Pikchachanja

Not quite up to the standard of


Channel 4's animation but getting there.


Timothy Closs keeps things moving.





Pikchachanja for your Spectrum





Thanks to a technique like the one American animation


experts use, Pikchachanja allows one picture to be trans-


formed 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 chan-


ging 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.


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 trans-


fers the first picture to the lower third of the screen.


Now you can draw the second picture in the same way, enter-


ing lines in the appropriate order so that pairing is auto-


matic.


The Spectrum will then proceed to draw up each inter-


mediate 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 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 dis-


played. 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.








Picture 1. Picture 1.


1 1


+-----+ +-----------+ Picture 2.


| | | | +


| | Picture 2. | | / \


| | | | 2+3 / \


4| |2 4 4| |2 / \


| | +-----------+ | | / \ 1


| | | | | | / \


| | 3| |1 | | / \


| | | | | | / \


+-----+ +-----------+ +-----------+ +-------------+


3 2 3 4


Example 1. Example 2. If the two pictures


do not have equal numbers of


lines, superimposing two or


more lines will complete the


picture without changing its


appearance.