it seems that turning off the option to enhance thin lines (Page Display->Rendering) does not work, quite similar to how turning off image smoothing has no effect on the actual rendering.
Here is an image comparing the original 1 pixel line art to viewing a PDF created via XChange Standard in both Acrobat DC Reader and Editor v320. Editor renders the 1 pixel line as 2 pixels, switching the Preferences option has no effect on the rendering output in Editor, whereas it does have an effect in Acrobat Reader.
Just to mention it: the comparison images (1 pixel line boxes) are screenshots taken from the various sources (original, Reader, Editor) and then copy & pasted into a single image for comparison. They are not just some arbitrary boxes drawn by me to demonstrate the issue.
Thanks for the sample. Indeed we do use a different anti aliasing engine than other products - so it might produce a slightly different result. I will ask a colleague to take a look.
Just got a word from a colleague from the dev team - that this issue is related to "Stroke Adjust" - with this feature on - you can "adjust" a horizontal/vertical line to be displayed in just one row/column of pixels on the screen. Without it, and given that page coordinates are with floating point precision - we normally would need to display a thin line over two rows/columns of pixels. One of them will be with a solid color and the other one will be "shaded" due to anti aliasing algorithms, or with the smoothing option off - the full two pixel rows will be ocupied.
We are working on our Stroke Adjustment algorithms and will add them in a future build, but for now indeed the Editor will show such very thin lines thicker than other products.
I guess there is no right or wrong in this. The original program (Hero Lab) starts painting the lines as single pixel black at an equivalent zoom of 495% in Reader/Editor (101 dpi Windows setting). Before that it uses two gray lines, one stronger one weaker.
Acrobat Reader uses a single gray line up to 800%, most lines even up to 1200% (using CTRL-wheel steps). At 1600% it starts to use two gray lines, one being stronger, at 3200% it begins to introduce full black in the stronger of the two lines. With anti-aliasing turned off it always uses a 1 pixel black line, though, even for zoom levels below 100%.
Editor introduces black in the stronger of the two lines even at zoom levels below 100%. This is not necessarily a bad thing, because these lines are black. At lower zoom levels they do look stronger and fuzzier (AA below 400%) than in the other programs, though, which use single light gray lines for small zoom levels (with the gray becoming stronger/darker as you zoom in).
The main issue is with Editor using two pixels per line when anti-aliasing is turned off, this should not happen. A single-pixel line should remain to be a single-pixel line, especially when CAD based architectural or engineering files are viewed.
I need to underline again that switching the "Enhance thin lines" options seems to have zero effect. The lines in my sample document look the very same (even magnified), both with anti-aliasing on or off. I tried all combinations and it just doesn't make any difference.
In Acrobat Reader switching this option on makes Reader render the thin lines as 1 pixel black lines regardless of zoom setting and regardless of whether anti-aliasing is turned on or off. Once you turn off the option in Acrobat it will render thin lines as varying gray lines when anti-aliasing is turned on.
Thanks again. I didn't understand that the stroke adjust thing is a "bug", I thought you meant this rather to be some kind of design/implementation choice.
It will depend on the point of view really
I perceive that as a missing advanced feature, which will allow thin lines to be displayed a single pixel width/height, but given that other products already do handle such lines 'better' might make it look like a bug.
The thing is that we do have an implementation that does render the files on screen, and we will be working on adding the Stroke Adjust so that we can display them better!
Thanks for the patience and understanding while we work on this!
