composite_ops.cpp - master - SilovAndrey/easel_examples

composite_ops.cpp
123 строки4 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;

module App;

using namespace easel;
constexpr auto xsize = 150.0f;
constexpr auto ysize = 170.0f;
auto constexpr window_size = point{(xsize*4)*2, (ysize*3)+10};
auto constexpr bkd_color = colors::white;

static Initialiser<init_paths> setter;

char const* mode_name(canvas::composite_op_enum mode)
{
   switch (mode)
   {
      case canvas::source_over:       return "source_over";
      case canvas::source_atop:       return "source_atop";
      case canvas::source_in:         return "source_in";
      case canvas::source_out:        return "source_out";

      case canvas::destination_over:  return "destination_over";
      case canvas::destination_atop:  return "destination_atop";
      case canvas::destination_in:    return "destination_in";
      case canvas::destination_out:   return "destination_out";

      case canvas::lighter:           return "lighter";
      case canvas::darker:            return "darker";
      case canvas::copy:              return "copy";
      case canvas::xor_:              return "xor_";

      case canvas::difference:        return "difference";
      case canvas::exclusion:         return "exclusion";
      case canvas::multiply:          return "multiply";
      case canvas::screen:            return "screen";

      case canvas::color_dodge:       return "color_dodge";
      case canvas::color_burn:        return "color_burn";
      case canvas::soft_light:        return "soft_light";
      case canvas::hard_light:        return "hard_light";

      case canvas::hue:               return "hue";
      case canvas::saturation:        return "saturation";
      case canvas::color_op:          return "color_op";
      case canvas::luminosity:        return "luminosity";
   };
   return "";
}

image dest{"dest.png"};
image src{"src.png"};

void composite_draw(canvas& cnv, point p, canvas::composite_op_enum mode)
{
   {
      auto save = cnv.new_state();
      cnv.add_rect({p.x, p.y, p.x + xsize, p.y + ysize});
      cnv.clip();

      cnv.global_composite_operation(canvas::source_over);
      cnv.draw(dest, p, 0.5);
      cnv.global_composite_operation(mode);
      cnv.draw(src, p, 0.5);
   }

   cnv.fill_style(colors::black);
   cnv.text_align(cnv.center);
   cnv.text_baseline(cnv.bottom);
   cnv.fill_text(mode_name(mode), p.x+(xsize/2), p.y+ysize);
}

void composite_ops(canvas& cnv)
{
   cnv.font(font_descr{"Open Sans", 10});

   auto col2 = xsize*4;

   composite_draw(cnv, {0, 0}, cnv.source_over);
   composite_draw(cnv, {xsize, 0}, cnv.source_atop);
   composite_draw(cnv, {xsize*2, 0}, cnv.source_in);
   composite_draw(cnv, {xsize*3, 0}, cnv.source_out);

   composite_draw(cnv, {0, ysize}, cnv.destination_over);
   composite_draw(cnv, {xsize, ysize}, cnv.destination_atop);
   composite_draw(cnv, {xsize*2, ysize}, cnv.destination_in);
   composite_draw(cnv, {xsize*3, ysize}, cnv.destination_out);

   composite_draw(cnv, {0, ysize*2}, cnv.lighter);
   composite_draw(cnv, {xsize, ysize*2}, cnv.darker);
   composite_draw(cnv, {xsize*2, ysize*2}, cnv.copy);
   composite_draw(cnv, {xsize*3, ysize*2}, cnv.xor_);

   composite_draw(cnv, {col2, 0}, cnv.difference);
   composite_draw(cnv, {col2+xsize, 0}, cnv.exclusion);
   composite_draw(cnv, {col2+(xsize*2), 0}, cnv.multiply);
   composite_draw(cnv, {col2+(xsize*3), 0}, cnv.screen);

   composite_draw(cnv, {col2, ysize}, cnv.color_dodge);
   composite_draw(cnv, {col2+xsize, ysize}, cnv.color_burn);
   composite_draw(cnv, {col2+(xsize*2), ysize}, cnv.soft_light);
   composite_draw(cnv, {col2+(xsize*3), ysize}, cnv.hard_light);

   composite_draw(cnv, {col2, ysize*2}, cnv.hue);
   composite_draw(cnv, {col2+xsize, ysize*2}, cnv.saturation);
   composite_draw(cnv, {col2+(xsize*2), ysize*2}, cnv.color_op);
   composite_draw(cnv, {col2+(xsize*3), ysize*2}, cnv.luminosity);
}

void draw(canvas& cnv)
{
   Image img{window_size};
   {
      offscreen_image ctx{img};
      canvas pm_cnv{ctx.context()};
      composite_ops(pm_cnv);
   }
   cnv.draw(img);
}

int start(int argc, char const* argv[])
{
   return run_app(argc, argv, window_size, bkd_color);
}