BloodTransitionEffectLib — Plan9Basic Documentation

Overview

BloodTransitionEffectLib reveals the target image through a dripping pattern, wrapping the FireMonkey TBloodTransitionEffect component. Creates a dramatic, horror-style visual transition with irregular drip edges flowing downward.

Property	Details
Library	`BloodTransitionEffectLib`
Prefix	`bloodtrans_`
Wraps	`TBloodTransitionEffect`
Functions	15
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
Random Seed	2	Get/set drip pattern randomization
Effect Control	2	Enabled get/set
Error Handling	4	Error codes and messages

🎃 Horror Style: The drip pattern flows downward with irregular edges. Use a slower animation speed (50ms+ timer interval) for a creepier effect. Change RandomSeed to get different drip patterns.

Cross-Platform Support

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

Creation & Destruction

bloodtrans#(parent#)

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

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

bloodtrans_free(effect#)

Destroys the effect and releases associated resources.

Error Handling

Function	Signature	Description
`bloodtrans_error()`	`bloodtrans_error@`	Returns last error code (0 = none)
`bloodtrans_errormsg$()`	`bloodtrans_errormsg$@`	Returns last error message
`bloodtrans_strerror$(code)`	`bloodtrans_strerror$@n`	Converts error code to text
`bloodtrans_clearerror()`	`bloodtrans_clearerror@`	Clears the error state

Target Image

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

Progress

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

Random Seed

Controls the randomization of the drip pattern. Different seed values produce different drip shapes.

Function	Signature	Description
`bloodtrans_randomseed#(effect#, value)`	`bloodtrans_randomseed#@#n`	Set random seed (0.0–1.0)
`bloodtrans_randomseed(effect#)`	`bloodtrans_randomseed@#`	Get random seed

Effect Control

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

Complete Examples

Example 1: Animated Drip Transition

╯ blood-drip.bas─◻✕
let frm# = Pointer#(0)
let img# = Pointer#(0)
let trans# = Pointer#(0)
let tmr# = Pointer#(0)
let btn# = Pointer#(0)
let progress = 0

frm# = form#("Horror Transition", 400, 350)

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

trans# = bloodtrans#(img#)
bloodtrans_loadtarget#(trans#, "https://picsum.photos/200/150?random=2")
bloodtrans_randomseed#(trans#, 0.3)

tmr# = timer#()
timer_interval#(tmr#, 50)
timer_enabled#(tmr#, 0)
timer_ontimer#(tmr#, "Animate")

btn# = button#(frm#, "Start Drip")
button_bounds#(btn#, 140, 210, 120, 30)
button_onclick#(btn#, "StartAnim")

form_show(frm#)

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

function Animate(sender#)
  progress = progress + 0.015
  bloodtrans_progress#(trans#, progress)
  
  if progress >= 1 then
    timer_enabled#(tmr#, 0)
    button_enabled#(btn#, 1)
  endif
endfunction

Quick Reference

Function	Signature	Description
CREATION & DESTRUCTION
`bloodtrans#(parent#)`	`bloodtrans#@#`	Create effect
`bloodtrans_free(effect#)`	`bloodtrans_free@#`	Destroy effect
TARGET IMAGE
`bloodtrans_target#(effect#, bitmap#)`	`bloodtrans_target#@##`	Set target bitmap
`bloodtrans_target#(effect#)`	`bloodtrans_target#@#`	Get target bitmap
`bloodtrans_loadtarget#(effect#, url$)`	`bloodtrans_loadtarget#@#$`	Load target
PROGRESS
`bloodtrans_progress#(effect#, value)`	`bloodtrans_progress#@#n`	Set progress (0–1)
`bloodtrans_progress(effect#)`	`bloodtrans_progress@#`	Get progress
RANDOM SEED
`bloodtrans_randomseed#(effect#, value)`	`bloodtrans_randomseed#@#n`	Set drip seed (0–1)
`bloodtrans_randomseed(effect#)`	`bloodtrans_randomseed@#`	Get seed
EFFECT CONTROL
`bloodtrans_enabled#(effect#, value)`	`bloodtrans_enabled#@#n`	Enable/disable
`bloodtrans_enabled(effect#)`	`bloodtrans_enabled@#`	Get enabled state
ERROR HANDLING
`bloodtrans_error()`	`bloodtrans_error@`	Last error code
`bloodtrans_errormsg$()`	`bloodtrans_errormsg$@`	Last error message
`bloodtrans_strerror$(code)`	`bloodtrans_strerror$@n`	Code to text
`bloodtrans_clearerror()`	`bloodtrans_clearerror@`	Clear error state

Library	Description
`DissolveTransitionEffectLib`	Dissolve transition
`FadeTransitionEffectLib`	Fade transition
`WaterTransitionEffectLib`	Water ripple transition