X-Git-Url: https://git.cworth.org/git?a=blobdiff_plain;f=acre.c;h=e91248c77e92c4a5d960d9b41d27db3ad5b8f376;hb=3a0fcbced3dfbdaef697f47219e5308df0210c5a;hp=a01dbe5c2f1275c0c4f77b049844c8220b2c69e8;hpb=5897f1f7f868e2fdfa51fc8e3bb9e02d49171b2b;p=acre

diff --git a/acre.c b/acre.c
index a01dbe5..e91248c 100644
--- a/acre.c
+++ b/acre.c
@@ -162,7 +162,8 @@ acre_add_data (acre_t *acre, acre_data_t *data)
 #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
 
@@ -333,7 +334,7 @@ _draw_title_and_labels (acre_t *acre)
 /* 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;
 
@@ -349,15 +350,21 @@ _step_for_range (double range)
      * 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
@@ -373,11 +380,12 @@ static void
 _expand_range_for_width (double *axis_min, double *axis_max, int pixel_size)
 {
     double range, new_range, step, 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);
+    pixel_step = step * pixel_size / range / minor_divisions;
 
     /* We expand the range by the ratio of the pixel step to the floor
      * of the pixel_step.
@@ -510,49 +518,63 @@ _draw_ticks (acre_t *acre,
 	     acre_ticks_t ticks)
 {
     cairo_t *cr = acre->cr;
-    double i, step;
+    double t, step, sub_step;
+    int minor_divisions;
 
     cairo_save (cr);
 
     _set_transform_to_data_space (acre);
 
-    step = _step_for_range (axis_max - axis_min);
-    i = (floor (axis_min / step) + 1) * step;
+    step = _step_for_range (axis_max - axis_min, &minor_divisions);
+    sub_step = step / minor_divisions;
 
-    while (i <= axis_max) {
-	if (ticks == ACRE_TICKS_X)
-	    cairo_move_to (cr, i, acre->y_axis.min);
+    for (t = (floor (axis_min / sub_step) + 1) * sub_step;
+	 t <= axis_max;
+	 t += sub_step)
+    {
+	int tick_size;
+	if (fabs((t / step) - (int) (t / step)) < 0.5 * (sub_step / step))
+	    tick_size = ACRE_TICK_MAJOR_SIZE;
 	else
-	    cairo_move_to (cr, acre->x_axis.min, i);
+	    tick_size = ACRE_TICK_MINOR_SIZE;
 
 	/* 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, -ACRE_TICK_SIZE-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, ACRE_TICK_SIZE+0.5, 0);
+		cairo_rel_line_to (cr, tick_size + 0.5, 0);
 	    }
+
 	    cairo_set_line_width (cr, 1.0);
 	    cairo_stroke (cr);
 	}
 	cairo_restore (cr);
 
 	/* label */
-	cairo_save (cr);
+	if (tick_size == ACRE_TICK_MAJOR_SIZE)
 	{
 	    PangoLayout *layout;
 	    int width, height;
 
-	    layout = _create_layout_printf (acre, "%g", i);
+	    cairo_save (cr);
+
+	    layout = _create_layout_printf (acre, "%g", t);
 
 	    if (ticks == ACRE_TICKS_X)
-		cairo_move_to (cr, i, acre->y_axis.min);
+		cairo_move_to (cr, t, acre->y_axis.min);
 	    else
-		cairo_move_to (cr, acre->x_axis.min, i);
+		cairo_move_to (cr, acre->x_axis.min, t);
 
 	    cairo_identity_matrix (cr);
 	    pango_layout_get_pixel_size (layout, &width, &height);
@@ -564,10 +586,9 @@ _draw_ticks (acre_t *acre,
 				   -height/2);
 
 	    _show_layout (cr, layout);
-	}
-	cairo_restore (cr);
 
-	i += step;
+	    cairo_restore (cr);
+	}
     }
 
     cairo_restore (cr);