simulator/transform.cpp (5bca604) - libetherpix · BlinkenArea

transform.cpp

/*
 * EtherPix simulator
 *
 * Copyright 2017 Stefan Schuermans <stefan schuermans info>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, version 3 of the License.
 *
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

#include "bbox.h"
#include "transform.h"

/**
 * @brief constructor
 * @param[in] bb boundig box of input coordinates
 * @param[in] width width of output coordinate speace (left to right)
 * @param[in] height height of output coordinate space (top to bottom)
 */
Transform::Transform(BBox const &bb, double width, double height):
  m_init(false),
  m_zoom(1.0),
  m_shift_x(0.0),
  m_shift_y(0.0)
{
  double bb_x_min, bb_x_max, bb_y_min, bb_y_max;
  if (! bb.get(bb_x_min, bb_x_max, bb_y_min, bb_y_max))
    return;

double delta_x = bb_x_max - bb_x_min;
  double delta_y = bb_y_max - bb_y_min;
  if (delta_x <= 0.0 || delta_y <= 0.0)
    return;

// compute zoom factor (keep aspect ration, fit into window)
  double zoom_x = (double)width / delta_x;
  double zoom_y = (double)height / delta_y;
  m_zoom = zoom_x < zoom_y ? zoom_x : zoom_y;

// compute shift (center of pixels should be center of window)
  m_shift_x = 0.5 * (double)width - 0.5 * (bb_x_min + bb_x_max) * m_zoom;
  m_shift_y = 0.5 * (double)height - 0.5 * (bb_y_min + bb_y_max) * -m_zoom;

// initialized
  m_init = true;
};

/**
 * @brief apply transformation
 * @param[in] in_x input x coordinate
 * @param[in] in_y input y coordinate
 * @param[out] out_x output x coordinate
 * @param[out] out_y output y coordinate
 */
void Transform::apply(double in_x, double in_y,
                      double &out_x, double &out_y) const
{
  out_x = in_x * m_zoom + m_shift_x;
  out_y = in_y * -m_zoom + m_shift_y;
}

/**
 * @brief apply zoom
 * @param[in] in_r input radius
 * @param[out] out_r output radius
 */
void Transform::applyZoom(double in_r, double &out_r) const
{
  out_r = in_r * m_zoom;
}

libetherpix

implement drawing pixels