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gil/example/rasterizer_circle.cpp
Olzhas Zhumabek a37f12b3e9 Add implementation of Hough transforms (#512)
Support construction from step_size, step_count, and a function for angles

Implement angle and radious version of Hough line transform and adds a demo
with static line that goes over secondary diagonal.

Implement incremental line raster
Implement naive line raster
Implement Bresenham line raster
Leave only Bresenham line rasterization

Naive and incremental algorithms were removed because they are supposed
to produce the same results anyway.
The reason for diverging results is inaccuracy of floating point numbers

Add circle rendering through trigonometric functions, using
arctan(1 / (radius + 1)) as minimal angle step.

Trigonometric circle rasterizer does not follow circle equation, but still
produces very round shapes.
A new testing methodology needs to be devised for this rasterizer.

The new version accepts start and points inclusively and tries to use
canonic representation during computations.

Slope decided to be is (diff_y + 1) / (diff_x + 1).
2021-01-25 23:31:39 +01:00

34 lines
1.0 KiB
C++

// Boost.GIL (Generic Image Library) - tests
//
// Copyright 2020 Olzhas Zhumabek <anonymous.from.applecity@gmail.com>
//
// Use, modification and distribution are subject to the Boost Software License,
// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//
#include <boost/gil.hpp>
#include <boost/gil/extension/io/png.hpp>
#include <cmath>
#include <limits>
#include <vector>
namespace gil = boost::gil;
int main()
{
const std::ptrdiff_t size = 256;
gil::gray8_image_t buffer_image(size, size);
auto buffer = gil::view(buffer_image);
const std::ptrdiff_t radius = 64;
const auto rasterizer = gil::trigonometric_circle_rasterizer{};
std::vector<gil::point_t> circle_points(rasterizer.point_count(radius));
rasterizer(radius, {128, 128}, circle_points.begin());
for (const auto& point : circle_points)
{
buffer(point) = std::numeric_limits<gil::uint8_t>::max();
}
gil::write_view("circle.png", buffer, gil::png_tag{});
}