X-Git-Url: https://git.cworth.org/git?p=acre;a=blobdiff_plain;f=acre.c;h=9f6f26ebaab1f854cd8cd392c92d19fa64a92e6c;hp=35d0541d9c4b14bc58eef0da4d86bc61121be27a;hb=HEAD;hpb=4df04fc13a5b7411dbdba561528e18f234a5364d

diff --git a/acre.c b/acre.c
index 35d0541..9f6f26e 100644
--- a/acre.c
+++ b/acre.c
@@ -26,27 +26,65 @@
 
 #include <string.h>
 #include <stdarg.h>
+#include <stdbool.h>
 #include <math.h>
 
+#include <lcms.h>
+
 typedef struct _acre_data_point_2d {
     double x;
     double y;
 } acre_data_point_2d_t;
 
 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;
+
+    /* The data itself. */
     acre_data_point_2d_t *points;
     unsigned int points_size;
     unsigned int num_points;
+
+    /* The names of data points (if any).
+     *
+     * This array is indexed with the same index as the 'points' array
+     * to provide names for points. It is legal for this array to be
+     * NULL or smaller than 'points', (in which case, the
+     * corresponding points simply have no names).
+     */
+    char **names;
+    unsigned int names_size;
+    unsigned int num_names;
 };
 
 typedef struct _acre_axis {
     char *label;
-    double min;
-    double max;
+
+    /* Range of data */
+    double data_min;
+    double data_max;
+
+    /* Range of data to be viewed. */
+    double view_min;
+    double view_max;
+
+    /* Has the view range been set? */
+    bool view_range_set;
 } acre_axis_t;
 
+typedef struct _acre_color {
+    double red;
+    double green;
+    double blue;
+} acre_color_t;
+
 struct _acre {
     char *title;
     acre_axis_t x_axis;
@@ -59,7 +97,8 @@ struct _acre {
     /* Data for drawing. */
     cairo_t *cr;
     PangoFontDescription *font;
-    struct { double r; double g; double b;} colors[3];
+    acre_color_t *colors;
+    int colors_size;
     int num_colors;
 
     /* Total size including labels. */
@@ -70,6 +109,16 @@ struct _acre {
     PangoRectangle chart;
 };
 
+static void
+_find_x_range_given_y_range (acre_t *acre,
+			     double *x_min, double *x_max,
+			     double y_min, double y_max);
+
+static void
+_find_y_range_given_x_range (acre_t *acre,
+			     double *y_min, double *y_max,
+			     double x_min, double x_max);
+
 /* Create a new, empty plot. */
 acre_t *
 acre_create (void)
@@ -81,17 +130,32 @@ acre_create (void)
     acre->title = NULL;
 
     acre->x_axis.label = NULL;
-    acre->x_axis.min = 0.0;
-    acre->x_axis.max = 0.0;
+    acre->x_axis.data_min = 0.0;
+    acre->x_axis.data_max = 0.0;
+    acre->x_axis.view_min = 0.0;
+    acre->x_axis.view_max = 0.0;
+    acre->x_axis.view_range_set = false;
 
     acre->y_axis.label = NULL;
-    acre->y_axis.min = 0.0;
-    acre->y_axis.max = 0.0;
+    acre->y_axis.data_min = 0.0;
+    acre->y_axis.data_max = 0.0;
+    acre->y_axis.view_min = 0.0;
+    acre->y_axis.view_max = 0.0;
+    acre->y_axis.view_range_set = false;
 
     acre->data = NULL;
     acre->data_size = 0;
     acre->num_data = 0;
 
+    acre->cr = NULL;
+    acre->font = NULL;
+    acre->colors = NULL;
+    acre->num_colors = 0;
+    acre->colors_size = 0;
+
+    acre->width = 0;
+    acre->height = 0;
+
     acre->chart.x = 0;
     acre->chart.y = 0;
     acre->chart.width = 0;
@@ -115,6 +179,8 @@ acre_destroy (acre_t *acre)
 
     free (acre->data);
 
+    free (acre->colors);
+
     free (acre);
 }
 
@@ -142,6 +208,110 @@ acre_set_y_axis_label (acre_t *acre, const char *label)
     acre->y_axis.label = strdup (label);
 }
 
+void
+acre_get_x_axis_data_range (acre_t *acre, double *x_min, double *x_max)
+{
+    if (x_min)
+	*x_min = acre->x_axis.data_min;
+
+    if (x_max)
+	*x_max = acre->x_axis.data_max;
+}
+
+void
+acre_get_x_axis_range (acre_t *acre, double *x_min, double *x_max)
+{
+    /* If an X range has been set, return that. */
+    if (acre->x_axis.view_range_set) {
+	if (x_min)
+	    *x_min = acre->x_axis.view_min;
+
+	if (x_max)
+	    *x_max = acre->x_axis.view_max;
+
+	return;
+    }
+
+    /* Otherwise, if a Y range has been set, use that to compute X. */
+    if (acre->y_axis.view_range_set) {
+	_find_x_range_given_y_range (acre, x_min, x_max,
+				     acre->y_axis.view_min,
+				     acre->y_axis.view_max);
+
+	return;
+    }
+
+    /* Neither view range set. Return full, data-based X range. */
+    acre_get_x_axis_data_range (acre, x_min, x_max);
+}
+
+void
+acre_set_x_axis_range (acre_t *acre, double x_min, double x_max)
+{
+    acre->x_axis.view_min = x_min;
+    acre->x_axis.view_max = x_max;
+
+    acre->x_axis.view_range_set = true;
+}
+
+void
+acre_set_x_axis_range_auto (acre_t *acre)
+{
+    acre->x_axis.view_range_set = false;
+}
+
+void
+acre_get_y_axis_data_range (acre_t *acre, double *y_min, double *y_max)
+{
+    if (y_min)
+	*y_min = acre->y_axis.data_min;
+
+    if (y_max)
+	*y_max = acre->y_axis.data_max;
+}
+
+void
+acre_get_y_axis_range (acre_t *acre, double *y_min, double *y_max)
+{
+    /* If a Y range has been set, return that. */
+    if (acre->y_axis.view_range_set) {
+	if (y_min)
+	    *y_min = acre->y_axis.view_min;
+
+	if (y_max)
+	    *y_max = acre->y_axis.view_max;
+
+	return;
+    }
+
+    /* Otherwise, if an X range has been set, use that to compute Y. */
+    if (acre->x_axis.view_range_set) {
+	_find_y_range_given_x_range (acre, y_min, y_max,
+				     acre->x_axis.view_min,
+				     acre->x_axis.view_max);
+
+	return;
+    }
+
+    /* Neither view range set. Return full data-based Y range. */
+    acre_get_y_axis_data_range (acre, y_min, y_max);
+}
+
+void
+acre_set_y_axis_range (acre_t *acre, double y_min, double y_max)
+{
+    acre->y_axis.view_min = y_min;
+    acre->y_axis.view_max = y_max;
+
+    acre->y_axis.view_range_set = true;
+}
+
+void
+acre_set_y_axis_range_auto (acre_t *acre)
+{
+    acre->y_axis.view_range_set = false;
+}
+
 /* 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. */
 void
@@ -157,6 +327,39 @@ 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;
+
+	acre->x_axis.data_max = data->max.x;
+	acre->y_axis.data_max = data->max.y;
+    } else {
+	if (data->min.x < acre->x_axis.data_min)
+	    acre->x_axis.data_min = data->min.x;
+	if (data->min.y < acre->y_axis.data_min)
+	    acre->y_axis.data_min = data->min.y;
+
+	if (data->max.x > acre->x_axis.data_max)
+	    acre->x_axis.data_max = data->max.x;
+	if (data->max.y > acre->y_axis.data_max)
+	    acre->y_axis.data_max = data->max.y;
+    }
+
     acre->num_data++;
 }
 
@@ -176,11 +379,19 @@ _create_layout (acre_t *acre, const char *text)
 {
     PangoLayout *layout;
 
+    if (text == NULL)
+	    text = "";
+
+    cairo_save (acre->cr);
+    cairo_identity_matrix (acre->cr);
+
     layout = pango_cairo_create_layout (acre->cr);
     pango_layout_set_font_description (layout, acre->font);
     pango_layout_set_text (layout, text, -1);
     pango_layout_set_alignment (layout, PANGO_ALIGN_CENTER);
 
+    cairo_restore (acre->cr);
+
     return layout;
 }
 
@@ -261,14 +472,15 @@ _draw_title_and_labels (acre_t *acre)
 
     title_layout = _create_layout (acre, acre->title);
     pango_layout_set_font_description (title_layout, title_font);
+    pango_font_description_free (title_font);
 
     x_axis_layout = _create_layout (acre, acre->x_axis.label);
     y_axis_layout = _create_layout (acre, acre->y_axis.label);
 
     min_y = _create_layout_printf (acre, "%g",
-				   round (acre->y_axis.min));
+				   round (acre->y_axis.view_min));
     max_y = _create_layout_printf (acre, "%g",
-				   round (acre->y_axis.max));
+				   round (acre->y_axis.view_max));
 
     pango_layout_get_pixel_size (min_y, &min_y_width, NULL);
     pango_layout_get_pixel_size (max_y, &max_y_width, NULL);
@@ -415,66 +627,133 @@ _set_transform_to_data_space (acre_t *acre)
 		     acre->chart.x,
 		     acre->chart.y + acre->chart.height);
     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);
+		 acre->chart.width / (acre->x_axis.view_max - acre->x_axis.view_min),
+		 - acre->chart.height /(acre->y_axis.view_max - acre->y_axis.view_min));
+    cairo_translate (cr, -acre->x_axis.view_min, -acre->y_axis.view_min);
 }
 
 static void
-_compute_axis_ranges (acre_t *acre)
+_find_x_range_given_y_range (acre_t *acre,
+			     double *x_min, double *x_max,
+			     double y_min, double y_max)
 {
-    unsigned int d, i;
     acre_data_t *data;
-    double x_adjust, y_adjust;
-    cairo_t *cr = acre->cr;
+    unsigned d, i;
+    bool first;
 
-    acre->x_axis.min = acre->data[0]->points[0].x;
-    acre->x_axis.max = acre->data[0]->points[0].x;
-    acre->y_axis.min = acre->data[0]->points[0].y;
-    acre->y_axis.min = acre->data[0]->points[0].y;
+    first = true;
 
-    /* First, simply find the extrema of the 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;
+	    if (data->points[i].y >= y_min &&
+		data->points[i].y <= y_max)
+	    {
+		if (first) {
+		    *x_min = data->points[i].x;
+		    *x_max = data->points[i].x;
+		    first = false;
+		} else {
+		    if (data->points[i].x < *x_min)
+			*x_min = data->points[i].x;
+		    if (data->points[i].x > *x_max)
+			*x_max = data->points[i].x;
+		}
+	    }
 	}
     }
 
-    /* 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;
+    /* If nothing is visible, punt to full X data range. */
+    if (first) {
+	*x_min = acre->x_axis.data_min;
+	*x_max = acre->x_axis.data_max;
+    }
+}
 
-	_set_transform_to_data_space (acre);
+static void
+_find_y_range_given_x_range (acre_t *acre,
+			     double *y_min, double *y_max,
+			     double x_min, double x_max)
+{
+    acre_data_t *data;
+    unsigned d, i;
+    bool first;
 
-	x = ACRE_TICK_MAJOR_SIZE + 2.0;
-	y = ACRE_TICK_MAJOR_SIZE + 2.0;
-	cairo_device_to_user_distance (cr, &x, &y);
+    first = true;
 
-	acre->x_axis.min -= x;
-	acre->y_axis.min += y;
+    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)
+	    {
+		if (first) {
+		    *y_min = data->points[i].y;
+		    *y_max = data->points[i].y;
+		    first = false;
+		} else {
+		    if (data->points[i].y < *y_min)
+			*y_min = data->points[i].y;
+		    if (data->points[i].y > *y_max)
+			*y_max = data->points[i].y;
+		}
+	    }
+	}
+    }
+
+    /* If nothing is visible, punt to full Y data range. */
+    if (first) {
+	*y_min = acre->y_axis.data_min;
+	*y_max = acre->y_axis.data_max;
+    }
+}
+
+static void
+_compute_axis_ranges (acre_t *acre)
+{
+    double x_adjust, y_adjust;
+    cairo_t *cr = acre->cr;
+
+    /* If neither view range is set, set both to data ranges. */
+    if (! acre->x_axis.view_range_set && ! acre->y_axis.view_range_set)
+    {
+	acre->x_axis.view_min = acre->x_axis.data_min;
+	acre->x_axis.view_max = acre->x_axis.data_max;
+
+	acre->y_axis.view_min = acre->y_axis.data_min;
+	acre->y_axis.view_max = acre->y_axis.data_max;
+    } else {
+	/* Otherwise, auto-fit unset range based on data. */
+	if (acre->x_axis.view_range_set && ! acre->y_axis.view_range_set) {
+	    _find_y_range_given_x_range (acre,
+					 &acre->y_axis.view_min,
+					 &acre->y_axis.view_max,
+					 acre->x_axis.view_min,
+					 acre->x_axis.view_max);
+	}
+	else if (acre->y_axis.view_range_set && ! acre->x_axis.view_range_set) {
+	    _find_x_range_given_y_range (acre,
+					 &acre->x_axis.view_min,
+					 &acre->x_axis.view_max,
+					 acre->y_axis.view_min,
+					 acre->y_axis.view_max);
+	}
     }
-    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,
-			     &acre->x_axis.max,
+    _expand_range_for_width (&acre->x_axis.view_min,
+			     &acre->x_axis.view_max,
 			     acre->chart.width);
 
-    _expand_range_for_width (&acre->y_axis.min,
-			     &acre->y_axis.max,
+    _expand_range_for_width (&acre->y_axis.view_min,
+			     &acre->y_axis.view_max,
 			     acre->chart.height);
 
     /* Finally, we also translate the axis ranges slightly so that the
@@ -491,11 +770,11 @@ _compute_axis_ranges (acre_t *acre)
 	y_adjust = (round (y_adjust + 0.5) - 0.5) - y_adjust;
 	cairo_device_to_user_distance (cr, &x_adjust, &y_adjust);
 
-	acre->x_axis.min -= x_adjust;
-	acre->x_axis.max -= x_adjust;
+	acre->x_axis.view_min -= x_adjust;
+	acre->x_axis.view_max -= x_adjust;
 
-	acre->y_axis.min -= y_adjust;
-	acre->y_axis.max -= y_adjust;
+	acre->y_axis.view_min -= y_adjust;
+	acre->y_axis.view_max -= y_adjust;
     }
     cairo_restore (cr);
 }
@@ -503,56 +782,225 @@ _compute_axis_ranges (acre_t *acre)
 static void
 _choose_colors (acre_t *acre)
 {
-    /* XXX: Should choose N, equally-spaced colors from a perceptually
-     * linear space here. */
-    acre->num_colors = 3;
+    cmsHPROFILE lab_profile, srgb_profile;
+    cmsHTRANSFORM lab_to_srgb;
+    int i;
+    double theta, radius, srgb[3];
+    cmsCIELab lab;
+
+    lab_profile = cmsCreateLabProfile (NULL); /* D50 */
+    srgb_profile = cmsCreate_sRGBProfile ();
+
+    lab_to_srgb = cmsCreateTransform (lab_profile, TYPE_Lab_DBL,
+				      srgb_profile, TYPE_RGB_DBL,
+				      INTENT_PERCEPTUAL, 0);
+
+    acre->num_colors = acre->num_data;
+
+    if (acre->num_colors > acre->colors_size) {
+	acre->colors_size = acre->num_colors;
+	acre->colors = xrealloc (acre->colors,
+				 acre->colors_size * sizeof (acre_color_t));
+    }
 
-    acre->colors[0].r = 1;
-    acre->colors[0].g = 0;
-    acre->colors[0].b = 0;
+    lab.L = 36;
+    radius = 130;
+    for (i = 0; i < acre->num_colors; i++) {
+	theta = 0.713 + 2 * M_PI * (double) i / acre->num_colors;
+	lab.a = radius * cos (theta);
+	lab.b = radius * sin (theta);
 
-    acre->colors[1].r = 0;
-    acre->colors[1].g = 1;
-    acre->colors[1].b = 0;
+	cmsDoTransform (lab_to_srgb, &lab, srgb, 1);
 
-    acre->colors[2].r = 0;
-    acre->colors[2].g = 0;
-    acre->colors[2].b = 1;
+	acre->colors[i].red = srgb[0];
+	acre->colors[i].green = srgb[1];
+	acre->colors[i].blue = srgb[2];
+    }
+
+    cmsDeleteTransform (lab_to_srgb);
+    cmsCloseProfile (lab_profile);
+    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);
+}
+
+#define BARS_WIDTH 0.8
+
+/* Draw the given dataset as bars. */
+static void
+_draw_data_bars (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_rectangle (cr,
+			 data->points[i].x - BARS_WIDTH / 2.0, 0.0,
+			 BARS_WIDTH, data->points[i].y);
+    }
+
+    cairo_identity_matrix (cr);
+    cairo_set_line_width (cr, 1.0);
+    cairo_stroke (cr);
+
+    cairo_restore (cr);
+}
+
+/* Draw the given dataset as bars if there is room for that.
+ *
+ * Or, if the bars would run into each other, use a line instead.
+ */
+static void
+_draw_data_bars_or_line (acre_t *acre, acre_data_t *data)
+{
+    cairo_t *cr = acre->cr;
+    double ignored, width;
+
+    /* Check device-space width available for inter-bar padding. */
+    width = 1.0 - BARS_WIDTH;
+    ignored = 0.0;
+    cairo_user_to_device_distance (cr, &width, &ignored);
+
+    /* If padding is less than two pixels, draw with a line instead. */
+    if (width < 2.0)
+	_draw_data_line (acre, data);
+    else
+	_draw_data_bars (acre, data);
+}
+
+#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)
 {
     cairo_t *cr = acre->cr;
-    unsigned int d, i;
+    unsigned int i;
     acre_data_t *data;
 
     cairo_save (cr);
 
+    cairo_rectangle (cr,
+		     acre->chart.x, acre->chart.y,
+		     acre->chart.width, acre->chart.height);
+    cairo_clip (cr);
+
     cairo_set_source_rgb (cr, 0, 0, 0);
 
     _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].r,
-			      acre->colors[color].g,
-			      acre->colors[color].b);
-	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);
+			      acre->colors[color].red,
+			      acre->colors[color].green,
+			      acre->colors[color].blue);
+	data = acre->data[i];
+
+	switch (data->style) {
+	case ACRE_STYLE_LINE:
+	    _draw_data_line (acre, data);
+	    break;
+	case ACRE_STYLE_BARS:
+	    _draw_data_bars (acre, data);
+	    break;
+	case ACRE_STYLE_BARS_OR_LINE:
+	    _draw_data_bars_or_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;
 	}
-	cairo_restore (cr);
     }
 
     cairo_restore (cr);
@@ -590,9 +1038,9 @@ _draw_ticks (acre_t *acre,
 	cairo_save (cr);
 	{
 	    if (ticks == ACRE_TICKS_X)
-		cairo_move_to (cr, t, acre->y_axis.min);
+		cairo_move_to (cr, t, acre->y_axis.view_min);
 	    else
-		cairo_move_to (cr, acre->x_axis.min, t);
+		cairo_move_to (cr, acre->x_axis.view_min, t);
 
 	    cairo_identity_matrix (cr);
 
@@ -614,15 +1062,19 @@ _draw_ticks (acre_t *acre,
 	{
 	    PangoLayout *layout;
 	    int width, height;
+	    double label_value;
 
 	    cairo_save (cr);
 
-	    layout = _create_layout_printf (acre, "%g", t);
+	    label_value = t;
+	    if (fabs (label_value) < (sub_step / 1000.))
+		label_value = 0.0;
+	    layout = _create_layout_printf (acre, "%g", label_value);
 
 	    if (ticks == ACRE_TICKS_X)
-		cairo_move_to (cr, t, acre->y_axis.min);
+		cairo_move_to (cr, t, acre->y_axis.view_min);
 	    else
-		cairo_move_to (cr, acre->x_axis.min, t);
+		cairo_move_to (cr, acre->x_axis.view_min, t);
 
 	    cairo_identity_matrix (cr);
 	    pango_layout_get_pixel_size (layout, &width, &height);
@@ -680,13 +1132,14 @@ _draw_legend (acre_t *acre)
     cairo_translate (cr, ACRE_LEGEND_PAD, ACRE_LEGEND_PAD);
 
     for (i = 0; i < acre->num_data; i++) {
-	cairo_move_to (cr, 0, ACRE_FONT_SIZE / 2 + 0.5);
-	cairo_rel_line_to (cr, ACRE_LEGEND_LINE_SIZE, 0);
+	cairo_rectangle (cr,
+			 0, ACRE_LEGEND_LINE_SIZE / 2,
+			 ACRE_LEGEND_LINE_SIZE, ACRE_LEGEND_LINE_SIZE / 2);
 	cairo_set_source_rgb (cr,
-			      acre->colors[i % acre->num_colors].r,
-			      acre->colors[i % acre->num_colors].g,
-			      acre->colors[i % acre->num_colors].b);
-	cairo_stroke (cr);
+			      acre->colors[i % acre->num_colors].red,
+			      acre->colors[i % acre->num_colors].green,
+			      acre->colors[i % acre->num_colors].blue);
+	cairo_fill (cr);
 
 	layout = _create_layout (acre, acre->data[i]->name);
 	cairo_move_to (cr, ACRE_LEGEND_LINE_SIZE + ACRE_LEGEND_PAD, 0);
@@ -709,8 +1162,8 @@ _draw_frame_and_ticks (acre_t *acre)
     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);
+    _draw_ticks (acre, acre->x_axis.view_min, acre->x_axis.view_max, ACRE_TICKS_X);
+    _draw_ticks (acre, acre->y_axis.view_min, acre->y_axis.view_max, ACRE_TICKS_Y);
 
     /* frame */
     cairo_rectangle (cr,
@@ -773,6 +1226,8 @@ acre_data_create (void)
 
     data->name = NULL;
 
+    data->style = ACRE_STYLE_LINE;
+
     data->points = NULL;
     data->points_size = 0;
     data->num_points = 0;
@@ -785,11 +1240,27 @@ acre_data_create (void)
 void
 acre_data_destroy (acre_data_t *data)
 {
+    unsigned i;
+
+    for (i = 0; i < data->num_names; i++) {
+	if (data->names[i])
+	    free (data->names[i]);
+    }
+    free (data->names);
+
+    free (data->name);
+
     free (data->points);
 
     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)
@@ -814,5 +1285,48 @@ acre_data_add_point_2d (acre_data_t *data, double x, double y)
 
     data->points[data->num_points].x = x;
     data->points[data->num_points].y = y;
+
+    if (data->num_points == 0) {
+	data->min.x = x;
+	data->min.y = y;
+
+	data->max.x = x;
+	data->max.y = y;
+    } else {
+	if (x < data->min.x)
+	    data->min.x = x;
+	if (y < data->min.y)
+	    data->min.y = y;
+
+	if (x > data->max.x)
+	    data->max.x = x;
+	if (y > data->max.y)
+	    data->max.y = y;
+    }
+
     data->num_points++;
 }
+
+/* Add a datapoint with a name to the given dataset. */
+void
+acre_data_add_point_2d_named (acre_data_t *data, double x, double y, const char *name)
+{
+    unsigned i;
+
+    acre_data_add_point_2d (data, x, y);
+
+    if (data->names_size < data->points_size) {
+	data->names_size = data->points_size;
+	data->names = xrealloc_ab (data->names,
+				   data->names_size,
+				   sizeof (char *));
+    }
+
+    /* Initialize any newly-created holes in the array to NULL. */
+    for (i = data->num_names; i < data->num_points - 1; i++)
+	data->names[i] = NULL;
+
+    data->num_names = data->num_points;
+
+    data->names[data->num_names - 1] = xstrdup (name);
+}