Add image.getSize(filename) function

Add getPPMsize and getPGMsize functions
Combine them with getPNGsize and getJPGsize for getSize function

1 files changed, 22 insertions, 10 deletions

diff --git a/doc/saveload.md b/doc/saveload.md
index d90fc20..b9fa1fd 100644
--- a/doc/saveload.md
+++ b/doc/saveload.md
@@ -1,23 +1,23 @@
 <a name="image.saveload"></a>
 ## Saving and Loading ##
-This sections includes functions for saving and loading different types 
+This sections includes functions for saving and loading different types
 of images to and from disk.
 
 <a name="image.load"></a>
 ### [res] image.load(filename, [depth, tensortype]) ###
 Loads an image located at path `filename` having `depth` channels (1 or 3)
 into a [Tensor](https://github.com/torch/torch7/blob/master/doc/tensor.md#tensor)
-of type `tensortype` (*float*, *double* or *byte*). The last two arguments 
+of type `tensortype` (*float*, *double* or *byte*). The last two arguments
 are optional.
 
-The image format is determined from the `filename`'s 
-extension suffix. Supported formats are 
-[JPEG](https://en.wikipedia.org/wiki/JPEG), 
-[PNG](https://en.wikipedia.org/wiki/Portable_Network_Graphics), 
+The image format is determined from the `filename`'s
+extension suffix. Supported formats are
+[JPEG](https://en.wikipedia.org/wiki/JPEG),
+[PNG](https://en.wikipedia.org/wiki/Portable_Network_Graphics),
 [PPM and PGM](https://en.wikipedia.org/wiki/Netpbm_format).
- 
-The returned `res` Tensor has size `nChannel x height x width` where `nChannel` is 
-1 (greyscale) or 3 (usually [RGB](https://en.wikipedia.org/wiki/RGB_color_model) 
+
+The returned `res` Tensor has size `nChannel x height x width` where `nChannel` is
+1 (greyscale) or 3 (usually [RGB](https://en.wikipedia.org/wiki/RGB_color_model)
 or [YUV](https://en.wikipedia.org/wiki/YUV).
 
 Usage:
@@ -30,9 +30,21 @@ local img = image.load(imagefile,1,'byte')
 
 ```
 
+<a name="image.getSize"></a>
+### [res] image.getSize(filename) ###
+Return the size of an image located at path `filename` into a LongTensor.
+
+The image format is determined from the `filename`'s
+extension suffix. Supported formats are
+[JPEG](https://en.wikipedia.org/wiki/JPEG),
+[PNG](https://en.wikipedia.org/wiki/Portable_Network_Graphics),
+[PPM and PGM](https://en.wikipedia.org/wiki/Netpbm_format).
+
+The returned `res` Tensor has size `3` (nChannel, height, width).
+
 <a name="image.save"></a>
 ### image.save(filename, tensor) ###
-Saves Tensor `tensor` to disk at path `filename`. The format to which 
+Saves Tensor `tensor` to disk at path `filename`. The format to which
 the image is saved is extrapolated from the `filename`'s extension suffix.
 The `tensor` should be of size `nChannel x height x width`.
 To save with a minimal loss, the tensor values should lie in the range [0, 1] since the tensor is clamped between 0 and 1 before being saved to the disk.