#325 north east line pattern tearing in different viewers

[Lenard Szolnoki]

It could be a device problem, but when I view line patterns in a pdf viewer there is often tearing at the boundaries of the pattern's bounding box. I've looked into both postscript's and pdf's reference manual and both have options to deal with this behavior. For a tiling pattern dictionary there is a "TilingType" option:

1 Constant spacing.

Pattern cells are spaced consistently—that is, by a multiple of a device pixel. To achieve this, the application may need to distort the pattern cell slightly by making small adjustments to XStep, YStep, and the transformation matrix. The amount of distortion does not exceed 1 device pixel.

2 No distortion.

The pattern cell is not distorted, but the spacing between pattern cells may vary by as much as 1 device pixel, both horizontally and vertically, when the pattern is painted. This achieves the spacing requested by XStep and YStep on average but not necessarily for each individual pattern cell.

3 Constant spacing and faster tiling.

Pattern cells are spaced consistently as in tiling type 1 but with additional distortion permitted to enable a more efficient implementation.

I think tiling type 1 could solve this problem.

[Henri Menke]

Viewer issue. Close as wont-fix.