add more tests

add network capability to example app

cmd/zplgfa/image.go

@@ -0,0 +1,49 @@
+package main
+
+import (
+	"image"
+	"image/color"
+	"math"
+)
+
+type imageSet interface {
+	Set(x, y int, c color.Color)
+}
+
+func editImageInvert(img image.Image) image.Image {
+	b := img.Bounds()
+
+	imgSet := img.(imageSet)
+	for y := b.Min.Y; y < b.Max.Y; y++ {
+		for x := b.Min.X; x < b.Max.X; x++ {
+			oldPixel := img.At(x, y)
+			r, g, b, a := oldPixel.RGBA()
+			r = 65535 - r
+			g = 65535 - g
+			b = 65535 - b
+			pixel := color.RGBA{uint8(r), uint8(g), uint8(b), uint8(a)}
+			imgSet.Set(x, y, pixel)
+		}
+	}
+	return img
+}
+
+func editImageMonochrome(img image.Image) image.Image {
+	b := img.Bounds()
+
+	imgSet := img.(imageSet)
+	for y := b.Min.Y; y < b.Max.Y; y++ {
+		for x := b.Min.X; x < b.Max.X; x++ {
+			oldPixel := img.At(x, y)
+			r, g, b, a := oldPixel.RGBA()
+			if r > math.MaxUint16/2 || g > math.MaxUint16/2 || b > math.MaxUint16/2 {
+				r, g, b = 65535, 65535, 65535
+			} else {
+				r, g, b = 0, 0, 0
+			}
+			pixel := color.RGBA{uint8(r), uint8(g), uint8(b), uint8(a)}
+			imgSet.Set(x, y, pixel)
+		}
+	}
+	return img
+}