From 13b9e6aee5e539eab613303a78fa6c2d9306c8a8 Mon Sep 17 00:00:00 2001
From: faiface <faiface@ksp.sk>
Date: Mon, 10 Apr 2017 00:20:19 +0200
Subject: [PATCH] add ComposeTarget interface
---
interface.go | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
diff --git a/interface.go b/interface.go
index 5f48f65..5287a1d 100644
--- a/interface.go
+++ b/interface.go
@@ -38,6 +38,30 @@ type BasicTarget interface {
SetColorMask(color.Color)
}
+// ComposeTarget is a BasicTarget capable of Porter-Duff composition.
+type ComposeTarget interface {
+ BasicTarget
+
+ // SetComposeMethod sets a Porter-Duff composition method to be used.
+ SetComposeMethod(ComposeMethod)
+}
+
+// ComposeMethod is a Porter-Duff composition method.
+type ComposeMethod int
+
+// Here's the list of all available Porter-Duff composition methods. User ComposeOver for the basic
+// alpha blending.
+const (
+ ComposeOver ComposeMethod = iota
+ ComposeIn
+ ComposeOut
+ ComposeAtop
+ ComposeDstIn
+ ComposeDstOut
+ ComposeDstAtop
+ ComposeXor
+)
+
// Triangles represents a list of vertices, where each three vertices form a triangle. (First,
// second and third is the first triangle, fourth, fifth and sixth is the second triangle, etc.)
type Triangles interface {
--
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