Shuttle Space

Following scripts open a roundrect theme, link a video and an image to a fade transform, then play video and change the progress value in between the frames. The progress value is modified to make the image fade in and then fade out like a ghost. You may control the video position to fade in/out an image.

package require media
package require mcllib
_mcl

open media and mcllib packages.

set iname [getPath media image image001.png]
set vname [getPath media video movie.avi]

get image and video name

_theme {
  title    "Ladybug Studio XP" 
  orgx     250
  orgy     90
  width    [expr 352] 
  height   [expr 240] 
  region   roundrect
  wcorner  10
  hcorner  10
  mode     windowless}

open theme in windowless

  while 1 {
    set r 0.0
    set s 0.01
    set downlimit 0.0
    set uplimit 0.4
    set direction 0

set initial values. r is the progress variable, s is the step variable, downlimit is the down limit of progress, uplimit is the up limit of progress, direction as 0 means increasment (1 means decreament).

    _video {name $vname}
      _image {name $iname}
        _transform {name Fade progress 0.0}

open video, image, and transform

           _graph {theme {transform video image}}

set graph links where video and image are transform's inputs, and trnasform's output links to theme.

             graph play {from 0 to 1000} {
               if {$direction == 0} {
                 # the ghost image is fade in
                 set r [expr {$r+$s}]
                 if {$r >= $uplimit} {
                   set direction 1
                 }

"graph play argument internal" will run the objects one after another. The argument may have attributes from and to. The internal is the scripts that may control in each frame. In the above code r is the value for transform progress. Each frame loop will change to a new value with $r added $s (step). When r value is over the up limit, the direction will be changed, so the progress value is decreased.

               } else {
                 # the ghost image is fade out
                 set r [expr {$r-$s}]
                 if {$r <= $downlimit} {
                   set direction 0
                 }
               }

The ghost image is faded out.

               !transform {progress $r}
             }

set new transform progress value.

             graph rewind

rewind video to start position. This rewind is required to play video in loop.

           graph_
         transform_
       image_
     video_
  }
theme_
mcl_

close graph, transform, image, video, theme, and mcl.