Btw, here's latest version with zero-termination and other fixes:

diff --git a/ngx_http_image_filter_module.c b/ngx_http_image_filter_module.c
index 3aee1a4..b086e3c 100644
--- a/ngx_http_image_filter_module.c
+++ b/ngx_http_image_filter_module.c
@@ -32,6 +32,11 @@
#define NGX_HTTP_IMAGE_GIF 2
#define NGX_HTTP_IMAGE_PNG 3

+#define NGX_HTTP_IMAGE_OFFSET_CENTER 0
+#define NGX_HTTP_IMAGE_OFFSET_LEFT 1
+#define NGX_HTTP_IMAGE_OFFSET_RIGHT 2
+#define NGX_HTTP_IMAGE_OFFSET_TOP 3
+#define NGX_HTTP_IMAGE_OFFSET_BOTTOM 4

#define NGX_HTTP_IMAGE_BUFFERED 0x08

@@ -43,11 +48,15 @@ typedef struct {
ngx_uint_t angle;
ngx_uint_t jpeg_quality;
ngx_uint_t sharpen;
+ ngx_uint_t offset_x;
+ ngx_uint_t offset_y;

ngx_flag_t transparency;

ngx_http_complex_value_t *wcv;
ngx_http_complex_value_t *hcv;
+ ngx_http_complex_value_t *oxcv;
+ ngx_http_complex_value_t *oycv;
ngx_http_complex_value_t *acv;
ngx_http_complex_value_t *jqcv;
ngx_http_complex_value_t *shcv;
@@ -66,6 +75,8 @@ typedef struct {
ngx_uint_t height;
ngx_uint_t max_width;
ngx_uint_t max_height;
+ ngx_uint_t offset_x;
+ ngx_uint_t offset_y;
ngx_uint_t angle;

ngx_uint_t phase;
@@ -110,6 +121,8 @@ static char
*ngx_http_image_filter_jpeg_quality(ngx_conf_t *cf,
ngx_command_t *cmd, void *conf);
static char *ngx_http_image_filter_sharpen(ngx_conf_t *cf, ngx_command_t
*cmd,
void *conf);
+static char *ngx_http_image_filter_offset(ngx_conf_t *cf, ngx_command_t
*cmd,
+ void *conf);
static ngx_int_t ngx_http_image_filter_init(ngx_conf_t *cf);


@@ -150,6 +163,13 @@ static ngx_command_t ngx_http_image_filter_commands[]
= {
offsetof(ngx_http_image_filter_conf_t, buffer_size),
NULL },

+ { ngx_string("image_filter_crop_offset"),
+
NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE2,
+ ngx_http_image_filter_offset,
+ NGX_HTTP_LOC_CONF_OFFSET,
+ 0,
+ NULL },
+
ngx_null_command
};

@@ -737,7 +757,8 @@ ngx_http_image_resize(ngx_http_request_t *r,
ngx_http_image_filter_ctx_t *ctx)
{
int sx, sy, dx, dy, ox, oy, ax, ay, size,
colors, palette, transparent, sharpen,
- red, green, blue, t;
+ red, green, blue, t,
+ offset_x, offset_y;
u_char *out;
ngx_buf_t *b;
ngx_uint_t resize;
@@ -932,8 +953,24 @@ transparent:
return NULL;
}

- ox /= 2;
- oy /= 2;
+ offset_x = ngx_http_image_filter_get_value(r, conf->oxcv,
+ conf->offset_x);
+ offset_y = ngx_http_image_filter_get_value(r, conf->oycv,
+ conf->offset_y);
+
+ if (offset_x == NGX_HTTP_IMAGE_OFFSET_LEFT) {
+ ox = 0;
+
+ } else if (offset_x == NGX_HTTP_IMAGE_OFFSET_CENTER) {
+ ox /= 2;
+ }
+
+ if (offset_y == NGX_HTTP_IMAGE_OFFSET_TOP) {
+ oy = 0;
+
+ } else if (offset_y == NGX_HTTP_IMAGE_OFFSET_CENTER) {
+ oy /= 2;
+ }

ngx_log_debug4(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"image crop: %d x %d @ %d x %d",
@@ -1141,17 +1178,43 @@ ngx_http_image_filter_get_value(ngx_http_request_t
*r,


static ngx_uint_t
-ngx_http_image_filter_value(ngx_str_t *value)
+ngx_http_image_filter_value(ngx_str_t *v)
{
ngx_int_t n;

- if (value->len == 1 && value->data[0] == '-') {
+ if (v->len == 1 && v->data[0] == '-') {
return (ngx_uint_t) -1;
}

- n = ngx_atoi(value->data, value->len);
+ n = ngx_atoi(v->data, v->len);
+
+ if (n == NGX_ERROR) {
+
+ if (v->len == sizeof("left") - 1
+ && ngx_strncmp(v->data, "left", v->len) == 0)
+ {
+ return NGX_HTTP_IMAGE_OFFSET_LEFT;
+
+ } else if (v->len == sizeof("right") - 1
+ && ngx_strncmp(v->data, "right", sizeof("right") - 1)
== 0)
+ {
+ return NGX_HTTP_IMAGE_OFFSET_RIGHT;
+
+ } else if (v->len == sizeof("top") - 1
+ && ngx_strncmp(v->data, "top", sizeof("top") - 1) == 0)
+ {
+ return NGX_HTTP_IMAGE_OFFSET_TOP;

- if (n > 0) {
+ } else if (v->len == sizeof("bottom") - 1
+ && ngx_strncmp(v->data, "bottom", sizeof("bottom") - 1)
== 0)
+ {
+ return NGX_HTTP_IMAGE_OFFSET_BOTTOM;
+
+ } else {
+ return NGX_HTTP_IMAGE_OFFSET_CENTER;
+ }
+
+ } else if (n > 0) {
return (ngx_uint_t) n;
}

@@ -1175,6 +1238,8 @@ ngx_http_image_filter_create_conf(ngx_conf_t *cf)
conf->angle = NGX_CONF_UNSET_UINT;
conf->transparency = NGX_CONF_UNSET;
conf->buffer_size = NGX_CONF_UNSET_SIZE;
+ conf->offset_x = NGX_CONF_UNSET_UINT;
+ conf->offset_y = NGX_CONF_UNSET_UINT;

return conf;
}
@@ -1230,6 +1295,24 @@ ngx_http_image_filter_merge_conf(ngx_conf_t *cf,
void *parent, void *child)
ngx_conf_merge_size_value(conf->buffer_size, prev->buffer_size,
1 * 1024 * 1024);

+ if (conf->offset_x == NGX_CONF_UNSET_UINT) {
+ ngx_conf_merge_uint_value(conf->offset_x, prev->offset_x,
+ NGX_HTTP_IMAGE_OFFSET_CENTER);
+
+ if (conf->oxcv == NULL) {
+ conf->oxcv = prev->oxcv;
+ }
+ }
+
+ if (conf->offset_y == NGX_CONF_UNSET_UINT) {
+ ngx_conf_merge_uint_value(conf->offset_y, prev->offset_y,
+ NGX_HTTP_IMAGE_OFFSET_CENTER);
+
+ if (conf->oycv == NULL) {
+ conf->oycv = prev->oycv;
+ }
+ }
+
return NGX_CONF_OK;
}

@@ -1481,6 +1564,66 @@ ngx_http_image_filter_sharpen(ngx_conf_t *cf,
ngx_command_t *cmd,
}


+static char *
+ngx_http_image_filter_offset(ngx_conf_t *cf, ngx_command_t *cmd,
+ void *conf)
+{
+ ngx_http_image_filter_conf_t *imcf = conf;
+
+ ngx_str_t *value;
+ ngx_http_complex_value_t cv;
+ ngx_http_compile_complex_value_t ccv;
+
+ value = cf->args->elts;
+
+ ngx_memzero(&ccv, sizeof(ngx_http_compile_complex_value_t));
+
+ ccv.cf = cf;
+ ccv.value = &value[1];
+ ccv.complex_value = &cv;
+
+ if (ngx_http_compile_complex_value(&ccv) != NGX_OK) {
+ return NGX_CONF_ERROR;
+ }
+
+ if (cv.lengths == NULL) {
+ imcf->offset_x = ngx_http_image_filter_value(&value[1]);
+
+ } else {
+ imcf->oxcv = ngx_palloc(cf->pool,
sizeof(ngx_http_complex_value_t));
+ if (imcf->oxcv == NULL) {
+ return NGX_CONF_ERROR;
+ }
+
+ *imcf->oxcv = cv;
+ }
+
+ ngx_memzero(&ccv, sizeof(ngx_http_compile_complex_value_t));
+
+ ccv.cf = cf;
+ ccv.value = &value[2];
+ ccv.complex_value = &cv;
+
+ if (ngx_http_compile_complex_value(&ccv) != NGX_OK) {
+ return NGX_CONF_ERROR;
+ }
+
+ if (cv.lengths == NULL) {
+ imcf->offset_y = ngx_http_image_filter_value(&value[2]);
+
+ } else {
+ imcf->oycv = ngx_palloc(cf->pool,
sizeof(ngx_http_complex_value_t));
+ if (imcf->oycv == NULL) {
+ return NGX_CONF_ERROR;
+ }
+
+ *imcf->oycv = cv;
+ }
+
+ return NGX_CONF_OK;
+}
+
+
static ngx_int_t
ngx_http_image_filter_init(ngx_conf_t *cf)
{



On 25 December 2012 20:05, Maxim Dounin <mdounin@mdounin.ru> wrote:

> Hello!
>
> On Thu, Dec 20, 2012 at 09:01:38PM +0400, ivan babrou wrote:
>
> > I've send patch for configuration semantics in separate thread.
> >
> > Here's lastest version of my patch that may be applied after. Is there
> > something else that I should fix?
>
> I would like to see clarification on how are you going to handle
> just bare numbers specified. As of now the code seems to don't do
> any special processing and seems to assume all values are correct,
> which might not be true and will result in some mostly arbitray
> crop offset selection. It might make sense to actually support
> percents as in Maxim Bublis's patch[1].
>
> [1] http://mailman.nginx.org/pipermail/nginx-devel/2012-April/002156.html
>
> [...]
>
> > @@ -1151,7 +1188,24 @@ ngx_http_image_filter_value(ngx_str_t *value)
> >
> > n = ngx_atoi(value->data, value->len);
> >
> > - if (n > 0) {
> > + if (n == NGX_ERROR) {
> > + if (ngx_strncmp(value->data, "left", value->len) == 0) {
> > + return NGX_HTTP_IMAGE_OFFSET_LEFT;
> > +
> > + } else if (ngx_strncmp(value->data, "right", value->len) == 0) {
> > + return NGX_HTTP_IMAGE_OFFSET_RIGHT;
> > +
> > + } else if (ngx_strncmp(value->data, "top", value->len) == 0) {
> > + return NGX_HTTP_IMAGE_OFFSET_TOP;
> > +
> > + } else if (ngx_strncmp(value->data, "bottom", value->len) == 0)
> {
> > + return NGX_HTTP_IMAGE_OFFSET_BOTTOM;
> > +
> > + } else {
> > + return NGX_HTTP_IMAGE_OFFSET_CENTER;
> > + }
> > +
> > + } else if (n > 0) {
> > return (ngx_uint_t) n;
> > }
> >
>
> The ngx_strncmp() checks are incorrect, see here:
> http://mailman.nginx.org/pipermail/nginx-devel/2012-December/003065.html
>
> You may also move them below "if (n > 0)" the check for better
> readability.
>
> > @@ -1175,6 +1229,8 @@ ngx_http_image_filter_create_conf(ngx_conf_t *cf)
> > conf->angle = NGX_CONF_UNSET_UINT;
> > conf->transparency = NGX_CONF_UNSET;
> > conf->buffer_size = NGX_CONF_UNSET_SIZE;
> > + conf->crop_offset_x = NGX_CONF_UNSET_UINT;
> > + conf->crop_offset_y = NGX_CONF_UNSET_UINT;
>
> The "crop_" prefix probably should be dropped here for better
> readability (and to match other names in the code like "oxcv").
>
> [...]
>
> --
> Maxim Dounin
> http://nginx.com/support.html
>
> _______________________________________________
> nginx-devel mailing list
> nginx-devel@nginx.org
> http://mailman.nginx.org/mailman/listinfo/nginx-devel
>



--
Regards, Ian Babrou
http://bobrik.name http://twitter.com/ibobrik skype:i.babrou
_______________________________________________
nginx-devel mailing list
nginx-devel@nginx.org
http://mailman.nginx.org/mailman/listinfo/nginx-devel