BlitImageAlphaBlendImages

BlitImageAlphaBlendImages ThisImage, Xpos, Ypos, BlendImage, AlphaLevel#

Parameters:     ThisImage = The Index of the image you wish to draw     Xpos = The X coordinate to draw this image     Ypos = The Y coordinate to draw this image     BlendImage = The index of the image to you wish to Alpha Subtract from the primary image before drawing     AlphaLevel# = The amount of blending between the two image. Range from 0 to 1

Returns: NONE

BlitImageAlphaBlendImages is most similar to the DrawAlphaImage function, except it has merge processing. What it does, is it takes two images (of the same size) and uses Variable Alpha Blending to blend them together before drawing the resulting blended pixels out. The Pixels are calculated by using the Alpha level parameter. Which controls amount of colour from either image that ends up in the output. The level ranges between 0 to 1, so setting it to 0.5 means we'll get a 50% blend between both. Regardless of blend level though neither source image is modified during the process.       To create equivalent functionally, you'd need three images. The two images you wish to draw blended and third to store the temporary blended state. So we'd first copy the src image #1 to image 3, then blend src image 2 onto image 3 and finally draw image 3 to it's destination.       The combined processing is not just to save you a few lines of code, it's actually a more optimal way of performing this action. FACTS:      * BlitImageAlphaBlendImages is only intend for drawing FX or AFX formatted surfaces.      * BlitImageAlphaBlendImages doesn't support mask & alpha channel transparency.

Example Source: Download This Example ; Load a bigger font   LoadFont "veranda",1,36       ; Inlude the Blit Image functions   #Include "BlitImage"    ; Create an FX image the size of the screen   MyImage=NewFXImage(GetScreenWidth(),GetScreenHeight())       ; Create a second  FX image the size of the screen ; we'll be using to blend with our other image   Backdrop=NewFXImage(GetScreenWidth(),GetScreenHeight())    ; fill the backdrop with something so we can see it   Tile=LoadNewFxImage("..\../Media/bg22.jpg")   RenderToImage Backdrop   TileImage Tile,0,0,false       ; Set Fps of the program   SetFPS 30         Col=$803030       ; Start of Demo loop   Do          ; redirect all drawing to this image      RenderToImage MyImage                  If MouseButton()<>0 Then Col=RndRGB()          ; draw a circle at the mouses current position      CircleC MouseX(),MouseY(),100, true,Col          ; redirect all drawing to screen back buffer      RenderToScreen                ; Compoute blend level betwen the two images      Alpha#=0.5+Sin(BlendAngle#)*0.5      BlendAngle#=WrapAngle(BlendAngle#,5)                ; To do combined Blit (copy) our Image.  This    ; version Alpha Blends the pixels in the blend    ; image (MyImage) from the backdrop image.    ; The amount of blending is controlled via the Alpha parameter      BlitImageAlphaBlendImages(BackDrop,0,0,MyImage,Alpha#)                ; Display Message      Text 0,0,"Cross Fading via BlitImageAlphaBlendImages"          ; flip the back buffer to the front, so the user can see it      Sync         Loop

Related Info:	BlitImageAlpha50Colour | BlitImageClear | Box | DrawAlphaImage | DrawImage | InkMode :

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