1 files changed, 68 insertions, 0 deletions
diff --git a/pkg/jp/primitives/line.go b/pkg/jp/primitives/line.go
new file mode 100644
index 0000000..4bcedca
--- /dev/null
+++ b/pkg/jp/primitives/line.go
@@ -0,0 +1,68 @@
+package primitives
+
+// Adapted from https://github.com/buger/goterm under the MIT License.
+
+/*
+MIT License
+
+Copyright (c) 2016 Leonid Bugaev
+
+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.
+
+*/
+
+// http://en.wikipedia.org/wiki/Bresenham's_line_algorithm
+func DrawLine(x0, y0, x1, y1 int, plot func(int, int)) {
+	dx := x1 - x0
+	if dx < 0 {
+		dx = -dx
+	}
+	dy := y1 - y0
+	if dy < 0 {
+		dy = -dy
+	}
+	var sx, sy int
+	if x0 < x1 {
+		sx = 1
+	} else {
+		sx = -1
+	}
+	if y0 < y1 {
+		sy = 1
+	} else {
+		sy = -1
+	}
+	err := dx - dy
+
+	for {
+		plot(x0, y0)
+		if x0 == x1 && y0 == y1 {
+			break
+		}
+		e2 := 2 * err
+		if e2 > -dy {
+			err -= dy
+			x0 += sx
+		}
+		if e2 < dx {
+			err += dx
+			y0 += sy
+		}
+	}
+}