demo/cpml-demo.c

   1 #include <cpml/cpml.h>
   2 #include <gtk/gtk.h>
   3 #include <math.h>
   4
   5 #include "demo.h"
   6
   7
   8 static cairo_path_t *
   9                 duplicate_and_stroke    (cairo_t        *cr);
  10 static void     stroke_and_destroy      (cairo_t        *cr,
  11                                          cairo_path_t   *path);
  12
  13 static void     browsing                (GtkWidget      *widget,
  14                                          GdkEventExpose *event,
  15                                          gpointer        user_data);
  16 static void     browsing_segment        (GtkToggleButton*togglebutton,
  17                                          gpointer        user_data);
  18 static void     browsing_primitive      (GtkToggleButton*togglebutton,
  19                                          gpointer        user_data);
  20 static void     browsing_reset          (GtkButton      *button,
  21                                          gpointer        user_data);
  22 static void     browsing_next           (GtkButton      *button,
  23                                          gpointer        user_data);
  24
  25 static void     arcs                    (GtkWidget      *widget,
  26                                          GdkEventExpose *event,
  27                                          gpointer        user_data);
  28 static void     arc3p                   (cairo_t        *cr,
  29                                          double          x1,
  30                                          double          y1,
  31                                          double          x2,
  32                                          double          y2,
  33                                          double          x3,
  34                                          double          y3);
  35
  36 static void     intersections           (GtkWidget      *widget,
  37                                          GdkEventExpose *event,
  38                                          gpointer        user_data);
  39
  40 static void     offset_curves           (GtkWidget      *widget,
  41                                          GdkEventExpose *event,
  42                                          gpointer        user_data);
  43
  44 static void     offset_segments         (GtkWidget      *widget,
  45                                          GdkEventExpose *event,
  46                                          gpointer        user_data);
  47
  48 static void     circle_callback         (cairo_t        *cr);
  49 static void     piston_callback         (cairo_t        *cr);
  50 static void     curve1_callback         (cairo_t        *cr);
  51 static void     line1_callback          (cairo_t        *cr);
  52
  53 static struct {
  54     GtkWidget           *area;
  55     cairo_path_t        *cairo_path;
  56     gboolean             use_segment;
  57     CpmlSegment          segment;
  58     CpmlPrimitive        primitive;
  59 } browsing_data = {
  60     NULL,
  61 };
  62
  63 static CpmlPair bezier_samples[][4] = {
  64     { { 0, 0 }, { 0, 40 }, { 120, 40 }, { 120, 0 } },   /* Simmetric low */
  65     { { 40, 0 }, { 40, 160 }, { 80, 160 }, { 80, 0 } }, /* Simmetric high */
  66     { { 0, 0 }, { 33.1371, 33.1371 }, { 86.8629, 33.1371 }, { 120, 0 } },
  67                                                         /* Arc approximation */
  68     { { 0, 0 }, { 70, 120 }, { 50, 120 }, { 120, 0 } }, /* Twisted controls */
  69
  70     { { 0, 0 }, { 0, 120 }, { 60, 120 }, { 120, 0 } },  /* Vertical p1-p2 */
  71     { { 0, 0 }, { 60, 120 }, { 120, 120 }, { 120, 0 } },/* Vertical p3-p4 */
  72     { { 0, 120 }, { 120, 120 }, { 120, 60 }, { 0, 0 } },/* Horizontal p1-p2 */
  73     { { 0, 120 }, { 120, 60 }, { 120, 0 }, { 0, 0 } },  /* Horizontal p3-p4 */
  74
  75     { { 0, 0 }, { 0, 120 }, { 120, 120 }, { 120, 0 } }, /* Down */
  76     { { 0, 120 }, { 120, 120 }, { 120, 0 }, { 0, 0 } }, /* Right */
  77     { { 0, 120 }, { 0, 0 }, { 120, 0 }, { 120, 120 } }, /* Up */
  78     { { 120, 120 }, { 0, 120 }, { 0, 0 }, { 120, 0 } }, /* Left */
  79
  80     { { 0, 60 }, { 60, 120 }, { 120, 60 }, { 60, 0 } }, /* Down-right */
  81     { { 60, 120 }, { 120, 60 }, { 60, 0 }, { 0, 60 } }, /* Up-right */
  82     { { 120, 60 }, { 60, 0 }, { 0, 60 }, { 60, 120 } }, /* Up-left */
  83     { { 60, 0 }, { 0, 60 }, { 60, 120 }, { 120, 60 } }, /* Down-left*/
  84
  85     { { 0, 0 }, { 60, 0 }, { 60, 120 }, { 120, 120 } }, /* Step left */
  86     { { 120, 0 }, { 60, 0 }, { 60, 120 }, { 0, 120 } }, /* Step right */
  87     { { 0, 0 }, { 60, 90 }, { 90, 120 }, { 120, 90 } }, /* Unbalanced opened */
  88     { { 0, 0 }, { 40, 120 }, { 120, 120 }, { 60, 80 } } /* Unbalanced closed */
  89 };
  90
  91 static void (*path_samples[]) (cairo_t *cr) = {
  92     circle_callback,
  93     piston_callback,
  94     curve1_callback,
  95     line1_callback,
  96 };
  97
  98
  99 int
 100 main(gint argc, gchar **argv)
 101 {
 102     gchar *path;
 103     GtkBuilder *builder;
 104     GError *error;
 105     GtkWidget *window;
 106
 107     gtk_init(&argc, &argv);
 108
 109     path = demo_find_data_file("cpml-demo.ui");
 110     if (path == NULL) {
 111         g_print("cpml-demo.ui not found!\n");
 112         return 1;
 113     }
 114
 115     builder = gtk_builder_new();
 116     error = NULL;
 117
 118     gtk_builder_add_from_file(builder, path, &error);
 119     if (error != NULL) {
 120         g_print("%s\n", error->message);
 121         return 2;
 122     }
 123
 124     window = (GtkWidget *) gtk_builder_get_object(builder, "wndMain");
 125
 126     /* Connect signals */
 127     g_signal_connect(window, "delete-event", G_CALLBACK(gtk_main_quit), NULL);
 128     g_signal_connect(gtk_builder_get_object(builder, "areaBrowsing"),
 129                      "expose-event", G_CALLBACK(browsing), NULL);
 130     g_signal_connect(gtk_builder_get_object(builder, "optBrowsingSegment"),
 131                      "toggled", G_CALLBACK(browsing_segment), NULL);
 132     g_signal_connect(gtk_builder_get_object(builder, "optBrowsingPrimitive"),
 133                      "toggled", G_CALLBACK(browsing_primitive), NULL);
 134     g_signal_connect(gtk_builder_get_object(builder, "btnBrowsingReset"),
 135                      "clicked", G_CALLBACK(browsing_reset), NULL);
 136     g_signal_connect(gtk_builder_get_object(builder, "btnBrowsingNext"),
 137                      "clicked", G_CALLBACK(browsing_next), NULL);
 138     g_signal_connect(gtk_builder_get_object(builder, "areaArcs"),
 139                      "expose-event", G_CALLBACK(arcs), NULL);
 140     g_signal_connect(gtk_builder_get_object(builder, "areaIntersections"),
 141                      "expose-event", G_CALLBACK(intersections), NULL);
 142     g_signal_connect(gtk_builder_get_object(builder, "areaOffsetCurves"),
 143                      "expose-event", G_CALLBACK(offset_curves), NULL);
 144     g_signal_connect(gtk_builder_get_object(builder, "areaOffsetSegments"),
 145                      "expose-event", G_CALLBACK(offset_segments), NULL);
 146     g_signal_connect(gtk_builder_get_object(builder, "btnQuit"),
 147                      "clicked", G_CALLBACK(gtk_main_quit), NULL);
 148
 149     g_object_unref(builder);
 150
 151     gtk_widget_show_all(window);
 152     gtk_main();
 153
 154     return 0;
 155 }
 156
 157
 158 static cairo_path_t *
 159 duplicate_and_stroke(cairo_t *cr)
 160 {
 161     cairo_path_t *path = cairo_copy_path(cr);
 162
 163     cairo_set_line_width(cr, 2.);
 164     cairo_stroke(cr);
 165
 166     return path;
 167 }
 168
 169 static void
 170 stroke_and_destroy(cairo_t *cr, cairo_path_t *path)
 171 {
 172     cairo_append_path(cr, path);
 173     cairo_path_destroy(path);
 174
 175     cairo_set_line_width(cr, 1.);
 176     cairo_stroke(cr);
 177 }
 178
 179
 180 static void
 181 browsing(GtkWidget *widget, GdkEventExpose *event, gpointer user_data)
 182 {
 183     cairo_t *cr;
 184     int n;
 185
 186     cr = gdk_cairo_create(widget->window);
 187
 188     if (browsing_data.area == NULL) {
 189         /* Initialize browsing_data */
 190         browsing_data.area = widget;
 191         browsing_data.use_segment = TRUE;
 192
 193         /* Append all the path samples to the cairo context */
 194         cairo_save(cr);
 195         cairo_translate(cr, 270.5, -120.5);
 196         for (n = 0; n < G_N_ELEMENTS(path_samples); ++n) {
 197             if ((n & 1) == 0) {
 198                 cairo_translate(cr, -270., 240.);
 199             } else {
 200                 cairo_translate(cr, 270., 0.);
 201             }
 202
 203             (path_samples[n]) (cr);
 204         }
 205
 206         cairo_restore(cr);
 207         browsing_data.cairo_path = cairo_copy_path(cr);
 208         cpml_segment_from_cairo(&browsing_data.segment,
 209                                 browsing_data.cairo_path);
 210         cpml_primitive_from_segment(&browsing_data.primitive,
 211                                     &browsing_data.segment);
 212     } else {
 213         cairo_append_path(cr, browsing_data.cairo_path);
 214     }
 215
 216     cairo_set_line_width(cr, 2.);
 217     cairo_stroke(cr);
 218
 219     cairo_set_source_rgb(cr, 1., 0.4, 0.);
 220     cairo_set_line_width(cr, 5.);
 221
 222     if (browsing_data.use_segment)
 223         cpml_segment_to_cairo(&browsing_data.segment, cr);
 224     else
 225         cpml_primitive_to_cairo(&browsing_data.primitive, cr);
 226
 227     cairo_stroke(cr);
 228     cairo_destroy(cr);
 229 }
 230
 231 static void
 232 browsing_segment(GtkToggleButton *togglebutton, gpointer user_data)
 233 {
 234     if (!gtk_toggle_button_get_active(togglebutton))
 235         return;
 236
 237     browsing_data.use_segment = TRUE;
 238     gtk_widget_queue_draw(browsing_data.area);
 239 }
 240
 241 static void
 242 browsing_primitive(GtkToggleButton*togglebutton, gpointer user_data)
 243 {
 244     if (!gtk_toggle_button_get_active(togglebutton))
 245         return;
 246
 247     browsing_data.use_segment = FALSE;
 248     gtk_widget_queue_draw(browsing_data.area);
 249 }
 250
 251 static void
 252 browsing_reset(GtkButton *button, gpointer user_data)
 253 {
 254     if (browsing_data.use_segment) {
 255         cpml_segment_reset(&browsing_data.segment);
 256         cpml_primitive_from_segment(&browsing_data.primitive,
 257                                     &browsing_data.segment);
 258     } else {
 259         cpml_primitive_reset(&browsing_data.primitive);
 260     }
 261
 262     gtk_widget_queue_draw(browsing_data.area);
 263 }
 264
 265 static void
 266 browsing_next(GtkButton *button, gpointer user_data)
 267 {
 268     if (browsing_data.use_segment) {
 269         cpml_segment_next(&browsing_data.segment);
 270         cpml_primitive_from_segment(&browsing_data.primitive,
 271                                     &browsing_data.segment);
 272     } else {
 273         cpml_primitive_next(&browsing_data.primitive);
 274     }
 275
 276     gtk_widget_queue_draw(browsing_data.area);
 277 }
 278
 279
 280 static void
 281 arcs(GtkWidget *widget, GdkEventExpose *event, gpointer user_data)
 282 {
 283     cairo_t *cr = gdk_cairo_create(widget->window);
 284
 285     cairo_translate(cr, 100.5, 100.5);
 286     arc3p(cr, 0, 0, 0, 120, 120, 120);
 287
 288     cairo_translate(cr, 200, 0.);
 289     arc3p(cr, 0, 0, 120, 0, 120, 120);
 290
 291     cairo_translate(cr, 200, 0.);
 292     arc3p(cr, 60, 0, 0, 120, 120, 120);
 293
 294     cairo_translate(cr, -400, 200);
 295     arc3p(cr, 0, 50, -2, 85, 120, 0);
 296
 297     cairo_translate(cr, 200, 0);
 298     arc3p(cr, -2, 85, 0, 50, 120, 0);
 299
 300     cairo_destroy(cr);
 301 }
 302
 303 static void
 304 arc3p(cairo_t *cr, double x1, double y1,
 305       double x2, double y2, double x3, double y3)
 306 {
 307     CpmlPrimitive arc;
 308     cairo_path_data_t p[4];
 309     CpmlPair center;
 310     double r, start, end;
 311
 312     arc.segment = NULL;
 313     arc.org = &p[0];
 314     arc.data = &p[1];
 315
 316     p[1].header.type = CAIRO_PATH_ARC_TO;
 317     p[1].header.length = 3;
 318
 319     p[0].point.x = x1;
 320     p[0].point.y = y1;
 321     p[2].point.x = x2;
 322     p[2].point.y = y2;
 323     p[3].point.x = x3;
 324     p[3].point.y = y3;
 325
 326     cpml_primitive_to_cairo(&arc, cr);
 327
 328     cairo_set_line_width(cr, 1.);
 329     cairo_stroke(cr);
 330
 331     /* Add an arc generated by cairo, just for reference */
 332     if (!cpml_arc_info(&arc, &center, &r, &start, &end)) {
 333         g_print("Unable to get arc info (%lf, %lf) (%lf, %lf) (%lf, %lf)\n",
 334                 x1, y1, x2, y2, x3, y3);
 335         return;
 336     }
 337
 338     if (start < end)
 339         cairo_arc(cr, center.x, center.y, r-5., start, end);
 340     else
 341         cairo_arc_negative(cr, center.x, center.y, r-5., start, end);
 342
 343     /* Show the inscribed triangle */
 344     cairo_move_to(cr, x1, y1);
 345     cairo_line_to(cr, x2, y2);
 346     cairo_line_to(cr, x3, y3);
 347
 348     cairo_set_line_width(cr, 0.5);
 349     cairo_stroke(cr);
 350 }
 351
 352
 353 static void
 354 intersections(GtkWidget *widget, GdkEventExpose *event, gpointer user_data)
 355 {
 356     cairo_t *cr;
 357     cairo_path_t *path;
 358     CpmlSegment segment1, segment2;
 359     CpmlPair intersection;
 360
 361     cr = gdk_cairo_create(widget->window);
 362     cairo_translate(cr, 10.5, 120.5);
 363
 364     line1_callback(cr);
 365
 366     path = cairo_copy_path(cr);
 367
 368     cairo_set_line_width(cr, 1.);
 369     cairo_stroke(cr);
 370
 371     cpml_segment_from_cairo(&segment1, path);
 372     cpml_segment_from_cairo(&segment2, path);
 373
 374     while (cpml_segment_next(&segment2)) {
 375         cpml_segment_intersection(&segment1, &segment2, &intersection, 1);
 376
 377         cairo_arc(cr, intersection.x, intersection.y, 2.5, 0, 2 * M_PI);
 378         cairo_fill(cr);
 379
 380         cpml_segment_next(&segment1);
 381     }
 382
 383     cairo_path_destroy(path);
 384     cairo_destroy(cr);
 385 }
 386
 387
 388 static void
 389 offset_curves(GtkWidget *widget, GdkEventExpose *event, gpointer user_data)
 390 {
 391     cairo_t *cr;
 392     gint n;
 393     CpmlPair *bezier;
 394     cairo_path_t *path, *path_copy;
 395     CpmlSegment segment;
 396     CpmlPrimitive primitive;
 397     CpmlPair pair;
 398     CpmlVector vector;
 399     double t;
 400
 401     cr = gdk_cairo_create(widget->window);
 402
 403     /* Add the Bézier curve samples */
 404     for (n = 0; n < G_N_ELEMENTS(bezier_samples); ++n) {
 405         bezier = &bezier_samples[n][0];
 406
 407         /* The samples are arranged in a 4x? matrix of 200x150 cells */
 408         if (n == 0)
 409             cairo_translate(cr, 25., 25.);
 410         else if (n % 4 == 0)
 411             cairo_translate(cr, -600., 150.);
 412         else
 413             cairo_translate(cr, 200., 0.);
 414
 415         /* Draw the Bézier curve */
 416         cairo_move_to(cr, bezier[0].x, bezier[0].y);
 417         cairo_curve_to(cr, bezier[1].x, bezier[1].y,
 418                        bezier[2].x, bezier[2].y, bezier[3].x, bezier[3].y);
 419
 420         /* Create a copy, to be used after */
 421         path_copy = cairo_copy_path(cr);
 422
 423         path = duplicate_and_stroke(cr);
 424         cpml_segment_from_cairo(&segment, path);
 425         cpml_segment_offset(&segment, 20.);
 426         stroke_and_destroy(cr, path);
 427
 428         cpml_segment_from_cairo(&segment, path_copy);
 429         cpml_primitive_from_segment(&primitive, &segment);
 430
 431         /* Checking cpml_curve_pair_at_time and cpml_curve_vector_at_time */
 432         cairo_set_line_width(cr, 1.);
 433         for (t = 0; t < 1; t += 0.1) {
 434             cpml_curve_pair_at_time(&primitive, &pair, t);
 435             cpml_curve_vector_at_time(&primitive, &vector, t);
 436             cpml_vector_set_length(&vector, 20.);
 437             cpml_vector_normal(&vector);
 438
 439             cairo_new_sub_path(cr);
 440             cairo_arc(cr, pair.x, pair.y, 2.5, 0, M_PI*2);
 441             cairo_fill(cr);
 442
 443             cairo_move_to(cr, pair.x, pair.y);
 444             cairo_line_to(cr, pair.x + vector.x, pair.y + vector.y);
 445             cairo_stroke(cr);
 446         }
 447
 448         cairo_path_destroy(path_copy);
 449     }
 450
 451     cairo_destroy(cr);
 452 }
 453
 454
 455 static void
 456 offset_segments(GtkWidget *widget, GdkEventExpose *event, gpointer user_data)
 457 {
 458     cairo_t *cr;
 459     cairo_path_t *path;
 460     CpmlSegment segment;
 461     int n;
 462
 463     cr = gdk_cairo_create(widget->window);
 464     cairo_translate(cr, 270.5, -120.5);
 465
 466     /* Offset the path samples */
 467     for (n = 0; n < G_N_ELEMENTS(path_samples); ++n) {
 468         if ((n & 1) == 0) {
 469             cairo_translate(cr, -270., 240.);
 470         } else {
 471             cairo_translate(cr, 270., 0.);
 472         }
 473
 474         /* Call the path callback */
 475         (path_samples[n]) (cr);
 476
 477         path = duplicate_and_stroke(cr);
 478         cpml_segment_from_cairo(&segment, path);
 479         cpml_segment_offset(&segment, 15.);
 480         stroke_and_destroy(cr, path);
 481     }
 482
 483     cairo_destroy(cr);
 484 }
 485
 486
 487 static void
 488 circle_callback(cairo_t *cr)
 489 {
 490     cairo_new_sub_path(cr);
 491     cairo_arc(cr, 120., 0., 100., 0., M_PI*2);
 492 }
 493
 494 static void
 495 piston_callback(cairo_t *cr)
 496 {
 497     cairo_path_t *old_path, *path;
 498     cairo_matrix_t matrix;
 499     CpmlSegment segment;
 500
 501     /* Save the previous path, if any */
 502     old_path = cairo_copy_path(cr);
 503
 504     cairo_new_path(cr);
 505     cairo_move_to(cr,  0.,   46.5);
 506     cairo_line_to(cr, 210.,   46.5);
 507     cairo_line_to(cr, 222.5,  35.);
 508     cairo_line_to(cr, 270.,   35.);
 509     cairo_line_to(cr, 270.,   56.);
 510     cairo_line_to(cr, 273.,   59.);
 511     cairo_line_to(cr, 302.,   59.);
 512     cairo_line_to(cr, 305.,   56.);
 513     cairo_arc(cr,     325.,   52.5,  20., G_PI, 3. * G_PI_2);
 514     cairo_line_to(cr, 400.,   32.5);
 515     cairo_line_to(cr, 410.,   22.5);
 516     cairo_line_to(cr, 450.,   22.5);
 517     cairo_arc_negative(cr,
 518                       452.,   34.,    2., G_PI,      G_PI_2);
 519     cairo_line_to(cr, 460.,   36.);
 520     cairo_line_to(cr, 470.,   30.);
 521     cairo_line_to(cr, 472.,   12.5);
 522
 523     /* Mirror a reversed copy of the current path on the y = 0 axis */
 524     path = cairo_copy_path(cr);
 525     cpml_segment_from_cairo(&segment, path);
 526
 527     cpml_segment_reverse(&segment);
 528     cairo_matrix_init_scale(&matrix, 1., -1.);
 529     cpml_segment_transform(&segment, &matrix);
 530
 531     /* Join the mirrored path to the old path... */
 532     path->data[0].header.type = CAIRO_PATH_LINE_TO;
 533     cairo_append_path(cr, path);
 534     cairo_path_destroy(path);
 535
 536     /* ...and close the shape */
 537     cairo_close_path(cr);
 538
 539     /* Save the resulting path and clear the path memory */
 540     path = cairo_copy_path(cr);
 541     cairo_new_path(cr);
 542
 543     /* Restore the previous path and reappend the new path */
 544     cairo_append_path(cr, old_path);
 545     cairo_path_destroy(old_path);
 546     cairo_append_path(cr, path);
 547     cairo_path_destroy(path);
 548 }
 549
 550 static void
 551 curve1_callback(cairo_t *cr)
 552 {
 553     cairo_move_to(cr,    30.,   0.);
 554     cairo_curve_to(cr,  120., 120.,  180., 100.,  180.,  20.);
 555     cairo_curve_to(cr,  180., -20.,   50.,  40.,  150.,  40.);
 556     cairo_curve_to(cr,  220.,  40.,  190., -60.,  150., -60.);
 557     cairo_curve_to(cr,  100., -60.,   80., -40.,   60., -60.);
 558 }
 559
 560 static void
 561 line1_callback(cairo_t *cr)
 562 {
 563     cairo_move_to(cr, 0, -50);
 564     cairo_line_to(cr, 100, 50);
 565
 566     cairo_move_to(cr, 100, -50);
 567     cairo_line_to(cr, 0, 50);
 568
 569     cairo_move_to(cr, 120, -50);
 570     cairo_line_to(cr, 200, -10);
 571
 572     cairo_move_to(cr, 120, 50);
 573     cairo_line_to(cr, 200, 10);
 574
 575     cairo_move_to(cr, 220, 0);
 576     cairo_line_to(cr, 280, 0);
 577
 578     cairo_move_to(cr, 270, -40);
 579     cairo_line_to(cr, 270, 20);
 580
 581     cairo_move_to(cr, 320, 60);
 582     cairo_line_to(cr, 380, 60);
 583
 584     cairo_move_to(cr, 300, -40);
 585     cairo_line_to(cr, 340, 0);
 586
 587     cairo_move_to(cr, 480, 10);
 588     cairo_line_to(cr, 400, 40);
 589
 590     cairo_move_to(cr, 400, 40);
 591     cairo_line_to(cr, 450, -40);
 592 }