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+--- Forum: HP Prime (/forum-5.html)
+--- Thread: Smooth scrolling (/thread-585.html)
Smooth scrolling - Jurgen Keller - 02-01-2014 08:15 AM
I've added scrolling to my Cellular Automaton program I did a while ago. However, the result is somewhat disappointing: the scrolling produces quite some flickering. Here is a small test program that shows the same effect:
Code:
EXPORT Flicker()
BEGIN
LOCAL X,Y;
DIMGROB_P(G1,320,240);
RECT_P(G1,0,0,320,240,#0);
Y:=-1;
FOR I FROM 1 TO 960 DO
IF Y=239 THEN
BLIT_P(G1,G1,0,1,320,240);
ELSE
Y:=Y+1;
END;
FOR X FROM 0 TO 319 DO
PIXON_P(G1,X,Y,RGB(RANDINT(0,255),RANDINT(0,255),RANDINT(0,255)));
END;
BLIT_P(G0,G1,0,0,320,240);
IF ISKEYDOWN(4) THEN
BREAK;
END;
END;
END;From my old days I remember that you could synchronize screen updates with the CRT's vertical refresh, i.e., update the screen while the electronic beam was moving from the bottom right to the top left. I don't know if such an approach would also be possible for the Prime? Have TFT displays also such a refresh cycle like CRTs? Or is there something wrong with my program? Smooth scrolling would be such a nice thing to have for game programming and other fun stuff ...