--- bill lam <[EMAIL PROTECTED]> wrote:
> The scale x2 method for print preview works but its speed is very slow > (already > grayscale), it needs about 5 secs to process and display one page. Every > zoom-in > and zoom-out need another 5 secs. Is there any quicker method? The slowest thing is the scale filter, which takes 3.4 sec or about 70% or more of total paint (on a 700 MHz PIII). ts=: 6!:2 , 7!:[EMAIL PROTECTED] A=. i.2400 2048 NB. double screen of 1200x1024 av2=: _2&((+/ <[EMAIL PROTECTED] #)\) ts '16b010101*av2 av2&.|: 256| A' 3.47908 1.17607e8 Now we replace that with a new scaler, where all three improvements matter: placement of |:, delayed division and division by shift. s2=: _2&(+/\) av2x2=: _2 (33 b.) [: s2&.|: s2 ts '16b010101*av2x2 f. 256| A' 1.15549 9.23276e7 3 times cumulative improvement. __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
