Add some distinguishing colors for the datasets

[acre] / acre.c

diff --git a/acre.c b/acre.c
index e91248c77e92c4a5d960d9b41d27db3ad5b8f376..12be71d249952421f0fb17caa956e3cd74377a0f 100644 (file)
--- a/acre.c
+++ b/acre.c
@@ -160,7 +160,7 @@ acre_add_data (acre_t *acre, acre_data_t *data)
 
 #define ACRE_FONT_FAMILY "sans"
 #define ACRE_FONT_SIZE 12
-#define ACRE_TITLE_FONT_SIZE 32
+#define ACRE_TITLE_FONT_SIZE 20
 #define ACRE_PAD (ACRE_FONT_SIZE)
 #define ACRE_TICK_MAJOR_SIZE 6
 #define ACRE_TICK_MINOR_SIZE 3
@@ -377,15 +377,17 @@ _step_for_range (double range, int *minor_divisions)
  * 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, &minor_divisions);
-    pixel_step = step * pixel_size / 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.
@@ -443,7 +445,24 @@ _compute_axis_ranges (acre_t *acre)
        }
     }
 
-    /* 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,
@@ -483,6 +502,16 @@ _draw_data (acre_t *acre)
     cairo_t *cr = acre->cr;
     unsigned int d, i;
     acre_data_t *data;
+#define NUM_COLORS 3
+    struct {
+       double r;
+       double g;
+       double b;
+    } colors [NUM_COLORS] = {
+       {1, 0, 0},
+       {0, 1, 0},
+       {0, 0, 1}
+    };
 
     cairo_save (cr);
 
@@ -491,6 +520,11 @@ _draw_data (acre_t *acre)
     _set_transform_to_data_space (acre);
 
     for (d = 0; d < acre->num_data; d++) {
+       int color = d % NUM_COLORS;
+       cairo_set_source_rgb (cr,
+                             colors[color].r,
+                             colors[color].g,
+                             colors[color].b);
        data = acre->data[d];
        cairo_new_path (cr);
        for (i = 0; i < data->num_points; i++) {
@@ -533,7 +567,7 @@ _draw_ticks (acre_t *acre,
         t += sub_step)
     {
        int tick_size;
-       if (fabs((t / step) - (int) (t / step)) < 0.5 * (sub_step / step))
+       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;