lost-sia/src/utils/windowViewport.js

Single Image Annotation Tool

export function getViewportCoordinates(w, svg) {
  const window = {
    xMin: -1 * svg.translateX,
    xMax: -1 * svg.translateX + svg.width / svg.scale,
    yMin: -1 * svg.translateY,
    yMax: -1 * svg.translateY + svg.height / svg.scale,
  };
  const viewport = {
    xMin: 0,
    xMax: svg.width,
    yMin: 0,
    yMax: svg.height,
  };
  const scaleX = (viewport.xMax - viewport.xMin) / (window.xMax - window.xMin);
  const scaleY = (viewport.yMax - viewport.yMin) / (window.yMax - window.yMin);

  const vX = viewport.xMin + (w.x - window.xMin) * scaleX;
  const vY = viewport.yMin + (w.y - window.yMin) * scaleY;
  return { window, viewport, vX, vY, scaleX, scaleY };
}

/**
 *
 * @param {*} w0 Point in image coordinate system
 * @param {*} svg Svg with old translation values and old scales
 * @param {*} s1 New scale/zoom
 */
export function getZoomTranslation(w0, svg, s1) {
  const s0 = svg.scale;
  let translation = { x: 0, y: 0 };
  translation.x = (s0 / s1) * (w0.x + svg.translateX) - w0.x;
  translation.y = (s0 / s1) * (w0.y + svg.translateY) - w0.y;
  return translation;
}