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draw: tool to draw via lua
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,237 @@ | ||
| package img | ||
|
|
||
| import ( | ||
| "image" | ||
| "image/color" | ||
| "image/png" | ||
| "io" | ||
| "math" | ||
| "os" | ||
|
|
||
| lua "github.com/yuin/gopher-lua" | ||
| ) | ||
|
|
||
| func Draw(args []string, _ io.Reader) error { | ||
| if len(args) == 1 { | ||
| args = append(args, "") | ||
| } | ||
|
|
||
| img := image.NewNRGBA(image.Rect(0, 0, 128, 128)) | ||
| for x := 0; x < 128; x++ { | ||
| for y := 0; y < 128; y++ { | ||
| img.Set(x, y, color.Black) | ||
| } | ||
| } | ||
|
|
||
| if err := luaEval(img, args[1:]); err != nil { | ||
| return err | ||
| } | ||
|
|
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| return png.Encode(os.Stdout, img) | ||
| } | ||
|
|
||
| func luaEval(img *image.NRGBA, code []string) error { | ||
| L := lua.NewState() | ||
| defer L.Close() | ||
|
|
||
| registerImageFunctions(L, img) | ||
|
|
||
| for _, c := range code { | ||
| if err := L.DoString(c); err != nil { | ||
| return err | ||
| } | ||
| } | ||
|
|
||
| return nil | ||
| } | ||
|
|
||
| func checkColor(L *lua.LState, w int) color.Color { | ||
| ud := L.CheckUserData(w) | ||
| if v, ok := ud.Value.(color.Color); ok { | ||
| return v | ||
| } | ||
| L.ArgError(w, "image.Color expected") | ||
| return nil | ||
| } | ||
|
|
||
| func registerImageFunctions(L *lua.LState, img *image.NRGBA) { | ||
| L.SetGlobal("set", L.NewFunction(func(L *lua.LState) int { | ||
| x := L.CheckNumber(1) | ||
| y := L.CheckNumber(2) | ||
| c := checkColor(L, 3) | ||
|
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| img.Set(int(x), int(y), c) | ||
|
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| return 0 | ||
| })) | ||
|
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| L.SetGlobal("rgb", L.NewFunction(func(L *lua.LState) int { | ||
| r := L.CheckNumber(1) | ||
| g := L.CheckNumber(2) | ||
| b := L.CheckNumber(3) | ||
|
|
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| ud := L.NewUserData() | ||
| ud.Value = color.RGBA{uint8(r), uint8(g), uint8(b), 255} | ||
|
|
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| L.Push(ud) | ||
| return 1 | ||
| })) | ||
|
|
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| { | ||
| black := L.NewUserData() | ||
| black.Value = color.Black | ||
| L.SetGlobal("black", black) | ||
|
|
||
| white := L.NewUserData() | ||
| white.Value = color.RGBA{0, 0, 0, 255} | ||
| L.SetGlobal("white", white) | ||
|
|
||
| red := L.NewUserData() | ||
| red.Value = color.RGBA{255, 0, 0, 255} | ||
| L.SetGlobal("red", red) | ||
|
|
||
| blue := L.NewUserData() | ||
| blue.Value = color.RGBA{0, 0, 255, 255} | ||
| L.SetGlobal("blue", blue) | ||
|
|
||
| yellow := L.NewUserData() | ||
| yellow.Value = color.RGBA{255, 255, 0, 255} | ||
| L.SetGlobal("yellow", yellow) | ||
|
|
||
| green := L.NewUserData() | ||
| green.Value = color.RGBA{0, 255, 0, 255} | ||
| L.SetGlobal("green", green) | ||
|
|
||
| orange := L.NewUserData() | ||
| orange.Value = color.RGBA{255, 165, 0, 255} | ||
| L.SetGlobal("orange", orange) | ||
|
|
||
| purple := L.NewUserData() | ||
| purple.Value = color.RGBA{128, 0, 128, 255} | ||
| L.SetGlobal("purple", purple) | ||
|
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||
| cyan := L.NewUserData() | ||
| cyan.Value = color.RGBA{0, 255, 255, 255} | ||
| L.SetGlobal("cyan", cyan) | ||
|
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| magenta := L.NewUserData() | ||
| magenta.Value = color.RGBA{255, 0, 255, 255} | ||
| L.SetGlobal("magenta", magenta) | ||
| } | ||
|
|
||
| L.SetGlobal("sin", L.NewFunction(func(L *lua.LState) int { | ||
| t := L.CheckNumber(1) | ||
|
|
||
| L.Push(lua.LNumber(math.Sin(float64(t)))) | ||
| return 1 | ||
| })) | ||
|
|
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| L.SetGlobal("cos", L.NewFunction(func(L *lua.LState) int { | ||
| t := L.CheckNumber(1) | ||
|
|
||
| L.Push(lua.LNumber(math.Cos(float64(t)))) | ||
| return 1 | ||
| })) | ||
|
|
||
| L.SetGlobal("tan", L.NewFunction(func(L *lua.LState) int { | ||
| t := L.CheckNumber(1) | ||
|
|
||
| L.Push(lua.LNumber(math.Tan(float64(t)))) | ||
| return 1 | ||
| })) | ||
|
|
||
| L.SetGlobal("PI", lua.LNumber(math.Pi)) | ||
|
|
||
| L.SetGlobal("rect", L.NewFunction(func(L *lua.LState) int { | ||
| x1 := int(L.CheckNumber(1)) | ||
| y1 := int(L.CheckNumber(2)) | ||
| x2 := int(L.CheckNumber(3)) | ||
| y2 := int(L.CheckNumber(4)) | ||
| border := checkColor(L, 5) | ||
| fill := checkColor(L, 6) | ||
|
|
||
| // draw borders | ||
| for x := x1; x <= x2; x++ { | ||
| img.Set(x, y1, border) | ||
| img.Set(x, y2, border) | ||
| } | ||
| for y := y1 + 1; y < y2; y++ { | ||
| img.Set(x1, y, border) | ||
| img.Set(x2, y, border) | ||
| } | ||
|
|
||
| // draw fill | ||
| for x := x1 + 1; x < x2; x++ { | ||
| for y := y1 + 1; y < y2; y++ { | ||
| img.Set(x, y, fill) | ||
| } | ||
| } | ||
|
|
||
| return 0 | ||
| })) | ||
|
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||
| line := func(x1, y1, x2, y2 float64, c color.Color) { | ||
| m := (y2 - y1) / (x2 - x1) | ||
| // y = m*x + b | ||
| // y - m*x = b | ||
| // b = y - m*x | ||
| b := y1 - m*x1 | ||
| l := math.Sqrt(math.Pow(x2-x1, 2) + math.Pow(y2-y1, 2)) | ||
|
|
||
| if m == math.Inf(1) || m == math.Inf(-1) { | ||
| start, end := y1, y2 | ||
| if start > end { | ||
| start, end = end, start | ||
| } | ||
| for y := start; y <= end; y += l / 1000 { | ||
| img.Set(int(math.Round(x1)), int(math.Round(y)), c) | ||
| } | ||
| } else { | ||
| start, end := x1, x2 | ||
| if start > end { | ||
| start, end = end, start | ||
| } | ||
|
|
||
| for x := start; x <= end; x += l / 1000 { | ||
| y := m*x + b | ||
| img.Set(int(math.Round(x)), int(math.Round(y)), c) | ||
| } | ||
| } | ||
| } | ||
|
|
||
| L.SetGlobal("circ", L.NewFunction(func(L *lua.LState) int { | ||
| x := int(L.CheckNumber(1)) | ||
| y := int(L.CheckNumber(2)) | ||
| r := float64(L.CheckNumber(3)) | ||
| border := checkColor(L, 4) | ||
| fill := checkColor(L, 5) | ||
|
|
||
| // draw borders | ||
| for t := 0.0; t < 2*math.Pi; t += 0.001 /* uhh */ { | ||
| xt := r*math.Cos(t) + float64(x) | ||
| yt := r*math.Sin(t) + float64(y) | ||
|
|
||
| line(float64(x), float64(y), xt, yt, fill) | ||
| } | ||
| for t := 0.0; t < 2*math.Pi; t += 0.001 /* uhh */ { | ||
| xt := r*math.Cos(t) + float64(x) | ||
| yt := r*math.Sin(t) + float64(y) | ||
|
|
||
| img.Set(int(math.Round(xt)), int(math.Round(yt)), border) | ||
| } | ||
|
|
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| return 0 | ||
| })) | ||
|
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| L.SetGlobal("line", L.NewFunction(func(L *lua.LState) int { | ||
| x1 := float64(L.CheckNumber(1)) | ||
| y1 := float64(L.CheckNumber(2)) | ||
| x2 := float64(L.CheckNumber(3)) | ||
| y2 := float64(L.CheckNumber(4)) | ||
| c := checkColor(L, 5) | ||
|
|
||
| line(x1, y1, x2, y2, c) | ||
|
|
||
| return 0 | ||
| })) | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,71 @@ | ||
| Draws images with lua. | ||
|
|
||
| ```bash | ||
| $ draw 'rect(10, 10, 118, 118, red, yellow)' > x.png | ||
| ``` | ||
|
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||
| Inspired by pico-8. This tool takes lua scripts as strings and writes a png to | ||
| standard out. | ||
|
|
||
| Consider this tool unstable, I'll likely make it read scripts from either | ||
| standard in, or files, or both, and make arguments no longer the default. | ||
|
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||
| ## Lua API | ||
|
|
||
| ### `set(x, y, c)` | ||
|
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| Takes an x, y coordinate and sets it to a color. | ||
|
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| ### `rgb(r, g, b)` | ||
|
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| Takes a red, green, and blue value (from 0 to 255), returns a color value. | ||
|
|
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| The following colors are defined as globals for you: | ||
|
|
||
| * black | ||
| * white | ||
| * red | ||
| * blue | ||
| * yellow | ||
| * green | ||
| * orange | ||
| * purple | ||
| * cyan | ||
| * magenta | ||
|
|
||
| ### `sin(t)` | ||
|
|
||
| Returns sine of t, in terms of pi, not degrees. | ||
|
|
||
| ### `cos(t)` | ||
|
|
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| Returns cosine of t, in terms of pi, not degrees. | ||
|
|
||
| ### `tan(t)` | ||
|
|
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| Returns tangent of t, in terms of pi, not degrees. | ||
|
|
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| ### `PI` | ||
|
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| Constant for pi. | ||
|
|
||
| ### `rect(x1, y1, x2, y2, bordercolor, fillcolor)` | ||
|
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| Draws a rectangle from (x1, y1) to (x2, y2) with a border of bordercolor and | ||
| filled with fillcolor. | ||
|
|
||
| ### `circ(x, y, r, bordercolor, fillcolor)` | ||
|
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| Draws a circle around (x, y) with radius r with a border of bordercolor and | ||
| filled with fillcolor. | ||
|
|
||
| ### `line(x1, y1, x2, y2, color)` | ||
|
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| Draws a line from (x1, y1) to (x2, y2) in color. | ||
|
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| ## BUGS | ||
|
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||
| Something is wrong with `line` in certain situations (I'm assuming infinity or | ||
| NaN or something is causing the issue.) `line` is used when drawing `circle`s, | ||
| so you can see the bug by drawing a circle and there will be weird gaps in the | ||
| top and bottom of them. |