Robins's Visual Chart Form Tips

Limitation of Line Styles

This page created 1 Sep 2014

Hosted by Terry's TMG Tips

This section applies to any drawing of lines. There are two major limitations of line styles in TMG and VCF:

1. Width and Style interaction

There is a constraint in both TMG and VCF that solid lines can be of different widths, but lines with style that are discontinuous, like dashes, dots, etc may only have width of 0 points. That is you can’t have thicker dashed etc lines.

2. Difference in width units

   TMG line width user interface sets line widths in pixels (Pixels are 96 per inch).

VCF line width user interface sets line width in points. (Points are 72 per inch).

BUT as all distances inside VCF are stored as pixels this causing a rounding to occur when storing the point value as pixels. Therefore, some line widths that can be set via TMG, but cannot be duplicated by settings made within VCF.

It is not possible create a 2, 6, or 10 pixel width lines in VCF.

When is this problem noticeable?

1. When adding similar items to an existing chart. Always make a copy an object of the right type already on the chart, and then edit it to achieve the effect. The copy inherits the settings from TMG that VCF could not create.
2. When cutting and pasting from one chart onto another. Always create a new canvas of suitable size and then copy parts from the two charts onto the new chart. Some possible corruption occurs as the content is stored into the clipboard or copied from it. This strategy ensures that all components are modified in the same way (See Combining Charts).

 

There is an additional problem in line widths. I do not know how they are saved when copied to the Clipboard, but I am aware that copying a section of a chart and then pasting it back to the same chart can create lines of different thickness. Therefore some line widths are omitted or some line widths are merged.

If you copy a pieces of another chart onto an existing chart there is a chance that the line thickness that was the same will have become differenct in the process. A workaround is to copy both chart segments to a blank canvas. Thus both chart segments will suffer the same corruption of line widths in the process. It is sometimes not possible to create another line of the same apparent thickness as those already on the chart, because of this mismatch in units.

Copyright 2014- by Robin Lamacraft