Distance between two points

A very simple way of finding the distance between two points is by assuming it as a side of a right-angle triangle. The length of two sides can be easily found as x2 - x1 and y2 - y1.

In mathematics, the Pythagorean theorem or Pythagoras’s theorem is a fundamental relation in Euclidean geometry between the three sides of a right triangle - Pythagorean theorem

Chitra now provides a utility function findDistance(x1, y1, x2, y2) (dist(x1, y1, x2, y2) in Chitra Lua bindings).

Following example shows highlighting the boxes that are closer to center (or any other point of interest) and gets darker if it is away from the center.

Chitra (D)
Chitra Lua plugin

Source code

import chitra;

void main()
{
    auto ctx = new Chitra(1024);

    with (ctx)
    {
        // Grid of 32x32
        grid(32, 32);

        // Line color
        stroke(0, 0, 255, 0.1);

        auto mainX = 512;
        auto mainY = 512;
        auto within = 1024;

        foreach(i; 0 .. 1024)
        {
            // Get Grid cell one by one
            auto box = gridCell(i+1);
            auto x2 = box.x > mainX ? box.x + box.width : box.x;
            auto y2 = box.y > mainY ? box.y + box.height : box.y;

            // Find distance
            auto d = findDistance(mainX, mainY, x2, y2);
            fill(0, 0, 255, (d / within) + 0.1);

            rect(box.x, box.y, box.width, box.height);
        }

        saveAs("distance-highlight.png", resolution: 72);
    }
}

Source code (Using Chitra Lua plugin)

size(1024)

-- Grid of 32x32
grid(32, 32)

-- Line color
stroke(0, 0, 255, 0.1)

main_x = 512
main_y = 512
within = 1024

for i = 0, 1024 do
   -- Get Grid cell one by one
   local box = grid_cell(i+1)
   local x2 = box.x > main_x and box.x + box.width or box.x
   local y2 = box.y > main_y and box.y + box.height or box.y

   -- Find distance
   local d = dist(main_x, main_y, x2, y2)
   fill(0, 0, 255, (d / within) + 0.1)

   rect(box.x, box.y, box.width, box.height)
end

save("distance-highlight.png", {resolution=72})