| Pic.DrawFrames | Part of Pic module |
| Syntax | Pic.DrawFrames (picIds : array 1 .. * of int, x, y, mode : int,
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| Description | Pic.DrawFrames is used to draw a set of pictures stored in
an array of ints. The pictures are displayed one at a time,
and there is a delay of delayBetweenFrames milliseconds
between frames. The x, y, and mode parameters
are the same as in Pic.Draw. The
numFrames parameter specifies the number of frames to be
drawn (the picIds array must be at least this big). The
eraseAfter parameter specifies whether the last frame of the
animation should be left on the Run window when the call finishes.
If eraseAfter is set to true, then the background is
restored after the last picture has been drawn and
delayBetweenFrames milliseconds has passed.
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| Details | GIF files can contain multiple frames (pictures). Animated GIFs
function by each frame in the GIF one after another with a delay
between them.
Turing allows users to load multiple frame GIF images into a series of pictures into an array using the Pic.FileNewFrames procedure. The user can determine how many frames are found in the GIF file using Pic.Frames. The frames can be sequentially displayed using either Pic.DrawFrames or Pic.DrawFramesBack which display the images one at a time. (Pic.DrawFrames returns once all the images have been displayed, Pic.DrawFramesBack returns immediately allowing the program to continue execution while the frames are being displayed. Pic.Frames 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.
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| 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)
Pic.DrawFrames (pics, 10, 10, picCopy, numFrames, 50, false)
for i : 1 .. numFrames | |||||||||
| Execute | ||||||||||
| Status | Exported qualified. This means that you can only call the function by calling Pic.DrawFrames, not by calling DrawFrames.
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| See also | Pic.Frames for information on how
to determine the number of frames in a GIF image. Pic.FileNewFrames for information on how to load a GIF image with multiple frames into an array of ints. Pic.DrawFramesBack for information on how to sequentially display the images stored in array of pictures while continuing to execute the program.
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