Vibrating rectangles: Difference between revisions
Added Go
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}
</lang>
=={{header|Go}}==
This uses Go's 'image' packages in its standard library to create an animated GIF. The file itself can be created from the terminal as follows:
<pre>
$ go build vibrating.go
$ ./vibrating > vibrating.gif
</pre>
When played this is somewhat similar to the Python entry except that it uses a 7 (rather than 6) color palette and repeats indefinitely.
Although the .gif works fine in Firefox it might not do so in EOG due to optimizations made during its creation. If so, then the following ImageMagick command should fix it:
<pre>
$ convert vibrating.gif -coalesce vibrating2.gif
$ eog vibrating2.gif
</pre>
<lang go>package main
import (
"image"
"image/color"
"image/gif"
"os"
)
var (
black = color.RGBA{0, 0, 0, 255}
red = color.RGBA{255, 0, 0, 255}
green = color.RGBA{0, 255, 0, 255}
blue = color.RGBA{0, 0, 255, 255}
magenta = color.RGBA{255, 0, 255, 255}
cyan = color.RGBA{0, 255, 255, 255}
yellow = color.RGBA{255, 255, 0, 255}
white = color.RGBA{255, 255, 255, 255}
)
var palette = []color.Color{red, green, blue, magenta, cyan, yellow, white, black}
func hline(img *image.Paletted, x1, y, x2 int, ci uint8) {
for ; x1 <= x2; x1++ {
img.SetColorIndex(x1, y, ci)
}
}
func vline(img *image.Paletted, x, y1, y2 int, ci uint8) {
for ; y1 <= y2; y1++ {
img.SetColorIndex(x, y1, ci)
}
}
func setBackgroundColor(img *image.Paletted, w, h int, ci uint8) {
for x := 0; x < w; x++ {
for y := 0; y < h; y++ {
img.SetColorIndex(x, y, ci)
}
}
}
func drawRectangle(img *image.Paletted, x1, y1, x2, y2 int, ci uint8) {
hline(img, x1, y1, x2, ci)
hline(img, x1, y2, x2, ci)
vline(img, x1, y1, y2, ci)
vline(img, x2, y1, y2, ci)
}
func main() {
const nframes = 140
const delay = 10 // 100ms
width, height := 500, 500
anim := gif.GIF{LoopCount: nframes}
rect := image.Rect(0, 0, width, height)
for c := uint8(0); c < 7; c++ {
for f := 0; f < 20; f++ {
img := image.NewPaletted(rect, palette)
setBackgroundColor(img, width, height, 7) // black background
for r := 0; r < 20; r++ {
ix := c
if r < f {
ix = (ix + 1) % 7
}
x := width * (r + 1) / 50
y := height * (r + 1) / 50
w := width - x
h := height - y
drawRectangle(img, x, y, w, h, ix)
}
anim.Delay = append(anim.Delay, delay)
anim.Image = append(anim.Image, img)
}
}
gif.EncodeAll(os.Stdout, &anim)
}</lang>
=={{header|Javascript}}==
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