BlurTransitionEffectLib — Plan9Basic Documentation

Overview

BlurTransitionEffectLib creates a smooth, dreamy transition that blurs the source image while cross-fading to the target, wrapping the FireMonkey TBlurTransitionEffect component. The image blurs at the midpoint and sharpens at both ends — a soft, professional-looking transition ideal for photo slideshows.

Property	Details
Library	`BlurTransitionEffectLib`
Prefix	`blurtrans_`
Wraps	`TBlurTransitionEffect`
Functions	13
Type	Transition effect

Category	Count	Description
Creation / Destruction	2	Create and free effect
Target Image	3	Set/get/load target bitmap
Progress	2	Get/set transition progress
Effect Control	2	Enabled get/set
Error Handling	4	Error codes and messages

📸 Dreamy Crossfade: This is one of the simplest transition effects — just progress from 0 to 1. The blur peaks at the midpoint, making the image change feel natural and smooth. Great for photo slideshows and presentations.

Cross-Platform Support

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

Creation & Destruction

blurtrans#(parent#)

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

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

blurtrans_free(effect#)

Destroys the effect and releases associated resources.

Error Handling

Function	Signature	Description
`blurtrans_error()`	`blurtrans_error@`	Returns last error code (0 = none)
`blurtrans_errormsg$()`	`blurtrans_errormsg$@`	Returns last error message
`blurtrans_strerror$(code)`	`blurtrans_strerror$@n`	Converts error code to text
`blurtrans_clearerror()`	`blurtrans_clearerror@`	Clears the error state

Target Image

Function	Signature	Description
`blurtrans_target#(effect#, bitmap#)`	`blurtrans_target#@##`	Sets target from bitmap pointer
`blurtrans_target#(effect#)`	`blurtrans_target#@#`	Gets target bitmap pointer
`blurtrans_loadtarget#(effect#, url$)`	`blurtrans_loadtarget#@#$`	Loads target from URL or file

⚠ Target Required: Always load a target image before animating progress.

Progress

Function	Signature	Description
`blurtrans_progress#(effect#, value)`	`blurtrans_progress#@#n`	Set progress (0.0–1.0)
`blurtrans_progress(effect#)`	`blurtrans_progress@#`	Get current progress

At 0, the source is shown sharply. Around 0.5, maximum blur occurs as images cross-fade. At 1, the target is shown sharply.

Effect Control

Function	Signature	Description
`blurtrans_enabled#(effect#, value)`	`blurtrans_enabled#@#n`	Enable (1) or disable (0)
`blurtrans_enabled(effect#)`	`blurtrans_enabled@#`	Gets enabled state

Complete Examples

Example 1: Animated Blur Transition

╯ blur-transition.bas─◻✕
let frm# = Pointer#(0)
let img# = Pointer#(0)
let trans# = Pointer#(0)
let tmr# = Pointer#(0)
let btn# = Pointer#(0)
let progress = 0
let direction = 1

frm# = form#("Animated Blur", 400, 350)

img# = image#(frm#)
image_bounds#(img#, 100, 30, 200, 150)
image_load#(img#, "https://picsum.photos/200/150?random=1")

trans# = blurtrans#(img#)
blurtrans_loadtarget#(trans#, "https://picsum.photos/200/150?random=2")

tmr# = timer#()
timer_interval#(tmr#, 30)
timer_enabled#(tmr#, 0)
timer_ontimer#(tmr#, "Animate")

btn# = button#(frm#, "Start Transition")
button_bounds#(btn#, 130, 210, 140, 30)
button_onclick#(btn#, "StartAnim")

form_show(frm#)

function StartAnim(sender#)
  timer_enabled#(tmr#, 1)
  button_enabled#(btn#, 0)
endfunction

function Animate(sender#)
  progress = progress + (direction * 0.02)
  blurtrans_progress#(trans#, progress)
  
  if progress >= 1 then
    direction = -1
  endif
  if progress <= 0 then
    direction = 1
    timer_enabled#(tmr#, 0)
    button_enabled#(btn#, 1)
  endif
endfunction

Example 2: Toggle Effect On/Off

╯ blur-toggle.bas─◻✕
let frm# = Pointer#(0)
let img# = Pointer#(0)
let trans# = Pointer#(0)
let btn# = Pointer#(0)
let isOn = 1

frm# = form#("Toggle Blur Trans", 400, 300)

img# = image#(frm#)
image_bounds#(img#, 100, 30, 200, 150)
image_load#(img#, "https://picsum.photos/200/150?random=1")

trans# = blurtrans#(img#)
blurtrans_loadtarget#(trans#, "https://picsum.photos/200/150?random=2")
blurtrans_progress#(trans#, 0.5)

btn# = button#(frm#, "Disable Effect")
button_bounds#(btn#, 140, 210, 120, 30)
button_onclick#(btn#, "Toggle")

form_show(frm#)

function Toggle(sender#)
  if isOn = 1 then
    blurtrans_enabled#(trans#, 0)
    isOn = 0
    button_text#(btn#, "Enable Effect")
  else
    blurtrans_enabled#(trans#, 1)
    isOn = 1
    button_text#(btn#, "Disable Effect")
  endif
endfunction

Quick Reference

Function	Signature	Description
CREATION & DESTRUCTION
`blurtrans#(parent#)`	`blurtrans#@#`	Create effect
`blurtrans_free(effect#)`	`blurtrans_free@#`	Destroy effect
TARGET IMAGE
`blurtrans_target#(effect#, bitmap#)`	`blurtrans_target#@##`	Set target bitmap
`blurtrans_target#(effect#)`	`blurtrans_target#@#`	Get target bitmap
`blurtrans_loadtarget#(effect#, url$)`	`blurtrans_loadtarget#@#$`	Load target
PROGRESS
`blurtrans_progress#(effect#, value)`	`blurtrans_progress#@#n`	Set progress (0–1)
`blurtrans_progress(effect#)`	`blurtrans_progress@#`	Get progress
EFFECT CONTROL
`blurtrans_enabled#(effect#, value)`	`blurtrans_enabled#@#n`	Enable/disable
`blurtrans_enabled(effect#)`	`blurtrans_enabled@#`	Get enabled state
ERROR HANDLING
`blurtrans_error()`	`blurtrans_error@`	Last error code
`blurtrans_errormsg$()`	`blurtrans_errormsg$@`	Last error message
`blurtrans_strerror$(code)`	`blurtrans_strerror$@n`	Code to text
`blurtrans_clearerror()`	`blurtrans_clearerror@`	Clear error state

Library	Description
`FadeTransitionEffectLib`	Simple fade transition
`DissolveTransitionEffectLib`	Dissolve transition
`BrightTransitionEffectLib`	Brightness-based transition