add a simple font drawing function

2 files changed, 25 insertions, 0 deletions

diff --git a/doc/drawing.md b/doc/drawing.md
new file mode 100644
index 0000000..8bfe6bb
--- /dev/null
+++ b/doc/drawing.md
@@ -0,0 +1,24 @@
+<a name="image.drawing"></a>
+## Simple Drawing Routines ##
+This section includes simple routines to draw on images.
+
+<a name="image.drawText"></a>
+### [res] image.drawText(src, x, y, [options]) ###
+Draws text onto a 3-channel Tensor (C x H x W) at the x-offset `x` and y-offset `y`.
+
+The `options` table can be passed in to set color, background color, in-place etc.
+
+Options:
+* `color` - [table] The text color. A table of 3 numbers `{R, G, B}`, each number scaled between 0 and 255. For example, `red` is `{255, 0, 0}`
+* bg - [table] The background color where text is drawn. Same format as color.
+* size - [number] Size of the text to be drawn. `Default value = 1`.
+* wrap - [boolean] If the text goes out of bounds, wrap it with a newline automatically. `default value = true`
+* inplace - [boolean] If true, draws directly on the input tensor and returns it. `default value = false`
+
+Example:
+
+```lua
+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})
+```
\ No newline at end of file
diff --git a/doc/index.md b/doc/index.md
index bf2a3a3..62a987d 100644
--- a/doc/index.md
+++ b/doc/index.md
@@ -6,6 +6,7 @@ images. It contains a wide variety of functions divided into the following categ
   * [Saving and loading](saveload.md) images as JPEG, PNG, PPM and PGM;
   * [Simple transformations](simpletransform.md) like translation, scaling and rotation;
   * [Parameterized transformations](paramtransform.md) like convolutions and warping;
+  * [Simple Drawing Routines](doc/drawing.md) like drawing text on an image;
   * [Graphical user interfaces](gui.md) like display and window;
   * [Color Space Conversions](colorspace.md) from and to RGB, YUV, Lab, and HSL;
   * [Tensor Constructors](tensorconstruct.md) for creating Lenna, Fabio and Gaussian and Laplacian kernels;