在 Google 应用脚本中获取直线旋转角度

Question

Trying to get rotation angle of straight line with getRotation() method but it always returning 0.0

Tried this method: https://developers.google.com/apps-script/reference/slides/line#getrotation

Getting output: on line move from top or bottom always getting rotation 0.0.

function lineRotation() {
  var selection = SlidesApp.getActivePresentation().getSelection();
  if(selection.getPageElementRange() !== null){

   var pageElements = selection.getPageElementRange().getPageElements()

   // Iterate each page elements
   pageElements.forEach(function(item, index) {
    if(pageElements[index].getPageElementType() == 'LINE'){
    
      var rotation = pageElements[index].asLine().getRotation();
  
 }else{
   SlidesApp.getUi().alert('Please select line.');
 }
});

  }else{
   SlidesApp.getUi().alert('Please select elements.');
  }
 }

Desired output required: Line rotation in angle either it moved from top or bottom.

Update : Future scope - I want to get rotation and set rotation of line. If Line inclination < 45° ==> rotate horizontally or Line inclination > 45° ==> rotate vertically. https://prnt.sc/uervkw (line screenshot)

Answer 1

Rotation != angle of the line:

Check Line rotation :

Like other page elements, a line's rotation isn't the vertical angle of the line, but the rotation of its bounding box. When you create a line with specified start and end points, its rotation is always 0° .

If you want to get the actual rotation of a line, based on its start and end points, you have to get the position of these points.

You can get these positions via getStart() and getEnd() . Both these two methods return a Point , whose coordinates can be accessed via getX() and getY() .

Based on these coordinates, you can calculate the angle between the line and the axis you desire using some basic trigonometry.