From ac32a03148355f54e5d00a6defeea0cd177328a8 Mon Sep 17 00:00:00 2001
From: Carl Worth <cworth@cworth.org>
Date: Thu, 7 Nov 2013 09:48:53 -0800
Subject: [PATCH] Add the notion of a style for each data set.

There's no real change here yet, since the only style offered so far
is the default ACRE_STYLE_LINE, (which is the same as how acre has
always drawn things). But things will get more interesting as new
styles are added in the future.
---
 acre.c | 55 ++++++++++++++++++++++++++++++++++++++-----------------
 acre.h | 13 ++++++++++++-
 2 files changed, 50 insertions(+), 18 deletions(-)

diff --git a/acre.c b/acre.c
index 8945292..f46aebf 100644
--- a/acre.c
+++ b/acre.c
@@ -40,6 +40,9 @@ struct _acre_data {
     /* The name of this data set. */
     char *name;
 
+    /* The style for rendering (line, bar, etc.) */
+    acre_style_t style;
+
     /* Minimum and mximum extents of data. */
     acre_data_point_2d_t min;
     acre_data_point_2d_t max;
@@ -795,11 +798,36 @@ _choose_colors (acre_t *acre)
     cmsCloseProfile (srgb_profile);
 }
 
+/* Draw the given dataset as a line. */
+static void
+_draw_data_line (acre_t *acre, acre_data_t *data)
+{
+    unsigned i;
+    cairo_t *cr = acre->cr;
+
+    cairo_save (cr);
+
+    cairo_new_path (cr);
+
+    for (i = 0; i < data->num_points; i++) {
+	cairo_line_to (cr,
+		       data->points[i].x,
+		       data->points[i].y);
+    }
+
+    cairo_identity_matrix (cr);
+    cairo_set_line_width (cr, 1.0);
+    cairo_stroke (cr);
+
+    cairo_restore (cr);
+}
+
+/* Draw all the datasets of the chart. */
 static void
 _draw_data (acre_t *acre)
 {
     cairo_t *cr = acre->cr;
-    unsigned int d, i;
+    unsigned int i;
     acre_data_t *data;
 
     cairo_save (cr);
@@ -813,28 +841,19 @@ _draw_data (acre_t *acre)
 
     _set_transform_to_data_space (acre);
 
-    for (d = 0; d < acre->num_data; d++) {
-	int color = d % acre->num_colors;
+    for (i = 0; i < acre->num_data; i++) {
+	int color = i % acre->num_colors;
 	cairo_set_source_rgb (cr,
 			      acre->colors[color].red,
 			      acre->colors[color].green,
 			      acre->colors[color].blue);
-	data = acre->data[d];
-
-	cairo_new_path (cr);
+	data = acre->data[i];
 
-	for (i = 0; i < data->num_points; i++) {
-	    cairo_line_to (cr,
-			   data->points[i].x,
-			   data->points[i].y);
-	}
-	cairo_save (cr);
-	{
-	    cairo_identity_matrix (cr);
-	    cairo_set_line_width (cr, 1.0);
-	    cairo_stroke (cr);
+	switch (data->style) {
+	case ACRE_STYLE_LINE:
+	    _draw_data_line (acre, data);
+	    break;
 	}
-	cairo_restore (cr);
     }
 
     cairo_restore (cr);
@@ -1056,6 +1075,8 @@ acre_data_create (void)
 
     data->name = NULL;
 
+    data->style = ACRE_STYLE_LINE;
+
     data->points = NULL;
     data->points_size = 0;
     data->num_points = 0;
diff --git a/acre.h b/acre.h
index 663835c..6bad89a 100644
--- a/acre.h
+++ b/acre.h
@@ -89,7 +89,8 @@ void
 acre_set_y_axis_range_auto (acre_t *acre);
 
 /* Add a dataset to the plot. The plot assumes ownership of the
- * dataset so it is not necessary to call acre_data_destroy on it. */
+ * dataset so it is not necessary to call acre_data_destroy on it.
+ */
 void
 acre_add_data (acre_t *acre, acre_data_t *data);
 
@@ -111,6 +112,16 @@ acre_data_create (void);
 void
 acre_data_destroy (acre_data_t *data);
 
+/* The style to be used for rendering data sets. */
+typedef enum
+{
+	ACRE_STYLE_LINE
+} acre_style_t;
+
+/* Set the rendering style for this dataset. */
+void
+acre_data_set_style (acre_data_t *data, acre_style_t 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);
-- 
2.43.0