[cairo] rescaled fonts test
Jeff Muizelaar
jeff at infidigm.net
Mon Sep 15 16:52:37 PDT 2008
The attached adds a test case that uses user fonts to draw a monospaced
font with the metrics of Bitstream Vera Sans.
The ability to draw glyphs with different metrics is useful when doing
font substitution with fixed layout like in pdf and I eventually plan on
adding code to poppler to do something similar.
This test case also exposes a bug in the pdf backend: the glyphs do not
appear rescaled.
-Jeff
-------------- next part --------------
diff --git a/test/Makefile.am b/test/Makefile.am
index 2a27310..f0dc980 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -125,6 +125,7 @@ reflected-stroke$(EXEEXT) \
rel-path$(EXEEXT) \
rgb24-ignore-alpha$(EXEEXT) \
rotate-image-surface-paint$(EXEEXT) \
+rescaled-font$(EXEEXT) \
scale-down-source-surface-paint$(EXEEXT) \
scale-source-surface-paint$(EXEEXT) \
stroke-ctm-caps$(EXEEXT) \
diff --git a/test/rescaled-font.c b/test/rescaled-font.c
new file mode 100644
index 0000000..9bbf281
--- /dev/null
+++ b/test/rescaled-font.c
@@ -0,0 +1,329 @@
+/*
+ * Copyright ? 2008 Jeff Muizelaar
+ *
+ * Permission to use, copy, modify, distribute, and sell this software
+ * and its documentation for any purpose is hereby granted without
+ * fee, provided that the above copyright notice appear in all copies
+ * and that both that copyright notice and this permission notice
+ * appear in supporting documentation, and that the name of
+ * Jeff Muizelaar not be used in advertising or publicity pertaining to
+ * distribution of the software without specific, written prior
+ * permission. Jeff Muizelaar makes no representations about the
+ * suitability of this software for any purpose. It is provided "as
+ * is" without express or implied warranty.
+ *
+ * JEFF MUIZELAAR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
+ * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS, IN NO EVENT SHALL JEFF MUIZELAAR BE LIABLE FOR ANY SPECIAL,
+ * INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
+ * RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+ * IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ * Contributor(s):
+ * Jeff Muizelaar <jeff at infidigm.net>
+ * Kristian H?gsberg <krh at redhat.com>
+ * Behdad Esfahbod <behdad at behdad.org>
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#define __USE_ISOC99
+#include <math.h>
+
+#include "cairo-test.h"
+
+#define BORDER 10
+#define TEXT_SIZE 32
+#define WIDTH (TEXT_SIZE * 13.75 + 2*BORDER)
+#define HEIGHT ((TEXT_SIZE + 2*BORDER)*3 + BORDER)
+#define TEXT "test of rescaled glyphs";
+
+static cairo_test_draw_function_t draw;
+
+cairo_test_t test = {
+ "rescaled-font",
+ "Tests drawing text with user defined widths",
+ WIDTH, HEIGHT,
+ draw
+};
+
+static const cairo_user_data_key_t rescale_font_closure_key;
+
+struct rescaled_font {
+ cairo_font_face_t *substitute_font;
+ cairo_scaled_font_t *measuring_font;
+ unsigned long glyph_count;
+ unsigned long start;
+ double *desired_width;
+ double *rescale_factor;
+};
+
+static cairo_status_t
+test_scaled_font_render_glyph (cairo_scaled_font_t *scaled_font,
+ unsigned long glyph,
+ cairo_t *cr,
+ cairo_text_extents_t *metrics)
+{
+ cairo_font_face_t *user_font = cairo_scaled_font_get_font_face (scaled_font);
+ struct rescaled_font *r = cairo_font_face_get_user_data (user_font, &rescale_font_closure_key);
+ cairo_glyph_t cairo_glyph;
+
+ cairo_glyph.index = glyph;
+ cairo_glyph.x = 0;
+ cairo_glyph.y = 0;
+
+ cairo_set_font_face (cr, r->substitute_font);
+
+ if (glyph - r->start < r->glyph_count) {
+ cairo_matrix_t matrix;
+
+ if (isnan (r->rescale_factor[glyph - r->start])) {
+ double desired_width;
+ double actual_width;
+ cairo_text_extents_t extents;
+
+ /* measure the glyph and compute the necessary rescaling factor */
+ cairo_scaled_font_glyph_extents (r->measuring_font, &cairo_glyph, 1, &extents);
+
+ desired_width = r->desired_width[glyph - r->start];
+ actual_width = extents.x_advance;
+
+ r->rescale_factor[glyph - r->start] = desired_width / actual_width;
+ }
+
+ /* scale the font so that the glyph width matches the desired width */
+ cairo_get_font_matrix (cr, &matrix);
+ cairo_matrix_scale (&matrix, r->rescale_factor[glyph - r->start], 1.);
+ cairo_set_font_matrix (cr, &matrix);
+ }
+
+ cairo_show_glyphs (cr, &cairo_glyph, 1);
+ cairo_glyph_extents (cr, &cairo_glyph, 1, metrics);
+
+ return CAIRO_STATUS_SUCCESS;
+}
+
+/* UNICHAR_TO_UTF8 from Behdad
+ * http://mces.blogspot.com/2004/07/static-unicode-to-utf-8-converter.html */
+#define UNICHAR_TO_UTF8(Char) \
+ (const char []) \
+ { \
+ /* first octet */ \
+ (Char) < 0x00000080 ? (Char) : \
+ (Char) < 0x00000800 ? ((Char) >> 6) | 0xC0 : \
+ (Char) < 0x00010000 ? ((Char) >> 12) | 0xE0 : \
+ (Char) < 0x00200000 ? ((Char) >> 18) | 0xF0 : \
+ (Char) < 0x04000000 ? ((Char) >> 24) | 0xF8 : \
+ ((Char) >> 30) | 0xFC, \
+ /* second octet */ \
+ (Char) < 0x00000080 ? 0 /* null-terminator */ : \
+ (Char) < 0x00000800 ? ((Char) & 0x3F) | 0x80 : \
+ (Char) < 0x00010000 ? (((Char) >> 6) & 0x3F) | 0x80 : \
+ (Char) < 0x00200000 ? (((Char) >> 12) & 0x3F) | 0x80 : \
+ (Char) < 0x04000000 ? (((Char) >> 18) & 0x3F) | 0x80 : \
+ (((Char) >> 24) & 0x3F) | 0x80, \
+ /* third octet */ \
+ (Char) < 0x00000800 ? 0 /* null-terminator */ : \
+ (Char) < 0x00010000 ? ((Char) & 0x3F) | 0x80 : \
+ (Char) < 0x00200000 ? (((Char) >> 6) & 0x3F) | 0x80 : \
+ (Char) < 0x04000000 ? (((Char) >> 12) & 0x3F) | 0x80 : \
+ (((Char) >> 18) & 0x3F) | 0x80, \
+ /* fourth octet */ \
+ (Char) < 0x00010000 ? 0 /* null-terminator */ : \
+ (Char) < 0x00200000 ? ((Char) & 0x3F) | 0x80 : \
+ (Char) < 0x04000000 ? (((Char) >> 6) & 0x3F) | 0x80 : \
+ (((Char) >> 12) & 0x3F) | 0x80, \
+ /* fifth octet */ \
+ (Char) < 0x00200000 ? 0 /* null-terminator */ : \
+ (Char) < 0x04000000 ? ((Char) & 0x3F) | 0x80 : \
+ (((Char) >> 6) & 0x3F) | 0x80, \
+ /* sixth octet */ \
+ (Char) < 0x04000000 ? 0 /* null-terminator */ : \
+ ((Char) & 0x3F) | 0x80, \
+ 0 /* null-terminator */ \
+ }
+
+
+static cairo_status_t
+test_scaled_font_unicode_to_glyph (cairo_scaled_font_t *scaled_font,
+ unsigned long unicode,
+ unsigned long *glyph_index) {
+ cairo_font_face_t *user_font = cairo_scaled_font_get_font_face (scaled_font);
+ struct rescaled_font *r = cairo_font_face_get_user_data (user_font, &rescale_font_closure_key);
+ int num_glyphs;
+ cairo_glyph_t *glyphs = NULL;
+
+ cairo_status_t status = cairo_scaled_font_text_to_glyphs (r->measuring_font, 0, 0,
+ UNICHAR_TO_UTF8(unicode), -1,
+ &glyphs, &num_glyphs,
+ NULL, NULL,
+ NULL);
+ if (status)
+ return status;
+
+ *glyph_index = glyphs[0].index;
+
+ cairo_glyph_free (glyphs);
+ return CAIRO_STATUS_SUCCESS;
+}
+
+static void rescale_font_closure_destroy (void *data) {
+ struct rescaled_font *r = data;
+ cairo_scaled_font_destroy (r->measuring_font);
+ free (r->desired_width);
+ free (r->rescale_factor);
+ free (r);
+}
+
+static cairo_font_face_t *
+create_rescaled_font (cairo_font_face_t *substitute_font, int glyph_start, int glyph_count, double *desired_width)
+{
+ cairo_font_face_t *user_font_face = NULL;
+ struct rescaled_font *r = malloc (sizeof(struct rescaled_font));
+ cairo_font_options_t *options = cairo_font_options_create ();
+ cairo_matrix_t m;
+ unsigned long i;
+
+ user_font_face = cairo_user_font_face_create ();
+ cairo_user_font_face_set_render_glyph_func (user_font_face, test_scaled_font_render_glyph);
+ cairo_user_font_face_set_unicode_to_glyph_func (user_font_face, test_scaled_font_unicode_to_glyph);
+
+ r->substitute_font = substitute_font;
+
+ /* we don't want any hinting when doing the measuring */
+ cairo_font_options_set_hint_style (options, CAIRO_HINT_STYLE_NONE);
+ cairo_font_options_set_hint_metrics (options, CAIRO_HINT_METRICS_OFF);
+
+ cairo_matrix_init_identity (&m);
+
+ r->measuring_font = cairo_scaled_font_create (r->substitute_font, &m, &m, options);
+
+ r->start = glyph_start;
+ r->glyph_count = glyph_count;
+ r->desired_width = calloc (sizeof(double), r->glyph_count);
+ r->rescale_factor = calloc (sizeof(double), r->glyph_count);
+
+ for (i=0; i<r->glyph_count; i++) {
+ r->desired_width[i] = desired_width[i];
+ /* use NAN to specify unset */
+ r->rescale_factor[i] = NAN;
+ }
+
+ cairo_font_options_destroy (options);
+
+ cairo_font_face_set_user_data (user_font_face, &rescale_font_closure_key,
+ r, rescale_font_closure_destroy);
+
+ return user_font_face;
+}
+
+
+
+static cairo_font_face_t *
+get_user_font_face (cairo_font_face_t *substitute_font, const char *text, cairo_font_face_t *old)
+{
+ cairo_font_options_t *options = cairo_font_options_create ();
+ cairo_matrix_t m;
+ cairo_scaled_font_t *measure;
+ int i;
+ double *widths;
+ int count;
+ int num_glyphs;
+ unsigned long min_index, max_index;
+ cairo_font_face_t *ret;
+
+ cairo_glyph_t *glyphs = NULL;
+
+ /* we don't want any hinting when doing the measuring */
+ cairo_font_options_set_hint_style (options, CAIRO_HINT_STYLE_NONE);
+ cairo_font_options_set_hint_metrics (options, CAIRO_HINT_METRICS_OFF);
+
+ cairo_matrix_init_identity (&m);
+ measure = cairo_scaled_font_create (old, &m, &m, options);
+
+ cairo_scaled_font_text_to_glyphs (measure, 0, 0,
+ text, -1,
+ &glyphs, &num_glyphs,
+ NULL, NULL,
+ NULL);
+
+ /* find the glyph range the text covers */
+ max_index = glyphs[0].index;
+ min_index = glyphs[0].index;
+ for (i=0; i<num_glyphs; i++) {
+ if (glyphs[i].index < min_index)
+ min_index = glyphs[i].index;
+ if (glyphs[i].index > max_index)
+ max_index = glyphs[i].index;
+ }
+
+ count = max_index - min_index + 1;
+ widths = malloc (sizeof(double) * count);
+ /* measure all of the necessary glyphs individually */
+ for (i=0; i<num_glyphs; i++) {
+ cairo_text_extents_t extents;
+ cairo_scaled_font_glyph_extents (measure, &glyphs[i], 1, &extents);
+ widths[glyphs[i].index - min_index] = extents.x_advance;
+ }
+
+ cairo_glyph_free (glyphs);
+
+ cairo_font_options_destroy (options);
+ cairo_scaled_font_destroy (measure);
+
+ ret = create_rescaled_font (substitute_font, min_index, count, widths);
+ free (widths);
+ return ret;
+}
+
+static cairo_test_status_t
+draw (cairo_t *cr, int width, int height)
+{
+ cairo_font_extents_t font_extents;
+ cairo_text_extents_t extents;
+ cairo_font_face_t *rescaled;
+ cairo_font_face_t *old;
+ const char text[] = TEXT;
+
+ cairo_set_source_rgb (cr, 1, 1, 1);
+ cairo_paint (cr);
+
+ cairo_select_font_face (cr, "Bitstream Vera Sans", CAIRO_FONT_SLANT_NORMAL, CAIRO_FONT_WEIGHT_NORMAL);
+
+ cairo_set_font_size (cr, TEXT_SIZE);
+
+ cairo_font_extents (cr, &font_extents);
+ cairo_text_extents (cr, text, &extents);
+
+ cairo_set_source_rgba (cr, 0, 0, 0, 0.5);
+ cairo_move_to (cr, BORDER, BORDER + font_extents.ascent);
+ cairo_show_text (cr, text);
+
+ /* same text in 'mono' with widths that match the 'sans' version */
+ old = cairo_get_font_face (cr);
+ cairo_select_font_face (cr, "Bitstream Vera Sans Mono", CAIRO_FONT_SLANT_NORMAL, CAIRO_FONT_WEIGHT_NORMAL);
+ rescaled = get_user_font_face (cairo_get_font_face (cr), text, old);
+ cairo_set_font_face (cr, rescaled);
+
+ cairo_set_source_rgba (cr, 0, 0, 1, 0.5);
+ cairo_move_to (cr, BORDER, BORDER + font_extents.height + 2*BORDER + font_extents.ascent);
+ cairo_show_text (cr, text);
+
+ cairo_font_face_destroy (rescaled);
+
+ /* mono text */
+ cairo_select_font_face (cr, "Bitstream Vera Sans Mono", CAIRO_FONT_SLANT_NORMAL, CAIRO_FONT_WEIGHT_NORMAL);
+
+ cairo_set_source_rgba (cr, 0, 0, 1, 0.5);
+ cairo_move_to (cr, BORDER, BORDER + 2*font_extents.height + 4*BORDER + font_extents.ascent);
+ cairo_show_text (cr, text);
+
+ return CAIRO_TEST_SUCCESS;
+}
+
+int
+main (void)
+{
+ return cairo_test (&test);
+}
More information about the cairo
mailing list