
PIKCHACHANJA
by Timothy Closs for Sinclair Spectrum
from Your Computer vol.5,#4 (Apr.85)

Not quite up to the standard of Channel 4's animation, but getting there.
Timothy Closs keeps things moving.

[With the program as printed it was very difficult to get it to draw]
[and/or store the shapes reliably, so I made a few minor changes    ]
[(marked in INVERSE) to get it to work consistently.            JimG]

THANKS TO A technique like the one American animation experts use,
Pikchachanja allows one picture to be transformed into another in a
smooth, 15-frame animation sequence.

The pictures consist of a series of straight lines, with each line
having a partner in the other picture. By changing each line into its
partner you can achieve up to 125 lines, and by pairing lines
differently the animation can be changed, so prior planning can add a
lot to the finished product.

When you've finished typing in the program, run it and you'll see the
main menu:

PRESS S TO SAVE PRESENT DATA
      L TO LOAD DATA
      A TO SEE ANIMATION
      ANY OTHER KEY TO CONTINUE

Press any key other than S, L and A and the computer will ask how many
lines are required in the pictures - it must be the same number for each
picture as every line must have one partner, but see note with example 1
[see PIKCHA.GIF]. The screen will then clear and the cursor will appear,
together with information concerning the cursor position, the number of
lines entered and the present cursor jump in pixels.

The pictures are confined to the upper third of the screen for memory
reasons. Now you can enter the first picture lines in one of two ways:

1. Plot a point, move cursor and plot another point. A line is drawn
from one point to the other.
2. Draw a line from the last point plotted on the previous line to the
cursor.

Apart from using the cursor keys to move the cursor, here are the other
controls:

* 1 sets cursor jump to one pixel
* 2 sets cursor jump to 10 pixels
* 0 plots a point
* 9 draws a line from last point plotted

When all the lines have been entered, a short beep transfers the first
picture to the lower third of the screen. Now you can draw the second
picture in the same way, entering lines in the appropriate order so that
pairing is automatic.

The Spectrum will then proceed to draw up each intermediate frame on the
screen and store them in its memory. When all 15 frames have been
stored, the screen will clear and the pictures are transformed back and
forth in a smooth sequence, during which the main menu can be recalled
by the touch of a button.

[The above paragraph was repeated in the magazine.]

The data held in the computer can be saved by pressing S while the main
menu is displayed.

Data can be loaded by pressing L while the menu is displayed. Having
entered the file name the Spectrum will search for the file and, if
found, will begin to draw up the frames and store them in its memory as
mentioned earlier. The animation sequence present in memory can be
viewed by pressing A.

For a copy of Pikchachanja together with many other novel applications,
contact me at [address removed]. Simply send a blank tape and an SAE
together with 99p for recorded data which can be loaded directly into
your Spectrum.


--
Another Fine Product transcribed by:
Jim Grimwood, Weardale, England
http://www.users.globalnet.co.uk/~jimg/
--
