/**
* uber_line_graph_render_fast:
* @graph: A #UberGraph.
*
* XXX
*
* Returns: None.
* Side effects: None.
*/
static void
uber_line_graph_render_fast (UberGraph *graph, /* IN */
cairo_t *cr, /* IN */
GdkRectangle *rect, /* IN */
guint epoch, /* IN */
gfloat each) /* IN */
{
UberLineGraphPrivate *priv;
UberRange pixel_range;
LineInfo *line;
gdouble last_y;
gdouble y;
gint i;
g_return_if_fail(UBER_IS_LINE_GRAPH(graph));
g_return_if_fail(cr != NULL);
g_return_if_fail(rect != NULL);
priv = UBER_LINE_GRAPH(graph)->priv;
pixel_range.begin = rect->y + 1;
pixel_range.end = rect->y + rect->height;
pixel_range.range = pixel_range.end - pixel_range.begin;
/*
* Render most recent data point for each line.
*/
for (i = 0; i < priv->lines->len; i++) {
line = &g_array_index(priv->lines, LineInfo, i);
uber_line_graph_stylize_line(UBER_LINE_GRAPH(graph), line, cr);
/*
* Calculate positions.
*/
y = g_ring_get_index(line->raw_data, gdouble, 0);
last_y = g_ring_get_index(line->raw_data, gdouble, 1);
/*
* Don't try to draw before we have real values.
*/
if ((isnan(y) || isinf(y)) || (isnan(last_y) || isinf(last_y))) {
continue;
}
/*
* Translate to coordinate scale.
*/
if (!priv->scale(&priv->range, &pixel_range, &y, priv->scale_data) ||
!priv->scale(&priv->range, &pixel_range, &last_y, priv->scale_data)) {
continue;
}
/*
* Translate position from bottom right corner.
*/
y = (gint)(RECT_BOTTOM(*rect) - y) - .5;
last_y = (gint)(RECT_BOTTOM(*rect) - last_y) - .5;
/*
* Convert relative position to fixed from bottom pixel.
*/
cairo_new_path(cr);
cairo_move_to(cr, epoch, y);
cairo_curve_to(cr,
epoch - (each / 2.),
y,
epoch - (each / 2.),
last_y,
epoch - each,
last_y);
cairo_stroke(cr);
}
}
/**
* uber_line_graph_render:
* @graph: A #UberGraph.
* @cr: A #cairo_t context.
* @area: Full area to render contents within.
* @line: The line to render.
*
* Render a particular line to the graph.
*
* Returns: None.
* Side effects: None.
*/
static void
uber_line_graph_render_line (UberLineGraph *graph, /* IN */
cairo_t *cr, /* IN */
GdkRectangle *area, /* IN */
LineInfo *line, /* IN */
guint epoch, /* IN */
gfloat each) /* IN */
{
UberLineGraphPrivate *priv;
UberRange pixel_range;
GdkRectangle vis;
guint x;
guint last_x;
gdouble y;
gdouble last_y;
gdouble val;
gint i;
g_return_if_fail(UBER_IS_LINE_GRAPH(graph));
priv = graph->priv;
uber_graph_get_content_area(UBER_GRAPH(graph), &vis);
pixel_range.begin = area->y + 1;
pixel_range.end = area->y + area->height;
pixel_range.range = pixel_range.end - pixel_range.begin;
/*
* Prepare cairo settings.
*/
uber_line_graph_stylize_line(graph, line, cr);
/*
* Force a new path.
*/
cairo_new_path(cr);
/*
* Draw the line contents as bezier curves.
*/
for (i = 0; i < line->raw_data->len; i++) {
/*
* Retrieve data point.
*/
val = g_ring_get_index(line->raw_data, gdouble, i);
/*
* Once we get to -INFINITY, we must be at the end of the data
* sequence. This may not always be true in the future.
*/
if (val == -INFINITY) {
break;
}
/*
* Translate value to coordinate system.
*/
if (!priv->scale(&priv->range, &pixel_range, &val, priv->scale_data)) {
break;
}
/*
* Calculate X/Y coordinate.
*/
y = (gint)(RECT_BOTTOM(*area) - val) - .5;
x = epoch - (each * i);
if (i == 0) {
/*
* Just move to the right position on first entry.
*/
cairo_move_to(cr, x, y);
goto next;
} else {
/*
* Draw curve to data point using the last X/Y positions as
* control points.
*/
cairo_curve_to(cr,
last_x - (each / 2.),
last_y,
last_x - (each / 2.),
y, x, y);
}
next:
last_y = y;
last_x = x;
}
/*
* Stroke the line content.
*/
cairo_stroke(cr);
}