Resizing paths using input from user

[GoogleCodeExporter]

A nice, cool feature that is a ''basic'' function in modern vector editors is 
the ability to resize a path's box by inputting the height and width in 
textboxes.

Any ideas on how this can be achieved?

Original issue reported on code.google.com by nicholas.kyriakides@my.westminster.ac.uk on 16 Feb 2013 at 4:10

[GoogleCodeExporter]

Select an element
Grab height,width of bounding box of selected element

User is prompted for new values

current height is divided by the new height and this gives us a coefficient to 
use in the transformation matrix

current width is divided by the new width and this give us a coefficient to use 
in the transformation matrix

selected item is transformed using the transformation matrix and the 
height/width coefficients calculated in the previous step

svgCanvas.recalculateAllSelectedDimensions(); is called to update the 
dimensions and nodes

Original comment by nicholas.kyriakides@my.westminster.ac.uk on 17 Feb 2013 at 11:10

[GoogleCodeExporter]

function changeDimensions() 

        {

      svgNode = svgCanvas.getSelectedElems()[0];

      var transformw=prompt("Enter your new width");
      var transformh=prompt("Enter your new height");
      var lastw = svgNode.getBoundingClientRect().width;
     var lasth = svgNode.getBoundingClientRect().height;

     newW=transformw/lastw;
     newH=transformh/lasth;

svgCanvas.changeSelectedAttribute("transform", "matrix(" + newW + ", 0, 0, " + 
newH + ", 0, 0)");

svgCanvas.recalculateAllSelectedDimensions();

        }

Original comment by nicholas.kyriakides@my.westminster.ac.uk on 18 Feb 2013 at 10:42

[GoogleCodeExporter]

wrong. The bbox calculations are highly unrealiable cross browser speaking. 
Alexis ussed a bug against webkit couple of years ago however still the bbox 
calculations are highly unrealiable to use as a reference value within 
functions.

The coding above might work but it is unreliable. I suggest not accepting this 
enhancement.

Nicholas

Original comment by nicholas.kyriakides@my.westminster.ac.uk on 19 Feb 2013 at 3:30

[GoogleCodeExporter]

I've been spamming this issue like a newsletter but is important IMHO. Raphael 
implements a function that uses algebraic methods to calculate the paths width, 
height, x, y. It can be substituted in place of the browsers bbox API in the 
example above and produce accurate results. I will post a solution as soon as i 
have one. I suggest accepting the enhancement now.

Original comment by nicholas.kyriakides@my.westminster.ac.uk on 19 Feb 2013 at 3:24