# Transformations Tackk

## Translation

The movement of a set of coordinates (an image) from one location to another.

Rule: (x+h, y+v)

h = horizontal change; v = vertical change

## Reflection

The flipping of an image across a line.

Rules:

Reflection across X axis: (x,y) → (x, -y)

Reflection across Y axis: (x,y) → (-x, y)

Reflection across y=x: (x,y) → (y,x)

Reflection across x=y: (x,y) → (-y,-x)

## Rotation

The turning of an image around a center point.

Rules:

Rotation 90° counter-clockwise/270° clockwise: (x,y) → (-y,x)

Rotation 180° counter-clockwise/clockwise: (x,y) → (-y,-x)

Rotation 270° counter-clockwise/90° clockwise: (x,y) → (y,-x)

Rotation 360° counter-clockwise/clockwise: seriously? (x,y) → (x,y)

## Dialation

This is the re-sizing of an image. Please note that this is the only transformation to result in an image not congruent with it's pre-image.

Rule: (hx,vy)

h = horizontal scale factor; v = vertical scale factor

If you are resizing an image around a center point that is not the origin, then you must temporarily act as if it was. Whenever you run through the equation, you must make the x and y values equal to their position in relation to the center point. But do NOT change their actual positions to these coordinates afterwards.