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Graphics Utility Suites

After Effects exposes its internal transform and graphic utility routines through the following function suites.

Transform Worlds

These functions combine PF_EffectWorlds in interesting ways. When you use these, you're using the same code After Effects does internally.

PF_WorldTransformSuite1

Function

Purpose

composite_rect

Composite a rectangle from one PF_EffectWorld into another, using one of After Effects' transfer modes.

PF_Err composite_rect (
  PF_ProgPtr      effect_ref,
  PF_Rect         *src_rect,
  A_long          src_opacity,
  PF_EffectWorld  *src_world,
  A_long          dst_x,
  A_long          dst_y,
  PF_Field        field_rdr,
  PF_XferMode     xfer_mode,
  PF_EffectWorld  *dst);

field_rdr can be upper, lower or both.

xfer_mode is one of the following:

  • PF_Xfer_COPY
  • PF_Xfer_BEHIND
  • PF_Xfer_IN_FRONT

blend

Blends two images, alpha-weighted. Does not deal with different-sized sources, though the destination may be either PF_EffectWorld.

PF_Err blend (
  PF_ProgPtr            effect_ref,
  const PF_EffectWorld  *src1,
  const PF_EffectWorld  *src2,
  PF_Fixed              ratio,
  PF_EffectWorld        *dst);

convolve

Convolve an image with an arbitrary size kernel on each of the a, r, g, and b channels separately.

You can specify a rectangle to convolve (for instance, the extent_hint from PF_EffectWorld Structure), or pass 0 to convolve the entire image.

Do not use if the source is the destination.

Describe the convolution using Kernel Flags.

PF_Err convolve(
  PF_EffectWorld  *src,
  const PF_Rect   *area,
  PF_KernelFlags  flags,
  A_long          kernel_size,
  void            *a_kernel,
  void            *r_kernel,
  void            *g_kernel,
  void            *b_kernel,
  PF_EffectWorld  *dst);

copy

Copies a region from one PF_EffectWorld to another, preserving alpha (unlike the macOS CopyBits).

PF_Err copy (
  PF_EffectWorld  *src,
  PF_EffectWorld  *dst,
  PF_Rect         *src_r,
  PF_Rect         *dst_r);

copy_hq

A higher fidelity version of the above (using the same parameters).

transfer_rect

Blends using a transfer mode, with an optional mask.

PF_Err transfer_rect (
  PF_ProgPtr              effect_ref,
  PF_Quality              quality,
  PF_ModeFlags            m_flags,
  PF_Field                field,
  const PF_Rect           *src_rec,
  const PF_EffectWorld    *src_world,
  const PF_CompositeMode  *comp_mode,
  const PF_MaskWorld      *mask_world0,
  A_long                  dest_x,
  A_long                  dest_y,
  PF_EffectWorld          *dst_world);

transform_world

Given a PF_EffectWorld and a matrix (or array of matrices), transforms and blends using an After Effects transfer mode, with an optional mask.

The matrices pointer points to a matrix array used for motion-blur.

When is a transform not a transform? A Z-scale transform is not a transform, unless the transformed layer is a parent of other layers that do not all lie in the z=0 plane.

PF_Err transform_world (
  PF_InData               *in_data,
  PF_Quality              quality,
  PF_ModeFlags            m_flags,
  PF_Field                field,
  const PF_EffectWorld    *src_world,
  const PF_CompositeMode  *comp_mode,
  const PF_MaskWorld      *mask_world0,
  const PF_FloatMatrix    *matrices,
  A_long                  num_matrices,
  Boolean                 src2dst_matrix,
  const PF_Rect           *dest_rect,
  PF_EffectWorld          *dst_world);

Kernel Flags

Functions such as convolve or gaussian kernel work with kernels, or matrices of filter weight values. These matrices can be in any format. The kernel flags describe how the matrices should be created and used. OR together any flags you need.

The flags relevant to given routines are documented along with the routine prototype.The first entry in the left column is always the default and has value 0.

Kernel Flags

Indicates

PF_KernelFlag_2D

PF_KernelFlag_1D

Specifies a one or two dimensional kernel.

PF_KernelFlag_UNNORMALIZED

PF_KernelFlag_NORMALIZED

NORMALIZED equalizes the kernel; the volume under the kernel surface is the same as the volume under the covered area of pixels.

PF_KernelFlag_CLAMP

PF_KernelFlag_NO_CLAMP

CLAMP restricts values to the valid range for their data type.

PF_KernelFlag_USE_LONG

PF_KernelFlag_USE_CHAR

PF_KernelFlag_USE_FIXED

PF_KernelFlag_USE_UNDEFINED

USE_LONG defines the kernel as an array of longs valued from 0 to 255. USE_LONG is the only implemented flag.

USE_CHAR defines the kernel as an array of unsigned chars from 0 to 255.

USE_FIXED defines the kernel as an array of fixeds from 0 to 1.

PF_KernelFlag_HORIZONTAL

PF_KernelFlag_VERTICAL

Specifies the direction of the convolution.

PF_KernelFlag_TRANSPARENT_BORDERS

PF_KernelFlag_REPLICATE_BORDERS

Use TRANSPARENT_BORDERS to treat pixels off the edge as alpha zero (black).

Use REPLICATE_BORDERS to replicate border pixels when sampling off the edge.

REPLICATE_BORDERS is not implemented and will be ignored.

PF_KernelFlag_STRAIGHT_CONVOLVE

PF_KernelFlag_ALPHA_WEIGHT_CONVOLVE

Use STRAIGHT_CONVOLVE to indicate straight convolution.

Use ALPHA_WEIGHT_CONVOLVE to tell the convolution code to alpha-weight the contributions of pixels to the resulting convolved output. ALPHA_WEIGHT_CONVOLVE is not implemented and will be ignored.

Fill 'Em Up!

The FillMatteSuite can be used to fill a PF_EffectWorld, either with a specific color or premultiplied with an alpha value.

PF_FillMatteSuite2

Function

Purpose

fill

Fills a rect with a color (or, if the color pointer is null, fills with black and alpha zero).

If the rect is null, it fills the entire image.

PF_Err fill (
  PF_ProgPtr      effect_ref,
  const PF_Pixel  *color,
  const PF_Rect   *dst_rect,
  PF_EffectWorld  *world);

fill16

Same as fill, but takes a pointer to a PF_Pixel16 color.

fill_float

Takes a pointer to a PF_PixelFloat color.

premultiply

Converts to (and from) r, g, and b color values pre-multiplied with black to represent the alpha channel.

Quality independent.

  • forward is used as a boolean
  • true means convert non-premultiplied to pre-multiplied
  • false mean un-pre-multiply.

PF_Err premultiply (
  A_long          forward,
  PF_EffectWorld  *dst);

premultiply_color

Converts to (and from) having r, g, and b color values premultiplied with any color to represent the alpha channel.

PF_Err premultiply_color (
  PF_ProgPtr      effect_ref,
  PF_EffectWorld  *src,
  PF_Pixel        *color,
  A_long          forward,
  PF_EffectWorld  *dst);

premultiply_color16

Same as above, but takes a pointer to a PF_Pixel16 color.

premultiply_color_float

Takes a pointer to a PF_PixelFloat color.

Sampling Images

Note: areas outside the bounds of the image being sampled are treated as zero alpha. For convenience, the functions from PF_Sampling8Suite1, PF_Sampling16Suite1, and PF_SamplingFloatSuite1 are all listed in this table.

PF_SamplingSuite Functions (Multiple Suites)

Function

Purpose

nn_sample

Performs nearest neighbor sampling.

PF_Err nn_sample (
  PF_ProgPtr       effect_ref,
  PF_Fixed         x,
  PF_Fixed         y,
  const PF_SampPB  *params,
  PF_Pixel         *dst_pixel );

nn_sample16

Same as above, but takes a pointer to a PF_Pixel16 dst_pixel.

nn_sample_float

Takes a pointer to a PF_PixelFloat dst_pixel.

subpixel_sample

Queries the appropriate alpha-weighted interpolation of colors at a non-integral point in a source image, in high quality. Nearest neighbor sampling is used in low quality.

Because the sampling routine, if used, will typically be called many times, it is convenient to copy the function pointer out to the callbacks structure and into a register or onto the stack to speed up your inner loop.

See the sample code for an example.

Note

The sampling assumes that 0,0 is the center of the top left pixel.

PF_Err subpixel_sample (
  PF_ProgPtr       effect_ref,
  PF_Fixed         x,
  PF_Fixed         y,
  const PF_SampPB  *params,
  PF_Pixel         *dst_pixel);

subpixel_sample16

Same as above, but takes a pointer to a PF_Pixel16* dst_pixel.

subpixel_sample_float

Takes a pointer to a PF_PixelFloat* dst_pixel.

area_sample

Use this to calculate the appropriate alpha weighted average of an axis-aligned non-integral rectangle of color in a source image, in high quality.

Nearest neighbor sampling is used in low quality. Because of overflow issues, this can only average a maximum of a 256 x 256 pixel area (i.e. x and y radius < 128 pixels).

Note

The sampling radius must be at least one in both x and y.

PF_Err area_sample (
  PF_ProgPtr       effect_ref,
  PF_Fixed         x,
  PF_Fixed         y,
  const PF_SampPB  *params,
  PF_Pixel         *dst_pixel);

Note

Areas outside the boundaries of the layer are considered the same as zero alpha, for sampling purposes.

area_sample16

Same as above, but takes a PF_Pixel16* dst_pixel.

PF_BatchSamplingSuite1 Functions

Function

Purpose

begin_sampling

Your effect is going to perform some batch sampling; After Effects will perform setup tasks to optimize your sampling.

PF_Err (*begin_sampling)(
  PF_ProgPtr    effect_ref,
  PF_Quality    qual,
  PF_ModeFlags  mf,
  PF_SampPB     *params);

end_sampling

Tells After Effects you're done sampling.

PF_Err (*end_sampling)(
  PF_ProgPtr    effect_ref,
  PF_Quality    qual,
  PF_ModeFlags  mf,
  PF_SampPB     *params);

get_batch_func

Obtains a pointer to After Effects' batch sampling function (highly optimized).

PF_Err (*get_batch_func)(
  PF_ProgPtr          effect_ref,
  PF_Quality          quality,
  PF_ModeFlags        mode_flags,
  const PF_SampPB     *params,
  PF_BatchSampleFunc  *batch);

get_batch_func16

Obtains a pointer to After Effects' 16-bpc batch sampling function (also highly optimized).

PF_Err (*get_batch_func16)(
  PF_ProgPtr            effect_ref,
  PF_Quality            quality,
  PF_ModeFlags          mode_flags,
  const PF_SampPB       *params,
  PF_BatchSample16Func  *batch);

Do The Math For Me

Along with the variety of graphics utilities, we also provide a block of ANSI standard routines so that plug-ins will not need to include other libraries to use standard functions.

We give function pointers to a large number of math functions (trig functions, square root, logs, etc.).

Using our suite functions provides for some (application level) error handling, and prevents problems with including different versions of multiple "standard" libraries.

All functions return a double. All angles are expressed in radians, use PF_RAD_PER_DEGREE (a constant from AE_EffectCB.h) to convert from degrees to radians if necessary.

PF_ANSICallbackSuite1

Function Purpose Replaces
acos Returns the arc cosine of x. PF_ACOS
asin Returns the arc sine of x. PF_ASIN
atan Returns the arc tangent of x. PF_ATAN
atan2 Returns atan(y/x). PF_ATAN2
ceil Returns the next integer above x. PF_CEIL
cos Returns the cosine of x. PF_COS
exp Returns e to the power of x. PF_EXP
fabs Returns the absolute value of x. PF_FABS
floor Returns the closest integer below x. PF_FLOOR
fmod Returns x modulus y. PF_FMOD
hypot Returns the hypotenuse of x and y, which is sqrt(x*x + y*y). PF_HYPOT
log Returns the natural log (ln) of x. PF_LOG
log10 Returns the log (base 10) of x. PF_LOG10
pow Returns x to the power of y. PF_POW
sin Returns the sine of x. PF_SIN
sqrt Returns the square root of x. PF_SQRT
tan Returns the tangent of x. PF_TAN
(while not strictly math functions, these emulate ANSI functionality)
sprintf Emulates the C sprintf function. PF_SPRINTF
strcpy Emulates the C strcpy function. PF_STRCPY