pxt-calliope/docs/reference/images/scroll-image.md
Jan Karger 4a8d9ee9cd Update scroll-image.md ()
Just change the documentation here, cause the underlying API doesn't work correctly yet 2cff906f01/source/drivers/MicroBitDisplay.cpp (L931)
So negative values are not working for now.
2018-03-08 12:57:28 -08:00

1.5 KiB

Scroll Image

Scroll (slide) an image (picture) from one side to the other of the LED screen.

let item: Image = null;
item.scrollImage(5, 200);

Parameters

  • a number that means how many LEDs to scroll at a time from right to left. You must use a positive number like 2. If you use 5, the image will scroll one frame at a time. (A frame is a part of the image. It is a square with five LEDs on a side). This is useful for animation.

  • a number that means how many milliseconds to wait before scrolling the amount that offset says. (1000 milliseconds is one second.) The bigger you make this number, the slower the image will scroll.

Example

This program scrolls an image of two arrows five LEDs at a time, with a pause of 200 milliseconds between each time it scrolls. Because each frame is five LEDs wide, that means this program will look like it's animating one arrow flipping and flopping. Of course, you can use any two frames you want instead.

let arrows = images.createBigImage(`
    . . # . .   . . # . .
    . # # # .   . . # . .
    # . # . #   # . # . #
    . . # . .   . # # # .
    . . # . .   . . # . .
    `);
basic.forever(() => {
    arrows.scrollImage(5, 200);
});	

See also

show image, image, create image, show animation