/* Data for drawing. */
cairo_t *cr;
PangoFontDescription *font;
+ struct { double r; double g; double b;} colors[3];
+ int num_colors;
/* Total size including labels. */
int width;
#define ACRE_FONT_FAMILY "sans"
#define ACRE_FONT_SIZE 12
-#define ACRE_TITLE_FONT_SIZE 32
+#define ACRE_TITLE_FONT_SIZE 20
#define ACRE_PAD (ACRE_FONT_SIZE)
#define ACRE_TICK_MAJOR_SIZE 6
#define ACRE_TICK_MINOR_SIZE 3
-#define ACRE_TICK_MINOR_DIVISIONS 5
#define ACRE_X_TICK_VALUE_PAD 2
#define ACRE_Y_TICK_VALUE_PAD 4
+#define ACRE_LEGEND_PAD 4
+#define ACRE_LEGEND_LINE_SIZE 10
static PangoLayout *
_create_layout (acre_t *acre, const char *text)
/* For a given axis range, compute a step size (in data space) to
* generate a suitable number of ticks (5 or so). */
static double
-_step_for_range (double range)
+_step_for_range (double range, int *minor_divisions)
{
double step, scale_factor;
* 10). The threshold values between these are computed
* logarithmically. */
if (step < 3.535533905932738) {
- if (step < 1.58113883008419)
+ if (step < 1.58113883008419) {
step = 1.0;
- else
+ *minor_divisions = 4;
+ } else {
step = 2.5;
+ *minor_divisions = 5;
+ }
} else {
- if (step < 7.071067811865475)
+ if (step < 7.071067811865475) {
step = 5.0;
- else
+ *minor_divisions = 5;
+ } else {
step = 10.0;
+ *minor_divisions = 4;
+ }
}
/* Un-normalize and we now have the data value that we want to
* nice-looking pixel-snapped ticks we want to expand the range
* slightly. */
static void
-_expand_range_for_width (double *axis_min, double *axis_max, int pixel_size)
+_expand_range_for_width (double *axis_min, double *axis_max, int pixel_range)
{
- double range, new_range, step, pixel_step;
+ double range, new_range, step, step_minor, pixel_step;
+ int minor_divisions;
range = *axis_max - *axis_min;
- step = _step_for_range (range);
- pixel_step = step * pixel_size / range / ACRE_TICK_MINOR_DIVISIONS;
+ step = _step_for_range (range, &minor_divisions);
+ step_minor = step / minor_divisions;
+
+ pixel_step = step_minor * (pixel_range / range);
/* We expand the range by the ratio of the pixel step to the floor
* of the pixel_step.
}
}
- /* Next, increase the axis ranges just enough so that the step
+ /* 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.min -= x;
+ acre->y_axis.min += y;
+ }
+ 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,
cairo_restore (cr);
}
+static void
+_choose_colors (acre_t *acre)
+{
+ /* XXX: Should choose N, equally-spaced colors from a perceptually
+ * linear space here. */
+ acre->num_colors = 3;
+
+ acre->colors[0].r = 1;
+ acre->colors[0].g = 0;
+ acre->colors[0].b = 0;
+
+ acre->colors[1].r = 0;
+ acre->colors[1].g = 1;
+ acre->colors[1].b = 0;
+
+ acre->colors[2].r = 0;
+ acre->colors[2].g = 0;
+ acre->colors[2].b = 1;
+}
+
static void
_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;
+ 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_t *cr = acre->cr;
double t, step, sub_step;
+ int minor_divisions;
cairo_save (cr);
_set_transform_to_data_space (acre);
- step = _step_for_range (axis_max - axis_min);
- sub_step = step / ACRE_TICK_MINOR_DIVISIONS;
+ step = _step_for_range (axis_max - axis_min, &minor_divisions);
+ sub_step = step / minor_divisions;
for (t = (floor (axis_min / sub_step) + 1) * sub_step;
t <= axis_max;
t += sub_step)
{
int tick_size;
- if (fabs((t / step) - (int) (t / step)) < 0.5 * (sub_step / step))
+ if (fabs((t / step) - round (t / step)) < 0.5 * (sub_step / step))
tick_size = ACRE_TICK_MAJOR_SIZE;
else
tick_size = ACRE_TICK_MINOR_SIZE;
cairo_restore (cr);
}
+static void
+_draw_legend (acre_t *acre)
+{
+ PangoLayout *layout;
+ int label_width, max_label_width = 0;
+ int width, height;
+ unsigned int i;
+ cairo_t *cr = acre->cr;
+
+ cairo_save (cr);
+
+ for (i = 0; i < acre->num_data; i++) {
+ layout = _create_layout (acre, acre->data[i]->name);
+ pango_layout_get_pixel_size (layout, &label_width, NULL);
+ _destroy_layout (layout);
+ if (label_width > max_label_width)
+ max_label_width = label_width;
+ }
+
+ width = ACRE_LEGEND_PAD + ACRE_LEGEND_LINE_SIZE + ACRE_LEGEND_PAD +
+ max_label_width + ACRE_LEGEND_PAD;
+ height = ACRE_LEGEND_PAD +
+ acre->num_data * (ACRE_FONT_SIZE + ACRE_LEGEND_PAD);
+
+ cairo_translate (cr, acre->chart.x, acre->chart.y);
+
+ cairo_translate (cr,
+ acre->chart.width - ACRE_LEGEND_PAD - width,
+ ACRE_LEGEND_PAD);
+
+ cairo_rectangle (cr, -0.5, -0.5, width + 1.0, height + 1.0);
+ cairo_set_source_rgb (cr, 0, 0, 0);
+ cairo_set_line_width (cr, 1.0);
+ cairo_stroke (cr);
+
+ 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_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);
+
+ layout = _create_layout (acre, acre->data[i]->name);
+ cairo_move_to (cr, ACRE_LEGEND_LINE_SIZE + ACRE_LEGEND_PAD, 0);
+ cairo_set_source_rgb (cr, 0, 0, 0);
+ _show_layout (cr, layout);
+
+ cairo_translate (cr, 0, ACRE_LEGEND_PAD + ACRE_FONT_SIZE);
+ }
+
+ cairo_restore (cr);
+}
+
static void
_draw_frame_and_ticks (acre_t *acre)
{
cairo_set_source_rgb (cr, 1, 1, 1);
+ _choose_colors (acre);
+
/* We compute the axis ranges before doing label layout so that we
* can account for the width of the y-axis value labels. */
_compute_axis_ranges (acre);
_draw_data (acre);
+ if (acre->num_data > 1)
+ _draw_legend (acre);
+
_draw_frame_and_ticks (acre);
}
projects / acre / blobdiff