X-Git-Url: https://git.cworth.org/git?a=blobdiff_plain;f=acre.c;h=0851902c51d3b8e4bd029b81fd9c34c7b4a5594a;hb=df97f91d034186598ca0f4cb110c90fda4fef09a;hp=6a4728ba99313b8798fdd793000e4c03e601ccc4;hpb=4c5a0466539c8430602e95244e7550068621e0bd;p=acre diff --git a/acre.c b/acre.c index 6a4728b..0851902 100644 --- a/acre.c +++ b/acre.c @@ -17,10 +17,15 @@ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. */ +#define _ISOC99_SOURCE /* for round() */ +#define _XOPEN_SOURCE 500 +#define _GNU_SOURCE /* for asprintf() */ + #include "acre.h" #include "xmalloc.h" #include +#include #include typedef struct _acre_data_point_2d { @@ -53,6 +58,7 @@ struct _acre { /* Data for drawing. */ cairo_t *cr; + PangoFontDescription *font; /* Total size including labels. */ int width; @@ -153,11 +159,74 @@ acre_add_data (acre_t *acre, acre_data_t *data) #define ACRE_PAD (ACRE_FONT_SIZE) #define ACRE_TICK_SIZE 6 +static PangoLayout * +_create_layout (acre_t *acre, const char *text) +{ + PangoLayout *layout; + + 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); + + return layout; +} + +#define PRINTF_FORMAT(fmt_index, va_index) __attribute__ ((__format__(__printf__, fmt_index, va_index))) + +static PangoLayout * +_create_layout_vprintf (acre_t *acre, const char *fmt, va_list ap) +{ + PangoLayout *layout; + char *text; + + vasprintf (&text, fmt, ap); + + layout = _create_layout (acre, text); + + free (text); + + return layout; +} + +static PangoLayout * +_create_layout_printf (acre_t *acre, const char *fmt, ...) + PRINTF_FORMAT (2, 3); + +static PangoLayout * +_create_layout_printf (acre_t *acre, const char *fmt, ...) +{ + va_list ap; + PangoLayout *layout; + + va_start (ap, fmt); + + layout = _create_layout_vprintf (acre, fmt, ap); + + va_end (ap); + + return layout; +} + +static void +_destroy_layout (PangoLayout *layout) +{ + g_object_unref (layout); +} + +static void +_show_layout (cairo_t *cr, PangoLayout *layout) +{ + pango_cairo_show_layout (cr, layout); + + _destroy_layout (layout); +} + static void _draw_title_and_labels (acre_t *acre) { cairo_t *cr = acre->cr; - PangoFontDescription *acre_font, *title_font; + PangoFontDescription *title_font; PangoLayout *title_layout, *x_axis_layout, *y_axis_layout; int title_width, title_height; int x_axis_width, x_axis_height; @@ -166,9 +235,9 @@ _draw_title_and_labels (acre_t *acre) cairo_save (cr); - acre_font = pango_font_description_new (); - pango_font_description_set_family (acre_font, ACRE_FONT_FAMILY); - pango_font_description_set_absolute_size (acre_font, + acre->font = pango_font_description_new (); + pango_font_description_set_family (acre->font, ACRE_FONT_FAMILY); + pango_font_description_set_absolute_size (acre->font, ACRE_FONT_SIZE * PANGO_SCALE); title_font = pango_font_description_new (); @@ -176,20 +245,11 @@ _draw_title_and_labels (acre_t *acre) pango_font_description_set_absolute_size (title_font, ACRE_TITLE_FONT_SIZE * PANGO_SCALE); - title_layout = pango_cairo_create_layout (cr); + title_layout = _create_layout (acre, acre->title); pango_layout_set_font_description (title_layout, title_font); - pango_layout_set_text (title_layout, acre->title, -1); - pango_layout_set_alignment (title_layout, PANGO_ALIGN_CENTER); - - 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_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_alignment (y_axis_layout, PANGO_ALIGN_CENTER); + x_axis_layout = _create_layout (acre, acre->x_axis.label); + y_axis_layout = _create_layout (acre, acre->y_axis.label); /* Iterate with the layout of the title and axis labels until they * are stable, (this requires iteration since we don't know what @@ -232,21 +292,21 @@ _draw_title_and_labels (acre_t *acre) cairo_set_source_rgb (cr, 0, 0, 0); cairo_move_to (cr, acre->chart.x, ACRE_PAD); - pango_cairo_show_layout (cr, title_layout); + _show_layout (cr, title_layout); cairo_save (cr); { cairo_translate (cr, ACRE_PAD, acre->chart.y + acre->chart.height); cairo_rotate (cr, - M_PI / 2.0); cairo_move_to (cr, 0, 0); - pango_cairo_show_layout (cr, y_axis_layout); + _show_layout (cr, y_axis_layout); } cairo_restore (cr); cairo_move_to (cr, acre->chart.x, acre->chart.y + acre->chart.height + ACRE_FONT_SIZE + ACRE_PAD); - pango_cairo_show_layout (cr, x_axis_layout); + _show_layout (cr, x_axis_layout); cairo_restore (cr); } @@ -290,18 +350,41 @@ _step_for_range (double range) * amount for the major ticks (see _step_for_range). To get * nice-looking pixel-snapped ticks we want to expand the range * slightly. */ -static double -_expand_range (double data_range, int pixel_size) +static void +_expand_range_for_width (double *axis_min, double *axis_max, int pixel_size) { - double step, pixel_step; + double range, new_range, step, pixel_step; + + range = *axis_max - *axis_min; - step = _step_for_range (data_range); - pixel_step = step * pixel_size / data_range; + step = _step_for_range (range); + pixel_step = step * pixel_size / range; /* We expand the range by the ratio of the pixel step to the floor * of the pixel_step. */ - return data_range * pixel_step / floor (pixel_step); + new_range = range * pixel_step / floor (pixel_step); + + /* And spread the increase out on either side of the range. */ + *axis_min -= (new_range - range) / 2.0; + *axis_max += (new_range - range) / 2.0; +} + +/* Setup a transformation in acre->cr such that data values plotted + * will appear where they should within the chart. + */ +static void +_set_transform_to_data_space (acre_t *acre) +{ + cairo_t *cr = acre->cr; + + cairo_translate (cr, + 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); } static void @@ -309,8 +392,8 @@ _compute_axis_ranges (acre_t *acre) { unsigned int d, i; acre_data_t *data; - double x_range, new_x_range; - double y_range, new_y_range; + double x_adjust, y_adjust; + cairo_t *cr = acre->cr; /* First, simply find the extrema of the data. */ for (d = 0; d < acre->num_data; d++) { @@ -331,35 +414,35 @@ _compute_axis_ranges (acre_t *acre) /* Next, increase the axis ranges just enough so that the step * sizes for the ticks will be integers. */ - x_range = acre->x_axis.max - acre->x_axis.min; - new_x_range = _expand_range (x_range, acre->chart.width); + _expand_range_for_width (&acre->x_axis.min, + &acre->x_axis.max, + acre->chart.width); - y_range = acre->y_axis.max - acre->y_axis.min; - new_y_range = _expand_range (y_range, acre->chart.height); + _expand_range_for_width (&acre->y_axis.min, + &acre->y_axis.max, + acre->chart.height); - /* And spread the increase out on either side of the range. */ - acre->x_axis.min -= (new_x_range - x_range) / 2.0; - acre->x_axis.max += (new_x_range - x_range) / 2.0; + /* Finally, we also translate the axis ranges slightly so that the + * ticks land on half-integer device-pixel positions. + */ + cairo_save (cr); + { + _set_transform_to_data_space (acre); - acre->y_axis.min -= (new_y_range - y_range) / 2.0; - acre->y_axis.max += (new_y_range - y_range) / 2.0; -} + x_adjust = 0.0; + y_adjust = 0.0; + cairo_user_to_device (cr, &x_adjust, &y_adjust); + x_adjust = (round (x_adjust + 0.5) - 0.5) - x_adjust; + y_adjust = (round (y_adjust + 0.5) - 0.5) - y_adjust; + cairo_device_to_user_distance (cr, &x_adjust, &y_adjust); -/* Setup a transformation in acre->cr such that data values plotted - * will appear where they should within the chart. - */ -static void -_set_transform_to_data_space (acre_t *acre) -{ - cairo_t *cr = acre->cr; + acre->x_axis.min -= x_adjust; + acre->x_axis.max -= x_adjust; - cairo_translate (cr, - 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->y_axis.min -= y_adjust; + acre->y_axis.max -= y_adjust; + } + cairo_restore (cr); } static void @@ -416,11 +499,30 @@ _draw_frame_and_ticks (acre_t *acre) cairo_move_to (cr, x, acre->y_axis.min); cairo_save (cr); { - cairo_identity_matrix (cr); - cairo_rel_line_to (cr, 0, 0.5); - cairo_rel_line_to (cr, 0, -ACRE_TICK_SIZE); - cairo_set_line_width (cr, 1.0); - cairo_stroke (cr); + /* tick */ + cairo_save (cr); + { + cairo_identity_matrix (cr); + cairo_rel_line_to (cr, 0, 0.5); + cairo_rel_line_to (cr, 0, -ACRE_TICK_SIZE-0.5); + cairo_set_line_width (cr, 1.0); + cairo_stroke (cr); + } + cairo_restore (cr); + + /* label */ + cairo_save (cr); + { + PangoLayout *layout; + int width, height; + layout = _create_layout_printf (acre, "%g", x); + cairo_move_to (cr, x, acre->y_axis.min); + cairo_identity_matrix (cr); + pango_layout_get_pixel_size (layout, &width, &height); + cairo_rel_move_to (cr, -width / 2, 2); + _show_layout (cr, layout); + } + cairo_restore (cr); } cairo_restore (cr); x += step; @@ -432,11 +534,30 @@ _draw_frame_and_ticks (acre_t *acre) cairo_move_to (cr, acre->x_axis.min, y); cairo_save (cr); { - cairo_identity_matrix (cr); - cairo_rel_line_to (cr, -0.5, 0); - cairo_rel_line_to (cr, ACRE_TICK_SIZE, 0); - cairo_set_line_width (cr, 1.0); - cairo_stroke (cr); + /* tick */ + cairo_save (cr); + { + cairo_identity_matrix (cr); + cairo_rel_line_to (cr, -0.5, 0); + cairo_rel_line_to (cr, ACRE_TICK_SIZE+0.5, 0); + cairo_set_line_width (cr, 1.0); + cairo_stroke (cr); + } + cairo_restore (cr); + + /* label */ + cairo_save (cr); + { + PangoLayout *layout; + int width, height; + layout = _create_layout_printf (acre, "%g", y); + cairo_move_to (cr, acre->x_axis.min, y); + cairo_identity_matrix (cr); + pango_layout_get_pixel_size (layout, &width, &height); + cairo_rel_move_to (cr, -width-2, -height/2); + _show_layout (cr, layout); + } + cairo_restore (cr); } cairo_restore (cr); y += step;