acre-x: Fix zooming so that zoom-in and zoom-out use the same amounts

[acre] / acre.c

diff --git a/acre.c b/acre.c
index 8c64cadc47484c51181185aa7df7cc28e795cf7a..f46aebf6441271523aba89dda74d5e8d17e9e5f0 100644 (file)
--- a/acre.c
+++ b/acre.c
@@ -37,14 +37,31 @@ typedef struct _acre_data_point_2d {
 } 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 {
@@ -134,6 +151,7 @@ acre_create (void)
     acre->font = NULL;
     acre->colors = NULL;
     acre->num_colors = 0;
+    acre->colors_size = 0;
 
     acre->width = 0;
     acre->height = 0;
@@ -347,6 +365,9 @@ _create_layout (acre_t *acre, const char *text)
 {
     PangoLayout *layout;
 
+    if (text == NULL)
+           text = "";
+
     layout = pango_cairo_create_layout (acre->cr);
     pango_layout_set_font_description (layout, acre->font);
     pango_layout_set_text (layout, text, -1);
@@ -432,6 +453,7 @@ _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);
@@ -699,23 +721,6 @@ _compute_axis_ranges (acre_t *acre)
        }
     }
 
-    /* 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;
-
-       _set_transform_to_data_space (acre);
-
-       x = ACRE_TICK_MAJOR_SIZE + 2.0;
-       y = ACRE_TICK_MAJOR_SIZE + 2.0;
-       cairo_device_to_user_distance (cr, &x, &y);
-
-       acre->x_axis.view_min -= x;
-       acre->y_axis.view_min += y;
-    }
-    cairo_restore (cr);
-
     /* Then, increase the axis ranges just enough so that the step
      * sizes for the ticks will be integers.
      */
@@ -793,11 +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);
@@ -811,28 +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);
@@ -1054,6 +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;
@@ -1066,6 +1089,16 @@ 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);
@@ -1116,3 +1149,27 @@ acre_data_add_point_2d (acre_data_t *data, double x, double 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);
+}