The parchments

The text of the parchments is not written with the scoreboard letters but with the original's own stroke-based gothic font: each letter is a list of points painted one by one, with a delay, and that gives the quill effect. In the ROM each glyph is a chain code in nibbles (the first absolute point and then the direction to a neighbour), which preserves the order of the points. The texts are stored at 6 bits per character. The original's timings, at 50 Hz, are converted to 60 by counting in 1/256 of a frame and without divisions: one point every 0.41 frames, 1.5 frames per letter, 30 per line break and about 100 of wait before turning the page.

The original's parchment is 190 pixels wide. At half size, the gothic letter blurred depending on the column; at two thirds it fills the room's 128 and reads well. Out of every three columns, the first is left alone and the other two are merged, with a multiplication instead of the division. The bitmap is 128 × 190 and only the lines that change are recalculated.

To turn the page, 8 × 8 blocks become paper again diagonally, from the top-right corner to the bottom-left, in 39 steps. The "unrolling" at the beginning is the same sweep over a black bitmap.

In STRIP and STRIP+ a 48-pixel window is visible, and in DOUBLE a 96-pixel one. The window follows the quill, but only moves to the right, because the strokes of each letter go back and forth; it returns to the left at each line break. In FULL it is shown whole.

In the interlaced modes, what is not paper cannot be in ink, because it would flicker. So the background is black and the bitmap is inverted: the paper is painted with the players in the ink colour, and the text and the borders come out in solid black. In FULL the paper comes out in the same checkerboard as the room: on each line, half of the blocks, and on the next frame, the other half.