Misc Graphics Functions

[kevin]

  Misc Graphics Functions

    This thread is for those small graphic functions snippets that handy but really warrant their own thread..



    Related Threads:

            - Image Functions
            - Bordered Box





RainBoxCls()   Function

    This function alpha blend a pair of RGB colours drawing them to the current surface as a classic RainBow() effect.    

    Commands used:  RgbAlphaBlend, BoxC

PlayBASIC Code: [Select]

   setfps 10
   
   StartRGB = $223344
   EndRGB   = $f000ff
   frame =10
      
   do 

      RainBowCls(StartRGB,EndRGB)

      frame--
      if frame<0
         StartRGB = EndRGB
         EndRGB   = RndRGB()
         Frame=10
      endif
         

      sync
   loop spacekey()

explicit true

Function RainBowCLS(StartRGB,DestRGB)
   
      local lp,w,h,Scaler#
      w=getsurfacewidth()
      h=getsurfaceheight()
      
      Scaler#=100.0/h
      for lp =0 to h-1
         local NewRGB=RGBAlphaBlend(StartRGB,DestRGB, lp*Scaler#)
         boxc 0,lp,w,lp+1,true,NewRGB
      next
   
EndFunction 

explicit false

    -- Get Source Code PasteBin

[kevin]

DrawCenteredImage()   Function

     This function allows the use to draw an image while controlling the X and Y handles as a pair scalers hidden in the FLAG parameter.  Since FLAGS is 32bit and we're only using the bottom bit (bit zero) to toggle if we're rendering the image solid or transparent; we can store other data in this parameter. 

     So what i've done is store the X scaler is bits 24-17   and Y Scaler in bits 16 to 8;  which means we can use the RGB commands to PACK and unPACK the separate values.  The only limitation is these values are limited to a range of 0 to 255.  So we're using them as scalers against the images size to control the handle.   

     Commands used:  DrawImage, RGB, RGBR,RGBB, CLS

PlayBASIC Code: [Select]

   cls $ff
      getimage 1,0,0,128,128
      
      
      do
         cls
         
         mx=mousex()
         my=mouseY()
         
         
         XOffset-=LeftKey()           
         XOffset+=RightKey()           
         XOffset=XOffset and 255

         YOffset-=UpKey()           
         YOffset+=DownKey()           
         YOffset=YOffset and 255

         print "X offset:"+str$(Xoffset)
         print "Y offset:"+str$(Yoffset)
         
         drawcenteredImage(1,mx,my, rgb(Xoffset,Yoffset,0))          
         
         sync
      loop spacekey()




Function DrawCenteredImage(Thisimage,X,Y,Flag)
      if getImageStatus(Thisimage)
         iw=getimagewidth(ThisImage)
         ih=getimageheight(ThisImage)
         //  Read Offsets X offset
         
         XOffset_Scaler#=RgbR(Flag)/255.0
         YOffset_Scaler#=RgbG(Flag)/255.0

         X=X -(iw*XOffset_Scaler#)
         Y=Y -(IH*YOffset_Scaler#)
         
         Drawimage ThisImage ,X  , y, flag and 1

      endif
EndFunction