCESSED_OUTPUT
+                                 | ENABLE_WRAP_AT_EOL_OUTPUT
+                                 | ENABLE_VIRTUAL_TERMINAL_PROCESSING
+                                 | DISABLE_NEWLINE_AUTO_RETURN))
+                win32_stdout_is_file = TRUE;
+        }
+
+        /* Set UTF-8 code page I/O */
+
+        SetConsoleOutputCP (65001);
+        SetConsoleCP (65001);
+    }
+#endif
+}
+
+static GString *
+convert_image (const void *pixels, gint pix_width, gint pix_height,
+               gint pix_rowstride, ChafaPixelType pixel_type,
+               gint width_cells, gint height_cells,
+               gint cell_width, gint cell_height)
+{
+    ChafaTermInfo *term_info;
+    ChafaCanvasMode mode;
+    ChafaPixelMode pixel_mode;
+    ChafaSymbolMap *symbol_map;
+    ChafaCanvasConfig *config;
+    ChafaCanvas *canvas;
+    GString *printable;
+
+    detect_terminal (&term_info, &mode, &pixel_mode);
+
+    /* Specify the symbols we want */
+
+    symbol_map = chafa_symbol_map_new ();
+    chafa_symbol_map_add_by_tags (symbol_map, CHAFA_SYMBOL_TAG_BLOCK);
+
+    /* 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_pixel_mode (config, pixel_mode);
+    chafa_canvas_config_set_geometry (config, width_cells, height_cells);
+    chafa_canvas_config_set_symbol_map (config, symbol_map);
+
+    if (cell_width > 0 && cell_height > 0)
+    {
+        /* We know the pixel dimensions of each cell. Store it in the config. */
+
+        chafa_canvas_config_set_cell_geometry (config, cell_width, cell_height);
+    }
+
+    /* Create canvas */
+
+    canvas = chafa_canvas_new (config);
+
+    /* Draw pixels to the canvas */
+
+    chafa_canvas_draw_all_pixels (canvas,
+                                  pixel_type,
+                                  pixels,
+                                  pix_width,
+                                  pix_height,
+                                  pix_rowstride);
+
+    /* Build printable string */
+
+    printable = chafa_canvas_print (canvas, term_info);
+
+    /* Clean up and return */
+
+    chafa_canvas_unref (canvas);
+    chafa_canvas_config_unref (config);
+    chafa_symbol_map_unref (symbol_map);
+    chafa_term_info_unref (term_info);
+
+    return printable;
+}
+
+#define PIX_WIDTH 3
+#define PIX_HEIGHT 3
+#define N_CHANNELS 4
+
+int
+main (int argc, char *argv [])
+{
+    const guint8 pixels [PIX_WIDTH * PIX_HEIGHT * N_CHANNELS] =
+    {
+        0xff, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0xff,
+        0x00, 0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff,
+        0xff, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0xff
+    };
+    TermSize term_size;
+    GString *printable;
+    gfloat font_ratio = 0.5;
+    gint cell_width = -1, cell_height = -1;  /* Size of each character cell, in pixels */
+    gint width_cells, height_cells;  /* Size of output image, in cells */
+
+    /* Initialize the tty device if needed */
+
+    tty_init ();
+
+    /* Get the terminal dimensions and determine the output size, preserving
+     * aspect ratio */
+
+    get_tty_size (&term_size);
+
+    if (term_size.width_cells > 0
+        && term_size.height_cells > 0
+        && term_size.width_pixels > 0
+        && term_size.height_pixels > 0)
+    {
+        cell_width = term_size.width_pixels / term_size.width_cells;
+        cell_height = term_size.height_pixels / term_size.height_cells;
+        font_ratio = (gdouble) cell_width / (gdouble) cell_height;
+    }
+
+    width_cells = term_size.width_cells;
+    height_cells = term_size.height_cells;
+
+    chafa_calc_canvas_geometry (PIX_WIDTH,
+                                PIX_HEIGHT,
+                                &width_cells,
+                                &height_cells,
+                                font_ratio,
+                                TRUE,
+                                FALSE);
+
+    /* Convert the image to a printable string */
+
+    printable = convert_image (pixels,
+                               PIX_WIDTH,
+                               PIX_HEIGHT,
+                               PIX_WIDTH * N_CHANNELS,
+                               CHAFA_PIXEL_RGBA8_UNASSOCIATED,
+                               width_cells,
+                               height_cells,
+                               cell_width,
+                               cell_height);
+
+    /* Print the string */
+
+    fwrite (printable->str, sizeof (char), printable->len, stdout);
+    fputc ('\n', stdout);
+
+    /* Free resources and exit */
+
+    g_string_free (printable, TRUE);
+
+    return 0;
+}