more canvas size

examples/example02.hs

@@ -108,6 +108,7 @@ draw = do
     }
   process (nodeGraph M.! "sink")
   present (GeglRectangle 0 0 800 600) foreground True
+  render Nothing Nothing
 
 update :: Double -> Affection UserData ()
 update dt = do

examples/example03.hs

@@ -100,6 +100,7 @@ draw = do
     (G.GeglRectangle 0 0 800 600)
     foreground
     True
+  render Nothing Nothing
 
 update :: Double -> Affection UserData ()
 update dt = do

src/Affection.hs

@@ -78,19 +78,24 @@ withAffection AffectionConfig{..} = do
     renderer
     SDL.ABGR8888
     SDL.TextureAccessStreaming
-    (SDL.windowInitialSize windowConfig)
+    (case canvasSize of
+      Just (cw, ch) -> (SDL.V2
+        (CInt $ fromIntegral cw)
+        (CInt $ fromIntegral ch)
+        )
+      Nothing ->
+        SDL.windowInitialSize windowConfig
+      )
   -- make draw surface
-  surface <- SDL.createRGBSurface
-    (SDL.windowInitialSize windowConfig)
-    SDL.ABGR8888
-  let (SDL.Surface ptr _) = surface
-  pixelFormat <- liftIO $ peek . Raw.surfaceFormat =<< peek ptr
-  SDL.V2 (CInt rw) (CInt rh) <- liftIO $ SDL.surfaceDimensions surface
-  let (w, h) = (fromIntegral rw, fromIntegral rh)
-      stride = fromIntegral (Raw.pixelFormatBytesPerPixel pixelFormat) * w
-  pixels <- SDL.surfacePixels surface
-  let bablFormat = B.PixelFormat B.RGBA B.CFu8
+  -- pixelFormat <- liftIO $ peek . Raw.surfaceFormat =<< peek ptr
+  let SDL.V2 (CInt rw) (CInt rh) = windowInitialSize windowConfig
+      (w, h) = case canvasSize of
+        Just (cw, ch) -> (cw, ch)
+        Nothing       -> (fromIntegral rw, fromIntegral rh)
+      -- stride = fromIntegral (Raw.pixelFormatBytesPerPixel pixelFormat) * w
+      bablFormat = B.PixelFormat B.RGBA B.CFu8
       cpp        = B.babl_components_per_pixel bablFormat
+      !stride    = cpp * w
   format <- B.babl_format bablFormat
   initContainer <- (\x -> AffectionData
     { quitEvent       = False
@@ -100,8 +105,10 @@ withAffection AffectionConfig{..} = do
     -- , drawSurface     = surface
     , drawTexture     = texture
     , drawFormat      = format
-    , drawPixels      = pixels
-    , drawDimensions  = (w, h)
+    -- , drawPixels      = pixels
+    , drawDimensions  = case canvasSize of
+        Just (cw, ch) -> (cw, ch)
+        Nothing       -> (w, h)
     , drawStride      = stride
     , drawCPP         = cpp
     , drawStack       = []