Remove code duplication for X and Y ticks

I knew this code was repeated, and fortunately it wasn't as hard to
share it as I thought it might be. Adding minor-tick rendering will
be much easier now that this is shared.

diff --git a/acre.c b/acre.c
index cec8a2f2532a528ffdc32e6b1a9c0c227d1df68d..a01dbe5c2f1275c0c4f77b049844c8220b2c69e8 100644 (file)
--- a/acre.c
+++ b/acre.c
@@ -502,95 +502,91 @@ _draw_data (acre_t *acre)
     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 i, step;
 
     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);
-    {
-       _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 (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);
+    while (i <= axis_max) {
+       if (ticks == ACRE_TICKS_X)
+           cairo_move_to (cr, i, acre->y_axis.min);
+       else
+           cairo_move_to (cr, acre->x_axis.min, i);
+
+       /* tick */
+       cairo_save (cr);
+       {
+           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);
+           } else {
+               cairo_rel_line_to (cr, -0.5, 0);
+               cairo_rel_line_to (cr, ACRE_TICK_SIZE+0.5, 0);
            }
-           cairo_restore (cr);
-           x += step;
+           cairo_set_line_width (cr, 1.0);
+           cairo_stroke (cr);
        }
+       cairo_restore (cr);
 
-       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);
-           }
-           cairo_restore (cr);
-           y += step;
+       /* label */
+       cairo_save (cr);
+       {
+           PangoLayout *layout;
+           int width, height;
+
+           layout = _create_layout_printf (acre, "%g", i);
+
+           if (ticks == ACRE_TICKS_X)
+               cairo_move_to (cr, i, acre->y_axis.min);
+           else
+               cairo_move_to (cr, acre->x_axis.min, i);
+
+           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);
+
+       i += 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);