artist/artist.go

@@ -1,2 +1,52 @@
 package artist
 
+import "image"
+import "image/color"
+
+// Pattern is capable of generating a pattern pixel by pixel.
+type Pattern interface {
+	// AtWhen returns the color of the pixel located at (x, y) relative to
+	// the origin point of the pattern (0, 0), when the pattern has the
+	// specified width and height. Patterns may ignore the width and height
+	// parameters, but it may be useful for some patterns such as gradients.
+	AtWhen (x, y, width, height int) (color.RGBA)
+}
+
+// Texture is a struct that allows an image to be converted into a tiling
+// texture pattern.
+type Texture struct {
+	data []color.RGBA
+	width, height int
+}
+
+// NewTexture converts an image into a texture.
+func NewTexture (source image.Image) (texture Texture) {
+	bounds := source.Bounds()
+	texture.width  = bounds.Dx()
+	texture.height = bounds.Dy()
+	texture.data   = make([]color.RGBA, texture.width * texture.height)
+
+	index := 0
+	for y := bounds.Min.Y; y < bounds.Max.Y; y ++ {
+	for x := bounds.Min.X; x < bounds.Max.X; x ++ {
+		r, g, b, a := source.At(x, y).RGBA()
+		texture.data[index] = color.RGBA {
+			uint8(r >> 8),
+			uint8(g >> 8),
+			uint8(b >> 8),
+			uint8(a >> 8),
+		}
+		index ++
+	}}
+	return
+}
+
+// AtWhen returns the color at the specified x and y coordinates, wrapped to the
+// image's width. the width and height are ignored.
+func (texture Texture) AtWhen (x, y, width, height int) (pixel color.RGBA) {
+	x %= texture.width
+	y %= texture.height
+	if x < 0 { x += texture.width  }
+	if y < 0 { y += texture.height }
+	return texture.data[x + y * texture.width]
+}

artist/chisel.go

@@ -7,10 +7,10 @@ import "git.tebibyte.media/sashakoshka/tomo"
 // ShadingProfile contains shading information that can be used to draw chiseled
 // objects.
 type ShadingProfile struct {
-	Highlight     tomo.Image
+	Highlight     Pattern
-	Shadow        tomo.Image
+	Shadow        Pattern
-	Stroke        tomo.Image
+	Stroke        Pattern
-	Fill          tomo.Image
+	Fill          Pattern
 	StrokeWeight  int
 	ShadingWeight int
 }
@@ -43,6 +43,7 @@ func ChiseledRectangle (
 	strokeWeight  := profile.StrokeWeight
 	shadingWeight := profile.ShadingWeight
 
+	data, stride := destination.Buffer()
 	bounds = bounds.Canon()
 	updatedRegion = bounds