draw_trajectories.cc

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/*
 * Copyright 2016 The Cartographer Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "cartographer/io/draw_trajectories.h"

#include "cartographer/io/image.h"
#include "cartographer/transform/transform.h"

namespace cartographer {
namespace io {

void DrawTrajectory(const mapping::proto::Trajectory& trajectory,
                    const FloatColor& color,
                    const PoseToPixelFunction& pose_to_pixel,
                    cairo_surface_t* surface) {
  if (trajectory.node_size() == 0) {
    return;
  }
  constexpr double kTrajectoryWidth = 4.;
  constexpr double kTrajectoryEndMarkers = 6.;
  constexpr double kAlpha = 0.7;

  auto cr = ::cartographer::io::MakeUniqueCairoPtr(cairo_create(surface));

  cairo_set_source_rgba(cr.get(), color[0], color[1], color[2], kAlpha);
  cairo_set_line_width(cr.get(), kTrajectoryWidth);

  for (const auto& node : trajectory.node()) {
    const Eigen::Array2i pixel =
        pose_to_pixel(transform::ToRigid3(node.pose()));
    cairo_line_to(cr.get(), pixel.x(), pixel.y());
  }
  cairo_stroke(cr.get());

  // Draw beginning and end markers.
  {
    const Eigen::Array2i pixel =
        pose_to_pixel(transform::ToRigid3(trajectory.node(0).pose()));
    cairo_set_source_rgba(cr.get(), 0., 1., 0., kAlpha);
    cairo_arc(cr.get(), pixel.x(), pixel.y(), kTrajectoryEndMarkers, 0,
              2 * M_PI);
    cairo_fill(cr.get());
  }
  {
    const Eigen::Array2i pixel = pose_to_pixel(transform::ToRigid3(
        trajectory.node(trajectory.node_size() - 1).pose()));
    cairo_set_source_rgba(cr.get(), 1., 0., 0., kAlpha);
    cairo_arc(cr.get(), pixel.x(), pixel.y(), kTrajectoryEndMarkers, 0,
              2 * M_PI);
    cairo_fill(cr.get());
  }
  cairo_surface_flush(surface);
}

}  // namespace io
}  // namespace cartographer