shapes.cpp - master - SilovAndrey/easel_examples

shapes.cpp
318 строк7 KB
Andrey HomePC
Add easel_examples v0.1.0 with shapes, space, paths examples
10 июл 2026, 10:34
10 июл 2026, 10:348ecc405
module;

#include <numbers>

module App;

using namespace easel;
using std::numbers::pi;

auto constexpr window_size = point{640.0f, 480.0f};
auto constexpr bkd_color = rgb(44, 42, 45);

void background(canvas& cnv)
{
   cnv.fill_style(bkd_color);
   cnv.fill(path_rect({{0, 0}, window_size }));
}

void rectangles(canvas& cnv)
{
   constexpr auto x = 40.0f;
   constexpr auto y = 40.0f;
   cnv.line_width(2);

   auto preserve = path_rect({x, y, {150.0f, 100.0f}});
   cnv.fill_style(colors::red);
   cnv.fill(preserve);

   cnv.stroke_style(colors::navajo_white.opacity(0.5));
   cnv.stroke(preserve);

   preserve = path_round_rect({x + 30, y + 30, {150, 100}}, 10);
   cnv.fill_style(colors::blue.opacity(0.5));
   cnv.fill(preserve);

   cnv.stroke_style(colors::honeydew.opacity(0.5));
   cnv.stroke(preserve);
}

void circles_and_arcs(canvas& cnv)
{
   constexpr auto x = 300;
   constexpr auto y = 100;

   for (int i = 0; i != 7; ++i)
   {
      float cx = x+(i*45.0f);
      float cy = y;
      float ri = 7-i;
      float radius = 20+(ri*5);

      cnv.fill_style(hsl(360/7 * i, 0.8, 0.5).opacity(0.7));
      cnv.fill(path_circle({cx, cy, radius}));

      cnv.line_width((ri+1)/2);
      cnv.stroke_style(colors::light_sky_blue.opacity(0.8));
      Path pa;
      pa.arc(cx, cy, radius, 0.0f, pi + (pi * ((i+1)/7.0f)), false);
      cnv.stroke(pa);
   }
}

void arc_to(canvas& cnv)
{
    constexpr auto x = 40;
    constexpr auto y = 200;
    constexpr auto r = 40;

    auto make_arc = [=](Path& p)
    {
        p.move_to(x, y);
        p.line_to(x+(80-r), y);
        p.arc_to(x+80, y, x+80, y+20, r);
        p.line_to(x+80, y+80);
    };

   cnv.stroke_style(colors::dodger_blue.opacity(0.6));
   cnv.line_width(10);
   Path p;
   make_arc(p);
   cnv.stroke(p);

   cnv.fill_style(colors::dodger_blue.opacity(0.2));
   Path p1;
   make_arc(p1);
   p1.line_to(x, y+80);
   p1.close();
   cnv.fill(p1);

   cnv.stroke_style(colors::white);
   cnv.line_width(1);
   Path p2;
   p2.move_to(x, y);
   p2.line_to(x+80, y);
   p2.line_to(x+80, y+80);
   cnv.stroke(p2);
}

void line_caps(canvas& cnv)
{
    auto where = point{160, 215};
    auto spacing = 25;
    cnv.line_width(10);

    cnv.stroke_style(colors::gold);
    Path p;
    cnv.line_width(10);
    cnv.line_cap(cnv.butt);
    p.move_to(where.x, where.y);
    p.line_to(where.x+100, where.y);
    cnv.stroke(p);

    p.begin_path();
    cnv.stroke_style(colors::sky_blue);
    cnv.line_cap(cnv.round);
    p.move_to(where.x, where.y+spacing);
    p.line_to(where.x+100, where.y+spacing);
    cnv.stroke(p);

    p.begin_path();
    cnv.stroke_style(colors::light_sea_green);
    cnv.line_cap(cnv.square);
    p.move_to(where.x, where.y+spacing*2);
    p.line_to(where.x+100, where.y+spacing*2);
    cnv.stroke(p);

    cnv.stroke_style(colors::white);
    cnv.line_width(1);
    p.begin_path();
    p.move_to(where.x, where.y);
    p.line_to(where.x+100, where.y);
    cnv.stroke(p);

    p.begin_path();
    p.move_to(where.x, where.y+spacing);
    p.line_to(where.x+100, where.y+spacing);
    cnv.stroke(p);

    p.begin_path();
    p.move_to(where.x, where.y+spacing*2);
    p.line_to(where.x+100, where.y+spacing*2);
    cnv.stroke(p);
}

void line_joins(canvas& cnv)
{
   auto where = point{290, 100};
   cnv.line_width(10);
   cnv.line_cap(cnv.butt);

   cnv.stroke_style(colors::gold);
   Path p;
   cnv.line_join(cnv.bevel_join);
   p.move_to(where.x, where.y+100);
   p.line_to(where.x+60, where.y+140);
   p.line_to(where.x, where.y+180);
   cnv.stroke(p);

   cnv.stroke_style(colors::sky_blue);
   p.begin_path();
   cnv.line_join(cnv.round_join);
   p.move_to(where.x+40, where.y+100);
   p.line_to(where.x+100, where.y+140);
   p.line_to(where.x+40, where.y+180);
   cnv.stroke(p);

   cnv.stroke_style(colors::light_sea_green);
   p.begin_path();
   cnv.line_join(cnv.miter_join);
   p.move_to(where.x+80, where.y+100);
   p.line_to(where.x+140, where.y+140);
   p.line_to(where.x+80, where.y+180);
   cnv.stroke(p);

   cnv.stroke_style(colors::white);
   cnv.line_width(1);

   p.begin_path();
   p.move_to(where.x, where.y+100);
   p.line_to(where.x+60, where.y+140);
   p.line_to(where.x, where.y+180);
   cnv.stroke(p);

   p.begin_path();
   p.move_to(where.x+40, where.y+100);
   p.line_to(where.x+100, where.y+140);
   p.line_to(where.x+40, where.y+180);
   cnv.stroke(p);

   p.begin_path ();
   p.move_to(where.x+80, where.y+100);
   p.line_to(where.x+140, where.y+140);
   p.line_to(where.x+80, where.y+180);
   cnv.stroke(p);
}

void bezier(canvas& cnv)
{
   auto where = point{450, 280};
   auto height = 100;
   auto width = 120;
   auto xmove = 20;
   auto start = point{where.x, where.y};
   auto cp1 = point{where.x+xmove, where.y-height};
   auto cp2 = point{where.x+width-xmove, where.y-height};
   auto end = point{where.x+width, where.y};

   cnv.line_width(10);
   cnv.stroke_style(colors::dodger_blue.opacity(0.6));
   cnv.line_cap(cnv.round);

   Path p;
   p.move_to(start);
   p.bezier_curve_to(cp1, cp2, end);
   cnv.stroke(p);

   p.begin_path();
   cnv.fill_style(colors::pink.opacity(0.8));
   p.add_circle(cp1.x, cp1.y, 3);
   p.add_circle(cp2.x, cp2.y, 3);
   cnv.fill(p);

   p.begin_path();
   cnv.stroke_style(colors::white);
   cnv.line_width(1);
   p.move_to(start);
   p.line_to(cp1);
   p.move_to(cp2);
   p.line_to(end);
   cnv.stroke(p);
}

void quad(canvas& cnv)
{
   auto where = point{40, 420};
   auto height = 100;
   auto width = 120;
   auto start = point{where.x, where.y};
   auto cp = point{where.x+(width/2), where.y-height};
   auto end = point{where.x+width, where.y};

   cnv.line_width(10);
   cnv.stroke_style(colors::dodger_blue.opacity(0.6));
   cnv.line_cap(cnv.round);

   Path p;
   p.move_to(start);
   p.quadratic_curve_to(cp, end);
   cnv.stroke(p);

   p.begin_path();
   cnv.fill_style(colors::pink.opacity(0.8));
   p.add_circle(cp.x, cp.y, 3);
   cnv.fill(p);

   p.begin_path();
   cnv.stroke_style(colors::white);
   cnv.line_width(1);
   p.move_to(start);
   p.line_to(cp);
   p.line_to(end);
   cnv.stroke(p);
}

void rainbow(canvas::gradient& gr)
{
   gr.add_color_stop(0.0/6, colors::red);
   gr.add_color_stop(1.0/6, colors::orange);
   gr.add_color_stop(2.0/6, colors::yellow);
   gr.add_color_stop(3.0/6, colors::green);
   gr.add_color_stop(4.0/6, colors::blue);
   gr.add_color_stop(5.0/6, rgb(0x4B, 0x00, 0x82));
   gr.add_color_stop(6.0/6, colors::violet);
}

void linear_gradient(canvas& cnv)
{
   auto x = 300.0f;
   auto y = 330.0f;
   auto gr = canvas::linear_gradient{x, y, x+300, y};

   rainbow(gr);
   cnv.fill_style(gr);
   cnv.fill(path_round_rect({x, y, {300.0f, 80.0f}}, 5.0f));
}

void radial_gradient(canvas& cnv)
{
   auto center = point{208, 360};
   auto radius = 65.0f;
   auto gr = canvas::radial_gradient{center, 5, center.move(15, 10), radius};
   gr.add_color_stop(0.0, colors::red);
   gr.add_color_stop(1.0, colors::black);

   cnv.fill_style(gr);
   cnv.fill(path_circle({center.move(15, 10), radius - 10}));
}

void draw(canvas& cnv, int w, int h)
{
  //cnv.fill_style(rgb(240, 248, 255));
  //cnv.fill(path_rect({0, 0, w, h}));
   background(cnv);
   rectangles(cnv);
   circles_and_arcs(cnv);
   arc_to(cnv);
   line_caps(cnv);
   line_joins(cnv);
   bezier(cnv);
   quad(cnv);
   linear_gradient(cnv);
   radial_gradient(cnv);
}

int start(int argc, char const* argv[])
{
  return run_app(argc, argv, window_size, colors::white, false);
}