RadialBlurEffectLib — Plan9Basic Documentation

Overview

RadialBlurEffectLib applies a radial (zoom) blur emanating from a center point, wrapping the FireMonkey TRadialBlurEffect component. The effect creates a motion blur as if zooming in or out from the center — commonly used for speed, focus, or dramatic emphasis effects.

Property	Details
Library	`RadialBlurEffectLib`
Prefix	`radblur_`
Wraps	`TRadialBlurEffect`
Functions	16
Type	Visual effect (blur)

Category	Count	Description
Creation / Destruction	2	Create and free effect
Blur Amount	2	Get/set blur intensity
Center Position	4	Get/set X,Y center (0–1)
Effect Control	4	Enabled and trigger get/set
Error Handling	4	Error codes and messages

💨 Zoom Blur: Unlike Gaussian or Box blur which spread evenly, radial blur streaks outward from a center point — like zooming a camera during a long exposure. Great for action or speed effects.

Cross-Platform Support

Platform	Support
Windows	✅ Full support
Linux	✅ Full support
Android	✅ Full support

Creation & Destruction

radblur#(parent#)

Creates a new radial blur effect attached to the specified visual control.

Parameter	Type	Description
`parent#`	Pointer	Target visual control
Returns	Pointer	Effect handle, or 0 on failure

radblur_free(effect#)

Destroys the effect and releases associated resources.

Error Handling

Function	Signature	Description
`radblur_error()`	`radblur_error@`	Returns last error code (0 = none)
`radblur_errormsg$()`	`radblur_errormsg$@`	Returns last error message
`radblur_strerror$(code)`	`radblur_strerror$@n`	Converts error code to text
`radblur_clearerror()`	`radblur_clearerror@`	Clears the error state

Blur Amount

Controls the intensity of the radial blur. Higher values produce stronger zoom-blur streaks.

Function	Signature	Description
`radblur_bluramount#(effect#, value)`	`radblur_bluramount#@#n`	Set blur intensity (0–10)
`radblur_bluramount(effect#)`	`radblur_bluramount@#`	Get blur amount

Value	Effect	Use Case
`0–0.5`	Very subtle	Soft focus background
`1–3`	Gentle zoom blur	Subtle speed/depth feel
`4–7`	Medium intensity	Action or motion emphasis
`8–10`	Strong zoom streaks	Dramatic speed effect

Center Position

Normalized coordinates (0–1) specifying where the blur radiates from.

Function	Signature	Description
`radblur_centerx#(effect#, value)`	`radblur_centerx#@#n`	Set X center (0=left, 1=right)
`radblur_centerx(effect#)`	`radblur_centerx@#`	Get X center
`radblur_centery#(effect#, value)`	`radblur_centery#@#n`	Set Y center (0=top, 1=bottom)
`radblur_centery(effect#)`	`radblur_centery@#`	Get Y center

Effect Control

Function	Signature	Description
`radblur_enabled#(effect#, value)`	`radblur_enabled#@#n`	Enable (1) or disable (0)
`radblur_enabled(effect#)`	`radblur_enabled@#`	Gets enabled state
`radblur_trigger#(effect#, trigger$)`	`radblur_trigger#@#$`	Sets trigger string
`radblur_trigger$(effect#)`	`radblur_trigger$@#`	Gets trigger string

Complete Examples

Example 1: Basic Radial Blur

╯ radial-blur.bas─◻✕
let frm# = Pointer#(0)
let img# = Pointer#(0)
let blur# = Pointer#(0)

frm# = form#("Radial Blur Demo", 400, 350)

img# = image#(frm#)
image_bounds#(img#, 100, 30, 200, 150)
image_load#(img#, "https://picsum.photos/200/150")

' Apply radial (zoom) blur
blur# = radblur#(img#)
radblur_bluramount#(blur#, 2)

form_show(frm#)

Example 2: Adjustable Blur Intensity

╯ radblur-slider.bas─◻✕
let frm# = Pointer#(0)
let img# = Pointer#(0)
let blur# = Pointer#(0)
let trkBlur# = Pointer#(0)
let lblBlur# = Pointer#(0)

frm# = form#("Radial Blur Control", 450, 400)

img# = image#(frm#)
image_bounds#(img#, 125, 30, 200, 150)
image_load#(img#, "https://picsum.photos/200/150")

blur# = radblur#(img#)
radblur_bluramount#(blur#, 0)

lblBlur# = label#(frm#, "Blur: 0.0", 180, 200)
trkBlur# = trackbar#(frm#)
trackbar_bounds#(trkBlur#, 50, 230, 350, 30)
trackbar_max#(trkBlur#, 100)
trackbar_value#(trkBlur#, 0)
trackbar_onchange#(trkBlur#, "OnBlurChange")

form_show(frm#)

function OnBlurChange(sender#) local b
  let b = trackbar_value(trkBlur#) / 10
  radblur_bluramount#(blur#, b)
  label_text#(lblBlur#, "Blur: " + stri$(b, 1))
endfunction

Example 3: Move Blur Center

╯ radblur-center.bas─◻✕
let frm# = Pointer#(0)
let img# = Pointer#(0)
let blur# = Pointer#(0)
let trkX# = Pointer#(0)
let trkY# = Pointer#(0)
let lblX# = Pointer#(0)
let lblY# = Pointer#(0)

frm# = form#("Radial Blur Center", 500, 470)

img# = image#(frm#)
image_bounds#(img#, 150, 20, 200, 150)
image_load#(img#, "https://picsum.photos/200/150")

blur# = radblur#(img#)
radblur_bluramount#(blur#, 3)

lblX# = label#(frm#, "Center X: 0.50", 30, 190)
trkX# = trackbar#(frm#)
trackbar_bounds#(trkX#, 30, 215, 440, 25)
trackbar_max#(trkX#, 100)
trackbar_value#(trkX#, 50)
trackbar_onchange#(trkX#, "OnCenterX")

lblY# = label#(frm#, "Center Y: 0.50", 30, 260)
trkY# = trackbar#(frm#)
trackbar_bounds#(trkY#, 30, 285, 440, 25)
trackbar_max#(trkY#, 100)
trackbar_value#(trkY#, 50)
trackbar_onchange#(trkY#, "OnCenterY")

form_show(frm#)

function OnCenterX(sender#) local x
  let x = trackbar_value(trkX#) / 100
  radblur_centerx#(blur#, x)
  label_text#(lblX#, "Center X: " + stri$(x, 2))
endfunction

function OnCenterY(sender#) local y
  let y = trackbar_value(trkY#) / 100
  radblur_centery#(blur#, y)
  label_text#(lblY#, "Center Y: " + stri$(y, 2))
endfunction

Best Practices

Practice	Why
Use values 1–3 for subtle effects	Higher values are very dramatic
Center on the subject of interest	Draws focus to the center point
Map slider 0–100 ÷ 10 for range 0–10	Provides smooth control via trackbar
Combine with other blur types for variety	Directional for motion, Gaussian for softness, Radial for zoom

Quick Reference

Function	Signature	Description
CREATION & DESTRUCTION
`radblur#(parent#)`	`radblur#@#`	Create effect
`radblur_free(effect#)`	`radblur_free@#`	Destroy effect
BLUR AMOUNT
`radblur_bluramount#(effect#, value)`	`radblur_bluramount#@#n`	Set blur (0–10)
`radblur_bluramount(effect#)`	`radblur_bluramount@#`	Get blur
CENTER POSITION
`radblur_centerx#(effect#, value)`	`radblur_centerx#@#n`	Set X center (0–1)
`radblur_centerx(effect#)`	`radblur_centerx@#`	Get X center
`radblur_centery#(effect#, value)`	`radblur_centery#@#n`	Set Y center (0–1)
`radblur_centery(effect#)`	`radblur_centery@#`	Get Y center
EFFECT CONTROL
`radblur_enabled#(effect#, value)`	`radblur_enabled#@#n`	Enable/disable
`radblur_enabled(effect#)`	`radblur_enabled@#`	Get enabled state
`radblur_trigger#(effect#, trigger$)`	`radblur_trigger#@#$`	Set trigger
`radblur_trigger$(effect#)`	`radblur_trigger$@#`	Get trigger
ERROR HANDLING
`radblur_error()`	`radblur_error@`	Last error code
`radblur_errormsg$()`	`radblur_errormsg$@`	Last error message
`radblur_strerror$(code)`	`radblur_strerror$@n`	Code to text
`radblur_clearerror()`	`radblur_clearerror@`	Clear error state

Library	Description
`DirectionalBlurEffectLib`	Linear motion blur
`GaussianBlurEffectLib`	Smooth general blur
`BoxBlurEffectLib`	Fast box blur
`BlurEffectLib`	Standard blur effect