[pango/pango2: 21/118] Add a userfont example
- From: Matthias Clasen <matthiasc src gnome org>
- To: commits-list gnome org
- Cc:
- Subject: [pango/pango2: 21/118] Add a userfont example
- Date: Tue, 14 Jun 2022 01:34:20 +0000 (UTC)
commit 8a218c28a074f2b9c75bfe94e88892f5dd03b882
Author: Matthias Clasen <mclasen redhat com>
Date: Thu Jan 27 20:44:14 2022 -0500
Add a userfont example
This is a more-or-less direct adaptation of
the user-font test in cairo.
examples/meson.build | 1 +
examples/userfont.c | 358 +++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 359 insertions(+)
---
diff --git a/examples/meson.build b/examples/meson.build
index f1434972a..c9738cc59 100644
--- a/examples/meson.build
+++ b/examples/meson.build
@@ -7,6 +7,7 @@ if pango_cairo_backends.contains('png')
'cairotwisted',
'parshape',
'columns',
+ 'userfont',
]
endif
diff --git a/examples/userfont.c b/examples/userfont.c
new file mode 100644
index 000000000..e047d18e7
--- /dev/null
+++ b/examples/userfont.c
@@ -0,0 +1,358 @@
+/* Example code to show how to use user fonts with Pango
+ *
+ * Written by Matthias Clasen, 2022
+ *
+ * Permission to use, copy, modify, distribute, and sell this example
+ * for any purpose is hereby granted without fee.
+ * It is provided "as is" without express or implied warranty.
+ *
+ * Font data taken from the cairo user-font test, written by
+ * Kristian Høgsberg <krh redhat com>
+ * Behdad Esfahbod <behdad behdad org>
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+
+#include <pango/pangocairo.h>
+#include <pango/pangofc-hbfontmap.h>
+
+static PangoFontMap *fontmap;
+
+#define END_GLYPH 0
+#define STROKE 126
+#define CLOSE 127
+
+/* Simple glyph definition: 1 - 15 means lineto (or moveto for first
+ * point) for one of the points on this grid:
+ *
+ * 1 2 3
+ * 4 5 6
+ * 7 8 9
+ * ----10 11 12----(baseline)
+ * 13 14 15
+ */
+typedef struct
+{
+ gunichar ucs4;
+ int width;
+ char data[16];
+} test_scaled_font_glyph_t;
+
+/* Simple glyph definition: 1 - 15 means lineto (or moveto for first
+ * point) for one of the points on this grid:
+ *
+ * 1 2 3
+ * 4 5 6
+ * 7 8 9
+ * ----10 11 12----(baseline)
+ * 13 14 15
+ */
+static const test_scaled_font_glyph_t glyphs [] = {
+ { 'a', 3, { 4, 6, 12, 10, 7, 9, STROKE, END_GLYPH } },
+ { 'c', 3, { 6, 4, 10, 12, STROKE, END_GLYPH } },
+ { 'e', 3, { 12, 10, 4, 6, 9, 7, STROKE, END_GLYPH } },
+ { 'f', 3, { 3, 2, 11, STROKE, 4, 6, STROKE, END_GLYPH } },
+ { 'g', 3, { 12, 10, 4, 6, 15, 13, STROKE, END_GLYPH } },
+ { 'h', 3, { 1, 10, STROKE, 7, 5, 6, 12, STROKE, END_GLYPH } },
+ { 'i', 1, { 1, 1, STROKE, 4, 10, STROKE, END_GLYPH } },
+ { 'l', 1, { 1, 10, STROKE, END_GLYPH } },
+ { 'n', 3, { 10, 4, STROKE, 7, 5, 6, 12, STROKE, END_GLYPH } },
+ { 'o', 3, { 4, 10, 12, 6, CLOSE, END_GLYPH } },
+ { 'p', 3, { 4, 10, 12, 6, CLOSE, 4, 13, STROKE, END_GLYPH } },
+ { 'r', 3, { 4, 10, STROKE, 7, 5, 6, STROKE, END_GLYPH } },
+ { 's', 3, { 6, 4, 7, 9, 12, 10, STROKE, END_GLYPH } },
+ { 't', 3, { 2, 11, 12, STROKE, 4, 6, STROKE, END_GLYPH } },
+ { 'u', 3, { 4, 10, 12, 6, STROKE, END_GLYPH } },
+ { 'y', 3, { 4, 10, 12, 6, STROKE, 12, 15, 13, STROKE, END_GLYPH } },
+ { 'z', 3, { 4, 6, 10, 12, STROKE, END_GLYPH } },
+ { ' ', 1, { END_GLYPH } },
+ { '-', 2, { 7, 8, STROKE, END_GLYPH } },
+ { '.', 1, { 10, 10, STROKE, END_GLYPH } },
+ { 0xe000, 3, { 3, 2, 11, STROKE, 4, 6, STROKE, 3, 3, STROKE, 6, 12, STROKE, END_GLYPH } }, /* fi */
+ { -1, 0, { END_GLYPH } },
+};
+
+const char text[] = "finally... pango user-font";
+
+static PangoLayout *
+get_layout (void)
+{
+ PangoContext *context;
+ PangoLayout *layout;
+ PangoFontDescription *desc;
+
+ /* Create a PangoLayout, set the font and text */
+ context = pango_font_map_create_context (fontmap);
+ layout = pango_layout_new (context);
+ g_object_unref (context);
+
+ pango_layout_set_text (layout, text, -1);
+
+ desc = pango_font_description_from_string ("Userfont 20");
+ pango_layout_set_font_description (layout, desc);
+ pango_font_description_free (desc);
+
+ pango_layout_write_to_file (layout, "out.layout");
+
+ return layout;
+}
+
+static gboolean
+glyph_cb (PangoUserFace *face,
+ hb_codepoint_t unicode,
+ hb_codepoint_t *glyph,
+ gpointer user_data)
+{
+ test_scaled_font_glyph_t *glyphs = user_data;
+
+ for (int i = 0; glyphs[i].ucs4 != (gunichar) -1; i++)
+ {
+ if (glyphs[i].ucs4 == unicode)
+ {
+ *glyph = i;
+ return TRUE;
+ }
+ }
+
+ return FALSE;
+}
+
+static gboolean
+glyph_info_cb (PangoUserFace *face,
+ int size,
+ hb_codepoint_t glyph,
+ hb_glyph_extents_t *extents,
+ hb_position_t *h_advance,
+ hb_position_t *v_advance,
+ gboolean *is_color,
+ gpointer user_data)
+{
+ test_scaled_font_glyph_t *glyphs = user_data;
+
+ extents->x_bearing = 0;
+ extents->y_bearing = - 0.75 * size;
+ extents->width = glyphs[glyph].width / 4.0 * size;
+ extents->height = size;
+
+ *h_advance = *v_advance = glyphs[glyph].width / 4.0 * size;
+
+ *is_color = FALSE;
+
+ return TRUE;
+}
+
+static gboolean
+shape_cb (PangoUserFace *face,
+ int size,
+ const char *text,
+ int length,
+ const PangoAnalysis *analysis,
+ PangoGlyphString *glyphs,
+ PangoShapeFlags flags,
+ gpointer user_data)
+{
+ int n_chars;
+ const char *p;
+ int cluster = 0;
+ int i, j;
+ int last_cluster;
+ gboolean is_color;
+ hb_glyph_extents_t ext;
+ hb_position_t dummy;
+
+ n_chars = g_utf8_strlen (text, length);
+
+ pango_glyph_string_set_size (glyphs, n_chars);
+
+ last_cluster = -1;
+
+ p = text;
+ j = 0;
+ for (i = 0; i < n_chars; i++)
+ {
+ gunichar wc;
+ PangoGlyph glyph = 0;
+ PangoRectangle logical_rect;
+
+ wc = g_utf8_get_char (p);
+
+ if (g_unichar_type (wc) != G_UNICODE_NON_SPACING_MARK)
+ cluster = p - text;
+
+ /* Handle the fi ligature */
+ if (p[0] == 'f' && p[1] == 'i')
+ {
+ p = g_utf8_next_char (p);
+ i++;
+ glyph_cb (face, 0xe000, &glyph, user_data);
+ }
+ else if (pango_is_zero_width (wc))
+ glyph = PANGO_GLYPH_EMPTY;
+ else if (!glyph_cb (face, wc, &glyph, user_data))
+ glyph = PANGO_GET_UNKNOWN_GLYPH (wc);
+
+ glyph_info_cb (face, size, glyph, &ext, &dummy, &dummy, &is_color, user_data);
+ pango_font_get_glyph_extents (analysis->font, glyph, NULL, &logical_rect);
+
+ glyphs->glyphs[j].glyph = glyph;
+
+ glyphs->glyphs[j].attr.is_cluster_start = cluster != last_cluster;
+ glyphs->glyphs[j].attr.is_color = is_color;
+
+ glyphs->glyphs[j].geometry.x_offset = 0;
+ glyphs->glyphs[j].geometry.y_offset = 0;
+ glyphs->glyphs[j].geometry.width = logical_rect.width;
+
+ glyphs->log_clusters[j] = cluster;
+
+ j++;
+
+ last_cluster = cluster;
+
+ p = g_utf8_next_char (p);
+ }
+
+ glyphs->num_glyphs = j;
+
+#if 0
+ /* FIXME export this */
+ if (analysis->level & 1)
+ pango_glyph_string_reverse_range (glyphs, 0, glyphs->num_glyphs);
+#endif
+
+ return TRUE;
+}
+
+static gboolean
+font_info_cb (PangoUserFace *face,
+ int size,
+ hb_font_extents_t *extents,
+ gpointer user_data)
+{
+ extents->ascender = 0.75 * size;
+ extents->descender = - 0.25 * size;
+ extents->line_gap = 0;
+
+ return TRUE;
+}
+
+static gboolean
+render_cb (PangoUserFace *face,
+ int size,
+ hb_codepoint_t glyph,
+ gpointer user_data,
+ const char *backend_id,
+ gpointer backend_data)
+{
+ test_scaled_font_glyph_t *glyphs = user_data;
+ cairo_t *cr = backend_data;
+ const char *data;
+ div_t d;
+ double x, y;
+
+ if (strcmp (backend_id, "cairo") != 0)
+ return FALSE;
+
+ cairo_set_line_width (cr, 0.1);
+ cairo_set_line_join (cr, CAIRO_LINE_JOIN_ROUND);
+ cairo_set_line_cap (cr, CAIRO_LINE_CAP_ROUND);
+
+ data = glyphs[glyph].data;
+ for (int i = 0; data[i] != END_GLYPH; i++)
+ {
+ switch (data[i])
+ {
+ case STROKE:
+ cairo_new_sub_path (cr);
+ break;
+
+ case CLOSE:
+ cairo_close_path (cr);
+ break;
+
+ default:
+ d = div (data[i] - 1, 3);
+ x = d.rem / 4.0 + 0.125;
+ y = d.quot / 5.0 + 0.4 - 1.0;
+ cairo_line_to (cr, x, y);
+ }
+ }
+
+ cairo_stroke (cr);
+
+ return TRUE;
+}
+
+static void
+setup_fontmap (PangoHbFontMap *fontmap)
+{
+ PangoFontDescription *desc;
+ PangoUserFace *face;
+
+ desc = pango_font_description_new ();
+ pango_font_description_set_family (desc, "Userfont");
+ face = pango_user_face_new (font_info_cb,
+ glyph_cb,
+ glyph_info_cb,
+ shape_cb,
+ render_cb,
+ (gpointer) glyphs, NULL,
+ "Black", desc);
+ pango_hb_font_map_add_face (fontmap, PANGO_FONT_FACE (face));
+ pango_font_description_free (desc);
+}
+
+int
+main (int argc, char **argv)
+{
+ cairo_t *cr;
+ char *filename;
+ cairo_status_t status;
+ cairo_surface_t *surface;
+ PangoLayout *layout;
+ PangoRectangle ext;
+
+ if (argc != 2)
+ {
+ g_printerr ("Usage: userfont OUTPUT_FILENAME\n");
+ return 1;
+ }
+
+ filename = argv[1];
+
+ fontmap = PANGO_FONT_MAP (pango_fc_hb_font_map_new ());
+ setup_fontmap (PANGO_HB_FONT_MAP (fontmap));
+
+ layout = get_layout ();
+
+ pango_lines_get_extents (pango_layout_get_lines (layout), NULL, &ext);
+ pango_extents_to_pixels (&ext, NULL);
+
+ /* Now create the final surface and draw to it. */
+ surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32, ext.width + 20, ext.height + 20);
+ cr = cairo_create (surface);
+
+ cairo_set_source_rgb (cr, 1.0, 1.0, 1.0);
+ cairo_paint (cr);
+ cairo_set_source_rgb (cr, 0.0, 0.0, 0.5);
+
+ cairo_move_to (cr, 10, 10);
+ pango_cairo_show_layout (cr, layout);
+
+ cairo_destroy (cr);
+
+ g_object_unref (layout);
+
+ /* Write out the surface as PNG */
+ status = cairo_surface_write_to_png (surface, filename);
+ cairo_surface_destroy (surface);
+
+ if (status != CAIRO_STATUS_SUCCESS)
+ {
+ g_printerr ("Could not save png to '%s': %s\n", filename, cairo_status_to_string (status));
+ return 1;
+ }
+
+ return 0;
+}
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