I forgot to specify my environment.
Windows Server 2008 R2 x64, ghc 7.0.3.
However, I observed the same speed differences on a 64-bit ubuntu with ghc
6.12 - I profiled my application with cairo-trace, and cairo-perf-trace
drew in a fraction of a second the picture that my Haskell program spend a
dozen seconds drawing.
On Wed, Nov 2, 2011 at 1:17 PM, Eugene Kirpichov
Hello,
I've got two very simple programs that draw a very simple picture using cairo, doing a couple hundred thousand of cairo calls. One program is in C++. The other is in Haskell and uses the cairo library bindings.
The C++ program completes in a fraction of a second, the Haskell program takes about 7-8 seconds to run. They produce exactly the same output.
What could be at fault here? Why are the cairo bindings working so slow? (I suppose there isn't too much cairo-specific stuff here, perhaps it's a general FFI question?)
#include "cairo.h" int main() { cairo_surface_t *surface = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, 1024, 768); cairo_t *cr = cairo_create(surface); cairo_set_source_rgb(cr, 0, 255, 0); for(int x = 0; x < 1024; x += 2) for(int y = 0; y < 768; y += 2) { cairo_rectangle(cr, x, y, 1, 1); cairo_fill(cr); } cairo_surface_write_to_png(surface, "picture.png"); return 0; }
module Main where
import qualified Graphics.Rendering.Cairo as C import Control.Monad
main = C.withImageSurface C.FormatARGB32 1024 768 $ \s -> do C.renderWith s $ do C.setSourceRGBA 0 255 0 255 forM_ [0,2..1024] $ \x -> do forM_ [0,2..768] $ \y -> do C.rectangle x y 1 1 C.fill C.surfaceWriteToPNG s "picture.png"
-- Eugene Kirpichov Principal Engineer, Mirantis Inc. http://www.mirantis.com/ Editor, http://fprog.ru/
-- Eugene Kirpichov Principal Engineer, Mirantis Inc. http://www.mirantis.com/ Editor, http://fprog.ru/