1 files changed, 20 insertions, 0 deletions
diff --git a/doc/drawing.md b/doc/drawing.md
index de1044c..90aca0b 100644
--- a/doc/drawing.md
+++ b/doc/drawing.md
@@ -22,3 +22,23 @@ image.drawText(image.lena(), "hello\nworld", 10, 10)
 image.drawText(image.lena(), "hello\nworld", 10, 20,{color = {0, 255, 0}, size = 5})
 image.drawText(image.lena(), "hello\nworld", 10, 20,{color = {0, 255, 0}, bg = {255, 0, 0}, size = 5})
 ```
+
+<a name="image.drawRect"></a>
+### [res] image.drawRect(src, x1, y1, x2, y2, [options]) ###
+Draws a rectangle onto a 3-channel Tensor (C x H x W).  The top-left corner of
+the rectangle is `x1, y1`, and the bottom-right corner is `x2, y2`.
+
+The `options` table can be passed in to set color, in-place etc.
+
+Options:
+* `color` - [table] The rectangle color. A table of 3 numbers `{R, G, B}`, each
+    number scaled between 0 and 255. For example, `red` is `{255, 0, 0}`
+* `lineWidth` - [number] The width of the rectangle line, in pixels
+* `inplace` - [boolean] If true, draws directly on the input tensor and returns
+    it. `default value = false`
+
+Example:
+
+```lua
+image.drawRect(image.lena(), 200, 200, 370, 400, {lineWidth = 5, color = {0, 255, 0}})
+```