[hb-view] Use Chafa for terminal graphics if available

This produces high-quality terminal graphics using symbols or sixels
according to the detected terminal capabilities.

Fixes #2430.

configure.ac

@@ -214,6 +214,24 @@ AM_CONDITIONAL(HAVE_CAIRO_FT, $have_cairo_ft)
 
 dnl ==========================================================================
 
+AC_ARG_WITH(chafa,
+	[AS_HELP_STRING([--with-chafa=@<:@yes/no/auto@:>@],
+			[Use chafa @<:@default=auto@:>@])],,
+	[with_chafa=auto])
+have_chafa=false
+if test "x$with_chafa" = "xyes" -o "x$with_chafa" = "xauto"; then
+	PKG_CHECK_MODULES(CHAFA, chafa >= 1.6.0, have_chafa=true, :)
+fi
+if test "x$with_chafa" = "xyes" -a "x$have_chafa" != "xtrue"; then
+	AC_MSG_ERROR([chafa support requested but not found])
+fi
+if $have_chafa; then
+	AC_DEFINE(HAVE_CHAFA, 1, [Have chafa terminal graphics library])
+fi
+AM_CONDITIONAL(HAVE_CHAFA, $have_chafa)
+
+dnl ==========================================================================
+
 AC_ARG_WITH(icu,
 	[AS_HELP_STRING([--with-icu=@<:@yes/no/builtin/auto@:>@],
 			[Use ICU @<:@default=auto@:>@])],,
@@ -448,6 +466,7 @@ Font callbacks (the more the merrier):
 
 Tools used for command-line utilities:
 	Cairo:			${have_cairo}
+	Chafa:			${have_chafa}
 
 Additional shapers:
 	Graphite2:		${have_graphite2}

meson.build

@@ -154,6 +154,8 @@ if not get_option('cairo').disabled()
   endif
 endif
 
+chafa_dep = dependency('chafa', version: '>= 1.6.0', required: get_option('chafa'))
+
 conf = configuration_data()
 incconfig = include_directories('.')
 
@@ -181,6 +183,10 @@ if cairo_ft_dep.found()
   conf.set('HAVE_CAIRO_FT', 1)
 endif
 
+if chafa_dep.found()
+  conf.set('HAVE_CHAFA', 1)
+endif
+
 if graphite2_dep.found()
   conf.set('HAVE_GRAPHITE2', 1)
 endif
@@ -363,6 +369,7 @@ build_summary = {
     },
   'Dependencies used for command-line utilities':
     {'Cairo': conf.get('HAVE_CAIRO', 0) == 1,
+     'Chafa': conf.get('HAVE_CHAFA', 0) == 1,
     },
   'Additional shapers':
     {'Graphite2': conf.get('HAVE_GRAPHITE2', 0) == 1,

meson_options.txt

@@ -5,6 +5,8 @@ option('gobject', type: 'feature', value: 'auto',
   description: 'Enable GObject bindings')
 option('cairo', type: 'feature', value: 'auto',
   description: 'Use Cairo graphics library')
+option('chafa', type: 'feature', value: 'auto',
+  description: 'Use Chafa terminal graphics library')
 option('icu', type: 'feature', value: 'auto',
   description: 'Enable ICU library unicode functions')
 option('graphite', type: 'feature', value: 'disabled',

util/Makefile.am

@@ -25,6 +25,7 @@ AM_CPPFLAGS = \
 	$(GLIB_CFLAGS) \
 	$(FREETYPE_CFLAGS) \
 	$(CAIRO_FT_CFLAGS) \
+	$(CHAFA_CFLAGS) \
 	$(NULL)
 LDADD = \
 	$(top_builddir)/src/libharfbuzz.la \
@@ -42,6 +43,7 @@ hb_view_LDADD = \
 	$(LDADD) \
 	$(CAIRO_LIBS) \
 	$(CAIRO_FT_LIBS) \
+	$(CHAFA_LIBS) \
 	$(NULL)
 bin_PROGRAMS += hb-view
 endif # HAVE_CAIRO_FT

util/helper-cairo-ansi.cc

@@ -26,9 +26,102 @@
 
 #include "helper-cairo-ansi.hh"
 #include "options.hh"
-
 #include "ansi-print.hh"
 
+#ifdef HAVE_CHAFA
+# include <chafa.h>
+
+/* Similar to ansi-print.cc */
+# define CELL_W 8
+# define CELL_H (2 * CELL_W)
+
+static void
+chafa_print_image_rgb24 (const void *data, int width, int height, int stride)
+{
+  ChafaTermInfo *term_info;
+  ChafaSymbolMap *symbol_map;
+  ChafaCanvasConfig *config;
+  ChafaCanvas *canvas;
+  GString *gs;
+  unsigned int cols = (width +  CELL_W - 1) / CELL_W;
+  unsigned int rows = (height + CELL_H - 1) / CELL_H;
+  gchar **environ;
+  ChafaCanvasMode mode;
+  ChafaPixelMode pixel_mode;
+
+  /* Adapt to terminal; use sixels if available, and fall back to symbols
+   * with as many colors as are supported */
+
+  environ = g_get_environ ();
+  term_info = chafa_term_db_detect (chafa_term_db_get_default (),
+                                    environ);
+
+  pixel_mode = CHAFA_PIXEL_MODE_SYMBOLS;
+
+  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 if (chafa_term_info_have_seq (term_info, CHAFA_TERM_SEQ_SET_COLOR_FGBG_DIRECT))
+    mode = CHAFA_CANVAS_MODE_TRUECOLOR;
+  else if (chafa_term_info_have_seq (term_info, CHAFA_TERM_SEQ_SET_COLOR_FGBG_256))
+    mode = CHAFA_CANVAS_MODE_INDEXED_240;
+  else if (chafa_term_info_have_seq (term_info, CHAFA_TERM_SEQ_SET_COLOR_FGBG_16))
+    mode = CHAFA_CANVAS_MODE_INDEXED_16;
+  else if (chafa_term_info_have_seq (term_info, CHAFA_TERM_SEQ_INVERT_COLORS))
+    mode = CHAFA_CANVAS_MODE_FGBG_BGFG;
+  else
+    mode = CHAFA_CANVAS_MODE_FGBG;
+
+  /* Create the configuration */
+
+  symbol_map = chafa_symbol_map_new ();
+  chafa_symbol_map_add_by_tags (symbol_map,
+                                (ChafaSymbolTags) (CHAFA_SYMBOL_TAG_BLOCK
+                                                   | CHAFA_SYMBOL_TAG_SPACE));
+
+  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_cell_geometry (config, 10, 20);
+  chafa_canvas_config_set_geometry (config, cols, rows);
+  chafa_canvas_config_set_symbol_map (config, symbol_map);
+  chafa_canvas_config_set_color_extractor (config, CHAFA_COLOR_EXTRACTOR_MEDIAN);
+  chafa_canvas_config_set_work_factor (config, 1.0f);
+
+  /* Create canvas, draw to it and render output string */
+
+  canvas = chafa_canvas_new (config);
+  chafa_canvas_draw_all_pixels (canvas,
+                                /* Cairo byte order is host native */
+                                G_BYTE_ORDER == G_LITTLE_ENDIAN
+                                  ? CHAFA_PIXEL_BGRA8_PREMULTIPLIED
+                                  : CHAFA_PIXEL_ARGB8_PREMULTIPLIED,
+                                (const guint8 *) data,
+                                width,
+                                height,
+                                stride);
+  gs = chafa_canvas_print (canvas, term_info);
+
+  /* Print the string */
+
+  fwrite (gs->str, sizeof (char), gs->len, stdout);
+
+  if (pixel_mode != CHAFA_PIXEL_MODE_SIXELS)
+    fputc ('\n', stdout);
+
+  /* Free resources */
+
+  g_string_free (gs, TRUE);
+  chafa_canvas_unref (canvas);
+  chafa_canvas_config_unref (config);
+  chafa_symbol_map_unref (symbol_map);
+  chafa_term_info_unref (term_info);
+  g_strfreev (environ);
+}
+
+#endif /* HAVE_CHAFA */
 
 cairo_status_t
 helper_cairo_surface_write_to_ansi_stream (cairo_surface_t	*surface,
@@ -95,7 +188,14 @@ helper_cairo_surface_write_to_ansi_stream (cairo_surface_t	*surface,
     height++; /* Add one last blank row for padding. */
 
   if (width && height)
-    ansi_print_image_rgb24 (data, width, height, stride / 4);
+  {
+#ifdef HAVE_CHAFA
+    if (true)
+      chafa_print_image_rgb24 (data, width, height, stride);
+    else
+#endif
+      ansi_print_image_rgb24 (data, width, height, stride / 4);
+  }
 
   cairo_surface_destroy (surface);
   return CAIRO_STATUS_SUCCESS;

util/meson.build

@@ -31,7 +31,7 @@ if conf.get('HAVE_GLIB', 0) == 1
     hb_view = executable('hb-view', hb_view_sources,
       cpp_args: cpp_args,
       include_directories: [incconfig, incsrc],
-      dependencies: util_deps,
+      dependencies: [util_deps, chafa_dep],
       link_with: [libharfbuzz],
       install: true,
     )