77 lines
1.9 KiB
Go
77 lines
1.9 KiB
Go
package pixelflut
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import (
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"fmt"
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"image"
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"image/color"
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"math/rand"
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)
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// Commands represent a list of messages to be sent to a pixelflut server.
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type commands [][]byte
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// Chunk splits commands into equally sized chunks, while flattening each chunk
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// so that all commands are concatenated as a single `[]byte`.
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func (c commands) Chunk(numChunks int) [][]byte {
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chunks := make([][]byte, numChunks)
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chunkLength := len(c) / numChunks
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for i := 0; i < numChunks; i++ {
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cmdOffset := i * chunkLength
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for j := 0; j < chunkLength; j++ {
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chunks[i] = append(chunks[i], c[cmdOffset+j]...)
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}
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}
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return chunks
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}
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// Shuffle reorders commands randomly, in place.
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func (c commands) Shuffle() {
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for i := range c {
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j := rand.Intn(i + 1)
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c[i], c[j] = c[j], c[i]
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}
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}
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// CommandsFromImage converts an image to the respective pixelflut commands
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func commandsFromImage(img *image.NRGBA, offset image.Point) (cmds commands) {
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b := img.Bounds()
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cmds = make([][]byte, b.Size().X*b.Size().Y)
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numCmds := 0
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for x := b.Min.X; x < b.Max.X; x++ {
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for y := b.Min.Y; y < b.Max.Y; y++ {
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c := img.At(x, y).(color.NRGBA)
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// ignore transparent pixels
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if c.A == 0 {
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continue
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}
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var cmd string
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if c.A != 255 {
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cmd = fmt.Sprintf("PX %d %d %.2x%.2x%.2x%.2x\n",
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x+offset.X, y+offset.Y, c.R, c.G, c.B, c.A)
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} else {
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// @speed: this sprintf call is quite slow..
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cmd = fmt.Sprintf("PX %d %d %.2x%.2x%.2x\n",
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x+offset.X, y+offset.Y, c.R, c.G, c.B)
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}
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cmds[numCmds] = []byte(cmd)
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numCmds++
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}
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}
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return cmds[:numCmds]
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}
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func cmdsFetchImage(bounds image.Rectangle) (cmds commands) {
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cmds = make([][]byte, bounds.Size().X*bounds.Size().Y)
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numCmds := 0
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for x := bounds.Min.X; x < bounds.Max.X; x++ {
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for y := bounds.Min.Y; y < bounds.Max.Y; y++ {
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cmd := fmt.Sprintf("PX %d %d\n", x, y)
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cmds[numCmds] = []byte(cmd)
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numCmds++
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}
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}
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return cmds
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}
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