# Geometric Transforms

## IceMan Reference Guide |

#### Geometric Transforms

`ice.Image LinearTransform(matrix)`*matrix:*3x3 transformation matrix (list).This operation performs all coordinate transformations expressible as a 3x3 matrix. These include affine transformations (in which parallel lines stay parallel), translations and non-affine perspective transformations.

The resampling filter is a Catmull-Rom bicubic, whose width is calculated appropriately.

In the example below, i is of type ice.Image.

*matrix = [1, 0.3, 0, 0.1, 1, 0, 0, 0, 1.0] result = i.LinearTransform(matrix)*`ice.Image Translate(point, filterType)`*point:*Translate by a specified number of pixels (tuple)*filter:*resampling filter to use (int). Can be one of:- ice.constants.FILTER_BILINEAR
- ice.constants.FILTER_BSPLINE
- ice.constants.FILTER_CATROM
- ice.constants.FILTER_LANCZOS
- ice.constants.FILTER_MITCHELL_NETRAVALI
- ice.constants.FILTER_POINTSAMPLE

Defaults to FILTER_CATROM (CatmullRom).

Translate an image with appropriate resampling. Integral pixel translate operations are automatically optimized.

*filter = ice.constants.FILTER_BILINEAR amount = (23.5. 60.6) result = orig.Translate(amount, filter)*This is a special case of

*LinearTransform.*`ice.Image Move(point)`*point:*Move by a specified number of pixels (tuple)Returns a copy of the operand image with its world coordinates moved by an integral ammount. The copy will share data with the source, no resampling will be performed

`ice.Image Scale(scale, filter)`*scale:*Scale by specified factors in x and y (list)*filter:*resampling filter to use (int). Defaults to CatmullRom.Geometrically scale an image with appropriate resampling.

*filter = ice.constants.FILTER_LANCZOS amount = [0.5. 0.5] result = orig.Scale(amount, filter)*This is a special case of

*LinearTransform*.`ice.Image Rotate(degrees, filter)`*degrees:*Angle of rotation in degrees (float)*filter:*resampling filter to use (int). Defaults to CatmullRomRotate an image about

*(0, 0)*. The angle of rotation is measured counterclockwise.This is a special case of

*LinearTransform.*`ice.Image Resize(scale)`*scale:*Scale by specified factors in x and y (list)Fast geometric scaling using only point-sampling. Useful for previews and interactive display.

`ice.Image Reformat(newBox, preserveAR, crop, anamorph)`*newBox:*Desired box (list).*preserveAR:*Should the aspect ratio be preserved (bool)? default = true.*crop:*Should the image be cropped to preserve aspect ratio (bool)? default = true.*anamorph:*If the final image is destined for anamorphic display, the "stretch factor" (float). default = 1.0.This is an operation that fulfills a common need: that of changing the size of an image prior to saving. The arguments are self-explanatory: letter- or window-boxing is automatically performed if aspect ratio is to be preserved and cropping is not enabled. The

*anamorph*argument is unity when no anamorphic display is intended: larger than unity when it is.*Note: This is not a "native" operation: it internally comprises other operations arranged to yield the result desired.*`ice.Image Flip(x, y, transpose)`*x:*Flip in x (bool)?*y:*Flip in y (bool)?*transpose:*Transpose the image (bool)?This operation is optimized to perform the eight possible "unity-scale" transformations. These are illustrated below.

*# No-op result = m1_1.Flip(False, False, False)**# Transpose axes result = m1_1.Flip(False, False, True)**# Flip in Y result = m1_1.Flip(False, True, False)**# Flip in Y and transpose axes result = m1_1.Flip(False, True, True)**# Flip in X result = m1_1.Flip(True, False, False)**# Flip in X and transpose axes result = m1_1.Flip(True, False, True)**# Flip in X and Y result = m1_1.Flip(True, True, False)**# Flip in X and Y and transpose result = m1_1.Flip(True, True, True)*`ice.Image DisplacementWarp(warpImg, minMax, filterType, filterScale)`*warpImg:*Displacement image (ice.Image)*minMax:*Displacements corresponding to 0 and 1 (list). defaults to [0, 1].*filterType:*Filter type. Defaults to CatmullRom.*filterScale:*Scale equivalent for filter width (float) defaults to 1.0General displacement warp operation.

*WarpImg*is a two-channel vector field containing the offset of the source pixel for each result pixel. The actual offset is given by:*O' = o * (max − min) + min*The type of the filter is normally best set to FILTER_CATROM. Since it is not possible to analytically determine a single best filter width,

*filterScale*should be chosen to yield the best possible combination of sharpness and anti-aliasing. 1.0 is a good place to start: smaller values yield wider filters (and less sharpness).*Original**Displacement Image**Warped Image**minMax = [0, 10] filter = ice.constants.FILTER_MITCHELL_NETRAVALI fScale = 1.0 result = fruit.DisplacementWarp(disp, minMax, filter, fScale)*