Add support for a new TIMELINE style for drawing a data-set.

[acre] / acre.c

diff --git a/acre.c b/acre.c
index 8e7f1b17b6c20134201b547037660927a573e3ec..4e00beeee9557e9111d8a21467e1827e93ebc6e7 100644 (file)
--- a/acre.c
+++ b/acre.c
@@ -328,6 +328,20 @@ acre_add_data (acre_t *acre, acre_data_t *data)
 
     acre->data[acre->num_data] = data;
 
+    /* For timeline datasets, the X and Y ranges need to be
+     * adjusted. The desired X range is the min/max of the X and Y
+     * ranges, and the desired Y range has a size of 1.0 (centered
+     * around the dataset's index) */
+    if (data->style == ACRE_STYLE_TIMELINE) {
+       if (data->min.y < data->min.x)
+           data->min.x = data->min.y;
+       if (data->max.y > data->max.x)
+           data->max.x = data->max.y;
+
+       data->min.y = acre->num_data -0.5;
+       data->max.y = acre->num_data + 0.5;
+    }
+
     if (acre->num_data == 0) {
        acre->x_axis.data_min = data->min.x;
        acre->y_axis.data_min = data->min.y;
@@ -669,6 +683,11 @@ _find_y_range_given_x_range (acre_t *acre,
 
     for (d = 0; d < acre->num_data; d++) {
        data = acre->data[d];
+
+       /* Never mess with the Y range for timeline data. */
+       if (data->style == ACRE_STYLE_TIMELINE)
+           continue;
+
        for (i = 0; i < data->num_points; i++) {
            if (data->points[i].x >= x_min &&
                data->points[i].x <= x_max)
@@ -827,6 +846,71 @@ _draw_data_line (acre_t *acre, acre_data_t *data)
     cairo_restore (cr);
 }
 
+#define TIMELINE_BAR_HEIGHT 0.6
+
+/* Draw the given dataset as a timeline. Each (X,Y) point (potentially
+ * with a name) specifies the (start,stop) of a single timeline bar.
+ *
+ * Each independent timeline dataset in the chart is given its own
+ * vertical position, as specified by 'y_position'.
+ */
+static void
+_draw_data_timeline (acre_t *acre, acre_data_t *data, int y_position)
+{
+    unsigned i;
+    cairo_t *cr = acre->cr;
+    PangoLayout *timeline_label_layout;
+    double ignored, label_offset;
+    int labels_within_bar;
+
+    cairo_save (cr);
+
+    timeline_label_layout = _create_layout (acre, "Timeline");
+    pango_layout_set_font_description (timeline_label_layout, acre->font);
+
+    ignored = 0.0;
+    label_offset = ACRE_FONT_SIZE;
+    cairo_device_to_user_distance (cr, &ignored, &label_offset);
+
+    labels_within_bar = TIMELINE_BAR_HEIGHT / fabs (label_offset);
+
+    for (i = 0; i < data->num_points; i++) {
+       cairo_rectangle (cr,
+                        data->points[i].x,
+                        y_position - TIMELINE_BAR_HEIGHT / 2.0,
+                        data->points[i].y - data->points[i].x,
+                        TIMELINE_BAR_HEIGHT);
+
+       cairo_save (cr);
+       cairo_identity_matrix (cr);
+       cairo_set_line_width (cr, 1.0);
+       cairo_stroke_preserve (cr);
+       cairo_restore (cr);
+
+       cairo_new_path (cr);
+
+       if (i <= data->num_names && data->names[i]) {
+           cairo_save (cr);
+
+           cairo_move_to (cr, data->points[i].x,
+                          y_position + TIMELINE_BAR_HEIGHT / 2.0 +
+                          (i % labels_within_bar) * label_offset);
+           pango_layout_set_text (timeline_label_layout, data->names[i], -1);
+           cairo_identity_matrix (cr);
+           pango_cairo_show_layout (cr, timeline_label_layout);
+
+           cairo_restore (cr);
+       } else {
+           cairo_new_path (cr);
+       }
+
+    }
+
+    _destroy_layout (timeline_label_layout);
+
+    cairo_restore (cr);
+}
+
 /* Draw all the datasets of the chart. */
 static void
 _draw_data (acre_t *acre)
@@ -858,6 +942,10 @@ _draw_data (acre_t *acre)
        case ACRE_STYLE_LINE:
            _draw_data_line (acre, data);
            break;
+       case ACRE_STYLE_TIMELINE:
+           /* Position the timeline bars top-down */
+           _draw_data_timeline (acre, data, acre->num_data - 1 - i);
+           break;
        }
     }
 
@@ -1113,6 +1201,12 @@ acre_data_destroy (acre_data_t *data)
     free (data);
 }
 
+void
+acre_data_set_style (acre_data_t *data, acre_style_t style)
+{
+    data->style = style;
+}
+
 /* Set the label for this dataset (to appear in the plot's key). */
 void
 acre_data_set_name (acre_data_t *data, const char *name)