STMap node

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This documentation is for version 2.0 of STMap.

Description

Move pixels around an image, based on a UVmap.

The U and V channels give, for each pixel in the destination image, the normalized position of the pixel where the color is taken. (0,0) is the bottom left corner of the input image, while (1,1) is the top right corner. This plugin concatenates transforms upstream, so that if the nodes upstream output a 3x3 transform (e.g. Transform, CornerPin, Dot, NoOp, Switch), the original image is sampled only once.

This plugin concatenates transforms upstream.

Inputs

Input Description Optional
UV   No
Source   No
Mask   Yes

Controls

Parameter / script name Type Default Function
U Channel / channelU Choice UV.r
Input U channel from UV.
UV.r: Red channel from input UV
UV.g: Green channel from input UV
UV.b: Blue channel from input UV
UV.a: Alpha channel from input UV
0: 0 constant channel
1: 1 constant channel
V Channel / channelV Choice UV.g
Input V channel from UV.
UV.r: Red channel from input UV
UV.g: Green channel from input UV
UV.b: Blue channel from input UV
UV.a: Alpha channel from input UV
0: 0 constant channel
1: 1 constant channel
Alpha Channel / channelA Choice UV.a
Input Alpha channel from UV. The Output alpha is set to this value. If “Unpremult UV” is checked, the UV values are divided by alpha.
UV.r: Red channel from input UV
UV.g: Green channel from input UV
UV.b: Blue channel from input UV
UV.a: Alpha channel from input UV
0: 0 constant channel
1: 1 constant channel
Unpremult UV / unpremultUV Boolean Off Unpremult UV by Alpha from UV. Check if UV values look small for small values of Alpha (3D software sometimes write premultiplied UV values).
UV Offset / uvOffset Double U: 0 V: 0 Offset to apply to the U and V channel (useful if these were stored in a file that cannot handle negative numbers)
UV Scale / uvScale Double U: 1 V: 1 Scale factor to apply to the U and V channel (useful if these were stored in a file that can only store integer values)
U Wrap Mode / wrapU Choice Clamp
Wrap mode for U coordinate.
Clamp: Texture edges are black (if blackOutside is checked) or stretched indefinitely.
Repeat: Texture is repeated.
Mirror: Texture is mirrored alternatively.
V Wrap Mode / wrapV Choice Clamp
Wrap mode for V coordinate.
Clamp: Texture edges are black (if blackOutside is checked) or stretched indefinitely.
Repeat: Texture is repeated.
Mirror: Texture is mirrored alternatively.
Filter / filter Choice Cubic
Filtering algorithm - some filters may produce values outside of the initial range (*) or modify the values even if there is no movement (+).
Impulse: (nearest neighbor / box) Use original values.
Box: Integrate the source image over the bounding box of the back-transformed pixel.
Bilinear: (tent / triangle) Bilinear interpolation between original values.
Cubic: (cubic spline) Some smoothing.
Keys: (Catmull-Rom / Hermite spline) Some smoothing, plus minor sharpening (*).
Simon: Some smoothing, plus medium sharpening (*).
Rifman: Some smoothing, plus significant sharpening (*).
Mitchell: Some smoothing, plus blurring to hide pixelation (*+).
Parzen: (cubic B-spline) Greatest smoothing of all filters (+).
Notch: Flat smoothing (which tends to hide moire’ patterns) (+).
Clamp / clamp Boolean Off Clamp filter output within the original range - useful to avoid negative values in mattes
Black outside / black_outside Boolean On Fill the area outside the source image with black
(Un)premult / premult Boolean Off Divide the image by the alpha channel before processing, and re-multiply it afterwards. Use if the input images are premultiplied.
Invert Mask / maskInvert Boolean Off When checked, the effect is fully applied where the mask is 0.
Mix / mix Double 1 Mix factor between the original and the transformed image.