Apple MA434Z/A User Manual - Page 940

You can type an expression in any field. Some nodes, such as ColorX, WarpX, and TimeX, even support locally declared variables. For more information and a list of examples, see "ColorX" on page 647. If you are using the command-line method, you may have to enclose your expressions in quotes to avoid problems with the operating system reading the command. For example, don't use: shake my_image.iff -rot 45*6 Instead, use: shake my_image.iff -rot "45*6" Examples 1/2.2 2*Linear(0,0@1,200@20) 2*my_curve sqrt(my_curve-my_center)/2 time>20?1:0 cos(time/5)*50 Explanation 1 divided by 2.2. Gives you the inverse of 2.2 gamma. Multiplies the value of an animated curve by 2. Multiplies a variable by 2. Subtracts my_center from my_curve, takes the result square root, and then divides by 2. If time is greater than 20, then the parameter is 1, otherwise it equals 0. Gives a smooth ping-pong between -50 and 50. Precedence The above operators are listed in order of precedence-the order Shake evaluates each operator, left to right. If this is difficult to keep up with (and it is), make liberal use of parentheses to force the order of evaluation. For instance: a = 1 + 2 * 4 -2 This expression does "2*4" first, since the "*" has precedence over "+" and "-" which gives you "a=1+8-2."Then from left to right, Shake does "1+8," giving "a=9-2," finally resulting in "a=7." To add and subtract before multiplying, use parentheses to control the evaluation. a = (1 + 2) * (4 - 2) This results in "a=3*2" or "a=6." Note: In any expression, parentheses have the highest precedence. 940 Chapter 31 Expressions and Scripting