canvas_cairo.cc

   1
   2 ////////////////////////////////////////////////////////////////////
   3 // START_IP_HEADER                                                //
   4 //                                                                //
   5 // Written by Francois Fleuret                                    //
   6 // Contact <francois.fleuret@idiap.ch> for comments & bug reports //
   7 //                                                                //
   8 // END_IP_HEADER                                                  //
   9 ////////////////////////////////////////////////////////////////////
  10
  11 #include "canvas_cairo.h"
  12
  13 static cairo_status_t write_cairo_to_file(void *closure,
  14                                           const unsigned char *data,
  15                                           unsigned int length) {
  16   fwrite(data, 1, length, (FILE *) closure);
  17   return CAIRO_STATUS_SUCCESS;
  18 }
  19
  20 CanvasCairo::CanvasCairo(scalar_t scale, int width, int height) {
  21   const int actual_width = int(width * scale);
  22   const int actual_height = int(height * scale);
  23   const int depth = 4;
  24
  25   _data = new unsigned char [actual_width * actual_height * depth];
  26
  27   _image = cairo_image_surface_create_for_data(_data,
  28                                                CAIRO_FORMAT_RGB24,
  29                                                actual_width,
  30                                                actual_height,
  31                                                actual_width * depth);
  32
  33   _context_resource = cairo_create(_image);
  34
  35   cairo_scale(_context_resource, scale, scale);
  36
  37   cairo_set_source_rgb(_context_resource, 1.0, 1.0, 1.0);
  38   // cairo_set_source_rgb(_context_resource, 0.0, 0.0, 0.0);
  39
  40   cairo_rectangle(_context_resource, 0, 0, width, height);
  41
  42   cairo_fill(_context_resource);
  43 }
  44
  45 CanvasCairo::~CanvasCairo() {
  46   cairo_destroy(_context_resource);
  47   cairo_surface_destroy(_image);
  48   delete[] _data;
  49 }
  50
  51 void CanvasCairo::set_drawing_color(scalar_t r, scalar_t g, scalar_t b) {
  52   cairo_set_source_rgb(_context_resource, r, g, b);
  53 }
  54
  55 void CanvasCairo::draw_polygon(int filled, int nb, scalar_t *x, scalar_t *y) {
  56   cairo_set_line_width(_context_resource, 1.0);
  57   cairo_move_to(_context_resource, x[0], y[0]);
  58   for(int n = 0; n < nb; n++) {
  59     cairo_line_to(_context_resource, x[n], y[n]);
  60   }
  61   cairo_close_path(_context_resource);
  62
  63   if(filled) {
  64     cairo_stroke_preserve(_context_resource);
  65     cairo_fill(_context_resource);
  66   } else {
  67     cairo_stroke(_context_resource);
  68   }
  69 }
  70
  71 void CanvasCairo::write_png(FILE *file) {
  72   cairo_surface_write_to_png_stream(_image, write_cairo_to_file, file);
  73 }