Applies the displacement map filter effect.

This filter effect uses the pixel values from the image from Mix to spatially displace the image from Input. This is the transformation to be performed:

P'(x,y) <- P(x + Scale * (XC(x,y) - 0.5), y + Scale * (YC(x,y) - 0.5))

where P(x,y) is the Input image, and P'(x,y) is the Target. XC(x,y) and YC(x,y) are the component values of the channel designated by the XChannel and YChannel. For example, to use the red component of Mix to control displacement in X and the green component to control displacement in Y, set XChannel to CMP::RED and YChannel to CMP::GREEN.

The displacement map defines the inverse of the mapping performed.

The Input image is to remain premultiplied for this filter effect. The calculations using the pixel values from Mix are performed using non-premultiplied colour values. If the image from Mix consists of premultiplied colour values, those values are automatically converted into non-premultiplied colour values before performing this operation.

Structure

The DisplacementFX class consists of the following fields:

Access

Name

Type

Comment

ResampleMethod VSM The resample algorithm to use for transforming the source image.

Currently NEIGHBOUR and BILINEAR are supported. Other resample methods fall back to bilinear filtering.

Name	Description
VSM::AUTO	The default option is chosen by the system. This will typically be `BILINEAR`, but slow machines may switch to nearest neighbour and high speed machines could use more advanced methods.
VSM::BESSEL	Uses a broad Bessel filter that can preserve detail during resampling, but is slower than the smaller-kernel methods.
VSM::BICUBIC	Produces a similar result to `BILINEAR` at a slightly higher CPU cost and a marginally sharper after-effect.
VSM::BILINEAR	Bilinear is a common algorithm that produces a reasonable quality image quickly.
VSM::BLACKMAN	Five times slower than `BILINEAR`, the final result will be less sharp than SINC.
VSM::GAUSSIAN	Uses a Gaussian filter that softens the result, reducing aliasing at the cost of sharp edge detail.
VSM::KAISER	Uses a Kaiser-windowed filter, giving smooth interpolation with low ringing and a cost close to `BILINEAR`.
VSM::LANCZOS	This well known algorithm may serve as a point of comparison for evaluating the results of other methods. It shares characteristics with `SINC` and `BLACKMAN`.
VSM::MITCHELL	Uses a Mitchell-Netravali filter, balancing sharpness and smoothness at a cost similar to `BICUBIC`.
VSM::NEIGHBOUR	Nearest neighbour is the fastest sampler at the cost of poor quality.
VSM::QUADRIC	Uses a quadratic filter with a modest kernel, giving smoother results than `BILINEAR` with limited extra cost.
VSM::SINC	Five times slower than `BILINEAR`, the final result is of very good quality.
VSM::SPLINE16	About twice as slow as `BILINEAR`, this method samples a 4x4 area and produces a considerably better result, and is a good choice for enlarging images without producing artifacts when contrasting colours are present.

Scale DOUBLE Displacement scale factor.

The amount is expressed in the coordinate system established by VectorFilter⇒PrimitiveUnits on the parent VectorFilter. When the value of this field is 0, this operation has no effect on the source image.

XChannel CMP X axis channel selection.

Name	Description
CMP::ALL	All colour channels.
CMP::ALPHA	The alpha channel.
CMP::BLUE	The blue colour channel.
CMP::GREEN	The green colour channel.
CMP::RED	The red colour channel.

XMLDef STRING Returns an SVG compliant XML string that describes the effect.

YChannel CMP Y axis channel selection.

Name	Description
CMP::ALL	All colour channels.
CMP::ALPHA	The alpha channel.
CMP::BLUE	The blue colour channel.
CMP::GREEN	The green colour channel.
CMP::RED	The red colour channel.

Actions

The following actions are currently supported:

Draw

Render the effect to the target bitmap.

ERR acDraw(*Object, DOUBLE X, DOUBLE Y, DOUBLE Width, DOUBLE Height)

Parameter	Description
X	The X position of the region to be drawn.
Y	The Y position of the region to be drawn.
Width	The width of the region to be drawn.
Height	The height of the region to be drawn.

CMP Type

Component selection for RemapFX methods.

Name	Description
CMP::ALL	All colour channels.
CMP::ALPHA	The alpha channel.
CMP::BLUE	The blue colour channel.
CMP::GREEN	The green colour channel.
CMP::RED	The red colour channel.

VSM Type

Name	Description
VSM::AUTO	The default option is chosen by the system. This will typically be `BILINEAR`, but slow machines may switch to nearest neighbour and high speed machines could use more advanced methods.
VSM::BESSEL	Uses a broad Bessel filter that can preserve detail during resampling, but is slower than the smaller-kernel methods.
VSM::BICUBIC	Produces a similar result to `BILINEAR` at a slightly higher CPU cost and a marginally sharper after-effect.
VSM::BILINEAR	Bilinear is a common algorithm that produces a reasonable quality image quickly.
VSM::BLACKMAN	Five times slower than `BILINEAR`, the final result will be less sharp than SINC.
VSM::GAUSSIAN	Uses a Gaussian filter that softens the result, reducing aliasing at the cost of sharp edge detail.
VSM::KAISER	Uses a Kaiser-windowed filter, giving smooth interpolation with low ringing and a cost close to `BILINEAR`.
VSM::LANCZOS	This well known algorithm may serve as a point of comparison for evaluating the results of other methods. It shares characteristics with `SINC` and `BLACKMAN`.
VSM::MITCHELL	Uses a Mitchell-Netravali filter, balancing sharpness and smoothness at a cost similar to `BICUBIC`.
VSM::NEIGHBOUR	Nearest neighbour is the fastest sampler at the cost of poor quality.
VSM::QUADRIC	Uses a quadratic filter with a modest kernel, giving smoother results than `BILINEAR` with limited extra cost.
VSM::SINC	Five times slower than `BILINEAR`, the final result is of very good quality.
VSM::SPLINE16	About twice as slow as `BILINEAR`, this method samples a 4x4 area and produces a considerably better result, and is a good choice for enlarging images without producing artifacts when contrasting colours are present.

DisplacementFX Class

Structure

Actions

CMP Type

VSM Type