color is loaded a white background is drawn. The default
framemethod uses the following z-order similar to
- left line
- top line
- bottom line
- right line
Screens have usually a low resolution, thin lines can then have a line width of one pixel only. In the direct neighborhood the white background is drawn. Then it can happen that the white background also colors the pixels of the formerly black line, a part of the black line might contain to the background area (low resolution!, rounding issues, ...).
Printers are using higher resolutions, e.g. 600 dpi. Then a line with thickness of
0.4pt (default value). That are 3.3 pixels, when printed. Then the line will not vanish, if the thickness is one pixel short.
Test file for playing and analyzing:
- It makes a simple page with a frame. Fonts are not needed to keep the PDF file
- The page layout is simplified via package
- Unit is
bp, the default unit for PDF (and PS). This makes it easier to understand and interpret the numbers found in the page description of the PDF file.
- PDF compressions are disabled (
pdflatex). Then the PDF file can be easily
inspected in a text viewer or editor.
mdframed provides other
the frame is drawn after the background and therefore remains visible.