Jeremias,
I read your TableLayout/KnuthElementsForTables wiki page with
interest. Luca's algorithm is a fine algorithm.
I do have a problem with your last example. Half of the border-after
of the table-header is counted twice, once in the row heights and once
in the header itself. All heights before the page break except the
second one are 2 units too high, and those after the page break are 4
units too high when I compare them with your drawings of the table.
I believe it is better to omit half of the border-after
of the table-header and half of the border-before of the table-footer
from the row height. Then I get the following calculations:
Header is 5 + 8 = 13
Footer is 8 + 5 = 13
row1: 15 + (2/2) = (16,16,16)
row2: 20 + (2/2) = (21,21,21)
row group (37,37,37)
Step 1:
stepw= 10
maxRemainingHeight = 37
addedBoxHeight = 0
penalty = 10 + 37 - 37 = 10
effPenalty: w = 10 (space for block1) + 13 (header) + 4 (border-after-header) +
4 (border-before-footer) + 13 (footer)
box = 10 - 0 - 10 = 0
Step 2:
stepw = 15
maxRemaningHeight = 20
addedBoxHeight = 0
penalty = 15 + 20 - 37 = -2
offPenalty: w = -2 (calc penalty) + 13 + 4 + 4 + 13
box = 15 - 0 - (-2) = 17
Step 3:
stepw = 10 + 10 = 20
maxRemainingHeight = 20
addedBoxHeight = 17
penalty = 20 + 20 - 37 = 3
effPenalty: w = 3 (calc penalty) + 13 + 4 + 4 + 13
box = 20 - 17 - 3 = 0
Step 4:
stepw = 10 + 10 + 10 = 30
maxRemaningHeight = 20
addedBoxHeight = 17
penalty = 30 + 20 - 37 = 13
effPenalty: w = 14 (calc penalty) + 13 + 4 + 4 + 13
box = 30 - 17 - 13 = 0
Step 5:
stepw = 15 + 2 + 20 = 37
maxRemainingHeight = 0
addedBoxHeight = 17
penalty = 37 + 0 - 37 = 0 (last step, omit penalty)
box = 37 - 17 - 0 = 20
box(0)
penalty(10) - 10/37
box(17)
penalty(-2) - 15/20
box(0)
penalty(3) - 20/20
box(0)
penalty(13) - 30/20
box(20)
- 37
box(0)
penalty(44) //incl. header and footer - 44/71
box(17)
penalty(32) //incl. header and footer - 49/54
box(0)
penalty(37) //incl. header and footer - 54/54
box(0)
penalty(47) //incl. header and footer - 64/54
box(20)
box(17) //header
box(17) //footer
- 71
You see I can avoid the subtraction of 2 for the second page break,
which makes the calculation more regular. I do get a negative
penalty. I do not believe that that is a problem, less so because it
is added to the penalty for the header/footer/borders. It expresses
the fact that for this page break the table is shorter than without
page break, due to the merger of the row border with the header and
footer borders.
Regards, Simon
--
Simon Pepping
home page: http://www.leverkruid.nl
