[cairo] help to compile an example pangocairo.h
andrew james
andrew at systemssingular.com
Thu Sep 16 23:24:42 PDT 2010
I only wanted to try this short example, that fails to
compile. No compile instructor was written in the example,
I tried until an hour but the error is 'undefined reference'
to a few functions in 'pangocairo.h'
error
/tmp/ccvDU65O.o: In function `draw_text':
/programs/c/pango4.c:20: undefined reference to
`pango_cairo_create_layout'
/programs/c/pango4.c:37: undefined reference to
`pango_cairo_update_layout'
/programs/c/pango4.c:40: undefined reference to
`pango_cairo_show_layout'
collect2: ld returned 1 exit status
from compile instructor that I wrote after some research
gcc -Wall -g -I/usr/include/cairo -lcairo
-I/usr/include/pango-1.0 -lpango-1.0
-I/usr/lib/glib-2.0/include -I/usr/include/glib-2.0 pango4.c
-o pango4
I am novice but after research started to think this is not
my fault, hopefully someone at this list can help
code was from a pango cairo tutorial
http://x11.gp2x.de/personal/google/
#include <math.h>
#include <pango/pangocairo.h>
static void
draw_text (cairo_t *cr)
{
#define RADIUS 150
#define N_WORDS 10
#define FONT "Sans Bold 27"
PangoLayout *layout;
PangoFontDescription *desc;
int i;
/* Center coordinates on the middle of the region we are
drawing
*/
cairo_translate (cr, RADIUS, RADIUS);
/* Create a PangoLayout, set the font and text */
layout = pango_cairo_create_layout (cr);
pango_layout_set_text (layout, "Text", -1);
desc = pango_font_description_from_string (FONT);
pango_layout_set_font_description (layout, desc);
pango_font_description_free (desc);
/* Draw the layout N_WORDS times in a circle */
for (i = 0; i < N_WORDS; i++)
{
int width, height;
double angle = (360. * i) / N_WORDS;
double red;
cairo_save (cr);
/* Gradient from red at angle == 60 to blue at angle
== 240 */
red = (1 + cos ((angle - 60) * G_PI / 180.)) / 2;
cairo_set_source_rgb (cr, red, 0, 1.0 - red);
cairo_rotate (cr, angle * G_PI / 180.);
/* Inform Pango to re-layout the text with the new
transformation */
pango_cairo_update_layout (cr, layout);
pango_layout_get_size (layout, &width, &height);
cairo_move_to (cr, - ((double)width / PANGO_SCALE) /
2, - RADIUS);
pango_cairo_show_layout (cr, layout);
cairo_restore (cr);
}
/* free the layout object */
g_object_unref (layout);
}
int main (int argc, char **argv)
{
cairo_t *cr;
char *filename;
cairo_status_t status;
cairo_surface_t *surface;
if (argc != 2)
{
g_printerr ("Usage: cairosimple OUTPUT_FILENAME\n");
return 1;
}
filename = argv[1];
surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32,
2 * RADIUS, 2 * RADIUS);
cr = cairo_create (surface);
cairo_set_source_rgb (cr, 1.0, 1.0, 1.0);
cairo_paint (cr);
draw_text (cr);
cairo_destroy (cr);
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'\n", filename);
return 1;
}
return 0;
}
hello
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