Millisecond Forums

Hello,
I am running a program that contains 3 different tasks. One of the tasks is a visual analogue scale (VAS) that was modified from a version found here on the forums. I am having issues with variable screen resolutions. Because we are running the script remotely from participant computers at home, I need the VAS to scale according to different resolutions. I know that traditionally this is done by using percentage values for the line length, such as 94% of the screen, etc. When I do this, there are now problems with the clicking of the mouse on the VAS line, the corresponding "X" that is marked on that line, and the  % value that corresponds to where I just clicked. 

For example, when working on a laptop computer with a screen resolution of 1280 X 800, when the VAS line appears, I click all the way to the right, which should correspond to 100%. Instead the "X" appears about 1 inch to the left of where I clicked and the value says something like 83%. When I click all the way to the left (i.e. 0%), the "X" appears in the correct position and the percent value also indicates 0%. Thus, at the left-hand side of the screen, the mouse cursor, X, and % match, but the further I go to the right, the worse the discrepancy becomes. This leads me to believe that the issue lies with the multiplier that is given for the expression equation in the script:

<expressions>
/ correctionvalue = (display.width - shape.line.width) / 2
/ correctedscore = (trial.VisualAnalogueScale.responsex - expressions.correctionvalue) / shape.line.width * 100
/ roundedvalue = format("%.2f", expressions.correctedscore)
</expressions>

I can adjust this multiplier for my specific resolution, but then when I change the resolution, the issues obviously returns. One additional clue to the problem might be that when I specify that my VAS line should be 100% of the screen, it takes up maybe 80% of the screen. The same is true for my images during this task. When I specify the image should be 100% of the screen, there are two wide vertical borders (~1 inch) that flank the images. Thus, Inquisit might believe that the line is longer than it really is and when the score is calculated using the above equation, it incorrectly gives out a score. Therefore, I currently have the line length as a discrete length (eg. 1280, 6), but I would like to make it a % such as 94% as long as I can get the "X" to appear at the correct spot on the line and give a correct corresponding % (from 0-100). 

The final issue I have no clue as to why it might be occurring. When the first participant ran the task this morning on a mid 2012 13 inch macbook pro, the mouse cursor did not appear during this task, which prevented him from clicking on the VAS line. Any thoughts on this strange issue? I have attached the current script to this post for your reference. Thank you in advance.