The roCompositor allows the composition and animation of multiple roBitmaps and roRegions.
Supported Interfaces
Description
The roCompositor can create and manage roSprites in a z-ordered list. The sprites can be of arbitrary size and can be thought of as planes. The compositor can manage collision detection between the sprites, support scrolling the sprite bitmap source, and support animated sprites (multi-frame sprites with frame-flipping animation). You may have multiple roCompositor components, and they can composite onto the same or separate bitmaps. That said, the most common scenario is to have a single roCompositor
Example: Scrolling a bitmap
Library "v30/bslCore.brs"
Function main()
black=&hFF'RGBA
screen=CreateObject("roScreen")
compositor=CreateObject("roCompositor")
compositor.SetDrawTo(screen, black)
http = CreateObject("roUrlTransfer")
http.SetMessagePort(CreateObject("roMessagePort"))
http.SetUrl("http://rokudev.roku.com/rokudev/examples/scroll/VeryBigPng.png")
http.AsyncGetToFile("tmp:/VeryBigPng.png")
wait(0, http.GetPort())
bigbm=CreateObject("roBitmap","tmp:/VeryBigPng.png")
region=CreateObject("roRegion", bigbm, 0, 0, 1280, 720)
region.SetWrap(True)
view_sprite=compositor.NewSprite(0, 0, region)
compositor.draw()
screen.SwapBuffers()
msgport = CreateObject("roMessagePort")
screen.SetMessagePort(msgport)
codes = bslUniversalControlEventCodes()
While True
msg=wait(0, msgport) ' wait for a button
print "Msg: "; type(msg); " event: "; msg.GetInt()
If type(msg)="roUniversalControlEvent" Then
If msg.GetInt()=codes.BUTTON_UP_PRESSED Then
Zip(screen, view_sprite, compositor, 0,-4) 'up
Else If msg.GetInt()=codes.BUTTON_DOWN_PRESSED Then
Zip(screen, view_sprite, compositor, 0,+4) ' down
Else If msg.GetInt()=codes.BUTTON_RIGHT_PRESSED Then
Zip(screen, view_sprite, compositor, +4,0) ' right
Else If msg.GetInt()=codes.BUTTON_LEFT_PRESSED Then
Zip(screen, view_sprite, compositor, -4, 0) ' left
Else If msg.GetInt() = codes.BUTTON_BACK_PRESSED ' back button
Exit While
End If
End If
End While
End Function
Function Zip(screen, view_sprite, compositor, xd, yd)
For x=1 To 60
view_sprite.OffsetRegion(xd, yd, 0, 0)
compositor.draw()
screen.SwapBuffers()
End For
End Function