examples/svgtiny_display_x11.c

   1 /*
   2  * This file is part of Libsvgtiny
   3  * Licensed under the MIT License,
   4  *                http://opensource.org/licenses/mit-license.php
   5  * Copyright 2009-2010 James Bursa <james@semichrome.net>
   6  */
   7
   8 /*
   9  * This example loads an SVG using libsvgtiny and then displays it in an X11
  10  * window using cairo.
  11  *
  12  * Functions of interest for libsvgtiny use are:
  13  *  main() - loads an SVG using svgtiny_create() and svgtiny_parse()
  14  *  event_diagram_expose() - renders the SVG by stepping through the shapes
  15  *
  16  * Compile using:
  17  *  gcc -g -W -Wall -o svgtiny_display_x11 svgtiny_display_x11.c \
  18  *          `pkg-config --cflags --libs libsvgtiny cairo` -lX11
  19  */
  20
  21
  22 #include <libgen.h>
  23 #include <math.h>
  24 #include <stdbool.h>
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <sys/types.h>
  29 #include <sys/stat.h>
  30 #include <unistd.h>
  31 #include <X11/Xlib.h>
  32 #include <X11/keysym.h>
  33 #include <cairo.h>
  34 #include <cairo-xlib.h>
  35 #include "svgtiny.h"
  36
  37
  38 struct svgtiny_diagram *diagram;
  39 Display *display;
  40 Window diagram_window;
  41 Atom wm_protocols_atom, wm_delete_window_atom;
  42 char *svg_path;
  43 float scale = 1.0;
  44 bool quit = false;
  45
  46
  47 void gui_init(void);
  48 void gui_quit(void);
  49 void update_window_title(void);
  50 void gui_poll(void);
  51 void event_diagram_key_press(XKeyEvent *key_event);
  52 void event_diagram_expose(const XExposeEvent *expose_event);
  53 void render_path(cairo_t *cr, float scale, struct svgtiny_shape *path);
  54 void die(const char *message);
  55
  56
  57 /**
  58  * Main program.
  59  */
  60 int main(int argc, char *argv[])
  61 {
  62         FILE *fd;
  63         struct stat sb;
  64         char *buffer;
  65         size_t size;
  66         size_t n;
  67         svgtiny_code code;
  68
  69         if (argc != 2) {
  70                 fprintf(stderr, "Usage: %s FILE\n", argv[0]);
  71                 return 1;
  72         }
  73         svg_path = argv[1];
  74
  75         /* load file into memory buffer */
  76         fd = fopen(svg_path, "rb");
  77         if (!fd) {
  78                 perror(svg_path);
  79                 return 1;
  80         }
  81
  82         if (stat(svg_path, &sb)) {
  83                 perror(svg_path);
  84                 return 1;
  85         }
  86         size = sb.st_size;
  87
  88         buffer = malloc(size);
  89         if (!buffer) {
  90                 fprintf(stderr, "Unable to allocate %lld bytes\n",
  91                                 (long long) size);
  92                 return 1;
  93         }
  94
  95         n = fread(buffer, 1, size, fd);
  96         if (n != size) {
  97                 perror(svg_path);
  98                 return 1;
  99         }
 100
 101         fclose(fd);
 102
 103         /* create svgtiny object */
 104         diagram = svgtiny_create();
 105         if (!diagram) {
 106                 fprintf(stderr, "svgtiny_create failed\n");
 107                 return 1;
 108         }
 109
 110         /* parse */
 111         code = svgtiny_parse(diagram, buffer, size, svg_path, 1000, 1000);
 112         if (code != svgtiny_OK) {
 113                 fprintf(stderr, "svgtiny_parse failed: ");
 114                 switch (code) {
 115                 case svgtiny_OUT_OF_MEMORY:
 116                         fprintf(stderr, "svgtiny_OUT_OF_MEMORY");
 117                         break;
 118                 case svgtiny_LIBDOM_ERROR:
 119                         fprintf(stderr, "svgtiny_LIBDOM_ERROR");
 120                         break;
 121                 case svgtiny_NOT_SVG:
 122                         fprintf(stderr, "svgtiny_NOT_SVG");
 123                         break;
 124                 case svgtiny_SVG_ERROR:
 125                         fprintf(stderr, "svgtiny_SVG_ERROR: line %i: %s",
 126                                         diagram->error_line,
 127                                         diagram->error_message);
 128                         break;
 129                 default:
 130                         fprintf(stderr, "unknown svgtiny_code %i", code);
 131                         break;
 132                 }
 133                 fprintf(stderr, "\n");
 134         }
 135
 136         free(buffer);
 137
 138         /*printf("viewbox 0 0 %u %u\n",
 139                         diagram->width, diagram->height);*/
 140
 141         gui_init();
 142
 143         while (!quit) {
 144                 gui_poll();
 145         }
 146
 147         gui_quit();
 148         svgtiny_free(diagram);
 149
 150         return 0;
 151 }
 152
 153
 154 /**
 155  * Initialize X11 interface.
 156  */
 157 void gui_init(void)
 158 {
 159         display = XOpenDisplay(NULL);
 160         if (!display)
 161                 die("XOpenDisplay failed: is DISPLAY set?");
 162
 163         diagram_window = XCreateSimpleWindow(display,
 164                         DefaultRootWindow(display),
 165                         0, 0, diagram->width, diagram->height, 0, 0, 0);
 166
 167         update_window_title();
 168
 169         XMapWindow(display, diagram_window);
 170         XSelectInput(display, diagram_window,
 171                         KeyPressMask |
 172                         ButtonPressMask |
 173                         ExposureMask |
 174                         StructureNotifyMask);
 175
 176         wm_protocols_atom = XInternAtom(display, "WM_PROTOCOLS", False);
 177         wm_delete_window_atom = XInternAtom(display, "WM_DELETE_WINDOW", False);
 178         XSetWMProtocols(display, diagram_window, &wm_delete_window_atom, 1);
 179 }
 180
 181
 182 /**
 183  * Free X11 interface.
 184  */
 185 void gui_quit(void)
 186 {
 187         XCloseDisplay(display);
 188 }
 189
 190
 191 /**
 192  * Update window title to show current state.
 193  */
 194 void update_window_title(void)
 195 {
 196         char title[100];
 197         char *svg_path_copy;
 198         char *base_name;
 199
 200         svg_path_copy = strdup(svg_path);
 201         if (!svg_path_copy) {
 202                 fprintf(stderr, "out of memory\n");
 203                 return;
 204         }
 205
 206         base_name = basename(svg_path_copy);
 207
 208         snprintf(title, sizeof title, "%s (%i%%) - svgtiny",
 209                         base_name, (int) roundf(scale * 100.0));
 210
 211         XStoreName(display, diagram_window, title);
 212
 213         free(svg_path_copy);
 214 }
 215
 216
 217 /**
 218  * Handle an X11 event.
 219  */
 220 void gui_poll(void)
 221 {
 222         XEvent event;
 223         XNextEvent(display, &event);
 224
 225         switch (event.type) {
 226         case KeyPress:
 227                 if (event.xkey.window == diagram_window) {
 228                         event_diagram_key_press(&event.xkey);
 229                 }
 230                 break;
 231         case Expose:
 232                 if (event.xexpose.window == diagram_window) {
 233                         event_diagram_expose(&event.xexpose);
 234                 }
 235                 break;
 236         case ClientMessage:
 237                 if (event.xclient.message_type == wm_protocols_atom &&
 238                                 event.xclient.format == 32 &&
 239                                 (Atom) event.xclient.data.l[0] ==
 240                                 wm_delete_window_atom)
 241                         quit = true;
 242                 break;
 243         default:
 244                 /*printf("unknown event %i\n", event.type);*/
 245                 break;
 246         }
 247 }
 248
 249
 250 /**
 251  * Handle an X11 KeyPress event in the diagram window.
 252  */
 253 void event_diagram_key_press(XKeyEvent *key_event)
 254 {
 255         KeySym key_sym;
 256         float new_scale = scale;
 257         unsigned int width, height;
 258
 259         key_sym = XLookupKeysym(key_event, 0);
 260
 261         switch (key_sym) {
 262         case XK_q:
 263         case XK_Escape:
 264                 quit = true;
 265                 break;
 266
 267         case XK_minus:
 268         case XK_KP_Subtract:
 269                 new_scale -= 0.1;
 270                 break;
 271
 272         case XK_equal:
 273         case XK_plus:
 274         case XK_KP_Add:
 275                 new_scale += 0.1;
 276                 break;
 277
 278         case XK_1:
 279         case XK_KP_Multiply:
 280         case XK_KP_1:
 281                 new_scale = 1;
 282                 break;
 283
 284         case XK_2:
 285         case XK_KP_2:
 286                 new_scale = 2;
 287                 break;
 288
 289         default:
 290                 break;
 291         }
 292
 293         if (new_scale < 0.1)
 294                 new_scale = 0.1;
 295         else if (5 < new_scale)
 296                 new_scale = 5;
 297
 298         if (new_scale == scale)
 299                 return;
 300
 301         scale = new_scale;
 302         width = diagram->width * scale;
 303         height = diagram->height * scale;
 304         if (width < 400)
 305                 width = 400;
 306         if (height < 400)
 307                 height = 400;
 308         XResizeWindow(display, diagram_window, width, height);
 309         XClearArea(display, diagram_window, 0, 0, 0, 0, True);
 310         update_window_title();
 311 }
 312
 313
 314 /**
 315  * Handle an X11 Expose event of the diagram window.
 316  */
 317 void event_diagram_expose(const XExposeEvent *expose_event)
 318 {
 319         cairo_surface_t *surface;
 320         cairo_t *cr;
 321         cairo_status_t status;
 322         unsigned int i;
 323
 324         if (expose_event->count != 0)
 325                 return;
 326
 327         surface = cairo_xlib_surface_create(display, diagram_window,
 328                         DefaultVisual(display, DefaultScreen(display)),
 329                         diagram->width * scale, diagram->height * scale);
 330         if (!surface) {
 331                 fprintf(stderr, "cairo_xlib_surface_create failed\n");
 332                 return;
 333         }
 334
 335         cr = cairo_create(surface);
 336         status = cairo_status(cr);
 337         if (status != CAIRO_STATUS_SUCCESS) {
 338                 fprintf(stderr, "cairo_create failed: %s\n",
 339                                 cairo_status_to_string(status));
 340                 cairo_destroy(cr);
 341                 cairo_surface_destroy(surface);
 342                 return;
 343         }
 344
 345         cairo_set_source_rgb(cr, 1, 1, 1);
 346         cairo_paint(cr);
 347
 348         for (i = 0; i != diagram->shape_count; i++) {
 349                 if (diagram->shape[i].path) {
 350                         render_path(cr, scale, &diagram->shape[i]);
 351
 352                 } else if (diagram->shape[i].text) {
 353                         cairo_set_source_rgb(cr,
 354                                 svgtiny_RED(diagram->shape[i].stroke) / 255.0,
 355                                 svgtiny_GREEN(diagram->shape[i].stroke) / 255.0,
 356                                 svgtiny_BLUE(diagram->shape[i].stroke) / 255.0);
 357                         cairo_move_to(cr,
 358                                         scale * diagram->shape[i].text_x,
 359                                         scale * diagram->shape[i].text_y);
 360                         cairo_show_text(cr, diagram->shape[i].text);
 361                 }
 362         }
 363
 364         status = cairo_status(cr);
 365         if (status != CAIRO_STATUS_SUCCESS) {
 366                 fprintf(stderr, "cairo error: %s\n",
 367                                 cairo_status_to_string(status));
 368                 cairo_destroy(cr);
 369                 cairo_surface_destroy(surface);
 370                 return;
 371         }
 372
 373         cairo_destroy(cr);
 374         cairo_surface_destroy(surface);
 375 }
 376
 377
 378 /**
 379  * Render an svgtiny path using cairo.
 380  */
 381 void render_path(cairo_t *cr, float scale, struct svgtiny_shape *path)
 382 {
 383         unsigned int j;
 384
 385         cairo_new_path(cr);
 386         for (j = 0; j != path->path_length; ) {
 387                 switch ((int) path->path[j]) {
 388                 case svgtiny_PATH_MOVE:
 389                         cairo_move_to(cr,
 390                                         scale * path->path[j + 1],
 391                                         scale * path->path[j + 2]);
 392                         j += 3;
 393                         break;
 394                 case svgtiny_PATH_CLOSE:
 395                         cairo_close_path(cr);
 396                         j += 1;
 397                         break;
 398                 case svgtiny_PATH_LINE:
 399                         cairo_line_to(cr,
 400                                         scale * path->path[j + 1],
 401                                         scale * path->path[j + 2]);
 402                         j += 3;
 403                         break;
 404                 case svgtiny_PATH_BEZIER:
 405                         cairo_curve_to(cr,
 406                                         scale * path->path[j + 1],
 407                                         scale * path->path[j + 2],
 408                                         scale * path->path[j + 3],
 409                                         scale * path->path[j + 4],
 410                                         scale * path->path[j + 5],
 411                                         scale * path->path[j + 6]);
 412                         j += 7;
 413                         break;
 414                 default:
 415                         printf("error ");
 416                         j += 1;
 417                 }
 418         }
 419         if (path->fill != svgtiny_TRANSPARENT) {
 420                 cairo_set_source_rgb(cr,
 421                                 svgtiny_RED(path->fill) / 255.0,
 422                                 svgtiny_GREEN(path->fill) / 255.0,
 423                                 svgtiny_BLUE(path->fill) / 255.0);
 424                 cairo_fill_preserve(cr);
 425         }
 426         if (path->stroke != svgtiny_TRANSPARENT) {
 427                 cairo_set_source_rgb(cr,
 428                                 svgtiny_RED(path->stroke) / 255.0,
 429                                 svgtiny_GREEN(path->stroke) / 255.0,
 430                                 svgtiny_BLUE(path->stroke) / 255.0);
 431                 cairo_set_line_width(cr, scale * path->stroke_width);
 432                 cairo_stroke_preserve(cr);
 433         }
 434 }
 435
 436
 437 /**
 438  * Exit with fatal error.
 439  */
 440 void die(const char *message)
 441 {
 442         fprintf(stderr, "%s\n", message);
 443         exit(1);
 444 }
 445