asdf-games/lib/renderer/CanvasRenderer.js

class CanvasRenderer {
  
  constructor(w, h) {
    const canvas = document.createElement("canvas");
    this.w = canvas.width = w;
    this.h = canvas.height = h;
    this.view = canvas;
    this.ctx = canvas.getContext("2d");
    this.ctx.textBaseLine = "top";
  }

  setPixelated() {
    this.ctx['imageSmoothingEnabled'] = false;       /* standard */
    this.ctx['mozImageSmoothingEnabled'] = false;    /* Firefox */
    this.ctx['oImageSmoothingEnabled'] = false;      /* Opera */
    this.ctx['webkitImageSmoothingEnabled'] = false; /* Safari */
    this.ctx['msImageSmoothingEnabled'] = false;     /* IE */
  }

  render(container, clear = true) {
    const { ctx } = this;
    function renderRec(container) {
      // Render container children
      container.children.forEach(child => {
        if (child.visible == false) {
          return;
        }

        ctx.save();

        if (child.pos) {
          ctx.translate(Math.round(child.pos.x), Math.round(child.pos.y));
        }

        if (child.anchor) {
          ctx.translate(child.anchor.x, child.anchor.y);
        }

        if (child.scale) {
          ctx.scale(child.scale.x, child.scale.y);
        }

        if (child.rotation) {
          const px = child.pivot ? child.pivot.x : 0;
          const py = child.pivot ? child.pivot.y : 0;
          ctx.translate(px, py);
          ctx.rotate(child.rotation);
          ctx.translate(-px, -py);
        }

        if (child.text) {
          const { font, fill, align } = child.style;
          if (font) ctx.font = font;
          if (fill) ctx.fillStyle = fill;
          if (align) ctx.textAlign = align;
          ctx.fillText(child.text, 0, 0);
        }

        else if (child.texture) {
          const img = child.texture.img;
          if (child.tileW && child.tileH) {
            ctx.drawImage(
              img,
              child.frame.x * child.tileW,
              child.frame.y * child.tileH,
              child.tileW, child.tileH,
              0, 0,
              child.tileW, child.tileH
            );
          } else if (child.imgPos && child.width && child.height) {
            ctx.drawImage(
              img,
              child.imgPos.x,
              child.imgPos.y,
              child.width, child.height,
              0, 0,
              child.width, child.height
            );
          } else if (child.style && child.w && child.h) { 
            ctx.fillStyle = child.style.fill; 
            ctx.fillRect(0, 0, child.w, child.h)
          } else {
            ctx.drawImage(img, 0, 0);
          }
        }

        // Handle children with children
        if (child.children) {
          renderRec(child);
        }
        ctx.restore();
      })
    }
    if (clear) {
      ctx.clearRect(0, 0, this.w, this.h);
    }
    renderRec(container);
  }
}
module.exports = CanvasRenderer;