From Context Free Art
Shape Adjustments: Geometry and Color
There are two categories of shape adjustments: geometric and color.
Geometry Adjustments
The geometry of shapes is defined by a two dimensional affine transform which is represented internally as a matrix.
- x num
- translation along the x-axis by num
- y num
- translation along the y-axis by num
- z num*
- translation along the z-axis by num
- size num
- scale in x and y by num
- size num1 num2
- scale in x by num1 and in y by num2
- size num1 num2 num3*
- scale in x by num1, in y by num2, and in z by num3
- rotate num
- rotate in the x/y plane num degrees
- flip num
- reflect in x/y plane across a line through the origin at num degrees
- skew num1 num2
- shear transform in x/y plane num1 degrees from the y axis and num2 degrees from the x axis
- * The z-axis position and scale are not stored in the affine transform matrix and do not affect the shape of objects. The z-axis position determines which shape is on top when they overlap.
| Abbreviations: 'size' can be abreviated as 's', 'rotate' can be abbreviated as 'r', and 'flip' can be abbreviated as 'f'.
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Color Adjustments
The color of a shape is represented by two points in the HSBA color space (HSB color plus alpha, or opacity). One point is the color that the shape is actually drawn in and the other point is a target that the drawing color trends toward. The HSBA coordinates are [0,360) for hue, [0,1] for saturation, [0,1] for brightness, and [0,1] for alpha (opacity).
- hue num
- add num to the drawing hue value, modulo 360
- saturation num
- range [-1,1]. If num<0 then change the drawing saturation num% toward 0. If num>0 then change the drawing saturation num% toward 1.
- brightness num
- range [-1,1]. If num<0 then change the drawing brightness num% toward 0. If num>0 then change the drawing brightness num% toward 1.
- alpha num
- range [-1,1]. If num<0 then change the drawing alpha num% toward 0. If num>0 then change the drawing alpha num% toward 1.
- |hue num
- add num to the target hue value, modulo 360
- |saturation num
- range [-1,1]. If num<0 then change the target saturation num% toward 0. If num>0 then change the target saturation num% toward 1.
- |brightness num
- range [-1,1]. If num<0 then change the target brightness num% toward 0. If num>0 then change the target brightness num% toward 1.
- |alpha num
- range [-1,1]. If num<0 then change the target alpha num% toward 0. If num>0 then change the target alpha num% toward 1.
| Abbreviations: 'hue' can be abbreviated as 'h', 'saturation' can be abbreviated as 'sat', 'brightness' can be abbreviated as 'b', and 'alpha' can be abbreviated as 'a'.
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Targeting a Color
There are four more drawing color adjustments for changing the drawing color components with respect to the target color. This useful is you have a recursive shape rule that adjusts a color component and you don't want to overshoot a value. For example, the drawing hue is red and you want the drawing hue to trend toward yellow, but never go past yellow to green.
- hue num|
- range [-1,1]. If num<0 then change the drawing hue num% toward the target hue moving clockwise around the color wheel. If num>0 then change the drawing hue num% toward the target hue counter-clockwise around the color wheel.
- saturation num|
- range [-1,1]. If num<0 then change the drawing saturation num% toward 0 or the target saturation, whichever is closer. If num>0 then change the drawing saturation num% toward 1 or the target saturation, whichever is closer.
- brightness num|
- range [-1,1]. If num<0 then change the drawing brightness num% toward 0 or the target brightness, whichever is closer. If num>0 then change the drawing brightness num% toward 1 or the target brightness, whichever is closer.
- alpha num|
- range [-1,1]. If num<0 then change the drawing alpha num% toward 0 or the target alpha, whichever is closer. If num>0 then change the drawing alpha num% toward 1 or the target alpha, whichever is closer.
