Fedora 13 Success

Previously I stumbled across a way to print full DVD images with no clipping, but I had no real idea why it worked. The story continues here with the new Fedora 13 alpha and hplip-3.10.2-5.fc13.x86_64.

My kewpie program was still used for all the printing in this saga.

My first attempt was just copying all the ImageableArea and print margins settings from fedora 12. This was an abject failure. Clearly, something has changed.

My second attempt was to go back to the default ImageableArea and try centering my test image in the printable area by using 4.5 millimeter margins all around the edges of the 127 millimeter printable area (127 millimeters equal 360 points). This wasn't as bad, but still was not aligned in the center of the dvd.

For my third attempt, I scanned in the DVD I printed on the 2nd try, rotated and cropped the image so the triangle was pointing up in a 118 millimeter square image. Then I used gimp to pick off the actual locations of the vertices (extrapolating the lines for the lower right vertex which was cropped off during the printing). I compared these with the computed locations the vertices of a triangle inscribed on a 118 millimeter circle should have (doing all arithmetic in gimp coordinates and using pixel locations in the 1394 pixel 300dpi image):

Vertex	Computed	Measured
Top	(697,0)	(723,25)
Lower Left	(93, 1045)	(118,1068)
Lower Right	(1300, 1045)	(1327,1069)

Averaging the offsets, that tells me the triangle printed too far left by 26 pixels and too far down by 24 pixels, so I need to reduce the left margin and increase the right margin and reduce the top margin and increase the bottom margin, and in theory, my triangle will print out perfectly inscribed in the DVD circle.

I changed the margin settings in my kewpie config file to read (converting to points):

leftMargin=6.54

topMargin=7.02

rightMargin=19.02

bottomMargin=18.54

And, Voila! The triangle did indeed print perfectly. No clipping of the top vertex. So the new hplip has somehow magically eliminated the clipping the old one previously did when using the default ImageableArea setting.

The only question now is if the actual print location will keep shifting every time a new hplip is released? (As long as they don't start clipping the image again, I'll be OK I guess :-).