A dynamic image transformation module for nginx.
- Features
- Supported Formats
- Dependencies
- Installation
- Dynamic module
- Getting started
- Configuration example
- Directives
- small_light
- small_light_getparam_mode
- small_light_material_dir
- small_light_pattern_define
- small_light_imlib2_temp_dir
- small_light_buffer
- Parameters for small_light function
- Named Pattern
- Using GET parameters
- Enabling WebP transformation
- Optimizing Tips
- JPEG hinting
- Limit thread-number with OpenMP
- Limitations
- Not supported features with Imlib2
- Not supported features with GD
- Not supported animated GIF
- Running Tests
- License
Supports the various image-processings below.
- Resize
- Rotate
- Sharpen
- Unsharpen
- Blur
- Border
- Canvas
- Crop
- Composition
- JPEG Hinting(except GD)
- Format convert(e.g. PNG -> JPEG)
- Color-space convert(e.g. CMYK -> sRGB)
ngx_small_light
is developed for using as the same way as mod_small_light as possible in nginx.
Supports the formats below.
- JPEG
- GIF(except Imlib2)
- PNG
- WebP(except Imlib2)
- PCRE (required)
- ImageMagick (required)
- Imlib2 (optional)
- GD (optional)
cd ${ngx_small_light_src_dir}
./setup
cd {$nginx_src_dir}
./configure --add-module=${ngx_small_light_src_dir}
make
make install
If you want to enable the libraries except ImageMagick in ngx_small_light
, add the options below when executing setup
. (ImageMagick is always enabled)
./setup # enable ImageMagick
./setup --with-imlib2 # enable ImageMagick and Imlib2
./setup --with-gd # enable ImageMagick and GD
./setup --with-imlib2 --with-gd # enable ImageMagick and Imlib2 and GD
You can also compile ngx_small_light
as the dynamic module with --add-dynamic-module
in nginx-1.9.11 and ngx_small_light-0.6.15 or later.
cd ${ngx_small_light_src_dir}
./setup
cd {$nginx_src_dir}
./configure \
--modules-path=/usr/local/nginx/modules \
--add-dynamic-module=${ngx_small_light_src_dir}
make
make install
Add the configuration below for loading module dynamically.
load_module /usr/local/nginx/modules/ngx_http_small_light_module.so;
Add the configuration below to some server context in nginx.conf and start nginx.
small_light on;
location ~ small_light[^/]*/(.+)$ {
set $file $1;
rewrite ^ /$file;
}
If you can get the original image of image.jpg from the URL below,
https://$host:$port/img/image.jpg
You will be able to get the converted image of image.jpg from the URL below.
https://$host:$port/small_light(dw=300,dh=300)/img/image.jpg
The part of small_light(...)
is called small_light function.
There is some configuration example below.
server {
listen 8000;
server_name localhost;
small_light on;
small_light_pattern_define msize dw=500,dh=500,da=l,q=95,e=imagemagick,jpeghint=y;
small_light_pattern_define ssize dw=120,dh=120,da=l,q=95,e=imlib2,jpeghint=y;
# https://localhost:8000/small_light(p=msize)/img/filename.jpg -> generate msize image
# https://localhost:8000/small_light(p=ssize)/img/filename.jpg -> generate ssize image
# https://localhost:8000/small_light(of=gif,q=100)/img/filename.jpg -> generate gif image which quality is 100
location ~ small_light[^/]*/(.+)$ {
set $file $1;
rewrite ^ /$file;
}
}
Syntax | small_light on | off |
---|---|
Default | off |
Context | server, location |
This directive sets whether image-processing with ngx_small_light
is enabled in a server context.
Syntax | small_light_getparam_mode on | off |
---|---|
Default | off |
Context | server, location |
This directive sets whether converting-image is enabled by GET parameters
instead of small_light function (e.g. /small_light(dw=200,dh=200)
).
At the expense of it, a small_light function is disabled.
But you need to set both small_light
and small_light_getparam_mode
on to enable the feature of this directive.
Syntax | small_light_material_dir path |
---|---|
Default | |
Context | server |
This directive assigns the directory for embedded icon images.
Syntax | small_light_pattern_define pattern_name parameters |
---|---|
Default | |
Context | server |
This directive names comma-delimited parameters.
Syntax | small_light_radius_max number |
---|---|
Default | 10 |
Context | server,location |
This directive sets maximum radius value of geometry for sharpen
and unsharp
and blur
.
Syntax | small_light_sigma_max number |
---|---|
Default | 10 |
Context | server,location |
This directive sets maximum sigma value of geometry for sharpen
and unsharp
and blur
.
Syntax | small_light_imlib2_temp_dir path [level1 [level2 [level 3 ]]] |
---|---|
Default | small_light_imlib2_temp 1 2 |
Context | server |
This directive assigns the directory for temporary file for Imlib2 processing. This directive is available when Imlib2 is enabled.
Syntax | small_ligh_buffer size |
---|---|
Default | 1m |
Context | server |
This directive assigns the maximum size of the buffer used for reading images when Content-Length is not set in response headers.
Parameter | Type | Default | Description | ImageMagick | Imlib2 | GD |
---|---|---|---|---|---|---|
p | string | named pattern of comma-delimited parameters | ⭕ | ⭕ | ⭕ | |
e | string | imagemagick | engine name (imagemagick, imlib2, gd) | |||
q | number | quality | ⭕ | ⭕ | ⭕ | |
of | string | output format (jpg, gif, png, webp) | ⭕ | ⭕ | ⭕ | |
jpeghint | char | n | enable jpeg hinting (y, n) | ⭕ | ⭕ | ❌ |
dw | coord | sw | destination width | ⭕ | ⭕ | ⭕ |
dh | coord | sh | destination height | ⭕ | ⭕ | ⭕ |
dx | coord | sx | destination x coordinate | ⭕ | ⭕ | ⭕ |
dy | coord | sy | destination y coordinate | ⭕ | ⭕ | ⭕ |
da | char | l | destination aspect ratio contol (l, s, n) | ⭕ | ⭕ | ⭕ |
ds | char | n | destination scaling control (s, n) | ⭕ | ⭕ | ⭕ |
cw | number | canvas width | ⭕ | ⭕ | ⭕ | |
ch | number | canvas height | ⭕ | ⭕ | ⭕ | |
cc | color | 000000 | canvas color | ⭕ | ⭕ | ⭕ |
bw | number | border width | ⭕ | ⭕ | ⭕ | |
bh | number | border height | ⭕ | ⭕ | ⭕ | |
bc | color | 000000 | border color | ⭕ | ⭕ | ⭕ |
sw | coord | source witdh | ⭕ | ⭕ | ⭕ | |
sh | coord | source height | ⭕ | ⭕ | ⭕ | |
sx | coord | source x coordinate | ⭕ | ⭕ | ⭕ | |
sy | coord | source y coordinate | ⭕ | ⭕ | ⭕ | |
pt | char | n | pass through control (y, n) | ⭕ | ⭕ | ⭕ |
sharpen | string | radius,sigma (e.g. 10x5) | ⭕ | ⭕ | ⭕ | |
unsharp | string | radius,sigma,amount,threshold (e.g 2x5+0.5+0) | ⭕ | ❌ | ❌ | |
blur | string | radius,sigma (e.g. 5x10) | ⭕ | ⭕ | ❌ | |
embedicon | string | embedded icon file in small_light_material_dir |
⭕ | ❌ | ❌ | |
ix | number | 0 | embedded icon x coordinate | ⭕ | ❌ | ❌ |
iy | number | 0 | embedded icon y coordinate | ⭕ | ❌ | ❌ |
angle | number | 0 | angle of rotation (90, 180, 270) | ⭕ | ⭕ | ⭕ |
progressive | char | n | make JPEG progressive (y, n) | ⭕ | ❌ | ❌ |
cmyk2rgb | char | n | convert colorspace from CMYK to sRGB (y, n) | ⭕ | ❌ | ❌ |
rmprof | char | n | remove profile (y, n) | ⭕ | ❌ | ❌ |
autoorient | char | n | enable adjust image orientation automatically (y, n) | ⭕ | ❌ | ❌ |
The values of da
are l
and s
and n
. These present the meanings below.
l
: long-edge baseds
: short-edge basedn
: nope
There are any limitations below.
of=gif
andof=webp
are not supported whene=imlib2
.autoorient
is available ImageMagick-6.9.0 or later.- The value of
radius,sigma
forsharpen
andunsharp
andblur
is limited bysmall_light_radius_max
andsmall_light_sigma_max
.
There are the types of each parameter below.
Type | Description |
---|---|
coord | coordicante or pixel. percent when appending 'p' |
char | character |
number | integer number |
color | rrggbb or rrggbbaa |
string | string |
ngx_small_light
supports to name comma-delimited parameters with the small_light_define_patern
.
small_light_pattern_define small dw=120,dh=120,q=80,e=imagemagick,jpeghint=y;
If the line above is added to some server context in nginx.conf, the two URLs below return same response.
https://$host:$port/small_light(p=small)/img/image.jpg
https://$host:$port/small_light(dw=120,dh=120,q=80,e=imagemagick,jpeghint=y)/img/image.jpg
ngx_small_light
supports to convert image not only by small_light function but by GET paramenters in v0.5.0
or later.
You need to set both small_light
and small_light_getparam_mode
on to enable this feature.
At the expense of enabling this feature, small_light function (e.g. /small_light(dw=300,dh=300)/img.jpg
is disabled.
small_light on;
small_light_getparam_mode on;
In the configuration above, the url below does not return converted image.
https://localhost:8000/small_light(dw=200,dh=200)/img/image.jpg
Instead the url below returns converted image expected by right.
https://localhost:8000/img/image.jpg?dw=200&dh=200
ngx_small_light
supports WebP transformation with ImageMagick and GD.
Given of=webp
to small_light function, ngx_small_light
transforms image format into WebP.
But ImageMagick requires libwebp and GD requires libvpx.
You need to embed these libraries in building ImageMagick and GD for enabling WebP transformation.
If WebP transformation is not available, nginx
outputs the line like below in error.log in processing image with of=webp
.
WebP is not supported
If WebP transformation with ImageMagick is available, the output of convert -list format
includes the line like below.
$ convert -list format | grep -i webp
WEBP* WEBP rw- WebP Image Format (libwebp 0.5.0[0208])
If WebP transformation with GD is available, the output of gdlib-config --libs
includes -lvpx
.
In general, the packages of ImageMagick and GD provided from the linux distributions such as Ubuntu and CentOS does not embed the library for WebP transformation by default. In such cases, you need to build ImageMagick or GD yourself.
There are some optimizing tips for ngx_small_light
.
When the output format is JPEG and image-converting engine is ImageMagick or Imlib2,
you may give jpeghint=y
. The speed of processing images is improved dramatically.
When image-converting engine is ImageMagick and the version of ngx_small_light
is lower than v0.6.14
,
giving 1 to OMP_NUM_THREADS
or MAGICK_THREAD_LIMIT
in nginx.conf
is recommended strongly.
Because OpenMP is enabled in ImageMagick by default and ImageMagick enabled OpenMP is very slow on multi-process environment.
env OMP_NUM_THREADS=1; # or env MAGICK_THREAD_LIMIT=1;
Or you can avoid this problem by building ImageMagick with --disable-openmp
.
In v0.6.14
or later, they are no longer required. Because ngx_small_light
always sets the thread-number with OpenMP 1.
ngx_small_light
has the limitations below.
The transformation with Imlib2 does not support to write GIF-image.
Because Imlib2 has the function for loading GIF-image but does not have the function for saving.
Additionally, the transformation by Imlib2 does not support to write and read WebP-image.
So of=gif
and e=imlib2
are not enabled to specify at once.
If these are specified, ngx_small_light
returns 415(Unsupported Media Type).
The transformation with GD supports to write WebP-image. But it is the experimental feature.
ngx_small_light
does not support the transformation kept animation for animated GIF.
Because it takes long time to transform(e.g. resize, crop) animated GIF kept animation.
So it is not realistic for ngx_small_light
to support an animated GIF.
If the animated GIF is given, ngx_small_light
transforms only the first frame.
perl Build.PL
cpanm --installdeps .
NGINX_BIN=${nginx_prefix_dir}/sbin/nginx ./Build test
# or
NGINX_BIN=${nginx_prefix_dir}/sbin/nginx prove t/**/*.t
Please read the COPYING.