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https://github.com/peterhellberg/gfx
Convenience package for dealing with graphics in my pixel drawing experiments.
https://github.com/peterhellberg/gfx
blocks drawing gfx go graphics matrix noise palettes polygons signed-distance-functions simplex vectors
Last synced: 3 days ago
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Convenience package for dealing with graphics in my pixel drawing experiments.
- Host: GitHub
- URL: https://github.com/peterhellberg/gfx
- Owner: peterhellberg
- License: mit
- Created: 2019-01-12T21:08:20.000Z (almost 6 years ago)
- Default Branch: master
- Last Pushed: 2024-07-17T09:40:59.000Z (4 months ago)
- Last Synced: 2024-08-02T05:07:15.927Z (3 months ago)
- Topics: blocks, drawing, gfx, go, graphics, matrix, noise, palettes, polygons, signed-distance-functions, simplex, vectors
- Language: Go
- Homepage: https://godoc.org/github.com/peterhellberg/gfx
- Size: 871 KB
- Stars: 138
- Watchers: 8
- Forks: 5
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- Funding: .github/FUNDING.yml
- License: LICENSE
Awesome Lists containing this project
README
# gfx
[](https://github.com/peterhellberg/gfx/actions/workflows/test.yml)
[](https://goreportcard.com/report/github.com/peterhellberg/gfx)
[](https://pkg.go.dev/github.com/peterhellberg/gfx)
[](https://github.com/peterhellberg/gfx#license-mit)
Convenience package for dealing with graphics in my pixel drawing experiments.
#### :warning: NO STABILITY GUARANTEES :warning:
## Triangles
Triangles can be drawn to an image using a `*gfx.DrawTarget`.
[embedmd]:# (examples/gfx-example-triangles/gfx-example-triangles.go)
```go
package main
import "github.com/peterhellberg/gfx"
var p = gfx.PaletteFamicube
func main() {
n := 50
m := gfx.NewPaletted(900, 270, p, p.Color(n+7))
t := gfx.NewDrawTarget(m)
t.MakeTriangles(&gfx.TrianglesData{
vx(114, 16, n+1), vx(56, 142, n+2), vx(352, 142, n+3),
vx(350, 142, n+4), vx(500, 50, n+5), vx(640, 236, n+6),
vx(640, 70, n+8), vx(820, 160, n+9), vx(670, 236, n+10),
}).Draw()
gfx.SavePNG("gfx-example-triangles.png", m)
}
func vx(x, y float64, n int) gfx.Vertex {
return gfx.Vertex{Position: gfx.V(x, y), Color: p.Color(n)}
}
```
## Polygons
A `gfx.Polygon` is represented by a list of vectors.
There is also `gfx.Polyline` which is a slice of polygons forming a line.
[embedmd]:# (examples/gfx-example-polygon/gfx-example-polygon.go)
```go
package main
import "github.com/peterhellberg/gfx"
var edg32 = gfx.PaletteEDG32
func main() {
m := gfx.NewNRGBA(gfx.IR(0, 0, 1024, 256))
p := gfx.Polygon{
{80, 40},
{440, 60},
{700, 200},
{250, 230},
{310, 140},
}
p.EachPixel(m, func(x, y int) {
pv := gfx.IV(x, y)
l := pv.To(p.Rect().Center()).Len()
gfx.Mix(m, x, y, edg32.Color(int(l/18)%32))
})
for n, v := range p {
c := edg32.Color(n * 4)
gfx.DrawCircle(m, v, 15, 8, gfx.ColorWithAlpha(c, 96))
gfx.DrawCircle(m, v, 16, 1, c)
}
gfx.SavePNG("gfx-example-polygon.png", m)
}
```
## Blocks
You can draw (isometric) blocks using the `gfx.Blocks` and `gfx.Block` types.
[embedmd]:# (examples/gfx-example-blocks/gfx-example-blocks.go)
```go
package main
import "github.com/peterhellberg/gfx"
func main() {
var (
dst = gfx.NewPaletted(898, 330, gfx.PaletteGo, gfx.PaletteGo[14])
rect = gfx.BoundsToRect(dst.Bounds())
origin = rect.Center().ScaledXY(gfx.V(1.5, -2.5)).Vec3(0.55)
blocks gfx.Blocks
)
for i, bc := range gfx.BlockColorsGo {
var (
f = float64(i) + 0.5
v = f * 11
pos = gfx.V3(290+(v*3), 8.5*v, 9*(f+2))
size = gfx.V3(90, 90, 90)
)
blocks.AddNewBlock(pos, size, bc)
}
blocks.Draw(dst, origin)
gfx.SavePNG("gfx-example-blocks.png", dst)
}
```
## Signed Distance Functions
The `gfx.SignedDistance` type allows you to use basic [signed distance functions](http://jamie-wong.com/2016/07/15/ray-marching-signed-distance-functions/) (and operations) to produce some interesting graphics.
[embedmd]:# (examples/gfx-example-sdf/gfx-example-sdf.go)
```go
package main
import "github.com/peterhellberg/gfx"
func main() {
c := gfx.PaletteEDG36.Color
m := gfx.NewImage(1024, 256, c(5))
gfx.EachPixel(m.Bounds(), func(x, y int) {
sd := gfx.SignedDistance{gfx.IV(x, y)}
if d := sd.OpRepeat(gfx.V(128, 128), func(sd gfx.SignedDistance) float64 {
return sd.OpSubtraction(sd.Circle(50), sd.Line(gfx.V(0, 0), gfx.V(64, 64)))
}); d < 40 {
m.Set(x, y, c(int(gfx.MathAbs(d/5))))
}
})
gfx.SavePNG("gfx-example-sdf.png", m)
}
```
## Domain Coloring
You can use the `CmplxPhaseAt` method on a `gfx.Palette` to do [domain coloring](https://en.wikipedia.org/wiki/Domain_coloring).
[embedmd]:# (examples/gfx-example-domain-coloring/gfx-example-domain-coloring.go)
```go
package main
import "github.com/peterhellberg/gfx"
const (
w, h = 1800, 540
fovY = 1.9
aspectRatio = float64(w) / float64(h)
centerReal = 0
centerImag = 0
ahc = aspectRatio*fovY/2.0 + centerReal
hfc = fovY/2.0 + centerImag
)
func pixelCoordinates(px, py int) gfx.Vec {
return gfx.V(
((float64(px)/(w-1))*2-1)*ahc,
((float64(h-py-1)/(h-1))*2-1)*hfc,
)
}
func main() {
var (
p = gfx.PaletteEN4
p0 = pixelCoordinates(0, 0)
p1 = pixelCoordinates(w-1, h-1)
y = p0.Y
d = gfx.V((p1.X-p0.X)/(w-1), (p1.Y-p0.Y)/(h-1))
m = gfx.NewImage(w, h)
)
for py := 0; py < h; py++ {
x := p0.X
for px := 0; px < w; px++ {
cc := p.CmplxPhaseAt(gfx.CmplxCos(gfx.CmplxSin(0.42 / complex(y*x, x*x))))
m.Set(px, py, cc)
x += d.X
}
y += d.Y
}
gfx.SavePNG("gfx-example-domain-coloring.png", m)
}
```
## Animation
There is rudimentary support for making animations using `gfx.Animation`, the animations can then be encoded into GIF.
[embedmd]:# (examples/gfx-example-animation/gfx-example-animation.go)
```go
package main
import "github.com/peterhellberg/gfx"
func main() {
a := &gfx.Animation{}
p := gfx.PaletteEDG36
var fireflower = []uint8{
0, 1, 1, 1, 1, 1, 1, 0,
1, 1, 2, 2, 2, 2, 1, 1,
1, 2, 3, 3, 3, 3, 2, 1,
1, 1, 2, 2, 2, 2, 1, 1,
0, 1, 1, 1, 1, 1, 1, 0,
0, 0, 0, 4, 4, 0, 0, 0,
0, 0, 0, 4, 4, 0, 0, 0,
4, 4, 0, 4, 4, 0, 4, 4,
0, 4, 0, 4, 4, 0, 4, 0,
0, 4, 4, 4, 4, 4, 4, 0,
0, 0, 4, 4, 4, 4, 0, 0,
}
for i := 0; i < len(p)-4; i++ {
t := gfx.NewTile(p[i:i+4], 8, fireflower)
a.AddPalettedImage(gfx.NewScaledPalettedImage(t, 20))
}
a.SaveGIF("gfx-example-animation.gif")
}
```
## Line drawing
### DrawInt functions
Drawing functions based on [TinyDraw](https://github.com/tinygo-org/tinydraw),
which in turn is based on the [Adafruit GFX library](https://github.com/adafruit/Adafruit-GFX-Library).
[embedmd]:# (examples/gfx-example-draw-int/gfx-example-draw-int.go)
```go
package main
import "github.com/peterhellberg/gfx"
func main() {
m := gfx.NewImage(160, 128, gfx.ColorTransparent)
p := gfx.PaletteNight16
gfx.DrawIntLine(m, 10, 10, 94, 10, p.Color(0))
gfx.DrawIntLine(m, 94, 16, 10, 16, p.Color(1))
gfx.DrawIntLine(m, 10, 20, 10, 118, p.Color(2))
gfx.DrawIntLine(m, 16, 118, 16, 20, p.Color(4))
gfx.DrawIntLine(m, 40, 40, 80, 80, p.Color(5))
gfx.DrawIntLine(m, 40, 40, 80, 70, p.Color(6))
gfx.DrawIntLine(m, 40, 40, 80, 60, p.Color(7))
gfx.DrawIntLine(m, 40, 40, 80, 50, p.Color(8))
gfx.DrawIntLine(m, 40, 40, 80, 40, p.Color(9))
gfx.DrawIntLine(m, 100, 100, 40, 100, p.Color(10))
gfx.DrawIntLine(m, 100, 100, 40, 90, p.Color(11))
gfx.DrawIntLine(m, 100, 100, 40, 80, p.Color(12))
gfx.DrawIntLine(m, 100, 100, 40, 70, p.Color(13))
gfx.DrawIntLine(m, 100, 100, 40, 60, p.Color(14))
gfx.DrawIntLine(m, 100, 100, 40, 50, p.Color(15))
gfx.DrawIntRectangle(m, 30, 106, 120, 20, p.Color(14))
gfx.DrawIntFilledRectangle(m, 34, 110, 112, 12, p.Color(8))
gfx.DrawIntCircle(m, 120, 30, 20, p.Color(5))
gfx.DrawIntFilledCircle(m, 120, 30, 16, p.Color(4))
gfx.DrawIntTriangle(m, 120, 102, 100, 80, 152, 46, p.Color(9))
gfx.DrawIntFilledTriangle(m, 119, 98, 105, 80, 144, 54, p.Color(6))
s := gfx.NewScaledImage(m, 6)
gfx.SavePNG("gfx-example-draw-int.png", s)
}
```
### Bresenham's line algorithm
`gfx.DrawLineBresenham` draws a line using [Bresenham's line algorithm](http://en.wikipedia.org/wiki/Bresenham's_line_algorithm).
[embedmd]:# (examples/gfx-example-bresenham-line/gfx-example-bresenham-line.go)
```go
package main
import "github.com/peterhellberg/gfx"
var (
red = gfx.BlockColorRed.Medium
green = gfx.BlockColorGreen.Medium
blue = gfx.BlockColorBlue.Medium
)
func main() {
m := gfx.NewImage(32, 16, gfx.ColorTransparent)
gfx.DrawLineBresenham(m, gfx.V(2, 2), gfx.V(2, 14), red)
gfx.DrawLineBresenham(m, gfx.V(6, 2), gfx.V(32, 2), green)
gfx.DrawLineBresenham(m, gfx.V(6, 6), gfx.V(30, 14), blue)
s := gfx.NewScaledImage(m, 16)
gfx.SavePNG("gfx-example-bresenham-line.png", s)
}
```
## Geometry and Transformation
The (2D) geometry and transformation types are based on those found in (but indended for use without Pixel)
### 2D types
#### Vec
`gfx.Vec` is a 2D vector type with X and Y components.
#### Rect
`gfx.Rect` is a 2D rectangle aligned with the axes of the coordinate system. It is defined by two `gfx.Vec`, Min and Max.
#### Matrix
`gfx.Matrix` is a 2x3 affine matrix that can be used for all kinds of spatial transforms, such as movement, scaling and rotations.
[embedmd]:# (examples/gfx-example-matrix/gfx-example-matrix.go)
```go
package main
import "github.com/peterhellberg/gfx"
var en4 = gfx.PaletteEN4
func main() {
a := &gfx.Animation{Delay: 10}
c := gfx.V(128, 128)
p := gfx.Polygon{
{50, 50},
{50, 206},
{128, 96},
{206, 206},
{206, 50},
}
for d := 0.0; d < 360; d += 2 {
m := gfx.NewPaletted(256, 256, en4, en4.Color(3))
matrix := gfx.IM.RotatedDegrees(c, d)
gfx.DrawPolygon(m, p.Project(matrix), 0, en4.Color(2))
gfx.DrawPolygon(m, p.Project(matrix.Scaled(c, 0.5)), 0, en4.Color(1))
gfx.DrawCircleFilled(m, c, 5, en4.Color(0))
a.AddPalettedImage(m)
}
a.SaveGIF("/tmp/gfx-readme-examples-matrix.gif")
}
```
### 3D types
#### Vec3
`gfx.Vec3` is a 3D vector type with X, Y and Z components.
#### Box
`gfx.Box` is a 3D box. It is defined by two `gfx.Vec3`, Min and Max
## Errors
The `gfx.Error` type is a string that implements the `error` interface.
> If you are using [Ebiten](https://github.com/hajimehoshi/ebiten) then you can return the provided `gfx.ErrDone` error to exit its run loop.
## HTTP
You can use `gfx.GetPNG` to download and decode a PNG given an URL.
## Log
I find that it is fairly common for me to do some logging driven development
when experimenting with graphical effects, so I've included `gfx.Log`,
`gfx.Dump`, `gfx.Printf` and `gfx.Sprintf` in this package.
## Math
I have included a few functions that call functions in the `math` package.
There is also `gfx.Sign`, `gfx.Clamp` and `gfx.Lerp` functions for `float64`.
## Cmplx
I have included a few functions that call functions in the `cmplx` package.
## Reading files
It is fairly common to read files in my experiments, so I've included `gfx.ReadFile` and `gfx.ReadJSON` in this package.
## Resizing images
You can use `gfx.ResizeImage` to resize an image. (nearest neighbor, mainly useful for pixelated graphics)
## Noise
Different types of noise is often used in procedural generation.
### SimplexNoise
SimplexNoise is a speed-improved simplex noise algorithm for 2D, 3D and 4D.
[embedmd]:# (examples/gfx-example-simplex/gfx-example-simplex.go)
```go
package main
import "github.com/peterhellberg/gfx"
func main() {
sn := gfx.NewSimplexNoise(17)
dst := gfx.NewImage(1024, 256)
gfx.EachImageVec(dst, gfx.ZV, func(u gfx.Vec) {
n := sn.Noise2D(u.X/900, u.Y/900)
c := gfx.PaletteSplendor128.At(n / 2)
gfx.SetVec(dst, u, c)
})
gfx.SavePNG("gfx-example-simplex.png", dst)
}
```
## Colors
You can construct new colors using `gfx.ColorRGBA`, `gfx.ColorNRGBA`, `gfx.ColorGray`, `gfx.ColorGray16` and `gfx.ColorWithAlpha`.
There is also a `gfx.LerpColors` function that performs linear interpolation between two colors.
### Default colors
There are a few default colors in this package, convenient when you just want to experiment,
for more ambitious projects I suggest creating a `gfx.Palette` (or even use one of the included palettes).
| Variable | Color
|------------------------|---------------------------------------------------------
| `gfx.ColorBlack` | 
| `gfx.ColorWhite` | 
| `gfx.ColorTransparent` | 
| `gfx.ColorOpaque` | 
| `gfx.ColorRed` | 
| `gfx.ColorGreen` | 
| `gfx.ColorBlue` | 
| `gfx.ColorCyan` | 
| `gfx.ColorMagenta` | 
| `gfx.ColorYellow` | 
### Block colors
Each `gfx.BlockColor` consists of a `Dark`, `Medium` and `Light` shade of the same color.
| Variable | Block Color
|------------------------------|---------------------------------------------------------
| `gfx.BlockColorYellow` | 
| `gfx.BlockColorOrange` | 
| `gfx.BlockColorBrown` | 
| `gfx.BlockColorGreen` | 
| `gfx.BlockColorBlue` | 
| `gfx.BlockColorPurple` | 
| `gfx.BlockColorRed` | 
| `gfx.BlockColorWhite` | 
| `gfx.BlockColorBlack` | 
| `gfx.BlockColorGoGopherBlue` | 
| `gfx.BlockColorGoLightBlue` | 
| `gfx.BlockColorGoAqua` | 
| `gfx.BlockColorGoFuchsia` | 
| `gfx.BlockColorGoBlack` | 
| `gfx.BlockColorGoYellow` | 
### Palettes
There are a number of palettes in the `gfx` package,
most of them are found in the [Lospec Palette List](https://lospec.com/palette-list/).
| Variable | Colors | Lospec Palette
|----------------------------|-------:| -----------------------------------------------------
| `gfx.Palette1Bit` | 2 | 
| `gfx.Palette2BitGrayScale` | 4 | 
| `gfx.PaletteEN4` | 4 | 
| `gfx.PaletteARQ4` | 4 | 
| `gfx.PaletteInk` | 5 | 
| `gfx.Palette3Bit` | 8 | 
| `gfx.PaletteEDG8` | 8 | 
| `gfx.PaletteAmmo8` | 8 | 
| `gfx.PaletteNYX8` | 8 | 
| `gfx.Palette15PDX` | 15 | 
| `gfx.PaletteCGA` | 16 | 
| `gfx.PalettePICO8` | 16 | 
| `gfx.PaletteNight16` | 16 | 
| `gfx.PaletteAAP16` | 16 | 
| `gfx.PaletteArne16` | 16 | 
| `gfx.PaletteEDG16` | 16 | 
| `gfx.Palette20PDX` | 20 | 
| `gfx.PaletteTango` | 27 | 
| `gfx.PaletteEDG32` | 32 | 
| `gfx.PaletteEDG36` | 36 | 
| `gfx.PaletteEDG64` | 64 | 
| `gfx.PaletteAAP64` | 64 | 
| `gfx.PaletteFamicube` | 64 | 
| `gfx.PaletteSplendor128` | 128 | 
The palette images were generated like this:
[embedmd]:# (examples/gfx-palettes/gfx-palettes.go)
```go
package main
import "github.com/peterhellberg/gfx"
func main() {
for size, paletteLookup := range gfx.PalettesByNumberOfColors {
for name, palette := range paletteLookup {
dst := gfx.NewImage(size, 1)
for x, c := range palette {
dst.Set(x, 0, c)
}
filename := gfx.Sprintf("gfx-Palette%s.png", name)
gfx.SavePNG(filename, gfx.NewResizedImage(dst, 1120, 96))
}
}
}
```
## License (MIT)
Copyright (c) 2019-2024 [Peter Hellberg](https://c7.se)
> Permission is hereby granted, free of charge, to any person obtaining
> a copy of this software and associated documentation files (the
> "Software"), to deal in the Software without restriction, including
> without limitation the rights to use, copy, modify, merge, publish,
> distribute, sublicense, and/or sell copies of the Software, and to
> permit persons to whom the Software is furnished to do so, subject to
> the following conditions:
>
> The above copyright notice and this permission notice shall be
> included in all copies or substantial portions of the Software.
> THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
> EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
> MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
> NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
> LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
> OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
> WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.