Add function to create a pango layout with a printf-style format string

[acre] / acre.c

diff --git a/acre.c b/acre.c
index ca8a765abe1e3334557a8d39a8e3e0dab3cfd9c3..0851902c51d3b8e4bd029b81fd9c34c7b4a5594a 100644 (file)
--- a/acre.c
+++ b/acre.c
@@ -25,6 +25,7 @@
 #include "xmalloc.h"
 
 #include <string.h>
+#include <stdarg.h>
 #include <math.h>
 
 typedef struct _acre_data_point_2d {
@@ -158,6 +159,69 @@ acre_add_data (acre_t *acre, acre_data_t *data)
 #define ACRE_PAD (ACRE_FONT_SIZE)
 #define ACRE_TICK_SIZE 6
 
+static PangoLayout *
+_create_layout (acre_t *acre, const char *text)
+{
+    PangoLayout *layout;
+
+    layout = pango_cairo_create_layout (acre->cr);
+    pango_layout_set_font_description (layout, acre->font);
+    pango_layout_set_text (layout, text, -1);
+    pango_layout_set_alignment (layout, PANGO_ALIGN_CENTER);
+
+    return layout;
+}
+
+#define PRINTF_FORMAT(fmt_index, va_index) __attribute__ ((__format__(__printf__, fmt_index, va_index)))
+
+static PangoLayout *
+_create_layout_vprintf (acre_t *acre, const char *fmt, va_list ap)
+{
+    PangoLayout *layout;
+    char *text;
+
+    vasprintf (&text, fmt, ap);
+
+    layout = _create_layout (acre, text);
+
+    free (text);
+
+    return layout;
+}
+
+static PangoLayout *
+_create_layout_printf (acre_t *acre, const char *fmt, ...)
+    PRINTF_FORMAT (2, 3);
+
+static PangoLayout *
+_create_layout_printf (acre_t *acre, const char *fmt, ...)
+{
+    va_list ap;
+    PangoLayout *layout;
+
+    va_start (ap, fmt);
+
+    layout = _create_layout_vprintf (acre, fmt, ap);
+
+    va_end (ap);
+
+    return layout;
+}
+
+static void
+_destroy_layout (PangoLayout *layout)
+{
+    g_object_unref (layout);
+}
+
+static void
+_show_layout (cairo_t *cr, PangoLayout *layout)
+{
+    pango_cairo_show_layout (cr, layout);
+
+    _destroy_layout (layout);
+}
+
 static void
 _draw_title_and_labels (acre_t *acre)
 {
@@ -181,20 +245,11 @@ _draw_title_and_labels (acre_t *acre)
     pango_font_description_set_absolute_size (title_font,
                                              ACRE_TITLE_FONT_SIZE * PANGO_SCALE);
 
-    title_layout = pango_cairo_create_layout (cr);
+    title_layout = _create_layout (acre, acre->title);
     pango_layout_set_font_description (title_layout, title_font);
-    pango_layout_set_text (title_layout, acre->title, -1);
-    pango_layout_set_alignment (title_layout, PANGO_ALIGN_CENTER);
-
-    x_axis_layout = pango_cairo_create_layout (cr);
-    pango_layout_set_font_description (x_axis_layout, acre->font);
-    pango_layout_set_text (x_axis_layout, acre->x_axis.label, -1);
-    pango_layout_set_alignment (x_axis_layout, PANGO_ALIGN_CENTER);
 
-    y_axis_layout = pango_cairo_create_layout (cr);
-    pango_layout_set_font_description (y_axis_layout, acre->font);
-    pango_layout_set_text (y_axis_layout, acre->y_axis.label, -1);
-    pango_layout_set_alignment (y_axis_layout, PANGO_ALIGN_CENTER);
+    x_axis_layout = _create_layout (acre, acre->x_axis.label);
+    y_axis_layout = _create_layout (acre, acre->y_axis.label);
 
     /* Iterate with the layout of the title and axis labels until they
      * are stable, (this requires iteration since we don't know what
@@ -237,21 +292,21 @@ _draw_title_and_labels (acre_t *acre)
     cairo_set_source_rgb (cr, 0, 0, 0);
 
     cairo_move_to (cr, acre->chart.x, ACRE_PAD);
-    pango_cairo_show_layout (cr, title_layout);
+    _show_layout (cr, title_layout);
 
     cairo_save (cr);
     {
        cairo_translate (cr, ACRE_PAD, acre->chart.y + acre->chart.height);
        cairo_rotate (cr, - M_PI / 2.0);
        cairo_move_to (cr, 0, 0);
-       pango_cairo_show_layout (cr, y_axis_layout);
+       _show_layout (cr, y_axis_layout);
     }
     cairo_restore (cr);
 
     cairo_move_to (cr, acre->chart.x,
                   acre->chart.y + acre->chart.height +
                   ACRE_FONT_SIZE + ACRE_PAD);
-    pango_cairo_show_layout (cr, x_axis_layout);
+    _show_layout (cr, x_axis_layout);
 
     cairo_restore (cr);
 }
@@ -459,20 +514,13 @@ _draw_frame_and_ticks (acre_t *acre)
                cairo_save (cr);
                {
                    PangoLayout *layout;
-                   char *label;
                    int width, height;
-                   layout = pango_cairo_create_layout (cr);
-                   pango_layout_set_font_description (layout, acre->font);
-                   asprintf (&label, "%g", x);
-                   pango_layout_set_text (layout, label, -1);
-                   free (label);
-                   pango_layout_set_alignment (layout,
-                                               PANGO_ALIGN_CENTER);
+                   layout = _create_layout_printf (acre, "%g", x);
                    cairo_move_to (cr, x, acre->y_axis.min);
                    cairo_identity_matrix (cr);
                    pango_layout_get_pixel_size (layout, &width, &height);
                    cairo_rel_move_to (cr, -width / 2, 2);
-                   pango_cairo_show_layout (cr, layout);
+                   _show_layout (cr, layout);
                }
                cairo_restore (cr);
            }
@@ -501,20 +549,13 @@ _draw_frame_and_ticks (acre_t *acre)
                cairo_save (cr);
                {
                    PangoLayout *layout;
-                   char *label;
                    int width, height;
-                   layout = pango_cairo_create_layout (cr);
-                   pango_layout_set_font_description (layout, acre->font);
-                   asprintf (&label, "%g", y);
-                   pango_layout_set_text (layout, label, -1);
-                   free (label);
-                   pango_layout_set_alignment (layout,
-                                               PANGO_ALIGN_CENTER);
+                   layout = _create_layout_printf (acre, "%g", y);
                    cairo_move_to (cr, acre->x_axis.min, y);
                    cairo_identity_matrix (cr);
                    pango_layout_get_pixel_size (layout, &width, &height);
                    cairo_rel_move_to (cr, -width-2, -height/2);
-                   pango_cairo_show_layout (cr, layout);
+                   _show_layout (cr, layout);
                }
                cairo_restore (cr);
            }