src/output/cairo-chart.c

   1 /* PSPP - a program for statistical analysis.
   2    Copyright (C) 2004, 2009, 2010, 2011, 2014, 2015 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation, either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <http://www.gnu.org/licenses/>. */
  16
  17 #include <config.h>
  18
  19 #include "output/cairo-chart.h"
  20 #include "math/decimal.h"
  21 #include "math/chart-geometry.h"
  22
  23 #include <assert.h>
  24 #include <cairo/cairo.h>
  25 #include <pango/pango.h>
  26 #include <pango/pangocairo.h>
  27 #include <float.h>
  28 #include <math.h>
  29 #include <stdarg.h>
  30 #include <stdio.h>
  31 #include <stdlib.h>
  32 #include <string.h>
  33
  34 #include "libpspp/assertion.h"
  35 #include "math/chart-geometry.h"
  36 #include "output/cairo.h"
  37 #include "output/chart-item.h"
  38
  39 #include "gl/xalloc.h"
  40 #include "gl/xvasprintf.h"
  41
  42 #include "gettext.h"
  43 #define _(msgid) gettext (msgid)
  44
  45 void
  46 xrchart_geometry_init (cairo_t *cr, struct xrchart_geometry *geom,
  47                        double width, double length)
  48 {
  49   /* Set default chart geometry. */
  50   geom->axis[SCALE_ORDINATE].data_max = 0.900 * length;
  51   geom->axis[SCALE_ORDINATE].data_min = 0.120 * length;
  52
  53   geom->axis[SCALE_ABSCISSA].data_min = 0.150 * width;
  54   geom->axis[SCALE_ABSCISSA].data_max = 0.800 * width;
  55   geom->abscissa_bottom = 0.070 * length;
  56   geom->ordinate_left = 0.050 * width;
  57   geom->title_bottom = 0.920 * length;
  58   geom->legend_left = 0.810 * width;
  59   geom->legend_right = width;
  60   geom->font_size = 15.0;
  61   geom->in_path = false;
  62   geom->dataset = NULL;
  63   geom->n_datasets = 0;
  64
  65   geom->fill_colour = data_colour[0];
  66
  67   cairo_set_line_width (cr, 1.0);
  68
  69   cairo_rectangle (cr, geom->axis[SCALE_ABSCISSA].data_min, geom->axis[SCALE_ORDINATE].data_min,
  70                    geom->axis[SCALE_ABSCISSA].data_max - geom->axis[SCALE_ABSCISSA].data_min,
  71                    geom->axis[SCALE_ORDINATE].data_max - geom->axis[SCALE_ORDINATE].data_min);
  72   cairo_stroke (cr);
  73 }
  74
  75 void
  76 xrchart_geometry_free (cairo_t *cr UNUSED, struct xrchart_geometry *geom)
  77 {
  78   int i;
  79
  80   for (i = 0 ; i < geom->n_datasets; ++i)
  81     free (geom->dataset[i]);
  82   free (geom->dataset);
  83 }
  84
  85 #if ! PANGO_VERSION_CHECK (1, 22, 0)
  86 int pango_layout_get_baseline (PangoLayout    *layout);
  87
  88 /* Shamelessly copied from the pango source */
  89 int
  90 pango_layout_get_baseline (PangoLayout    *layout)
  91 {
  92   int baseline;
  93
  94   /* XXX this is so inefficient */
  95   PangoLayoutIter *iter = pango_layout_get_iter (layout);
  96   baseline = pango_layout_iter_get_baseline (iter);
  97   pango_layout_iter_free (iter);
  98
  99   return baseline;
 100 }
 101 #endif
 102
 103 /*
 104     These colours come from:
 105     http://tango.freedesktop.org/static/cvs/tango-art-tools/palettes/Tango-Palette.gpl */
 106 const struct xrchart_colour data_colour[XRCHART_N_COLOURS] =
 107   {
 108     {252, 233,  79},    /* Butter 1 */
 109     {138, 226,  52},    /* Chameleon 1 */
 110     {252, 175,  62},    /* Orange 1 */
 111     {114, 159, 207},    /* Sky Blue 1 */
 112     {173, 127, 168},    /* Plum 1 */
 113     {233, 185, 110},    /* Chocolate 1 */
 114     {239,  41,  41},    /* Scarlet Red 1 */
 115     {238, 238, 236},    /* Aluminium 1 */
 116
 117     {237, 212,   0},    /* Butter 2 */
 118     {115, 210,  22},    /* Chameleon 2 */
 119     {245, 121,   0},    /* Orange 2 */
 120     {52,  101, 164},    /* Sky Blue 2 */
 121     {117,  80, 123},    /* Plum 2 */
 122     {193, 125,  17},    /* Chocolate 2 */
 123     {204,   0,   0},    /* Scarlet Red 2 */
 124
 125     {136, 138, 133},    /* Aluminium 4 */
 126
 127     {196, 160,   0},    /* Butter 3 */
 128     {78,  154,   6},    /* Chameleon 3 */
 129     {206,  92,   0},    /* Orange 3 */
 130     {32,   74, 135},    /* Sky Blue 3 */
 131     {92,   53, 102},    /* Plum 3 */
 132     {143,  89,   2},    /* Chocolate 3 */
 133     {164,   0,   0},    /* Scarlet Red 3 */
 134     {85,   87,  83},    /* Aluminium 5 */
 135
 136     {211, 215, 207},    /* Aluminium 2 */
 137     {186, 189, 182},    /* Aluminium 3 */
 138     {46,   52,  54},    /* Aluminium 6 */
 139   };
 140
 141 void
 142 xrchart_draw_marker (cairo_t *cr, double x, double y,
 143                      enum xrmarker_type marker, double size)
 144 {
 145   cairo_save (cr);
 146   cairo_translate (cr, x, y);
 147   cairo_scale (cr, size / 2.0, size / 2.0);
 148   cairo_set_line_width (cr, cairo_get_line_width (cr) / (size / 2.0));
 149   switch (marker)
 150     {
 151     case XRMARKER_CIRCLE:
 152       cairo_arc (cr, 0, 0, 1.0, 0, 2 * M_PI);
 153       cairo_stroke (cr);
 154       break;
 155
 156     case XRMARKER_ASTERISK:
 157       cairo_move_to (cr, 0, -1.0); /* | */
 158       cairo_line_to (cr, 0, 1.0);
 159       cairo_move_to (cr, -M_SQRT1_2, -M_SQRT1_2); /* / */
 160       cairo_line_to (cr, M_SQRT1_2, M_SQRT1_2);
 161       cairo_move_to (cr, -M_SQRT1_2, M_SQRT1_2); /* \ */
 162       cairo_line_to (cr, M_SQRT1_2, -M_SQRT1_2);
 163       cairo_stroke (cr);
 164       break;
 165
 166     case XRMARKER_SQUARE:
 167       cairo_rectangle (cr, -1.0, -1.0, 2.0, 2.0);
 168       cairo_stroke (cr);
 169       break;
 170     }
 171   cairo_restore (cr);
 172 }
 173
 174 void
 175 xrchart_label_rotate (cairo_t *cr, int horz_justify, int vert_justify,
 176                       double font_size, const char *string, double angle)
 177 {
 178   PangoFontDescription *desc;
 179   PangoLayout *layout;
 180   double x, y;
 181
 182   desc = pango_font_description_from_string ("Sans");
 183   if (desc == NULL)
 184     {
 185       cairo_new_path (cr);
 186       return;
 187     }
 188   pango_font_description_set_absolute_size (desc, font_size * PANGO_SCALE);
 189
 190   cairo_save (cr);
 191   cairo_rotate (cr, angle);
 192   cairo_get_current_point (cr, &x, &y);
 193   cairo_translate (cr, x, y);
 194   cairo_move_to (cr, 0, 0);
 195   cairo_scale (cr, 1.0, -1.0);
 196
 197   layout = pango_cairo_create_layout (cr);
 198   pango_layout_set_font_description (layout, desc);
 199   pango_layout_set_text (layout, string, -1);
 200   if (horz_justify != 'l')
 201     {
 202       int width_pango;
 203       double width;
 204
 205       pango_layout_get_size (layout, &width_pango, NULL);
 206       width = (double) width_pango / PANGO_SCALE;
 207       if (horz_justify == 'r')
 208         cairo_rel_move_to (cr, -width, 0);
 209       else
 210         cairo_rel_move_to (cr, -width / 2.0, 0);
 211     }
 212   if (vert_justify == 'x')
 213     {
 214       int baseline_pango = pango_layout_get_baseline (layout);
 215       double baseline = (double) baseline_pango / PANGO_SCALE;
 216       cairo_rel_move_to (cr, 0, -baseline);
 217     }
 218   else if (vert_justify != 't')
 219     {
 220       int height_pango;
 221       double height;
 222
 223       pango_layout_get_size (layout, NULL, &height_pango);
 224       height = (double) height_pango / PANGO_SCALE;
 225       if (vert_justify == 'b')
 226         cairo_rel_move_to (cr, 0, -height);
 227       else if (vert_justify == 'c')
 228         cairo_rel_move_to (cr, 0, -height / 2.0);
 229     }
 230   pango_cairo_show_layout (cr, layout);
 231   g_object_unref (layout);
 232
 233   cairo_restore (cr);
 234
 235   cairo_new_path (cr);
 236
 237   pango_font_description_free (desc);
 238 }
 239
 240 void
 241 xrchart_label (cairo_t *cr, int horz_justify, int vert_justify,
 242                double font_size, const char *string)
 243 {
 244   xrchart_label_rotate (cr, horz_justify, vert_justify, font_size, string, 0);
 245 }
 246
 247
 248 /* Draw a tick mark at position
 249    If label is non null, then print it at the tick mark
 250 */
 251 static void
 252 draw_tick_internal (cairo_t *cr, const struct xrchart_geometry *geom,
 253                     enum tick_orientation orientation,
 254                     bool rotated,
 255                     double position,
 256                     const char *s);
 257
 258 void
 259 draw_tick (cairo_t *cr, const struct xrchart_geometry *geom,
 260            enum tick_orientation orientation,
 261            bool rotated,
 262            double position,
 263            const char *label, ...)
 264 {
 265   va_list ap;
 266   char *s;
 267   va_start (ap, label);
 268   s = xvasprintf (label, ap);
 269
 270   if (fabs (position) < DBL_EPSILON)
 271     position = 0;
 272
 273   draw_tick_internal (cr, geom, orientation, rotated, position, s);
 274   free (s);
 275   va_end (ap);
 276 }
 277
 278
 279 static void
 280 draw_tick_internal (cairo_t *cr, const struct xrchart_geometry *geom,
 281                     enum tick_orientation orientation,
 282                     bool rotated,
 283                     double position,
 284                     const char *s)
 285 {
 286   const int tickSize = 10;
 287   double x, y;
 288
 289   cairo_move_to (cr, geom->axis[SCALE_ABSCISSA].data_min, geom->axis[SCALE_ORDINATE].data_min);
 290
 291   if (orientation == SCALE_ABSCISSA)
 292     {
 293       cairo_rel_move_to (cr, position, 0);
 294       cairo_rel_line_to (cr, 0, -tickSize);
 295     }
 296   else if (orientation == SCALE_ORDINATE)
 297     {
 298       cairo_rel_move_to (cr, 0, position);
 299       cairo_rel_line_to (cr, -tickSize, 0);
 300     }
 301   else
 302     NOT_REACHED ();
 303   cairo_get_current_point (cr, &x, &y);
 304
 305   cairo_stroke (cr);
 306
 307   if (s != NULL)
 308     {
 309       cairo_move_to (cr, x, y);
 310
 311       if (orientation == SCALE_ABSCISSA)
 312         {
 313           if ( rotated)
 314             xrchart_label_rotate (cr, 'l', 'c', geom->font_size, s, -G_PI_4);
 315           else
 316             xrchart_label (cr, 'c', 't', geom->font_size, s);
 317         }
 318       else if (orientation == SCALE_ORDINATE)
 319         {
 320           if (fabs (position) < DBL_EPSILON)
 321             cairo_rel_move_to (cr, 0, 10);
 322           xrchart_label (cr, 'r', 'c', geom->font_size, s);
 323         }
 324     }
 325 }
 326
 327
 328 /* Write the title on a chart*/
 329 void
 330 xrchart_write_title (cairo_t *cr, const struct xrchart_geometry *geom,
 331                    const char *title, ...)
 332 {
 333   va_list ap;
 334   char *s;
 335
 336   cairo_save (cr);
 337   cairo_move_to (cr, geom->axis[SCALE_ABSCISSA].data_min, geom->title_bottom);
 338
 339   va_start(ap, title);
 340   s = xvasprintf (title, ap);
 341   xrchart_label (cr, 'l', 'x', geom->font_size * 1.5, s);
 342   free (s);
 343   va_end (ap);
 344
 345   cairo_restore (cr);
 346 }
 347
 348
 349
 350 static void
 351 xrchart_write_scale (cairo_t *cr, struct xrchart_geometry *geom,
 352                      double smin, double smax, enum tick_orientation orient)
 353 {
 354   int s;
 355   int ticks;
 356
 357   struct decimal dinterval;
 358   struct decimal dlower;
 359   struct decimal dupper;
 360
 361   chart_get_scale (smax, smin, &dlower, &dinterval, &ticks);
 362
 363   dupper = dinterval;
 364   decimal_int_multiply (&dupper, ticks);
 365   decimal_add (&dupper, &dlower);
 366
 367   double tick_interval = decimal_to_double (&dinterval);
 368
 369   geom->axis[orient].max = decimal_to_double (&dupper);
 370   geom->axis[orient].min = decimal_to_double (&dlower);
 371
 372   geom->axis[orient].scale = (fabs (geom->axis[orient].data_max - geom->axis[orient].data_min)
 373                               / fabs (geom->axis[orient].max - geom->axis[orient].min));
 374
 375   struct decimal pos = dlower;
 376
 377   for (s = 0 ; s < ticks; ++s)
 378     {
 379       char *str = decimal_to_string (&pos);
 380       draw_tick (cr, geom, orient, false,
 381                  s * tick_interval * geom->axis[orient].scale,
 382                  "%s", str);
 383       free (str);
 384
 385       decimal_add (&pos, &dinterval);
 386     }
 387 }
 388
 389 /* Set the scale for the ordinate */
 390 void
 391 xrchart_write_yscale (cairo_t *cr, struct xrchart_geometry *geom,
 392                     double smin, double smax)
 393 {
 394   xrchart_write_scale (cr, geom, smin, smax, SCALE_ORDINATE);
 395 }
 396
 397 /* Set the scale for the abscissa */
 398 void
 399 xrchart_write_xscale (cairo_t *cr, struct xrchart_geometry *geom,
 400                       double smin, double smax)
 401 {
 402   xrchart_write_scale (cr, geom, smin, smax, SCALE_ABSCISSA);
 403 }
 404
 405
 406 /* Write the abscissa label */
 407 void
 408 xrchart_write_xlabel (cairo_t *cr, const struct xrchart_geometry *geom,
 409                     const char *label)
 410 {
 411   cairo_move_to (cr, geom->axis[SCALE_ABSCISSA].data_min, geom->abscissa_bottom);
 412   xrchart_label (cr, 'l', 't', geom->font_size, label);
 413 }
 414
 415 /* Write the ordinate label */
 416 void
 417 xrchart_write_ylabel (cairo_t *cr, const struct xrchart_geometry *geom,
 418                     const char *label)
 419 {
 420   cairo_save (cr);
 421   cairo_translate (cr, geom->ordinate_left,   geom->axis[SCALE_ORDINATE].data_min);
 422   cairo_rotate (cr, M_PI / 2.0);
 423
 424   xrchart_label (cr, 'l', 'x', geom->font_size, label);
 425   cairo_restore (cr);
 426 }
 427
 428
 429 void
 430 xrchart_write_legend (cairo_t *cr, const struct xrchart_geometry *geom)
 431 {
 432   int i;
 433   const int vstep = geom->font_size * 2;
 434   const int xpad = 10;
 435   const int ypad = 10;
 436   const int swatch = 20;
 437   const int legend_top = geom->axis[SCALE_ORDINATE].data_max;
 438   const int legend_bottom = legend_top -
 439     (vstep * geom->n_datasets + 2 * ypad );
 440
 441   cairo_save (cr);
 442
 443   cairo_rectangle (cr, geom->legend_left, legend_top,
 444                    geom->legend_right - xpad - geom->legend_left,
 445                    legend_bottom - legend_top);
 446   cairo_stroke (cr);
 447
 448   for (i = 0 ; i < geom->n_datasets ; ++i )
 449     {
 450       const int ypos = legend_top - vstep * (i + 1);
 451       const int xpos = geom->legend_left + xpad;
 452       const struct xrchart_colour *colour;
 453
 454       cairo_move_to (cr, xpos, ypos);
 455
 456       cairo_save (cr);
 457       colour = &data_colour [ i % XRCHART_N_COLOURS];
 458       cairo_set_source_rgb (cr,
 459                             colour->red / 255.0,
 460                             colour->green / 255.0,
 461                             colour->blue / 255.0);
 462       cairo_rectangle (cr, xpos, ypos, swatch, swatch);
 463       cairo_fill_preserve (cr);
 464       cairo_stroke (cr);
 465       cairo_restore (cr);
 466
 467       cairo_move_to (cr, xpos + swatch * 1.5, ypos);
 468       xrchart_label (cr, 'l', 'x', geom->font_size, geom->dataset[i]);
 469     }
 470
 471   cairo_restore (cr);
 472 }
 473
 474 /* Start a new vector called NAME */
 475 void
 476 xrchart_vector_start (cairo_t *cr, struct xrchart_geometry *geom, const char *name)
 477 {
 478   const struct xrchart_colour *colour;
 479
 480   cairo_save (cr);
 481
 482   colour = &data_colour[geom->n_datasets % XRCHART_N_COLOURS];
 483   cairo_set_source_rgb (cr,
 484                         colour->red / 255.0,
 485                         colour->green / 255.0,
 486                         colour->blue / 255.0);
 487
 488   geom->n_datasets++;
 489   geom->dataset = xrealloc (geom->dataset,
 490                             geom->n_datasets * sizeof (*geom->dataset));
 491
 492   geom->dataset[geom->n_datasets - 1] = strdup (name);
 493 }
 494
 495 /* Plot a data point */
 496 void
 497 xrchart_datum (cairo_t *cr, const struct xrchart_geometry *geom,
 498              int dataset UNUSED, double x, double y)
 499 {
 500   double x_pos = (x - geom->axis[SCALE_ABSCISSA].min) * geom->axis[SCALE_ABSCISSA].scale + geom->axis[SCALE_ABSCISSA].data_min;
 501   double y_pos = (y - geom->axis[SCALE_ORDINATE].min) * geom->axis[SCALE_ORDINATE].scale + geom->axis[SCALE_ORDINATE].data_min;
 502
 503   xrchart_draw_marker (cr, x_pos, y_pos, XRMARKER_CIRCLE, 10);
 504 }
 505
 506 void
 507 xrchart_vector_end (cairo_t *cr, struct xrchart_geometry *geom)
 508 {
 509   cairo_stroke (cr);
 510   cairo_restore (cr);
 511   geom->in_path = false;
 512 }
 513
 514 /* Plot a data point */
 515 void
 516 xrchart_vector (cairo_t *cr, struct xrchart_geometry *geom, double x, double y)
 517 {
 518   const double x_pos =
 519     (x - geom->axis[SCALE_ABSCISSA].min) * geom->axis[SCALE_ABSCISSA].scale + geom->axis[SCALE_ABSCISSA].data_min ;
 520
 521   const double y_pos =
 522     (y - geom->axis[SCALE_ORDINATE].min) * geom->axis[SCALE_ORDINATE].scale + geom->axis[SCALE_ORDINATE].data_min ;
 523
 524   if (geom->in_path)
 525     cairo_line_to (cr, x_pos, y_pos);
 526   else
 527     {
 528       cairo_move_to (cr, x_pos, y_pos);
 529       geom->in_path = true;
 530     }
 531 }
 532
 533
 534
 535 /* Draw a line with slope SLOPE and intercept INTERCEPT.
 536    between the points limit1 and limit2.
 537    If lim_dim is XRCHART_DIM_Y then the limit{1,2} are on the
 538    y axis otherwise the x axis
 539 */
 540 void
 541 xrchart_line(cairo_t *cr, const struct xrchart_geometry *geom,
 542            double slope, double intercept,
 543            double limit1, double limit2, enum xrchart_dim lim_dim)
 544 {
 545   double x1, y1;
 546   double x2, y2;
 547
 548   if ( lim_dim == XRCHART_DIM_Y )
 549     {
 550       x1 = ( limit1 - intercept ) / slope;
 551       x2 = ( limit2 - intercept ) / slope;
 552       y1 = limit1;
 553       y2 = limit2;
 554     }
 555   else
 556     {
 557       x1 = limit1;
 558       x2 = limit2;
 559       y1 = slope * x1 + intercept;
 560       y2 = slope * x2 + intercept;
 561     }
 562
 563   y1 = (y1 - geom->axis[SCALE_ORDINATE].min) * geom->axis[SCALE_ORDINATE].scale + geom->axis[SCALE_ORDINATE].data_min;
 564   y2 = (y2 - geom->axis[SCALE_ORDINATE].min) * geom->axis[SCALE_ORDINATE].scale + geom->axis[SCALE_ORDINATE].data_min;
 565   x1 = (x1 - geom->axis[SCALE_ABSCISSA].min) * geom->axis[SCALE_ABSCISSA].scale + geom->axis[SCALE_ABSCISSA].data_min;
 566   x2 = (x2 - geom->axis[SCALE_ABSCISSA].min) * geom->axis[SCALE_ABSCISSA].scale + geom->axis[SCALE_ABSCISSA].data_min;
 567
 568   cairo_move_to (cr, x1, y1);
 569   cairo_line_to (cr, x2, y2);
 570   cairo_stroke (cr);
 571 }
 572
 573 void
 574 xrchart_text_extents (cairo_t *cr, const struct xrchart_geometry *geom,
 575                       const char *utf8,
 576                       double *width, double *height)
 577 {
 578   PangoFontDescription *desc;
 579   PangoLayout *layout;
 580   int width_pango;
 581   int height_pango;
 582
 583   desc = pango_font_description_from_string ("Sans");
 584   if (desc == NULL)
 585       return;
 586   pango_font_description_set_absolute_size (desc, geom->font_size * PANGO_SCALE);
 587   layout = pango_cairo_create_layout (cr);
 588   pango_layout_set_font_description (layout, desc);
 589   pango_layout_set_text (layout, utf8, -1);
 590   pango_layout_get_size (layout, &width_pango, &height_pango);
 591   *width = (double) width_pango / PANGO_SCALE;
 592   *height = (double) height_pango / PANGO_SCALE;
 593   g_object_unref (layout);
 594   pango_font_description_free (desc);
 595 }