#define ACRE_FONT_SIZE 12
#define ACRE_TITLE_FONT_SIZE 32
#define ACRE_PAD (ACRE_FONT_SIZE)
-#define ACRE_TICK_SIZE 6
+#define ACRE_TICK_MAJOR_SIZE 6
+#define ACRE_TICK_MINOR_SIZE 3
#define ACRE_X_TICK_VALUE_PAD 2
#define ACRE_Y_TICK_VALUE_PAD 4
/* For a given axis range, compute a step size (in data space) to
* generate a suitable number of ticks (5 or so). */
static double
-_step_for_range (double range)
+_step_for_range (double range, int *minor_divisions)
{
double step, scale_factor;
* 10). The threshold values between these are computed
* logarithmically. */
if (step < 3.535533905932738) {
- if (step < 1.58113883008419)
+ if (step < 1.58113883008419) {
step = 1.0;
- else
+ *minor_divisions = 4;
+ } else {
step = 2.5;
+ *minor_divisions = 5;
+ }
} else {
- if (step < 7.071067811865475)
+ if (step < 7.071067811865475) {
step = 5.0;
- else
+ *minor_divisions = 5;
+ } else {
step = 10.0;
+ *minor_divisions = 4;
+ }
}
/* Un-normalize and we now have the data value that we want to
* nice-looking pixel-snapped ticks we want to expand the range
* slightly. */
static void
-_expand_range_for_width (double *axis_min, double *axis_max, int pixel_size)
+_expand_range_for_width (double *axis_min, double *axis_max, int pixel_range)
{
- double range, new_range, step, pixel_step;
+ double range, new_range, step, step_minor, pixel_step;
+ int minor_divisions;
range = *axis_max - *axis_min;
- step = _step_for_range (range);
- pixel_step = step * pixel_size / range;
+ step = _step_for_range (range, &minor_divisions);
+ step_minor = step / minor_divisions;
+
+ pixel_step = step_minor * (pixel_range / range);
/* We expand the range by the ratio of the pixel step to the floor
* of the pixel_step.
}
}
- /* Next, increase the axis ranges just enough so that the step
+ /* Next, we want to ensure that the data never collides with the
+ * ticks. So we expand each axis on its minimum side as needed. */
+ cairo_save (cr);
+ {
+ double x, y;
+
+ _set_transform_to_data_space (acre);
+
+ x = ACRE_TICK_MAJOR_SIZE + 2.0;
+ y = ACRE_TICK_MAJOR_SIZE + 2.0;
+ cairo_device_to_user_distance (cr, &x, &y);
+
+ acre->x_axis.min -= x;
+ acre->y_axis.min += y;
+ }
+ cairo_restore (cr);
+
+ /* Then, increase the axis ranges just enough so that the step
* sizes for the ticks will be integers.
*/
_expand_range_for_width (&acre->x_axis.min,
cairo_restore (cr);
}
+typedef enum _ticks { ACRE_TICKS_X, ACRE_TICKS_Y } acre_ticks_t;
+
static void
-_draw_frame_and_ticks (acre_t *acre)
+_draw_ticks (acre_t *acre,
+ double axis_min, double axis_max,
+ acre_ticks_t ticks)
{
cairo_t *cr = acre->cr;
- double step, x, y;
+ double t, step, sub_step;
+ int minor_divisions;
cairo_save (cr);
- cairo_set_source_rgb (cr, 0, 0, 0); /* black */
+ _set_transform_to_data_space (acre);
- /* First the ticks within data space. */
- cairo_save (cr);
+ step = _step_for_range (axis_max - axis_min, &minor_divisions);
+ sub_step = step / minor_divisions;
+
+ for (t = (floor (axis_min / sub_step) + 1) * sub_step;
+ t <= axis_max;
+ t += sub_step)
{
- _set_transform_to_data_space (acre);
+ int tick_size;
+ if (fabs((t / step) - round (t / step)) < 0.5 * (sub_step / step))
+ tick_size = ACRE_TICK_MAJOR_SIZE;
+ else
+ tick_size = ACRE_TICK_MINOR_SIZE;
- step = _step_for_range (acre->x_axis.max -acre->x_axis.min);
- x = (floor (acre->x_axis.min / step) + 1) * step;
- while (x <= acre->x_axis.max) {
- cairo_move_to (cr, x, acre->y_axis.min);
- cairo_save (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, ACRE_X_TICK_VALUE_PAD);
- _show_layout (cr, layout);
- }
- cairo_restore (cr);
+ /* tick */
+ cairo_save (cr);
+ {
+ if (ticks == ACRE_TICKS_X)
+ cairo_move_to (cr, t, acre->y_axis.min);
+ else
+ cairo_move_to (cr, acre->x_axis.min, t);
+
+ cairo_identity_matrix (cr);
+
+ if (ticks == ACRE_TICKS_X) {
+ cairo_rel_line_to (cr, 0, 0.5);
+ cairo_rel_line_to (cr, 0, -tick_size - 0.5);
+ } else {
+ cairo_rel_line_to (cr, -0.5, 0);
+ cairo_rel_line_to (cr, tick_size + 0.5, 0);
}
- cairo_restore (cr);
- x += step;
+
+ cairo_set_line_width (cr, 1.0);
+ cairo_stroke (cr);
}
+ cairo_restore (cr);
+
+ /* label */
+ if (tick_size == ACRE_TICK_MAJOR_SIZE)
+ {
+ PangoLayout *layout;
+ int width, height;
- step = _step_for_range (acre->y_axis.max -acre->y_axis.min);
- y = (floor (acre->y_axis.min / step) + 1) * step;
- while (y <= acre->y_axis.max) {
- cairo_move_to (cr, acre->x_axis.min, y);
cairo_save (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 - ACRE_Y_TICK_VALUE_PAD,
- -height/2);
- _show_layout (cr, layout);
- }
- cairo_restore (cr);
- }
+
+ layout = _create_layout_printf (acre, "%g", t);
+
+ if (ticks == ACRE_TICKS_X)
+ cairo_move_to (cr, t, acre->y_axis.min);
+ else
+ cairo_move_to (cr, acre->x_axis.min, t);
+
+ cairo_identity_matrix (cr);
+ pango_layout_get_pixel_size (layout, &width, &height);
+
+ if (ticks == ACRE_TICKS_X)
+ cairo_rel_move_to (cr, -width / 2, ACRE_X_TICK_VALUE_PAD);
+ else
+ cairo_rel_move_to (cr, -width - ACRE_Y_TICK_VALUE_PAD,
+ -height/2);
+
+ _show_layout (cr, layout);
+
cairo_restore (cr);
- y += step;
}
}
+
cairo_restore (cr);
+}
+
+static void
+_draw_frame_and_ticks (acre_t *acre)
+{
+ cairo_t *cr = acre->cr;
+
+ cairo_save (cr);
+
+ cairo_set_source_rgb (cr, 0, 0, 0); /* black */
+
+ /* ticks */
+ _draw_ticks (acre, acre->x_axis.min, acre->x_axis.max, ACRE_TICKS_X);
+ _draw_ticks (acre, acre->y_axis.min, acre->y_axis.max, ACRE_TICKS_Y);
- /* Then the frame drawn in pixel space. */
+ /* frame */
cairo_rectangle (cr,
acre->chart.x - 0.5, acre->chart.y - 0.5,
acre->chart.width + 1.0, acre->chart.height + 1.0);
projects / acre / blobdiff