Image filter: compare aspect ratio more accurately during crop.

Previously used fixed-point calculation caused wrong code path selection
in some cases, resulting in incorrect image size.

See here for report:
http://mailman.nginx.org/pipermail/nginx-devel/2012-April/002123.html

diff --git a/src/http/modules/ngx_http_image_filter_module.c b/src/http/modules/ngx_http_image_filter_module.c
index dd3c9cee5aebb945ef1d99c0f64f5d8d8f397310..c853c33d092fdaf8f2196810e233cad08859abc6 100644 (file)
--- a/src/http/modules/ngx_http_image_filter_module.c
+++ b/src/http/modules/ngx_http_image_filter_module.c
@@ -817,9 +817,7 @@ transparent:
 
         resize = 0;
 
-        if ((ngx_uint_t) (dx * 100 / dy)
-            < ctx->max_width * 100 / ctx->max_height)
-        {
+        if ((double) dx / dy < (double) ctx->max_width / ctx->max_height) {
             if ((ngx_uint_t) dx > ctx->max_width) {
                 dy = dy * ctx->max_width / dx;
                 dy = dy ? dy : 1;