Cwidth integer bit width for rows

IV.3 A DIGITAL “DISOLVE” EFFECT

procedure dissolve2 (height, width: integer); rowshift: integer; shift dist to get row from element colmask: integer; mask to extract column from element		228
	how many bits needed for height? how many bits needed for width? how wide must the register be?


Now cycle through all sequence elements. seq ← 1; 1st element (could be any nonzero) loop do begin row ← rshift(seq, rowshift); find rownumber for this pixel and column number column ← seq bit-and colmask; if (row < height) doeselement fall in the array? GRAPHICS GEMS I Edited by ANDREW S. GLASSNER

IV.3 A DIGITAL “DISOLVE” EFFECT

When you code this, here are some reminders that probably apply to most implementations:

• Don't forget the (0, 0)th element of the array, as handled explicitly in Listings 1 and 3.