* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
*/
+#define _ISOC99_SOURCE /* for round() */
+#define _XOPEN_SOURCE 500
+#define _GNU_SOURCE /* for asprintf() */
+
#include "acre.h"
#include "xmalloc.h"
#include <string.h>
+#include <stdarg.h>
#include <math.h>
typedef struct _acre_data_point_2d {
/* Data for drawing. */
cairo_t *cr;
+ PangoFontDescription *font;
/* Total size including labels. */
int width;
#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)
{
cairo_t *cr = acre->cr;
- PangoFontDescription *acre_font, *title_font;
+ PangoFontDescription *title_font;
PangoLayout *title_layout, *x_axis_layout, *y_axis_layout;
int title_width, title_height;
int x_axis_width, x_axis_height;
cairo_save (cr);
- acre_font = pango_font_description_new ();
- pango_font_description_set_family (acre_font, ACRE_FONT_FAMILY);
- pango_font_description_set_absolute_size (acre_font,
+ acre->font = pango_font_description_new ();
+ pango_font_description_set_family (acre->font, ACRE_FONT_FAMILY);
+ pango_font_description_set_absolute_size (acre->font,
ACRE_FONT_SIZE * PANGO_SCALE);
title_font = pango_font_description_new ();
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
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);
}
* amount for the major ticks (see _step_for_range). To get
* nice-looking pixel-snapped ticks we want to expand the range
* slightly. */
-static double
-_expand_range (double data_range, int pixel_size)
+static void
+_expand_range_for_width (double *axis_min, double *axis_max, int pixel_size)
{
- double step, pixel_step;
+ double range, new_range, step, pixel_step;
+
+ range = *axis_max - *axis_min;
- step = _step_for_range (data_range);
- pixel_step = step * pixel_size / data_range;
+ step = _step_for_range (range);
+ pixel_step = step * pixel_size / range;
/* We expand the range by the ratio of the pixel step to the floor
* of the pixel_step.
*/
- return data_range * pixel_step / floor (pixel_step);
+ new_range = range * pixel_step / floor (pixel_step);
+
+ /* And spread the increase out on either side of the range. */
+ *axis_min -= (new_range - range) / 2.0;
+ *axis_max += (new_range - range) / 2.0;
+}
+
+/* Setup a transformation in acre->cr such that data values plotted
+ * will appear where they should within the chart.
+ */
+static void
+_set_transform_to_data_space (acre_t *acre)
+{
+ cairo_t *cr = acre->cr;
+
+ cairo_translate (cr,
+ acre->chart.x,
+ acre->chart.y + acre->chart.height);
+ cairo_scale (cr,
+ acre->chart.width / (acre->x_axis.max - acre->x_axis.min),
+ - acre->chart.height /(acre->y_axis.max - acre->y_axis.min));
+ cairo_translate (cr, -acre->x_axis.min, -acre->y_axis.min);
}
static void
{
unsigned int d, i;
acre_data_t *data;
- double x_range, new_x_range;
- double y_range, new_y_range;
+ double x_adjust, y_adjust;
+ cairo_t *cr = acre->cr;
/* First, simply find the extrema of the data. */
for (d = 0; d < acre->num_data; d++) {
/* Next, increase the axis ranges just enough so that the step
* sizes for the ticks will be integers.
*/
- x_range = acre->x_axis.max - acre->x_axis.min;
- new_x_range = _expand_range (x_range, acre->chart.width);
+ _expand_range_for_width (&acre->x_axis.min,
+ &acre->x_axis.max,
+ acre->chart.width);
- y_range = acre->y_axis.max - acre->y_axis.min;
- new_y_range = _expand_range (y_range, acre->chart.height);
+ _expand_range_for_width (&acre->y_axis.min,
+ &acre->y_axis.max,
+ acre->chart.height);
- /* And spread the increase out on either side of the range. */
- acre->x_axis.min -= (new_x_range - x_range) / 2.0;
- acre->x_axis.max += (new_x_range - x_range) / 2.0;
+ /* Finally, we also translate the axis ranges slightly so that the
+ * ticks land on half-integer device-pixel positions.
+ */
+ cairo_save (cr);
+ {
+ _set_transform_to_data_space (acre);
- acre->y_axis.min -= (new_y_range - y_range) / 2.0;
- acre->y_axis.max += (new_y_range - y_range) / 2.0;
-}
+ x_adjust = 0.0;
+ y_adjust = 0.0;
+ cairo_user_to_device (cr, &x_adjust, &y_adjust);
+ x_adjust = (round (x_adjust + 0.5) - 0.5) - x_adjust;
+ y_adjust = (round (y_adjust + 0.5) - 0.5) - y_adjust;
+ cairo_device_to_user_distance (cr, &x_adjust, &y_adjust);
-/* Setup a transformation in acre->cr such that data values plotted
- * will appear where they should within the chart.
- */
-static void
-_set_transform_to_data_space (acre_t *acre)
-{
- cairo_t *cr = acre->cr;
+ acre->x_axis.min -= x_adjust;
+ acre->x_axis.max -= x_adjust;
- cairo_translate (cr,
- acre->chart.x,
- acre->chart.y + acre->chart.height);
- cairo_scale (cr,
- acre->chart.width / (acre->x_axis.max - acre->x_axis.min),
- - acre->chart.height /(acre->y_axis.max - acre->y_axis.min));
- cairo_translate (cr, -acre->x_axis.min, -acre->y_axis.min);
+ acre->y_axis.min -= y_adjust;
+ acre->y_axis.max -= y_adjust;
+ }
+ cairo_restore (cr);
}
static void
cairo_move_to (cr, x, acre->y_axis.min);
cairo_save (cr);
{
- cairo_identity_matrix (cr);
- cairo_rel_line_to (cr, 0, 0.5);
- cairo_rel_line_to (cr, 0, -ACRE_TICK_SIZE);
- cairo_set_line_width (cr, 1.0);
- cairo_stroke (cr);
+ /* tick */
+ cairo_save (cr);
+ {
+ cairo_identity_matrix (cr);
+ cairo_rel_line_to (cr, 0, 0.5);
+ cairo_rel_line_to (cr, 0, -ACRE_TICK_SIZE-0.5);
+ cairo_set_line_width (cr, 1.0);
+ cairo_stroke (cr);
+ }
+ cairo_restore (cr);
+
+ /* label */
+ cairo_save (cr);
+ {
+ PangoLayout *layout;
+ int width, height;
+ 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);
+ _show_layout (cr, layout);
+ }
+ cairo_restore (cr);
}
cairo_restore (cr);
x += step;
cairo_move_to (cr, acre->x_axis.min, y);
cairo_save (cr);
{
- cairo_identity_matrix (cr);
- cairo_rel_line_to (cr, -0.5, 0);
- cairo_rel_line_to (cr, ACRE_TICK_SIZE, 0);
- cairo_set_line_width (cr, 1.0);
- cairo_stroke (cr);
+ /* tick */
+ cairo_save (cr);
+ {
+ cairo_identity_matrix (cr);
+ cairo_rel_line_to (cr, -0.5, 0);
+ cairo_rel_line_to (cr, ACRE_TICK_SIZE+0.5, 0);
+ cairo_set_line_width (cr, 1.0);
+ cairo_stroke (cr);
+ }
+ cairo_restore (cr);
+
+ /* label */
+ cairo_save (cr);
+ {
+ PangoLayout *layout;
+ int width, height;
+ 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);
+ _show_layout (cr, layout);
+ }
+ cairo_restore (cr);
}
cairo_restore (cr);
y += step;