Eliminate some code duplication in the tick adjustment phase.

We were repeating calculations for X and Y that can just happen
once in _expand_range_for_width.

diff --git a/acre.c b/acre.c
index 6d1262abe0af95f72864255d0781c688d3bf65fd..6149cd38515b849786643811547351970393bb5a 100644 (file)
--- a/acre.c
+++ b/acre.c
@@ -293,18 +293,24 @@ _step_for_range (double range)
  * 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;
 
-    step = _step_for_range (data_range);
-    pixel_step = step * pixel_size / data_range;
+    range = *axis_max - *axis_min;
+
+    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
@@ -329,8 +335,7 @@ _compute_axis_ranges (acre_t *acre)
 {
     unsigned int d, i;
     acre_data_t *data;
-    double x_range, new_x_range, x_adjust;
-    double y_range, new_y_range, y_adjust;
+    double x_adjust, y_adjust;
     cairo_t *cr = acre->cr;
 
     /* First, simply find the extrema of the data. */
@@ -352,18 +357,13 @@ _compute_axis_ranges (acre_t *acre)
     /* 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);
-
-    y_range = acre->y_axis.max - acre->y_axis.min;
-    new_y_range = _expand_range (y_range, 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;
+    _expand_range_for_width (&acre->x_axis.min,
+                            &acre->x_axis.max,
+                            acre->chart.width);
 
-    acre->y_axis.min -= (new_y_range - y_range) / 2.0;
-    acre->y_axis.max += (new_y_range - y_range) / 2.0;
+    _expand_range_for_width (&acre->y_axis.min,
+                            &acre->y_axis.max,
+                            acre->chart.height);
 
     /* Finally, we also translate the axis ranges slightly so that the
      * ticks land on half-integer device-pixel positions.