pic_drawframesback

#Pic.DrawFramesBack

##Syntax Pic.DrawFramesBack (picIds : array 1 .. * of int, x, y, mode : int, numFrames, delayBetweenFrames : int, eraseAfter : boolean)

##Description Pic.DrawFramesBack is very similar to pic_drawframes.html. The onlydifference is that Pic.DrawFramesBack returns immediatelyafter being called and program execution continues while the framesare being drawn. This allows you to continue to draw other graphicswhile the frames are being drawn.

For example, this procedure is necessary if you want to have two sets of frames being drawn simultaneously.

##Details If you are wish to have several sets of images displayed at the same time, you must use Pic.DrawFramesBack to display each setof images but the last and then use Pic.DrawFrames to displaythe last set so that Turing will wait until they are completed before continuing execution.

If you want to draw the same set of frames continuously, do not usePic.DrawFramesBack.

**for** _i_ : 1 .. 20 **Pic.DrawFrames** (_pics_, 10, 10, _picCopy_, 10, 50, **false**) % Do not use Pic.DrawFramesBack in the previous statement**end for**

If you do, Turing will attempt to run each of the calls at the sametime, and the animation will appear to only run once.

##Details GIF files can contain multiple frames (pictures). Animated GIFs function by each frame in the GIF one after another with a delaybetween them.

Turing allows users to load multiple frame GIF images into a seriesof pictures into an array using the pic_filenewframes.html procedure. The user can determine how many frames are found in the GIF file using pic_frames.html. The frames can be sequentially displayed using either pic_drawframes.html or which display the images one at a time.(pic_drawframes.html returns once all the images have been displayed, returns immediately allowing the program to continue execution while the frames are being displayed.

pic_frames.html is a function which returns the number of frames found in the GIF. If it is used on a GIF that does not contain multiple images, or on a non-GIF image file, it returns 1.

##Example The program loads a multiple frame GIF called "globe.gif" and displays it. % Determine the number of frames in "globe.gif" var numFrames := Pic.Frames ("globe.gif") % Load the picture var delayTime : int var pics : array 1 .. numFrames of int

Pic.FileNewFrames ("globe.gif", pics, delayTime)
for i : 1 .. 50
    Pic.DrawFramesBack (pics, 10, 10, picMerge, numFrames, 50, false)
    Pic.DrawFramesBack (pics, 20 + Pic.Width (pics(1)), 10, picMerge, numFrames, 50, false)
    % All 50 iterations will execute at once if the next call is 
    % Pic.DrawFramesBack, and not Pic.DrawFrames
    Pic.DrawFrames (pics, 30 + 2 * Pic.Width (pics(1)), 10, picMerge, numFrames, 50, false)
end for
for i : 1 .. numFramesPic.Free (pics (i))
end for

##Status Exported qualified.

This means that you can only call the function by calling Pic.DrawFrames, not by calling DrawFrames.

##See also pic_frames.html for information on howto determine the number of frames in a GIF image.

pic_filenewframes.html for informationon how to load a GIF image with multiple frames into an array of ints.

for information on how to sequentially display the images stored in array of pictures while continuing to execute the program.