From f69ff8a99cf0d5884fd8d820513104c7953822b0 Mon Sep 17 00:00:00 2001
From: Carl Worth <cworth@cworth.org>
Date: Sun, 25 Jan 2009 20:42:38 +1100
Subject: [PATCH] Add preliminary data plotting.

It's all in black for now, with no colors or styles.

Also, we don't yet have ticks nor axis value labels nor a key.
---
 acre.c | 101 ++++++++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 89 insertions(+), 12 deletions(-)

diff --git a/acre.c b/acre.c
index 5735695..394b700 100644
--- a/acre.c
+++ b/acre.c
@@ -36,10 +36,16 @@ struct _acre_data {
     unsigned int num_points;
 };
 
+typedef struct _acre_axis {
+    char *label;
+    double min;
+    double max;
+} acre_axis_t;
+
 struct _acre {
     char *title;
-    char *x_axis_label;
-    char *y_axis_label;
+    acre_axis_t x_axis;
+    acre_axis_t y_axis;
 
     acre_data_t **data;
     unsigned int data_size;
@@ -65,8 +71,14 @@ acre_create (void)
     acre = xmalloc (sizeof (acre_t));
 
     acre->title = NULL;
-    acre->x_axis_label = NULL;
-    acre->y_axis_label = NULL;
+
+    acre->x_axis.label = NULL;
+    acre->x_axis.min = 0.0;
+    acre->x_axis.max = 0.0;
+
+    acre->y_axis.label = NULL;
+    acre->y_axis.min = 0.0;
+    acre->y_axis.max = 0.0;
 
     acre->data = NULL;
     acre->data_size = 0;
@@ -82,8 +94,8 @@ acre_destroy (acre_t *acre)
     unsigned int i;
 
     free (acre->title);
-    free (acre->x_axis_label);
-    free (acre->y_axis_label);
+    free (acre->x_axis.label);
+    free (acre->y_axis.label);
 
     for (i = 0; i < acre->num_data; i++)
 	acre_data_destroy (acre->data[i]);
@@ -104,17 +116,17 @@ acre_set_title (acre_t *acre, const char *title)
 void
 acre_set_x_axis_label (acre_t *acre, const char *label)
 {
-    free (acre->x_axis_label);
+    free (acre->x_axis.label);
 
-    acre->x_axis_label = strdup (label);
+    acre->x_axis.label = strdup (label);
 }
 
 void
 acre_set_y_axis_label (acre_t *acre, const char *label)
 {
-    free (acre->y_axis_label);
+    free (acre->y_axis.label);
 
-    acre->y_axis_label = strdup (label);
+    acre->y_axis.label = strdup (label);
 }
 
 /* Add a dataset to the plot. The plot assumes ownership of the
@@ -171,12 +183,12 @@ _draw_title_and_labels (acre_t *acre)
 
     x_axis_layout = pango_cairo_create_layout (cr);
     pango_layout_set_font_description (x_axis_layout, acre_font);
-    pango_layout_set_text (x_axis_layout, acre->x_axis_label, -1);
+    pango_layout_set_text (x_axis_layout, acre->x_axis.label, -1);
     pango_layout_set_alignment (x_axis_layout, PANGO_ALIGN_CENTER);
 
     y_axis_layout = pango_cairo_create_layout (cr);
     pango_layout_set_font_description (y_axis_layout, acre_font);
-    pango_layout_set_text (y_axis_layout, acre->y_axis_label, -1);
+    pango_layout_set_text (y_axis_layout, acre->y_axis.label, -1);
     pango_layout_set_alignment (y_axis_layout, PANGO_ALIGN_CENTER);
 
     /* Iterate with the layout of the title and axis labels until they
@@ -239,6 +251,67 @@ _draw_title_and_labels (acre_t *acre)
     cairo_restore (cr);
 }
 
+static void
+_compute_axis_ranges (acre_t *acre)
+{
+    unsigned int d, i;
+    acre_data_t *data;
+
+    for (d = 0; d < acre->num_data; d++) {
+	data = acre->data[d];
+	for (i = 0; i < data->num_points; i++) {
+	    if (data->points[i].x < acre->x_axis.min)
+		acre->x_axis.min = data->points[i].x;
+	    if (data->points[i].x > acre->x_axis.max)
+		acre->x_axis.max = data->points[i].x;
+
+	    if (data->points[i].y < acre->y_axis.min)
+		acre->y_axis.min = data->points[i].y;
+	    if (data->points[i].y > acre->y_axis.max)
+		acre->y_axis.max = data->points[i].y;
+	}
+    }
+}
+
+static void
+_draw_data (acre_t *acre)
+{
+    cairo_t *cr = acre->cr;
+    unsigned int d, i;
+    acre_data_t *data;
+
+    cairo_save (cr);
+
+    cairo_set_source_rgb (cr, 0, 0, 0);
+
+    cairo_translate (cr,
+		     acre->chart.x + 0.5,
+		     acre->chart.y + acre->chart.height - 0.5);
+    cairo_scale (cr,
+		 acre->chart.width / (acre->x_axis.max - acre->x_axis.min),
+		 - acre->chart.height /(acre->y_axis.max - acre->y_axis.min));
+    cairo_translate (cr, -acre->x_axis.min, -acre->y_axis.min);
+
+    for (d = 0; d < acre->num_data; d++) {
+	data = acre->data[d];
+	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_save (cr);
+	{
+	    cairo_identity_matrix (cr);
+	    cairo_set_line_width (cr, 1.0);
+	    cairo_stroke (cr);
+	}
+	cairo_restore (cr);
+    }
+
+    cairo_restore (cr);
+}
+
 static void
 _draw_frame_and_ticks (acre_t *acre)
 {
@@ -276,6 +349,10 @@ acre_draw (acre_t *acre, cairo_t *cr, int width, int height)
 
     _draw_title_and_labels (acre);
 
+    _compute_axis_ranges (acre);
+
+    _draw_data (acre);
+
     _draw_frame_and_ticks (acre);
 }
 
-- 
2.43.0