ecg-prog-filtered/u02/src/dda_line_tool.cpp

//
// This source code is property of the Computer Graphics and Visualization
// chair of the TU Dresden. Do not distribute in modified or unmodified form!
// Copyright (C) 2016 CGV TU Dresden - All Rights Reserved
//
#include "dda_line_tool.h"
#include "util.h"
#include <algorithm>
#include <cmath>

// Initialize the tool and store a reference of a canvas_buffer
dda_line_tool::dda_line_tool(canvas_buffer &canvas) : tool_base(canvas) {
  shape = TS_LINE;
}

// Draw a line from (x0, y0) to (x1, y1)
void dda_line_tool::draw(int x0, int y0, int x1, int y1) {
  Transformation transformation =
      transformation_to_standard_case(x0, y0, x1, y1);
  transform_mut(transformation, x0, y0);
  transform_mut(transformation, x1, y1);
  float m = slope(x0, y0, x1, y1);
  float y = y0;
  for (int x = x0; x <= x1; x++) {
    int tx, ty;
    std::tie(tx, ty) = transform_inv(transformation, x, round(y));
    canvas.set_pixel(tx, ty);
    y += m;
  }
}

// Put debug output into the stream "stream" to be displayed in the
// main window
void dda_line_tool::set_text(std::stringstream &stream) {
  stream << "Tool: DDA-Line (click and drag mouse to draw)";
}