gx: convert Color values from int to byte and expand operators

vlib/gx/color.v

@@ -0,0 +1,107 @@
+module gx
+
+pub const (
+	blue   = Color { r:   0, g:   0, b: 255 }
+	red    = Color { r: 255, g:   0, b:   0 }
+	green  = Color { r:   0, g: 255, b:   0 }
+	yellow = Color { r: 255, g: 255, b:   0 }
+
+	orange = Color { r: 255, g: 165, b:   0 }
+	purple = Color { r: 128, g:   0, b: 128 }
+
+	black  = Color { r:   0, g:   0, b:   0 }
+	gray   = Color { r: 128, g: 128, b: 128 }
+	indigo = Color { r:  75, g:   0, b: 130 }
+	pink   = Color { r: 255, g: 192, b: 203 }
+	violet = Color { r: 238, g: 130, b: 238 }
+	white  = Color { r: 255, g: 255, b: 255 }
+
+	dark_blue   = Color { r:   0, g:   0, b: 139 }
+	dark_gray   = Color { r: 169, g: 169, b: 169 }
+	dark_green  = Color { r:   0, g: 100, b:   0 }
+	dark_red    = Color { r: 139, g:   0, b:   0 }
+	light_blue  = Color { r: 173, g: 216, b: 230 }
+	light_gray  = Color { r: 211, g: 211, b: 211 }
+	light_green = Color { r: 144, g: 238, b: 144 }
+	light_red   = Color { r: 255, g: 204, b: 203 }
+)
+
+// Color represents a 32 bit color value in sRGB format
+pub struct Color {
+pub mut:
+	r byte
+	g byte
+	b byte
+	a byte = 255
+}
+
+// hex takes in a 32 bit integer and splits it into 4 byte values
+pub fn hex(color int) Color {
+	return Color {
+		r: byte((color >> 24) & 0xFF),
+		g: byte((color >> 16) & 0xFF),
+		b: byte((color >>  8) & 0xFF),
+		a: byte((color      ) & 0xFF)
+	}
+}
+
+pub fn rgb(r, g, b byte) Color {
+	return Color{
+		r: r,
+		g: g,
+		b: b
+	}
+}
+
+pub fn rgba(r, g, b, a byte) Color {
+	return Color{
+		r: r,
+		g: g,
+		b: b,
+		a: a
+	}
+}
+
+pub fn (c Color) + (c2 Color) Color {
+	return Color {
+		r: c.r + c2.r,
+		g: c.g + c2.g,
+		b: c.b + c2.b,
+		a: c.b + c2.a
+	}
+}
+
+pub fn (c Color) - (c2 Color) Color {
+	return Color {
+		r: c.r - c2.r,
+		g: c.g - c2.g,
+		b: c.b - c2.b,
+		a: c.b - c2.a
+	}
+}
+
+pub fn (c Color) * (c2 Color) Color {
+	return Color {
+		r: c.r * c2.r,
+		g: c.g * c2.g,
+		b: c.b * c2.b,
+		a: c.b * c2.a
+	}
+}
+
+pub fn (c Color) / (c2 Color) Color {
+	return Color {
+		r: c.r / c2.r,
+		g: c.g / c2.g,
+		b: c.b / c2.b,
+		a: c.b / c2.a
+	}
+}
+
+pub fn (c Color) eq(c2 Color) bool {
+	return c.r == c2.r && c.g == c2.g && c.b == c2.b && c.a == c2.a
+}
+
+pub fn (c Color) str() string {
+	return 'Color{$c.r, $c.g, $c.b, $c.a}'
+}